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Abstract: This study aimed to evaluate the effects of chlorhexidine, metronidazole, and ozone application on the healing of palatal wounds in diabetic rats. A defect in the form of a 4 mm-diameter wound was created on the palatal mucosa of 84 adult female Wistar albino rats, which were randomly divided into 4 groups: control, chlorhexidine, metronidazole, and ozone groups. The animals were euthanized after 3, 6, and 10 days, and wound closure was histologically assessed. On day 3, polymorphonuclear leukocytes were significantly higher in the control group than in the chlorhexidine and ozone groups ( P < 0.05). Fibrosis was higher in the ozone group than in the control and chlorhexidine groups ( P < 0.05). Vascular endothelial growth factor was higher in the metronidazole and ozone groups than in the control group ( P < 0.05). On day 6, the quantity of polymorphonuclear leukocytes was higher in the control, metronidazole, and chlorhexidine groups than in the ozone group ( P < 0.05). Vascular endothelial growth factor was higher in the ozone group than in the control, chlorhexidine, and metronidazole groups ( P < 0.05). On day 10, Vascular endothelial growth factor was higher in the control, chlorhexidine, and metronidazole groups than in the ozone group ( P < 0.05). The authors concluded that the use of chlorhexidine, ozone, and metronidazole pastes resulted in enhanced wound healing, as determined histologically.The authors suggest that ozone supplementation can be an alternative therapy to chlorhexidine in impaired wound healing in diabetes mellitus., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)

Background: Helicobacter pylori infection is responsible for considerable morbidity and mortality worldwide, and eradication rates are falling in many countries, primarily due to clarithromycin and metronidazole resistance., Aims: There is a paucity of contemporary Australian data, which we sought to address by evaluating local rates of resistance of H. pylori to amoxicillin, clarithromycin, metronidazole and tetracycline over the past 20 years., Methods: All gastric biopsy specimens collected at endoscopy to detect H. pylori infection at a single centre underwent routine culture and antibiotic susceptibility testing between 1998 and 2017. Specimens from 12 842 patients were cultured for H. pylori, of which 1473 positive cultures were tested for antibiotic susceptibility., Results: Antibiotic resistance to clarithromycin increased by 3.7% per year (incidence rate ratio [IRR] 1.037; P = 0.014) over 20 years, with a corresponding 5.0% annual increase in minimum inhibitory concentration (MIC) (odds ratio 1.050; P < 0.001). Since 2010, average clarithromycin resistance has exceeded 20%, with >25% of isolates resistant in the past 2 years of data capture. In contrast, rates of resistance to metronidazole (35.3%), amoxicillin (0.14%) and tetracycline (0.34%) and their MIC have remained stable. Review of a representative sample (n = 120; 8%) of these patients revealed that only 5% had documented prior H. pylori eradication therapy., Conclusions: Over the past 20 years there has been a substantial rise in clarithromycin resistance, with stable metronidazole resistance and low rates of resistance to amoxicillin and tetracycline. Current first-line H. pylori eradication therapy may fail to achieve adequate eradication rates, and optimal first-line therapy in Australia should be revisited., (© 2021 Royal Australasian College of Physicians.)

Blastocystis hominis is a worldwide common enteric parasite. Its pathogenic potential has not yet been established, although many reports suggest that it may cause the development of various gastrointestinal symptoms. The aim of the present study is to evaluate the destructive effect of different doses of cytotoxic gamma (γ) irradiation combined with and compared to metronidazole (MTZ) on Blastocystis spp. in vitro. The detection of the parasite in the stool specimen was conventionally done by light microscopic examination of direct smears, cultivation, followed by PCR-sequencing. Evaluation of γ-irradiation and MTZ effects on B. hominis was carried out by trypan blue exclusion assay, caspase activity detection, acridine orange staining, DNA fragmentation assay and transmission electron microscopic (TEM) examination. The current study demonstrated that exposure to γ-irradiation in a dose of 0.5 kGray (kGy) significantly (P < 0.05) reduced the viability of B. hominis subtype 2 by 95.2% compared to the untreated and MTZ-treated parasites (87.1%) after 48 h incubation. Combining the same dose of irradiation (0.5 kGy) with MTZ yielded a viability reduction of 94.2% and 94% after 24 and 48 h respectively, which were statistically significant (P < 0.05) compared to MTZ alone. Moreover, our results showed features of programmed cell death in the form of morphological, biochemical, and molecular changes (TEM abnormalities, caspase-like activity, and DNA fragmentation, respectively) with the high doses of γ-irradiation (0.3 and 0.5 kGy) either singly or combined with MTZ. In conclusion, cytotoxic γ-irradiation plays an important role in the inactivation of Blastocystis spp., so, it can be a promising prophylactic water-sterilizing tool against blastocystosis., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Helicobacter pylori resistance to amoxicillin has usually been rare. We traced resistance evolution in 474 strains over 15 years. Although minimum inhibitory concentrations MIC 50 and MIC 90 were similar among subgroups, the overall resistance rate (MICs, >0.125-3 mg/L) significantly increased from 4.2% in 2007-2014 to 8.9% in 2015-2021., Competing Interests: Declaration of competing interest The authors have no relevant competing interests to disclose in relation to this work., (Copyright © 2022 Elsevier Inc. All rights reserved.)

