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Pest rodents persistently undermine crop yields and food security. Fertility control could be a viable alternative for managing rodent populations. This study investigates the antifertility effects of various concentrations of clarithromycin combined with 1.0 mg/kg quinestrol on male rodents to determine an effective contraceptive dose that minimizes quinestrol usage, addressing key concerns such as potential environmental residue, which may impact ecological balance, and poor palatability, which could reduce ingestion and limit the sterilant's effectiveness. Male mice were divided into five groups and administered different doses of clarithromycin or clarithromycin and quinestrol for three consecutive days, while the control group received sunflower seed oil only. After seven days, organ weights, reproductive organ weights, sperm density, serum hormone levels, and CYP3A4 content in small intestinal and liver tissues were measured to assess persistent effects. Compared with the control group, all treatment groups had significant reductions in epididymal weight, seminal vesicle weight, and serum T and LH levels. Higher concentrations of clarithromycin (2 mg/kg and 10 mg/kg) significantly impacted reproductive metrics, including sperm density, organ weights, and serum LH and testosterone levels, though complete sterilization was not achieved, with more than 60 million cauda epididymal spermatozoa remaining. However, the combination demonstrated potential as an effective strategy for male fertility control. The combination of 2.0 mg/kg clarithromycin and quinestrol can mitigate organ enlargement seen with quinestrol alone. This combination also decreased total enzyme content, thereby diminishing quinestrol's induction of CYP3A4, which may increase the sterilization effectiveness of the treatment., (© 2024. The Author(s).)

Introduction: Helicobacter pylori (H. pylori) causes several gastrointestinal diseases. Its virulence factors contributing to disease development include biofilm formation, cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA) proteins that induce host tissue damage. In addition, urease activity enables H. pylori growth in the gastric acidic environment. This work aimed to characterize bacterial factors associated with biofilm production among 89 clinical H. pylori isolates, collected from patient gastric biopsies., Methods: Biofilm production was detected using the crystal violet method. PCR was performed to determine vacA genotype (s1m1, s1m2, s2m1 and s2m2) and cagA gene presence. Urease activity was measured via the phenol red method. Susceptibility to six antibiotics was assessed by the Etest method., Results: Most H. pylori isolates produced biofilm. No association was found between biofilm-formation capacity and cagA presence or vacA genotype. Urease activity levels varied across isolates; no association was found between biofilm-formation and urease activity. Clarithromycin resistance was measured in 49 % of the isolates. Isolates susceptible to tetracycline were more commonly strong biofilm producers. In contrast, a significantly higher rate of strong biofilm producers was observed among resistant isolates to amoxicillin, levofloxacin and rifampicin, compared to susceptible isolates. Non-biofilm producers were more common among isolates sensitive to rifampicin and metronidazole, compared to resistant isolates., Conclusions: Further studies are needed to understand the factors that regulate biofilm production in order to search for treatments for H. pylori biofilm destruction., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background and Objectives: A pharmacokinetic model has been developed to quantify the drug-drug interactions of tacrolimus with concentration-dependent inhibition of cytochrome P450 (CYP) 3A4 from voriconazole and clarithromycin based on the CYP3A5 and CYP2C19 genotypes., Methods: This retrospective study recruited unrelated bone marrow transplant recipients receiving oral tacrolimus concomitantly with voriconazole and clarithromycin. The published population pharmacokinetic model that implemented genotypes of CYP3A5 (tacrolimus) and CYP2C19 (voriconazole) was integrated. The tested CYP3A4 inhibition models (Sigmoid efficacy maximum [E max ], E max , log-linear, and linear) were a function of competitive inhibition of voriconazole and mechanism-based inhibition of clarithromycin in a virtual enzyme compartment., Results: The total tacrolimus trough concentrations were 119 points, with a median of 4.3 (range: 2.0-9.9) ng/mL (n = 3). The final model comprised the Sigmoid E max model for voriconazole and clarithromycin, which depicted time-course alterations in tacrolimus concentration and clearance when given voriconazole and clarithromycin., Conclusions: These findings could facilitate the model-informed precision dosing of tacrolimus after unrelated bone marrow transplant., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Background: Empirical treatment needs to be supported by regional data, but knowledge of interregional differences is currently lacking in China. This study aimed to summarize and map the primary and secondary antibiotic resistance of Helicobacter pylori in different regions of mainland China., Methods: PubMed, EMBASE, Web of Science, China National Knowledge Infrastructure and Wanfang databases were systematically reviewed for studies published between 1 January 2000 and 15 July 2023. Data related to primary and secondary H. pylori antibiotic resistance rates were included. Random-effects models were used to synthesize the pooled resistance rates., Results: Ultimately, 74 studies were included in the final analysis. A total of 16 provinces reported resistance data. The overall resistance rates of H. pylori in mainland China were 30.72% (95% CI 27.53%-33.99%) to clarithromycin, 70.14% (95% CI 29.53%-37.46%) to metronidazole and 32.98% (95% CI 28.73%-37.37%) to levofloxacin; for amoxicillin, tetracycline, and furazolidone, the rates were 2.41% (95% CI 1.43%-3.60%), 2.53% (95% CI 1.19%-4.28%) and 1.54% (95% CI 0.28%-3.62%), respectively. Spatial and temporal differences were observed. The resistance rates increased after treatment failure; however, secondary resistance to amoxicillin, tetracycline and furazolidone were still low across the vast majority of study regions., Conclusion: Surveillance of the updated prevalence of antibiotic resistance of H. pylori for different regions is warranted, which should factor into clinical decision making and guideline recommendations., Competing Interests: Declarations Funding: This study was supported by the National Natural Science Foundation of China (82270580 and 82070552), Key Research and Development Program of Shandong Province (2021CXGC010506). Competing interests: The all authors in this study report no conflicts of interest. Ethical approval: This study was exempt from ethical review since it not involve patients. The study had been registered on PROSPERO with the ID: CRD42023447179. Sequence information: Not applicable. Author contributions: Qingzhou Kong conceived of the study. Shuyan Zeng and Qingzhou Kong performed the systematic review and were responsible for editing the manuscript. Yueyue Li supervised the entire study and performed a critical revision of this article. Shuyan Zeng, Qingzhou Kong and Xiaoqi Wu were responsible for data collection, selecting, interpretation. Miao Duan and Xueping Nan assisted with data processing and analysis. Xiaoyun Yang, Xiuli Zuo and Yanqing Li critically reviewed and revised the article. All authors commented on or edited drafts and approved the final version of the manuscript., (Copyright © 2024 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.)

We report here on the structure-activity relationships of hybrids combining 3-descladinosyl clarithromycin with quinolones linked by extended diamine connectors. Several hybrids, exemplified by 23Bc, 23Be, 23Bf, 26Be, and 30Bc, not only restored potency against inducibly resistant pathogens but also exhibited significantly enhanced activities against constitutively resistant strains of Staphylococcus pneumoniae and Staphylococcus pyogenes, which express high-level resistance independent of clarithromycin or erythromycin induction. Additionally, the novel hybrids showed susceptibility against Gram-negative Haemophilus influenzae. Notably, hybrid 23Be demonstrated dual modes of action by inhibiting both protein synthesis and DNA replication in vitro and in vivo. Given these promising characteristics, 23Be emerges as a potential candidate for the treatment of community-acquired bacterial pneumonia., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jian-Hua Liang reports financial support was provided by National Key Research and Development Program of China. Nothing to declare. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

The increasing clinical significance of Mycobacterium abscessus is owed to its innate high-level, broad-spectrum resistance to antibiotics and therefore rapidly evolves as an important human pathogen. This warrants the identification of novel targets for aiding the discovery of new drugs or drug combinations to treat M. abscessus infections. This study is inspired by the drug-hypersensitive profile of a mutant M. abscessus (U14) with transposon insertion in MAB_1915 . We validated the role of MAB_1915 in intrinsic drug resistance in M. abscessus by constructing a selectable marker-free in-frame deletion in MAB_1915 and complementing the mutant with the same or extended version of the gene and then followed by drug susceptibility testing. Judging by the putative function of MAB_1915, cell envelope permeability was studied by ethidium bromide accumulation assay and susceptibility testing against dyes and detergents. In this study, we established genetic evidence of the role of MAB_1915 in intrinsic resistance to rifampicin, rifabutin, linezolid, clarithromycin, vancomycin, and bedaquiline. Disruption of MAB_1915 has also been observed to cause a significant increase in cell envelope permeability in M. abscessus . Restoration of resistance is observed to depend on at least 27 base pairs upstream of the coding DNA sequence of MAB_1915 . MAB_1915 could therefore be associated with cell envelope permeability, and hence its role in intrinsic resistance to multiple drugs in M. abscessus , which presents it as a novel target for future development of effective antimicrobials to overcome intrinsic drug resistance in M. abscessus ., Importance: This study reports the role of a putative fadD (MAB_1915) in innate resistance to multiple drugs by M. abscessus , hence identifying MAB_1915 as a valuable target and providing a baseline for further mechanistic studies and development of effective antimicrobials to check the high level of intrinsic resistance in this pathogen., Competing Interests: The authors declare no conflict of interest.

Nontuberculous mycobacteria (NTM), which include the Mycobacterium avium complex, are classified as difficult-to-treat pathogens due to their ability to quickly develop drug resistance against the most common antibiotics used to treat NTM infections. The overexpression of efflux pumps (EPs) was demonstrated to be a key mechanism of clarithromycin (CLA) resistance in NTM. Therefore, in this work, 24 compounds from an in-house library, characterized by chemical diversity, were tested as potential NTM EP inhibitors (EPIs) against Mycobacterium smegmatis mc 2  155 and M. avium clinical isolates. Based on the acquired results, 12 novel analogs of the best derivatives 1b and 7b were designed and synthesized to improve the NTM EP inhibition activity. Among the second set of compounds, 13b emerged as the most potent NTM EPI. At a concentration of 4 µg/mL, it reduced the CLA minimum inhibitory concentration by 16-fold against the clinical isolate M. avium 2373 overexpressing EPs as primary mechanism of CLA resistance., (© 2024 Deutsche Pharmazeutische Gesellschaft.)