While previous research on zoonotic transmission of community-acquired Clostridioides difficile infection (CA-CDI) focused on food-producing animals, the present study aimed to investigate whether dogs are carriers of resistant and/or virulent C. difficile strains. Rectal swabs were collected from 323 dogs and 38 C. difficile isolates (11.8%) were obtained. Isolates were characterized by antimicrobial susceptibility testing, whole-genome sequencing (WGS) and a DNA hybridization assay. Multilocus sequence typing (MLST), core genome MLST (cgMLST) and screening for virulence and antimicrobial resistance genes were performed based on WGS. Minimum inhibitory concentrations for erythromycin, clindamycin, tetracycline, vancomycin and metronidazole were determined by E-test. Out of 38 C. difficile isolates, 28 (73.7%) carried genes for toxins. The majority of isolates belonged to MLST sequence types (STs) of clade I and one to clade V. Several isolates belonged to STs previously associated with human CA-CDI. However, cgMLST showed low genetic relatedness between the isolates of this study and C. difficile strains isolated from humans in Austria for which genome sequences were publicly available. Four isolates (10.5%) displayed resistance to three of the tested antimicrobial agents. Isolates exhibited resistance to erythromycin, clindamycin, tetracycline and metronidazole. These phenotypic resistances were supported by the presence of the resistance genes erm(B), cfr(C) and tet(M). All isolates were susceptible to vancomycin. Our results indicate that dogs may carry virulent and antimicrobial-resistant C. difficile strains., (© 2022 The Authors. Zoonoses and Public Health published by Wiley-VCH GmbH.)

Infections with the sexually transmitted parasite Trichomonas vaginalis are normally treated with metronidazole, but cure rates are suboptimal and recurrence rates following treatment are high. Therefore, our objective was to assess the in vitro antitrichomonas activities of three other 5-nitroimidazole drugs and compare them with metronidazole. T. vaginalis isolates ( n  = 94) isolated from South African women presenting with vaginal discharge syndrome at two sexually transmitted disease clinics in KwaZulu-Natal were grown from frozen stock. Twofold serial dilutions (16 to 0.25 mg/L) of metronidazole, tinidazole, ornidazole, and secnidazole were prepared in Diamond's broth. The MICs were read after 48 h of anaerobic incubation at 37°C. An MIC of <2 mg/L was defined as susceptible, an MIC of 2 mg/L was defined as intermediate, and an MIC of >2 mg/L was defined as resistant. Sixty-one percent (57/94) of the T. vaginalis isolates were susceptible to metronidazole, 80% (75/94) were susceptible to tinidazole, 75% (71/94) were susceptible to secnidazole, and 89% (84/94) were susceptible to ornidazole. Resistance levels were 11%, 2%, and 1% for metronidazole, tinidazole, and secnidazole, respectively, while no resistance was observed for ornidazole. Intermediate scores were 28% for metronidazole, 18% for tinidazole, 24% for secnidazole, and 11% for ornidazole. Isolates from a proportion of women with bacterial vaginosis (BV) had higher MICs, and no isolates from women coinfected with another sexually transmitted infectious organism were resistant to any of the antimicrobials tested. This study showed that among T. vaginalis isolates in KwaZulu-Natal, there is no in vitro resistance to ornidazole. Of the 5-nitroimidazoles, metronidazole showed the highest level of resistance. The very low levels of resistance for the other three antimicrobials indicate that all three are viable options as a replacement for metronidazole if these in vitro findings are found to correlate with clinical outcomes. IMPORTANCE Trichomonas vaginalis is the most common nonviral sexually transmitted infection associated with reproductive sequelae and HIV acquisition risk worldwide. Despite its role in reproductive health, a high prevalence in South Africa, and the reported metronidazole resistance worldwide, no alternative regimens have been tested against T. vaginalis in our setting. This study compared the susceptibility patterns of three other 5-nitroiminazoles (secnidazole, tinidazole, and ornidazole), which are active against T. vaginalis with metronidazole in vitro . Metronidazole, the drug of choice for the treatment of trichomoniasis, showed the highest level of resistance, while the three regimens showed very low levels of resistance. These data indicate that all three are viable options as a replacement for metronidazole if these in vitro findings are found to correlate with clinical outcomes.

Clostridioides difficile is one of the most important human pathogens. The identification of its possible sources is important for the understanding of C. difficile infection (CDI) epidemiology. A total of 16 water samples from wastewater and surface water in South Moravia in the Czech Republic and 82 samples of fish and gulls were collected between May and July 2019. C. difficile isolates were cultured by direct plating and after enrichment on chromogenic media. Susceptibility testing to eight antimicrobials was performed by Etest. C. difficile isolates were characterized by ribotyping, multilocus sequence typing, multilocus tandem repeats analysis, and toxin gene detection. Samples from fish and gulls were C. difficile negative; a total of 15 C. difficile isolates from 8 out of 16 water samples were cultured (6 out of 14 surface water samples yielded 6 isolates, and 2 out of 2 wastewater samples yielded 9 isolates). Direct plating was culture positive in 6 out of 16 samples (12 isolates), and enrichment culture was positive in an additional 2 out of 16 samples (3 isolates). Twelve different ribotyping profiles and 14 sequence types of clades 1, 4, and 5 were identified. Five isolates did not carry genes for toxins, and eight isolates carried genes for toxins A and B; the remaining two isolates (RT078) carried the genes for toxins A, B, and binary. All C. difficile isolates were susceptible to amoxicillin, moxifloxacin, tetracycline, and vancomycin and resistant to ciprofloxacin. A high level of erythromycin resistance (>256 mg/L) was detected in eight isolates. Clindamycin resistance was found in 14 isolates, 6 of which showed a high level of resistance (>256 mg/L) and carried ermB . Surprisingly, one isolate (RT010, ST15) showed resistance to metronidazole (12 mg/L) with the presence of the plasmid pCD-METRO. In conclusion, a diverse spectrum of C. difficile strains was found in wastewater and surface water. A recently discovered plasmid-bound resistance to metronidazole was detected in C. difficile from the surface water sample. IMPORTANCE The combination of direct plating and culture after enrichment was used in order to gain a spectrum of C. difficile ribotypes present in the water samples. Toxigenic C. difficile ribotypes detected in surface water and in wastewater treatment plants overlapped with those derived from patients with CDI and/or animals. Importantly, a recently discovered plasmid-mediated resistance to metronidazole, a drug used for the treatment of CDI, was detected in C. difficile from river water.