The treatment of Mycobacterium avium infections is still long, complex, and often poorly tolerated, besides emergence of resistances. New active molecules that are more effective and better tolerated are deeply needed. Mefloquine and its enantiomers ((+) Erythro-mefloquine ((+)-EMQ) and (-)-Erythro-mefloquine ((-)-EMQ)) have shown efficacy in both in vitro and in vivo, in a mouse model of M. avium intraveinous infection. However, no study reports aerosol model of infection or combination with gold standard treatment. That was the aim of our study. In an aerosol model of M. avium infection in BALB/c mice, we used five treatment groups as followed: Clarithromycin-Ethambutol-Rifampicin (CLR-EMB-RIF, standard of care, n = 15), CLR-EMB-MFQ (n = 15), CLR-EMB-(+)-EMQ (n = 15), CLR-EMB-(-)-EMQ (n = 15) and an untreated group (n = 25). To evaluate drug efficacy, we sacrificed each month over 3 months, 5 mice from each group. Lung homogenates were diluted and plated for colony forming unit count (CFU) expressed in Log10. At each time point, we found a significant difference between the untreated group and each of the treatment groups (p<0.005). The (+)-EMQ-CLR-EMB group was the group with the lowest CFU count at each time point but never reached statistical significance. The results of each group 3 months after treatment are: (+)-EMQ-CLR-EMB (4.43 ± 0.26), RIF-CLR-EMB (4.83 ± 0.37), (-)-EMQ-CLR-EMB (4.82 ± 0.18), MFQ-CLR-EMB (4.70 ± 0.21). In conclusion, MFQ and its enantiomers appear to be as effective as rifampicin in combination therapy. Further studies are needed to evaluate the ability of these drugs to prevent selection of clarithromycin resistant strains and potential for lung sterilization., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Froment et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Airway epithelial-mesenchymal transition (EMT) is the important pathological feature of airway remodeling in asthma. While macrolides are not commonly used to treat asthma, they have been shown to have protective effects on the airways, in which mechanisms are not yet fully understood. This study aims to investigate the impact of clarithromycin on airway EMT in asthma and its potential mechanism. The results revealed an increase in Kv1.3 expression in the airways of ovalbumin (OVA)-induced asthmatic mice, with symptoms and pathological changes being alleviated after treatment with the Kv1.3 inhibitor 5-(4-phenoxybutoxy)psoralen (PAP-1). Clarithromycin was found to attenuate airway epithelial-mesenchymal transition through the inhibition of Kv1.3 and PI3K/Akt signaling. Further experiments in vitro confirmed that PAP-1 could mitigate EMT by modulating the PI3K/Akt signaling in airway epithelial cells undergoing transformation into mesenchymal cells. These findings confirmed that clarithromycin might have a certain protective effect on asthma-related airway remodeling and represent a promising treatment strategy., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Helicobacter pylori infection constitutes a silent pandemic of global concern. In the last decades, the alarming increase in multidrug resistance evolved by this pathogen has led to a marked drop in the eradication rates of traditional therapies worldwide. By using a high-throughput screening strategy, in combination with in vitro DNA binding assays and antibacterial activity testing, we identified a battery of novel drug-like HsrA inhibitors with MIC values ranging from 0.031 to 4 mg/L against several antibiotic-resistant strains of H. pylori , and minor effects against both Gram-negative and Gram-positive species of human microbiota. The most potent anti- H. pylori candidate demonstrated a high therapeutic index, an additive effect in combination with metronidazole and clarithromycin as well as a strong antimicrobial action against Campylobacter jejuni , another clinically relevant pathogen of phylum Campylobacterota . Transcriptomic analysis suggests that the in vivo inhibition of HsrA triggers lethal global disturbances in H. pylori physiology including the arrest of protein biosynthesis, malfunction of respiratory chain, detriment in ATP generation, and oxidative stress. The novel drug-like HsrA inhibitors described here constitute valuable candidates to a new family of narrow-spectrum antibiotics that allow overcoming the current resistome, protecting from dysbiosis, and increasing therapeutic options for novel personalized treatments against H. pylori .

Objective: To establish a viable bacteria assay for Helicobacter pylori ( H. pylori ) by assessing the cgt gene expression, and to develop accordingly a rapid and novel testing method for clinical precision treatment., Methods: Viable bacteria count was determined in bacterial cultures. The transcriptional expression level of cgt ( hp0421 ), the conserved gene that encodes cholesterol-α-glucosyltransferase (CGT) in H. pylori , was measured by RT-PCR. The correlation between the number of colonies and cgt gene transcription expression was analyzed and the regression model was constructed. The linear range, sensitivity, and specificity of the new method were examined accordingly. The bactericidal action of clarithromycin was assessed using this method to verify the performance of the method in determining clinical bacterial drug resistance., Results: The Ct values of cgt for H. pylori colony counts of 10 2 , 10 4 , 10 6 , and 10 8 CFU/mL were 29.67±0.14, 23.37±0.36, 17.65±0.37, and 11.38±0.39, respectively. In the range of 10 1 -10 8 CFU/mL, the regression equation for cgt gene expression and viable bacterial counts determined by RT-qPCR was y =-0.3501 x +12.49, with the correlation coefficient being R 2 =0.9992 and the sensitivity being 10 1 CFU/mL, showing no cross-reaction with 13 other bacteria. The lg values of live H. pylori bacteria treated with clarithromycin at 0, 5, 10, 20, and 40 μg/mL for 12 h were 2.57±0.02, 2.45±0.01, 2.19±0.02, 1.91±0.07, and 1.33±0.05, respectively. The corresponding cgt gene Ct values were 27.76±0.09, 28.37±0.24, 29.51±0.14, 30.11±0.12, and 31.66±0.11. By applying the cgt gene expression in the equation, the estimated counts of viable bacteria were found to be 2.73±0.03, 2.52±0.08, 2.11±0.05, 1.89±0.02, and 1.33±0.04, showing no significant difference in statistical analysis ( P >0.05)., Conclusion: The method for assessing viable bacteria account by evaluating cgt gene expression in H. pylori was successfully established, significantly reducing the time required to determine viable bacteria count and providing a new method for clinical viable bacteria testing., Competing Interests: 利益冲突　贵州医科大学基础医学院陈峥宏教授赠送了H. pylori标准菌株。本文作者别明江是本刊编委会编委。该文在编辑评审过程中所有流程严格按照期刊政策进行，且未经其本人经手处理。除此之外，所有作者声明不存在利益冲突。, (© 2024《四川大学学报（医学版）》编辑部 版权所有Copyright ©2024 Editorial Office of Journal of Sichuan University (Medical Sciences).)

Background: One of the reasons for the decrease of Helicobacter pylori eradication effectiveness is its resistance to antibiotics., Aim: To examine the prevalence of H. pylori point mutations responsible for clarithromycin and levofloxacin resistance among the patients with upper gastrointestinal (GI) tract disorders in Kazan., Materials and Methods: The study included 203 patients with symptoms of dyspepsia who underwent upper GI endoscopy at the University Hospital of Kazan Federal University (Kazan, Russia) in 2019-2021. DNA isolation from gastric antrum mucosal biopsies was performed using PureLink Genomic DNA Mini Kits (Thermo Fisher Scientific, USA). Polymerase chain reaction was performed using primers specific for the V-region of the 23S gene and the A subunit DNA gyrase encoding gyrA gene region. The sequencing of obtained DNA fragments was performed on 3730 DNA Analyzer. The sequences were searched for point mutations responsible for H. pylori resistance to clarithromycin (A2143G, A2142G and A2142C193 mutations) and levofloxacin (mutations of the gyrA gene)., Results: H. pylori was detected in 47.78% of biopsy specimens using polymerase chain reaction. The proportion of H. pylori strains with mutations leading to clarithromycin resistance was 17.53%. Amino acid substitutions in the gyrA gene were found in 12.37% of samples. In case of two H. pylori strains (2.06%), dual resistance to clarithromycin and levofloxacin was found., Conclusion: So high incidence of mutations underlying the development of H. pylori resistance to clarithromycin and levofloxacin was observed among examined patients in Kazan.

Background: Helicobacter pylori ( H. pylori )is a Gram-negative, microaerophilic, and spiral shape bacterium that resides inside the human stomach. The human stomach serves as its primary reservoir. Complaints about stomach complication due to H. pylori infections are reported in the majority of populations around the globe. Chronic gastritis and intestinal metaplasia of the gastric mucosa are major complications of a long-term H. pylori infections that can lead to gastric cancer in severe cases. This study aims to characterize H. pylori isolates from gastroenteritis patients and to determine the resistance of H. pylori to various antibiotics., Methods: In the current study, a total of (n = 80) gastric biopsy samples were randomly collected from gastroenteritis patients in brain-heart infusion broth. These were inoculated on Columbia blood agar supplemented with Helicobacter pylori selective supplement (DENT). After culturing, Microscopy and biochemical tests were performed. The susceptibility profile of H. pylori isolates was evaluated using the Kirby Bauer disk diffusion method. On the basis of the drug resistance profile, a total of (n = 20) isolates including (n = 10) from females and (n = 10) from males were selected for the detection and characterization of resistant genes. After confirmation of H. pylori using 16s rRNA , polymerase chain reaction (PCR) was done for the detection of resistance genes including Metronidazole resistance ( rdxA gene), Clarithromycin resistance ( 23s rRNA gene) and Amoxicillin resistance (Penicillin-binding protein A1 ( pbpA1 ) gene)., Results: In a total of (n = 80) samples, H. pylori was isolated from 72.5% (n = 58) samples. Among the positive patients, there were 62% (n = 36) of female positive patients while in males, its ratio was 38% (n = 22). It was more common in the age between 30-50 years 55.17% (n = 32). It has shown the highest resistance towards Metronidazole 90% (n = 52), and the lowest toward Levofloxacin 65% (n = 38). Metronidazole resistance gene ( rdxA gene) was detected in (n = 13) isolates including (n = 9) isolates from females and (n = 4) from males. In the case of, the Clarithromycin resistance gene ( 23s rRNA ) (n = 10) was positive for H. pylori including (n = 6) isolates from females and (n = 7) were positive for Amoxicillin ( pbpA1 gene) including (n = 2) in female and (n = 5) from male patients., Conclusion: This study highlights the increasing incidence of H. pylori infections in both male and female patients. It also revealed the current status of antibiotic resistance and its resistance genes in patients facing gastrointestinal issues. Continuous surveillance of resistant clones will help in formulating strategies that can help in combating of resistant clone. It will also help clinician in proper prescription and management of H. pylori infections.