The aim of this study is to fabricate a new scaffold appropriate for tissue regeneration with antimicrobial activity and ability of controlled drug delivery. In this regard, scaffold nanofibers were produced using poly (methyl methacrylate) (PMMA), Mo 132 as a Keplerate polyoxometalate and metronidazole. The final scaffolds, obtained by electrospinning, represent the intrinsic features including exceptional doubling tensile strength, high hydrophilicity (126 ± 5.2° to 83.9 ± 3.2° for contact angle and 14.18 ± 0.62% to 35.62 ± 0.24% for water uptake), proper bioactivity and cell adhesion. Moreover, the addition of Mo 132 and metronidazole enhances the biodegradation rate of resulted scaffolds compared to the pure PMMA membrane. The controlled release of metronidazole over 14 days efficiently inhibits the colonization of anaerobic microorganisms. Overall, the results demonstrate high potential of Mo 132 and metronidazole-loaded PMMA scaffold for guided bone regeneration/guided tissue regeneration., (© 2022. The Author(s).)

Clostridioides difficile infection (CDI) is the fifth leading cause of death from nonmalignant gastrointestinal disease in the United States. The contribution of resistance to C. difficile-active antibiotics to the outcomes of CDI is unclear. We evaluated the antimicrobial susceptibility of C. difficile isolates in a U.S. hospital and determined associations of clinical variables and binary toxin positivity with antibiotic resistance. C. difficile spores were cultured from fecal specimens of adult patients with CDI for genotyping and antimicrobial susceptibility assay (for clindamycin [CLI], fidaxomicin [FDX], metronidazole [MTZ], moxifloxacin [MXF], tigecycline [TGC], and vancomycin [VAN]). Electronic medical records were reviewed for clinical data extraction. Ninety-seven of 130 (75%) fecal samples grew toxigenic C. difficile in culture. Most of the isolates were tcdA + tcdB + cdtB - (80.4%), and 18.6% and 1% were tcdA + tcdB + cdtB + and tcdA - tcdB + cdtB + , respectively. Susceptibility to VAN, MTZ, FDX, TGC, MXF, and CLI was 96%, 94%, 100%, 100%, 8%, and 79%, respectively. Six isolates, all cdtB positive and belonging to the 027 ribotype, were resistant to VAN and/or MTZ. Higher MICs were found in isolates with a mutation in the VAN-related resistance gene vanR , but not vanS . In addition, cdtB + isolates exhibited higher MICs of VAN, MTZ, TGC, CLI, and MXF compared to cdtB - strains. Patients with greater intestinal inflammation or severe disease were more likely to be infected with cdtB + strains. Decreased susceptibility to antibiotics is not directly associated with either severe or recurrent CDI. However, antimicrobial susceptibility of C. difficile is decreased in strains positive for the binary toxin gene.

Synthesis and characterization of novel copper complexes of metronidazole benzoate (MTZ Benz), metronidazole (MTZ) in the presence of another ligand; dichloroacetic acid (DCA) were compared and reported in the present work. Different bacterial and fungus strains were ascertained to evaluate the biological potency of the synthesized complexes, that is, Escherichia coli, Bordetella bronceptica, Staphylococcus epidermidis, Baccilus pumilus, Staphylococcus aureus and yeast strain Saccharomyces cerevisiae. Agar diffusion method was employed to investigate in vitro antibacterial activities of the synthesized metal complexes and the tested parent ligands. α-Amylase and α-glucosidase inhibition studies of the synthesized complexes were also carried out. The antibacterial potential and α-amylase and α-glucosidase inhibition studies of complexes were further investigated by molecular docking studies, which supported the experimental results. Significant α-amylase and α-glucosidase inhibition activities were shown by the synthesized complexes. S-1 and S-5 were found to be most inhibitors of α-amylase and α-glucosidase having IC 50 42.50, 44.80 and 4.52 µg/mL, 4.80 µg/mL, respectively. The newly synthesized copper complexes showed overall better biological activities compared to each parent ligands used.Communicated by Ramaswamy H. Sarma.

Trichomonas vaginalis (T. vaginalis) is the most prevalent sexually transmitted infection (STI) globally. Metronidazole is the drug of choice for treating T. vaginalis infections although metronidazole-resistant T. vaginalis has been reported in clinical isolates. The purpose of this study was to determine the presence of mutations in nitroreductase genes associated with metronidazole resistance in vaginal swabs testing positive for T. vaginalis. This study included 385 human immunodeficiency virus (HIV)-positive pregnant women. Vaginal swabs were collected from consenting pregnant women and used for the detection of T. vaginalis using the TaqMan assay. From the vaginal swabs, nitroreductase genes ntr4 and ntr6 containing mutations associated with metronidazole resistance were amplified using a quantitative polymerase chain reaction (PCR) assay. To validate the PCR assay, T. vaginalis cultured isolates with known metronidazole resistance profiles were used as controls in the mutation detection assays. The prevalence of T. vaginalis in the study population was 12.2% (47/385). Mutations associated with resistance to metronidazole were detected in more than 40% of the samples tested, i.e. 21/47 (45%) and 24/47 (51%) for ntr4 and ntr6, respectively. A total of 19 samples (40%) carried mutations for both ntr4 and ntr6 genes associated with metronidazole resistance. The validation assays showed a positive correlation between phenotypic and genotypic resistance profiles. This study found a high prevalence of mutations associated with metronidazole resistance. This is concerning since metronidazole is currently used in the syndromic management of STIs in South Africa. Molecular-based assays for monitoring metronidazole resistance profiles using nitroreductase genes may serve as a feasible method for antimicrobial surveillance studies for T. vaginalis., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Trichomoniasis is a sexually transmitted infection in humans caused by the protozoan Trichomonas vaginalis, the leading causative agent of vaginitis in women and urethritis in men worldwide. Metronidazole is the standard treatment for trichomoniasis, with tinidazole as the second line. There are currently no FDA-approved non-nitroimidazole alternative treatments for resistant strains. This study compares the efficacy of a newly synthesized non-nitroimidazole oral drug, amixicile, to that of both metronidazole and the synthetic precursor of amixicile, nitazoxanide with in vitro sensitivity testing. One standard strain from ATCC and three patient-isolated strains of T. vaginalis were used to compare treatments under anaerobic conditions. The minimum inhibitory concentration for metronidazole, nitazoxanide, and amixicile were 12.5 μM, 100 μM, and 6.25 μM, respectively. These results suggest that amixicile may be highly active against T. vaginalis and warrants further investigation as a potential alternative to metronidazole in the treatment of trichomoniasis., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Antimicrobial resistance among Helicobacter pylori strains has been rising globally, leading to declining eradication rates. We performed a systematic review and meta-analysis of the resistance patterns of H. pylori strains in the United States between 2011 and 2021., Methods: Ovid MEDLINE, Embase, CINAHL, and Cochrane CENTRAL databases were searched for manuscripts and conference abstracts published between 2011 and 2021 reporting H. pylori antibiotic resistance. A mixed-effects model estimated pooled rates of resistance to clarithromycin, amoxicillin, metronidazole, tetracycline, rifabutin, levofloxacin, or a combination of these, with 95% confidence intervals (CIs)., Results: A total of 19 studies including 2,660 samples, met inclusion criteria. The pooled rate of resistance to metronidazole was 42.1% (95% CI 27.3%-58.6%), levofloxacin 37.6% (95% CI 26.3%-50.4%), clarithromycin 31.5% (95% CI 23.6%-40.6%), amoxicillin 2.6% (95% CI 1.4%-5.0%), tetracycline 0.87% (95% CI 0.2%-3.8%), rifabutin 0.17% (95% CI 0.00%-10.9%), and dual clarithromycin and metronidazole 11.7% (95% CI 0.1%-94.0%). Considerable data heterogeneity was evident for pooled resistance prevalence rates (I 2 &gt; 50%), with the exception of rifabutin resistance., Discussion: Metronidazole, levofloxacin, and clarithromycin resistance rates each exceed 30%; thus, choosing an empiric antibiotic regimen without knowledge of the likely pattern of antibiotic resistance is not appropriate. Resistance to tetracycline, rifabutin, and amoxicillin remains low. Given the scarcity of available data with considerable heterogeneity among studies, continued surveillance, ideally with a more systematic approach to data collection, is an increasingly important goal in H. pylori management., (Copyright © 2022 by The American College of Gastroenterology.)

Objective: Knowledge of local antibiotic resistance is crucial to the adaption of the effective empirical first-line treatment for Helicobacter Pylori (H. pylori) infection. This study aimed to evaluate the prevalence of H. pylori resistance to clarithromycin and compare it with that of metronidazole, and highlight the impact of epidemiological factors and gastric lesions severity on H. pylori resistance., Methods: The susceptibility to clarithromycin of 96 isolates was determined by PCR-RFLP and the susceptibility to metronidazole of 185 isolates was determined by classic PCR., Result: Our results showed that the prevalence of H. pylori resistance to clarithromycin (‎14.6%) was low compared to that recorded with metronidazole (‎62.7%). Moreover, we remarked that 7.3% of isolates were co-resistant to both antibiotics. The assessment of epidemiological factors' impact on the resistance to studied antibiotics has revealed no association. Besides, our results had demonstrated that the metronidazole and clarithromycin resistance was not related to the severity of gastric lesions., Conclusion: In our population, clarithromycin seems to be an effective antibiotic as long as the resistance rate of H. pylori is low. In contrast to metronidazole, it appears that this antibiotic will lose its efficacy, due to the high rate of resistance among our population. Therefore, each population must conduct their epidemiologic studies separately to survey the resistance profile of strains and choose the appropriate antibiotic, in order to avoid the failure of H. pylori eradication and the development of severe gastric diseases.

Background: Bacterial vaginosis (BV), the most common cause of vaginal discharge, is characterized by the presence of a polymicrobial biofilm on the vaginal epithelium, formed primarily by Gardnerella spp., but also other anaerobic species. Interactions between bacteria in multi-species biofilms are likely to contribute to increased virulence and to enhanced antimicrobial tolerance observed in vivo. However, functional studies addressing this question are lacking., Objectives: To gain insights into the role that interactions between BV-associated species in multi-species BV biofilms might have on antimicrobial tolerance, single- and triple-species biofilms formed by Gardnerella vaginalis, Fannyhessea (Atopobium) vaginae and Peptostreptococcus anaerobius were characterized, before and after metronidazole or clindamycin treatment., Methods: Total biofilm biomass, total cells and cfu counts prior to and after antibiotic treatment were first determined. In addition, bacterial populations in the triple-species biofilms were also quantified by quantitative PCR (qPCR) and peptide nucleic acid (PNA) fluorescence in situ hybridization (FISH)., Results: Despite the effect observed in single-species biofilms, neither metronidazole nor clindamycin was effective in reducing triple-species biofilm biomass. Similar results were obtained when evaluating the number of total or culturable cells. Interestingly, despite differences between strain susceptibilities to antibiotics, the composition of the triple-species biofilms was not strongly affected by antibiotics., Conclusions: Taken together, these results strengthen the idea that, when co-incubated, bacteria can interact synergistically, leading to increased tolerance to antimicrobial therapy, which helps explain the observed clinically high BV recurrence rates., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Metronidazole (Met) is the first choice for treating Helicobacter pylori ( Hp ). However, Hp is easy to resistant, making Met unable to be widely used. How to overcome Hp 's Met resistance is still an issue. In this study, Met was used as the primary raw material with linolenic acid to prepare a novel compound-linolenic acid-metronidazole (Lla-Met). The MIC, minimum bactericidal concentration (MBC), colonization amount of Hp in gastric mucosa, etc., were evaluated, respectively. Lla-Met was successfully prepared by the detection of nuclear magnetic resonance, etc., and its MIC and MBC to Hp were 2~4 μg/mL, 8~16 μg/mL. Moreover, in vivo experiments, Lla-Met significantly reduced the colonization of drug-resistant Hp in gastric mucosa. In the toxicity test, Lla-Met inhibited rate to GES-1 and BGC823 cells were 15% at 128 μg/mL; the mice were administered 10 times treatment Lla-Met treatment (240 mg/kg), have no difference significant injuries were found in their stomach, liver, spleen, kidney, and weight. In addition, Hp G27 continued for 18 days in vitro with sub-Lla-Met concentration, G27 did not show drug resistance to Lla-Met; Lla-Met did not exert an effect on non- Hp species with 128 μg/mL; Compared with a neutral environment, when the acid concentration is 3.0, Lla-Met is not decomposed and has better stability. Conclusion: Lla-Met, a newly prepared compound, has relatively well antibacterial of Met-resistant and sensitive Hp , with a capability of overcoming the metronidazole resistance of Hp.