Background and Aim: Rates of antimicrobial-resistant Helicobacter pylori infection are rising globally, but little is known about contemporary resistance patterns, virulence factors, and phylogenetic patterns of isolates within Australia. We aimed to characterize antimicrobial resistance and genetic mutations associated with adverse clinical outcomes., Methods: Whole genome sequencing, culturing, and antibiotic sensitivity data for refractory H. pylori isolates at Australian centers were collected between 2013 and 2022. Phylogenetic origins, antibiotic resistance mutations, and virulence factors were examined with phenotypic resistance profiles., Results: One hundred thirty-five isolates underwent culture, with 109 of these undergoing whole genome sequencing. Forty-three isolates were isolated from patients in South Australia and 66 from Western Australia. Isolates originated primarily from hpEurope (59.6%), hpEastAsia (25.7%), and hpNEAfrica (6.4%). Antimicrobial resistance to clarithromycin was seen in 85% of isolates, metronidazole in 52%, levofloxacin in 18%, rifampicin in 14%, and amoxicillin in 9%. Most isolates (59%) were multi-drug resistant. Resistance concordance between genetically determined resistance and phenotypic resistance was 92% for clarithromycin and 94% for levofloxacin. Analysis of virulence factors demonstrated cag pathogenicity island (cagPAI) in 67% of isolates and cagA in 61%, correlating with isolate genetic origin. The most virulent s1m1 vacuolating cytotoxin A genotype was present in 26% of isolates., Conclusion: Refractory H. pylori isolates in Australia emanate from multiple global origins. Strong concordance between genetic and phenotypic antibiotic resistance profiles raises the possibility of utilizing genetic profiling in clinical practice. The dynamic landscape of H. pylori in Australia warrants the establishment of a national database to monitor H. pylori resistance and evolving virulence., (© 2024 The Author(s). Journal of Gastroenterology and Hepatology published by Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Helicobacter pylori is a bacterium that is present in the stomach of about 50% of the global population and is associated with several gastric disorders, including cancer. Natural products with antimicrobial activity have been tested against H. pylori, among them Trichilia catigua (catuaba), which is widely distributed in Brazil. This study aimed to evaluate extracts of T. catigua bark against H. pylori via determination of the minimum inhibitory and bactericidal concentrations (MIC and MBC); evaluation of virulence factors by real-time PCR, synergism with standard antimicrobials and morphology by scanning electron microscopy and simulations of the mechanism of action by molecular docking. The ethyl acetate fraction provided the best results, with an MIC 50 of 250 μg/mL and a 42.34% reduction in urease activity, along with reduced expression of the CagA and VacA genes, which encode for the main virulence factors. This fraction presented synergistic activity with clarithromycin, reducing the MIC of the drug by four-fold. Docking simulations suggested that the extracts inhibit fatty acid synthesis by the FAS-II system, causing damage to the cell membrane. Therefore, T. catigua extracts have potential as an adjuvant to treatment and are promising for the development of new anti-H. pylori drugs., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2023. Published by Elsevier B.V.)

The minimum bactericidal concentration (MBC) of antibiotics is an important parameter for the potency of a drug in eradicating a bacterium as well as an important measure of the potential of a drug candidate in research and development. We have established a fluorescence-based microscopy method for the determination of MBCs against the non-tuberculous mycobacterium Mycobacterium abscessus (Mycobacteroides abscessus) to simplify and accelerate the performance of MBC determination compared to counting colony forming units on agar. Bacteria are labelled with the trehalose-coupled dye 3HC-2-Tre and analysed in a 96-well plate. The results of the new method are consistent with MBC determination by plating on agar. The method was used to evaluate the bactericidality of the antibiotics rifabutin, moxifloxacin, amikacin, clarithromycin and bedaquiline. Bactericidal effects against M. abscessus were observed, which are consistent with literature data., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Adrian Richter reports financial support was provided by German Research Foundation. Adrian Richter reports financial support was provided by Deutsche Mukoviszidose Stiftung. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Antibiotics are essential for treating infections and reducing risks during medical interventions. However, many commonly used antibiotics lack the physiochemical properties for an efficient oral administration when treating systemic infection. Instead, we are reliant on intravenous delivery, which presents complications outside of clinical settings. Developing novel formulations for oral administration is a potential solution to this problem. We engineered hexosome and cubosome liquid crystal nanoparticles (LCNPs) characterized by small-angle X-ray scattering and cryogenic transmission electron microscopy, and could encapsulate the antibiotics vancomycin (VAN) and clarithromycin (CLA) with high loading efficiencies. By rationally choosing stable lipid building blocks, the loaded LCNPs demonstrated excellent resilience against enzymatic degradation in an in vitro gut model LCNP stability is crucial as premature antibiotic leakage can negatively impact the gut microbiota. In screens against the representative gut bacteria Enterococcus faecalis and Escherichia coli, our LCNPs provided a protective effect. Furthermore, we explored co-administration and dual loading strategies of VAN and CLA, and demonstrated effective loading, stability and protection for E. faecalis and E. coli. This work represents a proof of concept for the early-stage development of antibiotic-loaded LCNPs to treat systemic infection via oral administration, opening opportunities for combination antibiotic therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Introduction: The decreasing Helicobacter pylori eradication rate is primarily attributed to antibiotic resistance, and further exacerbated by uniform drug administration disregarding a host's metabolic capability. Consequently, applying personalized treatment based on antibiotic resistance-associated variants and the host's metabolic phenotype can potentially increase the eradication rate., Method: A custom next-generation sequencing panel for personalized H. pylori eradication treatment (NGS-PHET) was designed which targeted the regions for amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin-resistance in H. pylori and human proton-pump inhibitor (PPI) metabolism. The libraries were constructed following customized methods and sequenced simultaneously. The customized framework criteria, grounded in previously reported antibiotic resistance associated variants and the host's PPI metabolism, was applied to the NGS-PHET results and suggested a personalized treatment for each subject, which was validated through each subject's actual eradication outcome., Results: Both previously reported and novel variants were identified from H. pylori sequencing results. Concurrently, five CYP2C19 homozygous extensive metabolizers and three CYP3A4 intermediate metabolizers were identified. Among the total of 12 subjects, clarithromycin triple therapy was suggested for five subjects, bismuth quadruple therapy was suggested for six subjects, and rifabutin triple therapy was suggested for one subject by following the customized framework criteria. The treatment suggestion for nine of the 12 subjects was consistent with the treatment that each subject achieved eradication with., Discussion: Applying the methodology using the NGS-PHET and customized framework helps to perform eradication treatment quickly and effectively in most patients with antibiotic-resistant H. pylori strains, and is also useful in research to find novel antibiotic-resistance candidates., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Min, Seo, Bae, Kim and Kim.)

Clarithromycin (CLR) is currently a key antibiotic for Helicobacter pylori infection treatment, however, the data on CLR resistance patterns in Russia are missing. Here, we applied WGS-based approach to H. pylori clinical isolates from Russia to comprehensively investigate sequence variation, identify putative markers of CLR resistance and correlate them with phenotypic susceptibility testing. The phenotypic susceptibility of 44 H. pylori isolates (2014-2022) to CLR was determined by disc diffusion method: 23 isolates were CLR-resistant and 21-CLR-susceptible. All isolates were subjected to WGS and submitted to GenBank. Based on complete sequence analysis, we showed that among all sequence variants, the combination of mutations A2146G/A2147G in the 23S rRNA gene is the most reliable for prediction of phenotypic susceptibility. For the first time, the average number of mutations in 106 virulence-associated genes between resistant and susceptible groups were compared. Moreover, this study presents the first WGS insight into genetic diversity of H. pylori in Russia with a particular focus on the molecular basis of drug resistance: the novel mutations were described as potential markers for the resistance development. Of these, the most prominent was a frameshift deletion (252:CGGGT) in HP0820 coding region, which is a good candidate for further investigation., (© 2024. The Author(s).)

Background: In East Asia, Helicobacter pylori ( H. pylori ) infection and related diseases are common, primarily during childhood and adolescence. The rates of primary antibiotic resistance in H. pylori among East Asian children and adolescents have not been extensively explored; few relevant systematic reviews or meta-analyses have been conducted. We evaluated the rates of antibiotic resistance in H. pylori among East Asian children and adolescents, with the goal of facilitating individualized treatment recommendations., Methods: We searched PubMed, Embase, and the Cochrane Library for studies in any language published up to February 2023 that explored antibiotic resistance in H. pylori among East Asian children and adolescents. We used MeSH and non-MeSH terms related to the topic, including terms related to children, adolescents, antibiotic resistance, H. pylori , and nations or regions. Additionally, we reviewed the reference lists of relevant articles. Studies that matched our strict predefined eligibility criteria were included in the screening process. Using established assessment methods, we evaluated the quality of the included studies., Results: We identified 15 observational studies involving 4831 H. pylori isolates, all published between 2001 and 2022. There was substantial primary antibiotic resistance in H. pylori isolates from East Asian children and adolescents. The rates of primary resistance were 51% (95% confidence interval [CI]: 40-62%) for metronidazole; 37% (95% CI: 20-53%) for clarithromycin; 19% (95% CI: 11-28%) for levofloxacin; and less than 3% each for amoxicillin, tetracycline, and furazolidone. Subgroup analysis revealed a prominent increase in metronidazole resistance over time. Clarithromycin and levofloxacin resistance rates fluctuated between 2005 and 2015, then remained stable; other antibiotic resistance rates were generally stable. Metronidazole, clarithromycin, and levofloxacin resistance rates were significantly higher in the Chinese mainland than in other East Asian regions. The rates of dual and multiple antibiotic resistance were 28% (95% CI: 21-36%) and 10% (95% CI: 7-14%), highlighting the potential for diverse resistance patterns., Conclusions: H. pylori isolates from East Asian children and adolescents exhibit high levels of metronidazole and clarithromycin resistance, particularly in the Chinese mainland. The non-negligible rates of dual and multiple resistance highlight the complexity of this problem., Registration: PROSPERO, No. CRD42023402510., (Copyright © 2024 The Chinese Medical Association, produced by Wolters Kluwer, Inc. under the CC-BY-NC-ND license.)