Tooth removal, particularly for patients with severe periodontitis, can frequently cause massive bleeding, postoperative infection, and bone resorption, resulting in a dry socket. Thus, developing bio-multifunctional materials with excellent antibacterial, hemostatic, and osteogenic characteristics for the prevention of dry sockets after tooth removal is highly desirable in clinical applications. Herein, chitosan-CaP microflowers (CM) and metronidazole (MD) loaded calcium alginate (CA) sponges (CA@CM/MD) with enhanced antibacterial, hemostatic, and osteogenic properties were developed via Ca 2+ crosslinking, lyophilization, and electrostatic interaction for the prevention of dry socket after tooth removal. The fabricated CM particles display 3-dimensional, relatively homogeneous, and flower-shaped architectures. The CA@CM/MD composite sponges were facilely shaped into the tooth root as well as exhibit interconnected porous and lamellar structures with remarkable porosity, suitable maximum swelling ratio, as well as excellent compressive and hemostatic performance. Besides, the in vitro cellular assessment demonstrates that the prepared CA@CM/MD composite sponges possess satisfactory cytocompatibility. Importantly, the designed sponges significantly suppress the growth of S. aureus and E. coli, as well as promote cellular osteogenic differentiation by upregulating the formation of alkaline phosphatase. Our findings indicate that the tooth root-shaped composite sponges hold great promise for wound management after tooth removal., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The resistance of Helicobacter pylori (H. pylori) to antibiotics has been increasing worldwide and varies across different geographic areas and times. Limited studies reported the prevalence of antibiotic resistance and its related gene mutations in children in Chongqing, a city located in southwest China. We collected 112 H. pylori strains isolated from gastric biopsies of 156 children at Children's Hospital of Chongqing Medical University and calculated resistance rates of these strains to six antibiotics. The A2143G and A2142G mutations in 23S rRNA gene, which are related to clarithromycin resistance, and Asn87 and Asp91 mutations in gyrA gene, which are related to levofloxacin resistance, were investigated in 102 strains. The resistance rates to clarithromycin, metronidazole, and levofloxacin were 47.3% (53/112), 88.4% (99/112), and 18.8% (21/112), respectively. No resistance to amoxicillin, tetracycline, and furazolidone was observed. Dual and triple resistance percentages were 37.5% (42/112) and 10.7% (12/112), respectively. The detection rate of A2143G mutation in 23S rRNA gene was 83.3% (40/48). The detection rates of mutations of Asn87 and Asp91 in gyrA gene were 52.6% (10/19) and 36.8% (7/19), respectively. Conclusion: The prevalence of H. pylori resistance to clarithromycin, metronidazole, and levofloxacin was high in children in Chongqing, China. The A2143G mutation was detected in most clarithromycin-resistant strains, and Asn87 and Asp91 of gyrA mutation points were common in levofloxacin-resistant strains. In clinical practice, anti-H. pylori therapy should be individualized based on a susceptibility test.  What is Known: • The resistance of H. pylori to antibiotics changes with the geographic areas and that in Asia the resistance rate is high. • Mutation plays a vital role in antibiotics resistance of H. pylori. What is New: • High resistance rates to single and multiple antibiotics in children of Chongqing, a city located in southwest China, were observed. • Molecular assays showed good conformance with susceptibility test results to direct antibiotic resistance of H. pylori., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Giardia lamblia (G. lamblia) is an important cause of severe malabsorption, weight loss, physical and mental retardation especially in infants and children throughout the world. Metronidazole (MTZ) is the standard drug used for their treatment which possesses several drawbacks with low efficacy. Gold nanoparticles possess a broad-spectrum antimicrobial activity and could be considered as a future alternative to many microbial agents. This study aimed to evaluate the anti-Giardia effect of gold nanoparticles as an alternative to MTZ. This study was done on 70 experimentally albino rats that were divided into three main groups with seven subgroups (each of 10 rats). The effect of MTZ and gold nanoparticles as single or combined therapy were evaluated. The effect was assessed by counting Giardia fecal cysts in the stool and trophozoites in the intestinal wash, histopathological, transmission and scanning electron microscopic examinations of the small intestinal tissues. Toxic tests of biochemical parameters of liver and kidney function were also performed. A significant reduction of the parasite number in the stool and small intestinal sections was apparent in treated infected rats compared with the infected non-treated ones. Gold nanoparticles showed the best result and the highest effect in the eradication of the parasite from the stool and the intestine with marked improvement in the intestinal mucosal injury caused by G. lamblia trophozoites. Gold nanoparticles had a toxic effect on the liver, with no kidney toxicity. Nanogold can be considered as a potential therapeutic agent and as a promising alternative therapy for G. lamblia infection. Further studies using various dosages with different durations of treatment with gold nanoparticles can be tested on Giardia lamblia infection., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Gold nanoparticles (AuNPs) have shown interesting properties and specific biofunctions, providing benefits and new opportunities for controlled release systems. In this research, we demonstrated the use of natural rubber latex (NRL) from Hevea brasiliensis as a carrier of AuNPs and the antibiotic metronidazole (MET). We prepared AuNP-MET-NRL and characterized by physicochemical, biological and in vitro release assays. The effect of AuNPs on MET release was evaluated using UV-Vis and Laser-Induced Breakdown Spectroscopy (LIBS) techniques. AuNPs synthesized by Turkevich and Frens method resulted in a spherical shape with diameters of 34.8 ± 5.5 nm. We verified that there was no emergence or disappearance of new vibrational bands. Qualitatively and quantitatively, we showed that the MET crystals dispersed throughout the NRL. The Young's modulus and elongation values at dressing rupture were in the range appropriate for human skin application. 64.70% of the AuNP-MET complex was released within 100 h, exhibiting a second-order exponential release profile. The LIBS technique allowed monitoring of the AuNP release, indicating the Au emission peak reduction at 267.57 nm over time. Moreover, the dressing displayed an excellent hemocompatibility and fibroblast cell viability. These results demonstrated that the AuNP-MET-NRL wound dressing is a promising approach for dermal applications., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Introduction: surveillance data on Helicobacter pylori (H. pylori) antibiotic susceptibilities in Morocco are limited, despite resistance being the key factor in treatment failure. Virulence factors of H. pylori are associated with carcinogenesis and may be also associated with the efficacy of treatment. The aim of our study is to determine the prevalence of H. pylori metronidazole resistance in a Moroccan population infected with H. pylori and to study the impact of their virulence factors CagA and VacA on their resistance to metronidazole., Methods: the susceptibility to metronidazole of 185 isolates was determined by PCR. The isolates were also genotyped for CagA and VacA genes by PCR., Results: the metronidazole resistance rate was 62.70%. No association between resistance to metronidazole and social factors was detected. Regarding the virulence factors, we remarked that the moderate virulent strains s1/m2/i1/d1 with a CagA negative were the most resistant to metronidazole with a rate of 84% compared to the less virulent strains bearing the CagA negative VacA s2m2i2d2 genotype with a rate of 58% and the high virulent strains s1/m1/i1/d1-CagA positive with a rate of 47.06%., Conclusion: our study revealed a very high prevalence of resistance to metronidazole in our population. The resistance ability of H. pylori maybe affected by its virulence intensity. H. pylori eradication regimens should therefore be reevaluated in this setting., Competing Interests: The authors declare no competing interests., (Copyright: Essaidi Imane et al.)