The aim of the present study was first to isolate Helicobacter pylori from gastric biopsy specimens and to test their antibiotic susceptibility. Second, it was to evaluate the efficacy of the standard triple therapy from patients of the west central region of Colombia. H. pylori positive patients received standard triple therapy with proton pump inhibitor (PPI) (40 mg b.i.d.), clarithromycin (500 mg b.i.d.), and amoxicillin (1 g b.i.d.) for 14 days. Thereafter, antibiotic susceptibility of the isolates was assessed by E-Test. From 94 patients enrolled, 67 were positive for H. pylori by histology or culture. Overall resistance to metronidazole, levofloxacin, rifampicin, clarithromycin, and amoxicillin was 81%, 26.2%, 23.9%, 19%, and 9.5%, respectively. No resistance was found for tetracycline. A total of 54 patients received standard triple therapy, 48 attended follow-ups testing, and of them, 30 had resistance test reports. Overall eradication rate was 81.2%. Second-line treatment was given to eight patients, four of whom were followed up with a 13C urea breath test (UBT) and remained positive for H. pylori . Eradication was significantly higher in patients with clarithromycin susceptible than in resistant strains (95.6% vs 42.8% P = 0.001). The updated percentages of resistance to clarithromycin in this geographical area had increased, so this value must be considered when choosing the treatment regimen.IMPORTANCEAntibiotic resistance in Helicobacter pylori has increased worldwide, as has resistance to multiple antimicrobials (MDRs), which seriously hampers the successful eradication of the infection. The ideal success rate in eradicating H. pylori infection (≥90%) was not achieved in this study (81.2%). This is the first time that MDR is reported (14.3%) in the region; the resistance to clarithromycin increased over time (3.8%-19%), and levofloxacin (26.2%) and rifampicin (23%) resistant isolates were detected for the first time. With these results, strain susceptibility testing is increasingly important, and the selection of treatment regimen should be based on local antibiotic resistance patterns., Competing Interests: The authors declare no conflict of interest.

Objectives: Mycobacterium abscessus is a non-tuberculous mycobacterial pathogen that causes pulmonary and skin infections globally. Clarithromycin plays a pivotal role in treating M. abscessus infections, with resistance often leading to treatment failure. While canonical mutations in the 23S rRNA residue 2270/2271 are recognized as the primary mechanism for acquired clarithromycin resistance, resistant isolates lacking these mutations have been widely reported. This study aims to identify new mechanisms of clarithromycin resistance in M. abscessus., Methods: We selected spontaneous resistant mutants derived from two parental strains characterized by erm(41) T28 and C28 sequevars, respectively. Whole-genome sequencing was performed on mutants lacking the 23S rRNA 2270/2271 mutations. Site-directed mutagenesis was used to confirm the resistance phenotypes of newly identified mutations. Bioinformatic analysis of publicly available genomes was conducted to evaluate the presence of these mutations in clinical isolates. The spatial localization of these mutations in the ribosome was analyzed to investigate potential mechanisms of resistance., Results: A total of 135 resistant mutants were selected from the parental strains. Sequencing of the 78 mutants lacking the 23S rRNA 2270/2271 mutations identified mutations within the peptidyl-transferase center and hairpin loops 35, 49, and 74 of the 23S rRNA. These noncanonical mutations were identified in 57 of 1875 genomes of clinical isolates. Thirteen representative mutations were introduced into the bacterial genome, and their contributions to macrolide resistance were confirmed. The newly identified mutations all localized at the entrance of the nascent peptide exit tunnel, potentially contributing to resistance by disrupting the macrolide binding pocket., Conclusion: Several noncanonical 23S rRNA mutations conferring clarithromycin resistance were identified. These mutations enhance our understanding of macrolide resistance in M. abscessus and could serve as important markers for diagnosing clarithromycin resistance., (Copyright © 2024 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.)

Background: Mycobacterium avium is associated with pulmonary disease in otherwise healthy adults. Several clarithromycin-refractory cases have been reported, including some cases caused by clarithromycin-susceptible strains., Objectives: To characterize the reason for the discrepancy between clinical response and antibiotic susceptibility results., Methods: We conducted population analysis of clarithromycin-tolerant and heteroresistant subpopulations of M. avium cultured in vitro and in homogenates of infected lungs of mice. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for 28 M. avium and two M. kansasii strains. Mice were intranasally infected with M. avium and treated with or without clarithromycin (100 mg/kg) thrice weekly. They were sacrificed on day 35 and the bacteria in lung homogenates were tested for clarithromycin resistance. Population analysis assays were performed based on colony growth on plates containing two-fold dilutions of clarithromycin., Results: The MBC/MIC ratios were ≥8 in all 28 strains of M. avium tested. In the population analysis assay, several colonies were observed on the plates containing clarithromycin concentrations above the MIC (2-64 mg/L). No growth of M. kansasii colonies was observed on the plates containing clarithromycin concentrations ≥2 mg/L. M. avium in the homogenates of infected lungs showed clearer clarithromycin-resistant subpopulations than in vitro, regardless of clarithromycin exposure., Conclusion: M. avium shows intrinsic heterogeneous resistance (heteroresistance) to clarithromycin. This may explain the observed discrepancies between clarithromycin susceptibility testing results and clinical response to clarithromycin treatment. Further studies are needed to confirm a link between heteroresistance and clinical outcomes., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Purpose: We assessed the differential effect of clarithromycin, a strong inhibitor of cytochrome P450 (CYP) 3A4 and P-glycoprotein, on the pharmacokinetics of a regular dose of edoxaban and on a microdose cocktail of factor Xa inhibitors (FXaI). Concurrently, CYP3A activity was determined with a midazolam microdose., Methods: In an open-label fixed-sequence trial in 12 healthy volunteers, the pharmacokinetics of a microdosed FXaI cocktail (μ-FXaI; 25 μg apixaban, 50 μg edoxaban, and 25 μg rivaroxaban) and of 60 mg edoxaban before and during clarithromycin (2 x 500 mg/d) dosed to steady-state was evaluated. Plasma concentrations of study drugs were quantified using validated ultra-performance liquid chromatography-tandem mass spectrometry methods., Results: Therapeutic clarithromycin doses increased the exposure of a therapeutic 60 mg dose of edoxaban with a geometric mean ratio (GMR) of the area under the plasma concentration-time curve (AUC) of 1.53 (90 % CI: 1.37-1.70; p < 0.0001). Clarithromycin also increased the GMR (90% CI) of the exposure of microdosed FXaI apixaban to 1.38 (1.26-1.51), edoxaban to 2.03 (1.84-2.24), and rivaroxaban to 1.44 (1.27-1.63). AUC changes observed for the therapeutic edoxaban dose were significantly smaller than those observed with the microdose (p < 0.001)., Conclusion: Clarithromycin increases FXaI exposure. However, the magnitude of this drug interaction is not expected to be clinically relevant. The edoxaban microdose overestimates the extent of the drug interaction with the therapeutic dose, whereas AUC ratios for apixaban and rivaroxaban were comparable to the interaction with therapeutic doses as reported in the literature., Trial Registration: EudraCT Number: 2018-002490-22., (© 2023. The Author(s).)

Helicobacter pylori (H. pylori) is currently recognized as the primary carcinogenic pathogen associated with gastric tumorigenesis, and its high prevalence and resistance make it difficult to tackle. A graph neural network-based deep learning model, employing different training sets of 13,638 molecules for pre-training and fine-tuning, was aided in predicting and exploring novel molecules against H. pylori. A positively predicted novel berberine derivative 8 with 3,13-disubstituted alkene exhibited a potency against all tested drug-susceptible and resistant H. pylori strains with minimum inhibitory concentrations (MICs) of 0.25-0.5 μg/mL. Pharmacokinetic studies demonstrated an ideal gastric retention of 8, with the stomach concentration significantly higher than its MIC at 24 h post dose. Oral administration of 8 and omeprazole (OPZ) showed a comparable gastric bacterial reduction (2.2-log reduction) to the triple-therapy, namely OPZ + amoxicillin (AMX) + clarithromycin (CLA) without obvious disturbance on the intestinal flora. A combination of OPZ, AMX, CLA, and 8 could further decrease the bacteria load (2.8-log reduction). More importantly, the mono-therapy of 8 exhibited comparable eradication to both triple-therapy (OPZ + AMX + CLA) and quadruple-therapy (OPZ + AMX + CLA + bismuth citrate) groups. SecA and BamD, playing a major role in outer membrane protein (OMP) transport and assembling, were identified and verified as the direct targets of 8 by employing the chemoproteomics technique. In summary, by targeting the relatively conserved OMPs transport and assembling system, 8 has the potential to be developed as a novel anti-H. pylori candidate, especially for the eradication of drug-resistant strains., (© 2024. The Author(s).)