Metronidazole (MTZ) is a drug potentially used for the treatment of intestinal infections, namely, the ones caused by colorectal surgery. The traditional routes of administration decrease its local effectiveness and present off-site effects. To circumvent such limitations, herein a drug delivery system (DDS) based on MTZ-loaded nanoparticles (NPs) immobilized at the surface of electrospun fibrous meshes is proposed. MTZ at different concentrations (1, 2, 5, and 10 mg mL -1 ) was loaded into chitosan-sodium tripolyphosphate NPs. The MTZ loaded into NPs at the highest concentration showed a quick release in the first 12 h, followed by a gradual release. This DDS was not toxic to human colonic cells. When tested against different bacterial strains, a significant reduction of Escherichia coli and Staphylococcus aureus was observed, but no effect was found against Enterococcus faecalis . Therefore, this DDS offers high potential to locally prevent the occurrence of infections after colorectal anastomosis.

Previous studies have indicated that fucoidan could resist high-fat-diet (HFD)-induced obesity by modulating the composition of gut microbiota. However, the outcome of dietary intervention may differ between individuals due to large inter-individual variability in gut microbiota. Thus, the present study aimed to investigate the possible discrepancy of the anti-obesity effects of fucoidan supplementation in HFD-fed mice models with different gut microbiota communities. In the present study, the anti-obesity effects of fucoidan isolated from Laminaria japonica (Fuc Lj ) on normal mice and microbiota-altered mice treated with penicillin or metronidazole were compared and investigated. The 16S rRNA sequencing revealed the differences of gut microbiota among penicillin-treated, metronidazole-treated and normal groups, and mice treated with penicillin were characterized by greater relative abundance of the phylum Bacteroidetes and the families Muribaculaceae and Bacteroidaceae. Furthermore, Fuc Lj ameliorated HFD-induced body weight gain, fat accumulation, serum lipid profiles, insulin resistance, hepatic steatosis and adipocyte hypertrophy in penicillin-treated and untreated mice, while no effects were observed in metronidazole-treated mice. Overall, mice with different initial gut microbiota responded differently to Fuc Lj supplementation on a high-fat diet, and metronidazole-sensitive gut bacteria negatively correlated with obesity symptoms and were required for the anti-obesity effects of Fuc Lj . Moreover, the anti-obesity effects were not dependent on the utilization of Fuc Lj by gut microbiota to produce SCFAs. These findings indicate that evaluation of the gut microbiota structure before dietary interventions is helpful for enhancing the beneficial outcomes of dietary fiber supplementation and provide a rationale for the further application of dietary fucoidan in a personalized way.

Zebrafish lines expressing nitroreductase (NTR) in specific cell compartments, which sensitizes those cells to metronidazole (MTZ)-mediated ablation, have proven extremely useful for studying tissue regeneration and investigating cell function. In contrast to many cells, neutrophils are comparatively resistant to the NTR/MTZ targeted ablation strategy. Recently, a rationally engineered variant of NTR (NTR 2.0) has been described that exhibits greatly improved MTZ-mediated ablation efficacy in zebrafish. We show that a transgenic line with neutrophil-restricted expression of NTR 2.0 demonstrates complete neutrophil ablation, with an MTZ dose 100-fold less than current treatment regimens, and with treatment durations as short as 5 h.