Purpose: In India there is evidence of antimicrobial resistance in Helicobacter pylori, a definitive pathobiont whose only known niche is human gastric mucosa. This in turn can lead to failure of treatment, persistence or chronicity of infection. This hospital based, prospective, observational study investigates the presence of antimicrobial resistance in the organism with focus on detection of A2143G and A2142G major point mutations in domain V of H. pylori 23S rRNA gene as a molecular mechanism of conferring resistance., Methods: Endoscopic gastric biopsy samples from 52 patients presenting with dyspeptic symptoms from January 2016 to December 2016 were subjected to culture in a microaerophilic environment using Campylobacter agar with for 2-5 days. Isolates were identified using gram-staining, motility test and biochemical reactions. Modified Kirby-Bauer Disc diffusion method was used to determine antimicrobial susceptibility against Clarithromycin, Metronidazole, Amoxycillin, Levofloxacin, Tetracycline, Cotrimoxazole and Erythromycin. Additionally, detection of A2143G and A2142G point mutations conferring Clarithromycin resistance was carried out using real time PCR following extraction and quantification of bacterial DNA. Histopathological examination was carried out on all biopsy samples. Descriptive and inferential statistical analytical methods were used. Differences were considered significant for p < 0.05., Results: Culture positivity for H. pylori by phenotypic method was found to be 36.54%. Histopathologic Examination detected H. pylori in 55.7% and PCR detected 48.08% for either the wild type or one of two mutant strains A2143G and A2142G. No sample was found positive for both mutations. Metronidazole showed the highest resistance among antibiotics (78.9%) followed by Clarithromycin (47.3%)., Conclusion: Prevalence of antimicrobial resistance in H. pylori in North-Eastern India is substantially high with A2143G mutation being clinically most important in conferring Clarithromycin resistance. This resistance might be associated with low eradication rates despite initiation of therapy. ROC analysis of PCR proved it to be a good diagnostic tool., (Copyright © 2024 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

Antibiotics are ubiquitously present in aquatic environments, posing a serious ecological risk to aquatic ecosystems. However, the effects of antibiotics on the photosynthetic light reactions of freshwater algae and the underlying mechanisms are relatively less understood. In this study, the effects of 4 representative antibiotics (clarithromycin, enrofloxacin, tetracycline, and sulfamethazine) on a freshwater alga (Chlorella pyrenoidosa) and the associated mechanisms, primarily focusing on key regulators of the photosynthetic light reactions, were evaluated. Algae were exposed to different concentrations of clarithromycin (0.0-0.3 mg/L), enrofloxacin (0.0-30.0 mg/L), tetracycline (0.0-10.0 mg/L), and sulfamethazine (0.0-50.0 mg/L) for 7 days. The results showed that the 4 antibiotics inhibited the growth, the photosynthetic pigment contents, and the activity of antioxidant enzymes. In addition, exposure to clarithromycin caused a 118.4 % increase in malondialdehyde (MDA) levels at 0.3 mg/L. Furthermore, the transcripts of genes for the adenosine triphosphate (ATP) - dependent chloroplast proteases (ftsH and clpP), genes in photosystem II (psbA, psbB, and psbC), genes related to ATP synthase (atpA, atpB, and atpH), and petA (related to cytochrome b6/f complex) were altered by clarithromycin. This study contributes to a better understanding of the risk of antibiotics on primary producers in aquatic environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Helicobacter pylori (H. pylori) infection is a major cause of gastric diseases. Currently, bismuth-based quadruple therapy is widely adopted for eradicating H. pylori infection. However, this first-line strategy faces several challenges such as drug resistance, intestinal dysbacteriosis, and patients' poor compliance. To overcome these problems, an all-in-one therapeutic platform (CLA-Bi-ZnO 2 @Lipo) that composed of liposomes loading clarithromycin (CLA), Bi, and ZnO 2 hybrid nanoparticles was developed for eradicating multidrug-resistant (MDR) H. pylori. The in vitro and in vivo results showed that CLA-Bi-ZnO 2 @Lipo could target the infection-induced inflammatory mucosa through liposome mediated nanoparticle-tissue surface charge interaction and quickly respond to the gastric acid environment to release CLA, Bi 3+ , Zn 2+ , and H 2 O 2 . By oral administration per day, the acid triggered decomposition of CLA-Bi-ZnO 2 @Lipo could significantly increase intragastric pH to 6 within 30 min; The released CLA, Zn 2+ , and H 2 O 2 further exerted synergistical anti-bacterial effects in which a ∼2 order higher efficacy in reducing MDR H. pylori burden was achieved in comparison with standard quadruple therapy (p < 0.05); The released Zn 2+ and Bi 3+ could also alleviate mucosal inflammation. Most importantly, the CLA-Bi-ZnO 2 @Lipo exhibited superior biosafety and nearly no side effects on intestinal flora. Overall, this study developed a highly integrated and safe anti-MDR H. pylori agent which had great potential to be used as an alternative treatment for MDR H. pylori eradication., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Antibiotic resistance among bacteria is recognized as the primary factor contributing to the failure of treatment. In this research, our objective was to examine the prevalence of antibiotic resistance in H. pylori bacteria in Palestine. We enlisted 91 individuals suffering from dyspepsia, comprising 49 females and 42 males. These participants underwent esophagogastroduodenoscopy procedures with gastric biopsies. These biopsies were subsequently subjected to microbiological assessments and tested for their susceptibility to various antimicrobial drugs. Among the 91 patients, 38 (41.7%) exhibited the presence of H. pylori. Notably, Ciprofloxacin displayed the highest efficacy against H. pylori, followed by Levofloxacin, Moxifloxacin, and Amoxicillin, with resistance rates of 0%, 0%, 2.6%, and 18.4%, respectively. On the contrary, Metronidazole and Clarithromycin demonstrated the lowest effectiveness, with resistance percentages of 100% and 47.4%, respectively. The outcomes of this investigation emphasize that H. pylori strains within the Palestinian patient group exhibit substantial resistance to conventional first-line antibiotics like clarithromycin and metronidazole. However, alternative agents such as fluoroquinolones and amoxicillin remain efficacious choices. Consequently, we recommend favoring quinolone-based treatment regimens for H. pylori infections and adopting a more judicious approach to antibiotic usage among the Palestinian population., (© 2024. The Author(s).)

The latest guidelines include azithromycin as a preferred regimen for treating Mycobacterium avium complex (MAC) pulmonary disease. However, serially collected susceptibility data on clinical MAC isolates are limited, and no breakpoints have been determined. We investigated the minimum inhibitory concentrations (MICs) of azithromycin and clarithromycin for all MAC strains isolated in 2021 from a single center in Japan, excluding duplicates. The MICs were determined using a panel based on the microbroth dilution method, according to the latest Clinical and Laboratory Standards Institute recommendations. The MICs were determined for 318 MAC strains. Although there was a significant positive correlation between the MICs of azithromycin and clarithromycin, the MICs of azithromycin tended to be higher than those of clarithromycin. Among the cases in which the strains were isolated, 18 patients initiated treatment, including azithromycin treatment, after sample collection. Some patients infected with stains with relatively high azithromycin MICs achieved a microbiological cure with azithromycin-containing regimens. This study revealed a higher MIC distribution for azithromycin than clarithromycin, raising questions about the current practice of estimating azithromycin susceptibility based on the clarithromycin susceptibility test result. However, this was a single-center study that included only a limited number of cases treated with azithromycin. Therefore, further multicenter studies that include a greater number of cases treated with azithromycin are warranted to verify the distribution of azithromycin MICs and examine the correlation between azithromycin MICs and treatment effectiveness.IMPORTANCEThe macrolides serve as key drugs in the treatment of pulmonary Mycobacterium avium complex infection, and the administration of macrolide should be guided by susceptibility test results. Azithromycin is recommended as a preferred choice among macrolides, surpassing clarithromycin; however, drug susceptibility testing is often not conducted, and clarithromycin susceptibility is used as a surrogate. This study represents the first investigation into the minimum inhibitory concentration of azithromycin on a scale of several hundred clinical isolates, revealing an overall tendency for higher minimum inhibitory concentrations compared with clarithromycin. The results raise questions about the appropriateness of using clarithromycin susceptibility test outcomes for determining the administration of azithromycin. This study highlights the need for future discussions on the clinical breakpoints of azithromycin, based on large-scale clinical research correlating azithromycin susceptibility with treatment outcomes., Competing Interests: This study was supported by Kyokuto Pharmaceutical Industrial., co. Ltd. (Tokyo, Japan). Kyokuto Pharmaceutical Industrial., co. Ltd. manufactures and distributes BrothMIC NTM panels and BrothMIC SGM panels.

The high-consequence pathogen Bacillus anthracis causes human anthrax and often results in lethal infections without the rapid administration of effective antimicrobial treatment. Antimicrobial resistance profiling is therefore critical to inform post-exposure prophylaxis and treatment decisions, especially during emergencies such as outbreaks or where intentional release is suspected. Whole-genome sequencing using a rapid long-read sequencer can uncover antimicrobial resistance patterns if genetic markers of resistance are known. To identify genomic markers associated with antimicrobial resistance, we isolated B. anthracis derived from the avirulent Sterne strain with elevated minimal inhibitory concentrations to clarithromycin. Mutants were characterized both phenotypically through broth microdilution susceptibility testing and observations during culturing, as well as genotypically with whole-genome sequencing. We identified two different in-frame insertions in the L22 ribosomal protein-encoding gene rplV , which were subsequently confirmed to be involved in clarithromycin resistance through the reversion of the mutant gene to the parent (drug-susceptible) sequence. Detection of the rplV insertions was possible with rapid long-read sequencing, with a time-to-answer within 3 h. The mutations associated with clarithromycin resistance described here will be used in conjunction with known genetic markers of resistance for other antimicrobials to strengthen the prediction of antimicrobial resistance in B. anthracis .IMPORTANCEThe disease anthrax, caused by the pathogen Bacillus anthracis , is extremely deadly if not treated quickly and appropriately. Clarithromycin is an antibiotic recommended for the treatment and post-exposure prophylaxis of anthrax by the Centers for Disease Control and Prevention; however, little is known about the ability of B. anthracis to develop resistance to clarithromycin or the mechanism of that resistance. The characterization of clarithromycin-resistant isolates presented here provides valuable information for researchers and clinicians in the event of a release of the resistant strain. Additionally, knowledge of the genetic basis of resistance provides a foundation for susceptibility prediction through rapid genome sequencing to inform timely treatment decisions., Competing Interests: The authors declare no conflict of interest.

Objective: The non-invasive detection of Helicobacter pylori (H. pylori) and its resistance to clarithromycin and levofloxacin significantly improves the management of infected patients by enabling tailored eradication treatments without the need for endoscopic procedures. This study aimed to assess the effectiveness of real-time PCR (RT-PCR) assays in identifying H. pylori infection and antibiotic resistance in stool and gastric biopsy specimens., Patients and Methods: Stool and gastric biopsy samples were collected from patients within three days of post-hospitalization. A total of 115 samples were analyzed for H. pylori infection, and an additional 115 samples were evaluated for resistance to clarithromycin and levofloxacin using an RT-PCR-based molecular test. Statistical analyses were performed using (SPSS 26.0 IBM Corp., Armonk, NY, USA)., Results: Among 115 patients (53 males, average age 50.8±13.2 years), H. pylori was detected in 93.1% of stool samples and 93.9% of gastric biopsies. The RT-PCR assay demonstrated a sensitivity of 99.1% and a specificity of 100%, with an overall diagnostic accuracy of 99.1%. Clarithromycin resistance was found in 37.3% of stool and 46.9% of gastric biopsy specimens, with the assay showing 79.6% sensitivity and 98.4% specificity. Levofloxacin resistance was identified in 32.1% of stool samples and 31.3% of gastric biopsies, with 86.3% sensitivity and 91.1% specificity of the molecular test., Conclusions: The RT-PCR-based detection of H. pylori and its resistance to clarithromycin and levofloxacin in stool samples represents a promising approach to enhance eradication therapy outcomes, potentially improving treatment efficacy. Chictr.org.cn: ChiCTR2300070267.

Objective: Mycobacterium avium complex (MAC) and Mycobacterium abscessus are a group of nontuberculous mycobacteria (NTM) that have been described as human pathogens. Their ability to develop biofilms in tissues and medical devices is one of the most important pathogenicity factors, with important implications in diagnosis and treatment. Macrolides are usually considered one of the bases of this treatment., Methods: Here we have studied the biofilm prevention concentration (BPC) of 16 strains (n=16) with clarithromycin to avoid the biofilm development by these NTM., Results: In this study, all M. abscessus strains have similar BPC, while MAC strains showed different values. For MAC the concentrations ranged between 1-16 mg/L, while for M. abscessus the concentration was 32 mg/L for all strains except one that was 64 mg/L., Conclusions: These results open the possibility of using macrolides for the prevention of biofilm development in patients with a risk of developing NTM disease., (©The Author 2024. Published by Sociedad Española de Quimioterapia. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)(https://creativecommons.org/licenses/by-nc/4.0/).)

Antibiotics are commonly found in the aquatic environment, which can affect microbial community compositions and activities, and even have potential adverse impacts on human and ecosystem health. The current understanding of the effects of antibiotics on microalgae growth and algal dissolved organic matter (DOM) remains indistinct. To understand the toxic effects of antibiotics on the microalgae, Microcystis aeruginosa was exposed to clarithromycin (CLA) in this study. Cell density determination, chlorophyll content determination, and organic spectrum analysis were conducted to show the effect of CLA exposure on the growth, photosynthetic activity, and organic metabolic processes of Microcystis aeruginosa. The findings revealed that the physiological status of algae could be significantly influenced by CLA exposure in aquatic environments. Specifically, exposure to 1 μg/L CLA stimulated the growth and photosynthetic activity of algal cells. Conversely, CLA above 10 μg/L led to the inhibition of algal cell growth and photosynthesis. Notably, the inhibitory effects intensified with the increasing concentration of CLA. The molecular weight of DOM produced by Microcystis aeruginosa increased when exposed to CLA. Under the exposure of 60 μg/L CLA, a large number of algal cells ruptured and died, and the intracellular organic matter was released into the algal liquid. This resulted in an increase in high molecular weight substances and soluble microbial-like products in the DOM. Exposure to 1 and 10 μg/L CLA stimulated Microcystis aeruginosa to produce more humic acid-like substances, which may be a defense mechanism against CLA. The results were useful for assessing the effects of antibiotic pollution on the stability of the microalgae population and endogenous DOM characteristics in aquatic ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background: The increasing prevalence of antibiotic-resistant Helicobacter pylori strains poses a significant threat to children's health. This study investigated antibiotic resistance rates in Helicobacter pylori strains isolated from children in Shanghai and analyzed the presence of virulence genes in these strains., Methods: We obtained 201 Helicobacter pylori strains from pediatric patients with upper gastrointestinal symptoms who underwent gastrointestinal endoscopy between 2019 and 2022. Subsequently, we performed antibiotic susceptibility tests and virulence gene PCR assays on these strains., Results: Helicobacter pylori resistance rates of 45.8%, 15.4%, 1.0%, and 2.5% were detected for metronidazole, clarithromycin, amoxicillin, and levofloxacin, respectively. Among all isolates, 64.7% exhibited resistance to at least one antibiotic. Resistance to metronidazole and clarithromycin increased from 2019 to 2022. The predominant vacA gene subtype was vacA s1a/m2. The prevalence of vacA m2 and dupA exhibited an upward trend, while oipA presented a decreasing trend from 2019 to 2022. The prevalence of dupA was significantly higher in gastritis than peptic ulcer disease, and in non-treatment compared to treatment groups., Conclusions: Helicobacter pylori antibiotic resistance remains high in children and has risen in recent years. Therefore, the increasing use of metronidazole and clarithromycin requires increased monitoring in children. No association was observed between antibiotic resistance and virulence gene phenotypes., Competing Interests: Declaration of Competing Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Heterogeneity of Helicobacter pylori communities contributes to its pathogenicity and diverse clinical outcomes. We conducted drug-susceptibility tests using four antibiotics, clarithromycin (CLR), amoxicillin (AMX), metronidazole and sitafloxacin, to examine H. pylori population diversity. We also analyzed genes associated with resistance to CLR and AMX. We examined multiple isolates from 42 Japanese patients, including 28 patients in whom primary eradication with CLR and AMX had failed, and 14 treatment-naïve patients. We identified some patients with coexistence of drug resistant- and sensitive-isolates (drug-heteroR/S-patients). More than 60% of patients were drug-heteroR/S to all four drugs, indicating extensive heterogeneity. For the four drugs except AMX, the rates of drug-heteroR/S-patients were higher in treatment-naïve patients than in primary eradication-failure patients. In primary eradication-failure patients, isolates multi-resistant to all four drugs existed among other isolates. In primary eradication-failure drug-heteroR/S-patients, CLR- and AMX-resistant isolates were preferentially distributed to the corpus and antrum with different minimum inhibitory concentrations, respectively. We found two mutations in PBP1A, G591K and A480V, and analyzed these in recombinants to directly demonstrate their association with AMX resistance. Assessment of multiple isolates from different stomach regions will improve accurate assessment of H. pylori colonization status in the stomach., (© 2024. The Author(s).)

Background: Recently, a simple tailored therapy based on clarithromycin resistance has been implemented as Helicobacter pylori (H. pylori) eradication therapy. Nonetheless, despite the tailored therapy and frequent adverse events, studies on treatment period are lacking. This study aimed to compare the H. pylori eradication rates of 7-day and 14-day tailored therapy regimens according to clarithromycin resistance., Materials and Methods: This multicenter, prospective, randomized, noninferiority trial enrolled H. pylori-positive patients who were randomly assigned to 7-day and 14-day regimen groups, depending on the presence or absence of clarithromycin resistance by 23S rRNA gene point mutations. Standard triple therapy (STT) (20 mg rabeprazole, 1 g amoxicillin, and 500 mg clarithromycin twice daily) or bismuth quadruple therapy (BQT) (20 mg rabeprazole twice daily, 500 mg metronidazole thrice daily, 120 mg bismuth four times daily, and 500 mg tetracycline four times daily) was assigned by clarithromycin resistance. Eradication rates and adverse events were evaluated., Results: A total of 314 and 278 patients were included in the intention-to-treat (ITT) and per-protocol (PP) analyses, respectively; however, 31 patients were lost to follow-up, whereas five patients violated the protocol. Both the 7-day and 14-day regimens showed similar eradication rates in the ITT (7-day vs. 14-day: 78.3% vs. 78.3%, p > 0.99) and PP (87.9% vs. 89.1%, p = 0.851) analyses. Non-inferiority was confirmed (p < 0.025). A subgroup analysis according to clarithromycin resistance (clarithromycin resistance rate: 28.7%) revealed no significant difference in eradication rates between the 7-day and 14-day STT (90.0% vs. 90.1%, p > 0.99) and BQT (82.5% vs. 86.5%, p = 0.757). Furthermore, adverse events did not significantly differ between the two groups., Conclusions: The 7-day triple and quadruple therapy according to clarithromycin resistance showed similar eradication rates, as compared to the 14-day therapy., (© 2024 The Authors. Helicobacter published by John Wiley & Sons Ltd.)

Nontuberculous Mycobacteria (NTM) are a group of emerging bacterial pathogens that have been identified in cystic fibrosis (CF) patients with microbial lung infections. The treatment of NTM infection in CF patients is challenging due to the natural resistance of NTM species to many antibiotics. Mycobacterium abscessus is one of the most common NTM species found in the airways of CF patients. In this study, we characterized the extracellular vesicles (EVs) released by drug-sensitive M. abscessus untreated or treated with clarithromycin (CLR), one of the frontline anti-NTM drugs. Our data show that exposure to CLR increases mycobacterial protein trafficking into EVs as well as the secretion of EVs in culture. Additionally, EVs released by CLR-treated M. abscessus increase M. abscessus resistance to CLR when compared to EVs from untreated M. abscessus. Proteomic analysis further indicates that EVs released by CLR-treated M. abscessus carry an increased level of 50S ribosomal subunits, the target of CLR. Taken together, our results suggest that EVs play an important role in M. abscessus resistance to CLR treatment., (© 2024 Wiley‐VCH GmbH.)