In Egypt, antibiotic sensitivity analysis for Helicobacter pylori is not routinely performed. We aimed to identify the clarithromycin and metronidazole resistance directly from gastric biopsies for better guide treatment regimens. This cross-sectional descriptive study included 75 adult dyspeptic patients referred to the upper endoscopy unit in Suez Canal University Hospital, Ismailia, Egypt. Gastric biopsies were taken for rapid urease test (RUT) and cultured on brucella agar with antibiotic supplements. Genomic DNA was extracted directly from the specimen, and PCR was performed for direct detection of H. pylori. Also, to explore clarithromycin and metronidazole resistance, mutations in the 23S rRNA gene and the rdxA gene were investigated. We found that 60 samples were positive to RUT (80%), and only 4 samples were positive by culture. UreC gene was detected in 45 specimens. Meanwhile, 26 isolates were contained mutations at positions 2142 and 2143. Amplification of the metronidazole rdx gene was performed by conventional PCR. Out of 45 isolates, DNA sequence analysis of PCR product showed the wild type (ACA) in 9 isolates, while the mutant type (ATA) was detected in 28 isolates. We found a significant proportion of clarithromycin and metronidazole resistance among H. pylori infected patients in our region., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Trichomonas vaginalis is a protozoan that causes human trichomoniasis, the most common non-viral sexually transmitted infection (STI) affecting approximately 278 million people worldwide. The current treatment for trichomoniasis is based on 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole, known as metronidazole (MTZ). Although effective in clearing the parasite infection, MTZ is related to provoking severe side effects, and it is not recommended during pregnancy. In addition, some strains present resistance to 5'-nitroimidazoles, making urgent the development of alternative drugs for trichomoniasis. Amiodarone, an antiarrhythmic drug, exerts a significant anti-parasite effect, mainly due to its interference with calcium homeostasis and the biosynthesis of sterols. Therefore, we decided to test the effect of amiodarone and two other related compounds (amioder and dronedarone) on T. vaginalis. Our observations show that amiodarone stimulated, rather than inhibited, parasite growth, induced cell aggregation, and glycogen accumulation. Furthermore, the other two compounds displayed anti-parasite activity with IC50 of 3.15 and 11 µM, respectively, and the apoptosis-like process killed the cells. In addition, cells exhibited morphological changes, including an effect on hydrogenosomes structure., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Antimicrobial resistance of H. pylori can lead to treatment failure. Importantly, several studies have reported on heteroresistance, i.e. the presence of resistant and susceptible H. pylori populations in the same sample and/or a difference in the susceptibility patterns between biopsy samples. This meta-analysis aims to provide comprehensive data on the prevalence of metronidazole and clarithromycin heteroresistance and the approaches to their detection., Material and Methods: A systematic review was performed after the search of MEDLINE, Scopus and Web of Science. The study outcomes were the weighted pooled prevalence of heteroresistance to clarithromycin and metronidazole in H. pylori positive samples and/or isolates with a subanalysis by continent., Results: A total of 22 studies that had investigated 3852 H. pylori positive patients were included in the meta-analysis. Heteroresistance to clarithromycin was reported in 20 studies, with a weighted pooled prevalence of 6.8% (95% CI 5.1-8.6; 3654 H. pylori positive patients; the substantial heterogeneity I 2  = 55.6%). Heteroresistance to metronidazole was reported in 12 studies, with a weighted pooled prevalence of 13.8% (95% CI 8.9-18.6; 1670 H. pylori positive patients; the substantial heterogeneity I 2  = 60.9%). The weighted pooled prevalence of clarithromycin heteroresistance was similar in Asia and Europe (p = 0.174584), however, metronidazole heteroresistance was detected more often in Europe (p < 0.00001). Clarithromycin heteroresistance was detected more often by phenotype rather than by using genotyping methods (12 vs 8 studies), whereas heteroresistance to metronidazole was detected only by phenotype., Conclusion: The prevalence of heteroresistance to clarithromycin and/or metronidazole is not negligible and can be detected in approximately 7 and 14% of H. pylori positive samples, respectively. These findings highlight the need to raise the awareness of gastroenterologists and microbiologists to the heteroresistance to clarithromycin and metronidazole in patients with a H. pylori infection., (© 2022. The Author(s).)

Rising antibiotic resistance rates are a growing concern for all pathogens, including Helicobacter pylori. We previously examined the association of specific mutations in PBP1 with amoxicillin resistance and fitness in H. pylori and found that V374L and N562Y mutations were associated with resistance, but also resulted in fitness defects. Furthermore, we found that hyperosmotic stress differentially altered the fitness of strains bearing these mutations; survival of the V374L strain was decreased by hyperosmotic stress, but the N562Y strain showed increased cell survival relative to that of wild-type G27. The finding that amoxicillin-resistant strains show environmentally dictated changes in fitness suggests a previously unexplored interaction between amoxicillin resistance and osmotic stress in H. pylori. Here, we further characterized the interaction between osmotic stress and amoxicillin resistance. Wild-type and isogenic PBP1 mutant strains were exposed to amoxicillin, various osmotic stressors, or combined antibiotic and osmotic stress, and viability was monitored. While subinhibitory concentrations of NaCl did not affect H. pylori viability, the combination of NaCl and amoxicillin resulted in synergistic killing; this was true even for the antibiotic-resistant strains. Moreover, similar synergy was found with other beta-lactams, but not with antibiotics that did not target the cell wall. Similar synergistic killing was also demonstrated when KCl was utilized as the osmotic stressor. Conversely, osmolar equivalent concentrations of sucrose antagonized amoxicillin-mediated killing. Taken together, our results support a previously unrecognized interaction between amoxicillin resistance and osmotic stress in H. pylori. These findings have interesting implications for the effectiveness of antibiotic therapy for this pathogen. IMPORTANCE Rising antibiotic resistance rates in H. pylori are associated with increased rates of treatment failure. Understanding how stressors impact antibiotic resistance may shed light on the development of future treatment strategies. Previous studies found that mutations in PBP1 that conferred resistance to amoxicillin were also associated with a decrease in bacterial fitness. The current study demonstrated that osmotic stress can enhance beta lactam-mediated killing of H. pylori. The source of osmotic stress was found to be important for these interactions. Given that relatively little is known about how H. pylori responds to osmotic stress, these findings fill important knowledge gaps on this topic and provide interesting implications for the effectiveness of antibiotic therapy for this pathogen.