Objective: Helicobacter pylori (Hp) eradication therapy is crucial for preventing the development of gastritis, peptic ulcers, and gastric cancer. An increase in resistance against antibiotics used in the eradication of Hp is remarkable. This meta-analysis aims to examine the resistance rates of Hp strains isolated in Turkey over the last 20 years against clarithromycin (CLR), metronidazole (MTZ), levofloxacin (LVX), tetracycline (TET), and amoxicillin (AMX) antibiotics., Basic Methods: Literature search was carried out in electronic databases, by searching articles published in Turkish and English with the keywords ' helicobacter pylori ' or 'Hp' and 'antibiotic resistance' and 'Turkey'. That meta-analysis was carried out using random-effect model. First, the 20-year period data between 2002 and 2021 in Turkey were planned to be analyzed. As a second stage, the period between 2002 and 2011 was classified as Group 1, and the period between 2012 and 2021 as Group 2 for analysis, with the objective of revealing the 10-year temporal variation in antibiotic resistance rates., Main Results: In gastric biopsy specimens, 34 data from 29 studies were included in the analysis. Between 2002-2021, CLR resistance rate was 30.9% (95% CI: 25.9-36.2) in 2615 Hp strains. Specifically, in Group 1, the CLR resistance rate was 31% in 1912 strains, and in Group 2, it was 30.7% in 703 strains. The MTZ resistance rate was found to be 31.9% (95% CI: 19.8-45.4) in 789 strains, with rates of 21.5% in Group 1 and 46.6% in Group 2. The overall LVX resistance rate was 25.6%, with rates of 26.9% in Group 1 and 24.8% in Group 2. The 20-year TET resistance rate was 0.8%, with 1.50% in Group 1 and 0.2% in Group 2. The overall AMX resistance rate was 2.9%, 3.8% between 2002-2011, and 1.4% between 2012-2021., Principal Conclusion: Hp strains in Turkey exhibit high resistance rates due to frequent use of CLR, MTZ, and LVX antibiotics. However, a significant decrease has been observed in TET and AMX resistance to Hp in the last 10 years. Considering the CLR resistance rate surpasses 20%, we suggest reconsidering the use of conventional triple drug therapy as a first-line treatment. Instead, we recommend bismuth-containing quadruple therapy or sequential therapies (without bismuth) for first-line treatment, given the lower rates of TET and AMX resistance. Regimens containing a combination of AMX, CLR, and MTZ should be given priority in second-line therapy. Finally, in centers offering culture and antibiogram opportunities, regulating the Hp eradication treatment based on the antibiogram results is obviously more appropriate., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Potassium-competitive acid blockers (P-CABs) provide potent acid inhibition, yet studies on P-CAB-based quadruple therapy for H. pylori eradication are limited. We theorized that integrating bismuth subsalicylate into a quadruple therapy regimen could enhance eradication rates. However, data on the efficacy of vonoprazan bismuth quadruple therapy are notably scarce. Therefore, the aim of this study was to evaluate the efficacy of vonoprazan-based bismuth quadruple therapy in areas with high clarithromycin and levofloxacin resistance. This was a prospective, single-center, randomized trial conducted to compare the efficacy of 7-day and 14-day vonoprazan-based bismuth quadruple therapy for H. pylori eradication between June 1, 2021, and March 31, 2022. Qualified patients were randomly assigned to the 7-day or 14-day regimen (1:1 ratio by computer-generated randomized list as follows: 51 patients for the 7-day regimen and 50 patients for the 14-day regimen). The regimens consisted of vonoprazan (20 mg) twice daily, bismuth subsalicylate (1024 mg) twice daily, metronidazole (400 mg) three times daily, and tetracycline (500 mg) four times daily. CYP3A4/5 genotyping and antibiotic susceptibility tests were also performed. Successful eradication was defined as 13 negative C-UBTs 4 weeks after treatment. The primary endpoint was to compare the efficacy of 7-day and 14-day regimens as first-line treatments, which were assessed by intention-to-treat (ITT) and per-protocol (PP) analyses. The secondary endpoints included adverse effects. A total of 337 dyspeptic patients who underwent gastroscopy were included; 105 patients (31.1%) were diagnosed with H. pylori infection, and 101 patients were randomly assigned to each regimen. No dropouts were detected. The antibiotic resistance rate was 33.3% for clarithromycin, 29.4% for metronidazole, and 27.7% for levofloxacin. The CYP3A4 genotype was associated with 100% rapid metabolism. The H. pylori eradication rates for the 7-day and 14-day regimens were 84.4%, 95% CI 74.3-94.2 and 94%, 95% CI 87.4-100, respectively (RR difference 0.25, 95% CI 0.03-0.53, p value = 0.11). Interestingly, the 14-day regimen led to 100% eradication in the clarithromycin-resistant group. Among the patients in the 7-day regimen group, only two exhibited resistance to clarithromycin; unfortunately, neither of them achieved a cure from H. pylori infection. The incidence of adverse events was similar in both treatment groups, occurring in 29.4% (15/51) and 28% (14/50) of patients in the 7-day and 14-day regimens, respectively. No serious adverse reactions were reported. In conclusion, 14 days of vonoprazan-based bismuth quadruple therapy is highly effective for H. pylori eradication in areas with high levels of dual clarithromycin and levofloxacin resistance., (© 2024. The Author(s).)

Background: Buruli ulcer (BU) is a skin neglected tropical disease (NTD) caused by Mycobacterium ulcerans. WHO-recommended treatment requires 8-weeks of daily rifampicin (RIF) and clarithromycin (CLA) with wound care. Treatment compliance may be challenging due to socioeconomic determinants. Previous minimum Inhibitory Concentration and checkerboard assays showed that amoxicillin/clavulanate (AMX/CLV) combined with RIF+CLA were synergistic against M. ulcerans. However, in vitro time kill assays (TKA) are a better approach to understand the antimicrobial activity of a drug over time. Colony forming units (CFU) enumeration is the in vitro reference method to measure bacterial load, although this is a time-consuming method due to the slow growth of M. ulcerans. The aim of this study was to assess the in vitro activity of RIF, CLA and AMX/CLV combinations against M. ulcerans clinical isolates by TKA, while comparing four methodologies: CFU enumeration, luminescence by relative light unit (RLU) and optical density (at 600 nm) measurements, and 16S rRNA/IS2404 genes quantification., Methodology/principal Findings: TKA of RIF, CLA and AMX/CLV alone and in combination were performed against different M. ulcerans clinical isolates. Bacterial loads were quantified with different methodologies after 1, 3, 7, 10, 14, 21 and 28 days of treatment. RIF+AMX/CLV and the triple RIF+CLA+AMX/CLV combinations were bactericidal and more effective in vitro than the currently used RIF+CLA combination to treat BU. All methodologies except IS2404 quantitative PCR provided similar results with a good correlation with CFU enumeration. Measuring luminescence (RLU) was the most cost-effective methodology to quantify M. ulcerans bacterial loads in in vitro TKA., Conclusions/significance: Our study suggests that alternative and faster TKA methodologies can be used in BU research instead of the cumbersome CFU quantification method. These results provide an in vitro microbiological support to of the BLMs4BU clinical trial (NCT05169554, PACTR202209521256638) to shorten BU treatment., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Sáez-López et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Macrolide antibiotics such as clarithromycin (CLR) and azithromycin are the key drugs used in multidrug therapy for Mycobacterium avium complex (MAC) diseases. For these antibacterial drugs, drug susceptibility has been correlated with clinical response in MAC diseases. We have previously demonstrated the correlation between drug susceptibility and mutations in the 23S rRNA gene, which confers resistance to macrolides. Herein, we developed a rapid detection method using the amplification refractory mutation system (ARMS)-loop-mediated isothermal amplification (LAMP) technique to identify mutations in the 23S rRNA gene of M. avium . We examined the applicability of the ARMS-LAMP method to genomic DNA extracted from six genotypes of M. avium clinical isolates. The M. avium isolates were classified into 21 CLR-resistant and 9 CLR-susceptible strains based on the results of drug susceptibility tests; the 23S rRNA genes of these strains were sequenced and analyzed using the ARMS-LAMP method. Sequence analysis revealed that the 9 CLR-sensitive strains were wild-type strains, whereas the 21 CLR-resistant strains comprised 20 mutant-type strains and one wild-type strain. Using ARMS-LAMP, no amplification from genomic DNAs of the 10 wild-type strains was observed using the mutant-type mismatch primer sets (MTPSs); however, amplification from the 20 mutant-type strain DNAs was observed using the MTPSs. The rapid detection method developed by us integrates ARMS-LAMP with a real-time turbidimeter, which can help determine drug resistance in a few hours. In conclusion, ARMS-LAMP might be a new clinically beneficial technology for rapid detection of mutations.IMPORTANCEMultidrug therapy for pulmonary Mycobacterium avium complex disease is centered on the macrolide antibiotics clarithromycin and azithromycin, and resistance to macrolides is an important prognosticator for clinical aggravation. Therefore, it is important to develop a quick and easy method for detecting resistance to macrolides. Drug resistance is known to be correlated with mutations in macrolide resistance genes. We developed a rapid detection method using amplification refractory mutation system (ARMS)-loop-mediated isothermal amplification (LAMP) to identify a mutation in the 23S rRNA gene, which is a macrolide resistance gene. Furthermore, we examined the applicability of this method using M. avium clinical isolates. The rapid method developed by us for detection of the macrolide resistance gene by integrating ARMS-LAMP and a real-time turbidimeter can help in detection of drug resistance within a few hours. Since this method does not require expensive equipment or special techniques and shows high analytical speed, it would be very useful in clinical practice., Competing Interests: The authors declare no conflict of interest.

Aim: A less invasive evaluation method of cytochrome P450 3A (CYP3A) activity provides an important tool for personalized medicine. We aimed to clarify the usefulness of the plasma 6β-hydroxycortisol to cortisol concentration (6β-OHF/F) ratio as a minimally invasive CYP3A phenotyping method., Methods: Plasma 6β-OHF and cortisol concentrations were measured via liquid chromatography/tandem mass spectrometry. The plasma 6β-OHF/F ratio was compared with 6β-hydroxylation clearance of endogenous cortisol (CL m(6β) ; which we previously developed as an index of CYP3A activity) before, during and after oral contraceptive administration in 3 healthy women. The plasma 6β-OHF/F ratio was observed during oral clarithromycin administration. The plasma 6β-OHF/F ratio was also measured in 39 healthy participants., Results: The plasma 6β-OHF/F ratio in 3 healthy women on Day 21 of starting oral contraceptive administration decreased by 39, 49 and 61% compared with Day 0. These values were similar to CL m(6β) values (43, 54 and 59%, respectively). Plasma 6β-OHF/F ratio and CL m(6β) exhibited a good correlation (r = .9053). The 6β-OHF/F ratio decreased from 0.00921 to 0.00577 only 3 h following clarithromycin administration. The plasma 6β-OHF/F ratio ranged 0.00565-0.01556 in 39 healthy participants., Conclusion: Based on its close relationship with CL m(6β) and its decrease upon inhibition by clarithromycin, the plasma 6β-OHF/F ratio serves as an index of CYP3A activity. Using this minimally invasive index, we can identify patients with extremely low CYP3A activity before treatment initiation and optimize the initial drug dose, thereby mitigating the risk of severe adverse reactions., (© 2023 British Pharmacological Society.)

Introduction: Antibiotic resistance is one of the main factors that determine the efficacy of treatments to eradicate Helicobacter pylori infection. Our aim was to evaluate the effectiveness of first-line and rescue treatments against H. pylori in Europe according to antibiotics resistance., Methods: Prospective, multicenter, international registry on the management of H. pylori (European Registry on H. pylori Management). All infected and culture-diagnosed adult patients registered in the Spanish Association of Gastroenterology-Research Electronic Data Capture from 2013 to 2021 were included., Results: A total of 2,852 naive patients with culture results were analyzed. Resistance to clarithromycin, metronidazole, and quinolones was 22%, 27%, and 18%, respectively. The most effective treatment, regardless of resistance, were the 3-in-1 single capsule with bismuth, metronidazole, and tetracycline (91%) and the quadruple with bismuth, offering optimal cure rates even in the presence of bacterial resistance to clarithromycin or metronidazole. The concomitant regimen with tinidazole achieved an eradication rate of 99% (90/91) vs 84% (90/107) with metronidazole. Triple schedules, sequential, or concomitant regimen with metronidazole did not achieve optimal results. A total of 1,118 non-naive patients were analyzed. Resistance to clarithromycin, metronidazole, and quinolones was 49%, 41%, and 24%, respectively. The 3-in-1 single capsule (87%) and the triple therapy with levofloxacin (85%) were the only ones that provided encouraging results., Discussion: In regions where the antibiotic resistance rate of H. pylori is high, eradication treatment with the 3-in-1 single capsule, the quadruple with bismuth, and concomitant with tinidazole are the best options in naive patients. In non-naive patients, the 3-in-1 single capsule and the triple therapy with levofloxacin provided encouraging results., (Copyright © 2023 by The American College of Gastroenterology.)

The multidrug resistance of nontuberculous mycobacteria (NTM) poses a significant therapeutic challenge. Rapid and reliable drug susceptibility testing is urgently needed for evidence-based treatment decision, especially for macrolides. This study evaluated the utility of nucleotide matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (NMTMS) in detecting clarithromycin resistance. Sixty-four clinical isolates were identified to species by NMTMS, and mutations associated with clarithromycin resistance were detected. Twenty-three M. abscessus (MAB) isolates and 30 M. intracellulare isolates (including M. intracellulare alone and M. intracellulare in combination with other SGM species) were included for analysis. The predictive sensitivity of NMTMS in detecting clarithromycin resistance was 82.35% (95% CI, 56.57% to 96.20%), with an AUC of 0.89 (95% CI, 0.77 to 0.96) in all MAB and M. intracellulare (n = 53), and up to 93.33% (95% CI, 68.05% to 99.83%) in MAB alone (n = 23). The assay provides a rapid, high-throughput, and highly sensitive tool for detecting clarithromycin resistance in NTM, especially in MAB. Optimization of the panel is necessary to enhance diagnostic accuracy., Competing Interests: Declaration of competing interest All authors declared that no financial and personal relationships with other people or organizations could inappropriately influence (bias) their work., (Copyright © 2024. Published by Elsevier B.V.)

In H. pylori infection, antibiotic-resistance is one of the most common causes of treatment failure. Bacterial metabolic activities, such as energy production, bacterial growth, cell wall construction, and cell-cell communication, all play important roles in antimicrobial resistance mechanisms. Identification of microbial metabolites may result in the discovery of novel antimicrobial therapeutic targets and treatments. The purpose of this work is to assess H. pylori metabolomic reprogramming in order to reveal the underlying mechanisms associated with the development of clarithromycin resistance. Previously, four H. pylori isolates were induced to become resistant to clarithromycin in vitro by incrementally increasing the concentrations of clarithromycin. Bacterial metabolites were extracted using the Bligh and Dyer technique and analyzed using metabolomic fingerprinting based on Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (LC-Q-ToF-MS). The data was processed and analyzed using the MassHunter Qualitative Analysis and Mass Profiler Professional software. In parental sensitivity (S), breakpoint isolates (B), and induced resistance isolates (R) H. pylori isolates, 982 metabolites were found. Furthermore, based on accurate mass, isotope ratios, abundances, and spacing, 292 metabolites matched the metabolites in the Agilent METLIN precise Mass-Personal Metabolite Database and Library (AM-PCDL). Several metabolites associated with bacterial virulence, pathogenicity, survival, and proliferation (L-leucine, Pyridoxone [Vitamine B6], D-Mannitol, Sphingolipids, Indoleacrylic acid, Dulcitol, and D-Proline) were found to be elevated in generated resistant H. pylori isolates when compared to parental sensitive isolates. The elevated metabolites could be part of antibiotics resistance mechanisms. Understanding the fundamental metabolome changes in the course of progressing from clarithromycin-sensitive to breakpoint to resistant in H. pylori clinical isolates may be a promising strategy for discovering novel alternatives therapeutic targets., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Rosli et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Antibiotics are being increasingly detected in aquatic environments, and their potential ecological risk is of great concern. However, most antibiotic toxicity studies involve single-exposure experiments. Herein, we studied the effects and mechanisms of repeated versus single clarithromycin (CLA) exposure on Microcystis aeruginosa . The 96 h effective concentration of CLA was 13.37 μg/L upon single exposure but it reduced to 6.90 μg/L upon repeated exposure. Single-exposure CLA inhibited algal photosynthesis by disrupting energy absorption, dissipation and trapping, reaction center activation, and electron transport, thereby inducing oxidative stress and ultrastructural damage. In addition, CLA upregulated glycolysis, pyruvate metabolism, and the tricarboxylic acid cycle. Repeated exposure caused stronger inhibition of algal growth via altering photosynthetic pigments, reaction center subunits biosynthesis, and electron transport, thereby inducing more substantial oxidative damage. Furthermore, repeated exposure reduced carbohydrate utilization by blocking the pentose phosphate pathway, consequently altering the characteristics of extracellular polymeric substances and eventually impairing the defense mechanisms of M. aeruginosa . Risk quotients calculated from repeated exposure were higher than 1, indicating significant ecological risks. This study elucidated the strong influence of repeated antibiotic exposure on algae, providing new insight into antibiotic risk assessment.

Background: Clarithromycin (CAM) resistance is a major contributor to the failure to eradicate Helicobacter pylori (H. pylori). The mixed-infection ratio of CAM-susceptible and CAM-resistant H. pylori strains differs among individuals. Pyrosequencing analysis can be used to quantify gene mutations at position each 2142 and 2143 of the H. pylori 23S rRNA gene in intragastric fluid samples. Herein, we aimed to clarify the impact of the rate of mixed infection with CAM-susceptible and CAM-resistant H. pylori strains on the success rate of CAM-containing eradication therapy., Materials and Methods: Sixty-four H. pylori-positive participants who received CAM-based eradication therapy, also comprising vonoprazan and amoxicillin, were enrolled in this prospective cohort study. Biopsy and intragastric fluid samples were collected during esophagogastroduodenoscopy. H. pylori culture and CAM-susceptibility tests were performed on the biopsy samples, and real-time PCR and pyrosequencing analyses were performed on the intragastric fluid samples. The mutation rates and eradication success rates were compared., Results: The overall CAM-based eradication success rate was 84% (54/64): 62% (13/21) for CAM-resistant strains, and 95% (39/41) for CAM-sensitive strains. When the mutation rate of the 23S rRNA gene was 20% or lower for both positions (2142 and 2143), the eradication success rate was 90% or more. However, when the mutation rate was 20% or higher, the eradication success rate was lower (60%)., Conclusions: The mutation rate of the CAM-resistance gene was related to the success of eradication therapy, as determined via pyrosequencing analysis., (© 2024 John Wiley & Sons Ltd.)

Objectives: The management of Helicobacter pylori in Vietnam is becoming progressively more difficult due to increasing antibiotic resistance, particularly to clarithromycin (CLR) and levofloxaxin (LVX). In Vietnam, the selection of an H. pylori eradication regimen is predominantly based on empirical evidence. However, molecular analysis aimed at identifying H. pylori antibiotic-resistant genotypes is a promising method in antibiotic susceptibility testing. In this study, we aimed to determine the rates of genotypic H. pylori resistance to CLR and LVX by using DNA strip technology in Vietnam., Methods: We performed DNA-strip technology-based testing on 112 patients with H. pylori-positive gastroduodenal diseases to detect 23S rRNA and gyrA mutations., Results: Helicobacter pylori genotypic resistance to CLR and LVX was evident in 81.3% and 53.6% of the patients, respectively, and dual resistance was observed in 48.2%. The 23S rRNA A2142G and A2143G mutations accounted for 1.8% and 79.5% of cases, respectively. The gyrA N87K, D91N, D91G, and D91Y mutations were present in 37.5%, 11.6%, 5.4%, and 5.4% of patients, respectively. All four gyrA mutations were observed in both the naïve and failure patients. We further found an association between the 23S rRNA A2143G mutation and a history of CLR use as well as between the gyrA N87K mutation and a history of LVX use., Conclusions: We found a very high prevalence of H. pylori resistance to CLR and LVX and dual resistance to these antibiotics in Vietnam. The application of molecular assays is feasible and may improve the management of H. pylori infection in Vietnam., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)