Helicobacter pylori ( H. pylori ) infection is associated with a variety of gastrointestinal diseases. Here, we focused on the activity of a novel nanomedicine-liposomal linolenic acid (LipoLLA) against H. pylori and its impact on human fecal bacteria in vitro . The minimum inhibitory concentrations (MICs) of LipoLLA against 30 H. pylori clinical strains were determined in combination with amoxicillin (AMX), metronidazole (MTZ), levofloxacin (LVFX) and clarithromycin (CAM). Bactericidal activity was measured by generating concentration-bactericidal curves at different times and pH values. Leakage of glucose (GLU) and aspartate aminotransferase (AST) was detected, combined with detection of changes in morphology by electron microscopy, to study the mechanism of action of LipoLLA against H. pylori . The effect of LipoLLA on human fecal bacteria was studied by high-throughput sequencing of fecal samples. We observed a synergistic or additive effect when LipoLLA was combined with AMX, MTZ, LVFX and CAM. The concentration-sterilization curves were pH and time dependent. After treatment with LipoLLA, GLU and AST levels were increased (P<0.05), and the morphology of H. pylori changed significantly. Moreover, LipoLLA activity led to no significant changes in the intestinal flora in terms of alpha diversity, species composition, beta diversity, etc. In conclusion, LipoLLA showed good anti- H. pylori effects. It destroyed the outer membrane barrier and caused leakage of the bacterial contents to achieve anti- H. pylori effects. And LipoLLA had little effect on human fecal bacteria in vitro ., 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 © 2022 Wang, Wu, Wang, Wang, Liu, Fu and Xie.)

Decreased effectiveness of metronidazole for the treatment of Clostridioides difficile infection has been documented. One reason for this is that levels of metronidazole in the colon are generally low; therefore, a modest increase in the minimum inhibitory concentration of metronidazole for C. difficile may result in an insufficient therapeutic concentration. Due to the lack of efficient genetic manipulation tools for C. difficile strains, the resistance mechanism is largely unknown. In this study, a metronidazole-resistant strain (SH182IR) was acquired by in-vitro induction with metronidazole from a clinical metronidazole-heteroresistant strain (SH182), and the genomic and transcriptional changes were investigated through whole-genome sequencing and RNA-seq. The morphology of the two strains was studied by transmission electron microscopy, and the roles of drug efflux pumps in metronidazole resistance were determined by inhibition assay. Genomic analysis showed that the ferrous iron transporter feoB3 was truncated in SH182IR, indicating that feoB3 contributed to the metronidazole resistance of C. difficile. RNA-seq analysis showed that genes involved in peptidoglycan synthesis, efflux pumps and metronidazole reductive action were expressed differentially between the two strains. Further cell imaging confirmed that cell wall thickness was significantly greater in SH182IR. The efflux pump inhibitor test showed that addition of reserpine or cyanide 3-chlorophenylhydrazone reduced metronidazole resistance in SH182IR, thus proving the role of efflux pumps in metronidazole resistance. These results found an association between genomic variation and metronidazole resistance in C. difficile, and show that metronidazole resistance in C. difficile is multi-factorial, involving metronidazole metabolism, cell wall thickness and efflux pumps. These findings will help improve knowledge and understanding of metronidazole resistance of C. difficile., (Copyright © 2022 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.)

The dreadful bacterial resistance to clinical drugs calls for the development of novel antibacterials. This work developed a class of unique metronidazole-derived three-component hybrids as promising antibacterial therapeutic alternatives. Bioactive assay discovered that p-chlorophenylhydrazone derivative 6b possessed excellent ability to suppress the growth of drug-resistant E. coli (MIC = 0.5 µg/mL), being 16 folds more potent than norfloxacin (MIC = 8 µg/mL). The active molecule 6b with imperceptible hemolysis could effectively retard the development of bacterial drug resistance within 30 passages. Moreover, compound 6b displayed a favorable inhibitory effect on E. coli biofilms and could act rapidly in bactericidal efficacy. Subsequent exploration of mechanism revealed that 6b could destruct the bacterial cytoplasmic membrane, leading to the leakage of intracellular protein. The inactivation of lactate dehydrogenase, metabolic stagnation and the accumulation of reactive oxygen species caused by 6b were observed. Furthermore, molecule 6b could form a supramolecular complex with DNA to obstruct DNA replication. These results demonstrated that metronidazole-derived three-component hybrids provided a large potential for deep development as prospective antibacterial agents., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Antibiotic resistance represents the main challenge of Helicobacter pylori infection worldwide. This study investigates the potential bactericidal effects of fosfomycin combinations with clarithromycin, metronidazole, ciprofloxacin, amoxicillin, rifampicin, and doxycycline against thirty-six H. pylori strains using the checkerboard and time-kill assay methods. The results showed that ≥ 50% of the strains were resistant to the six antibiotics. Remarkably, only six strains exerted resistance to these antibiotics, with the minimum inhibitory concentrations (MICs) ranges of (3.2-12.8 mg/l), (32-256 mg/l), (3.2-51.2 mg/l), (3.2-25.6 mg/l), (1.6-3.2 mg/l), and (25.6 > 51.2 mg/l), respectively. The seven antibiotics were evaluated through in silico studies for their permeability and ability to bind UDP-N-acetylglucosamine1-carboxyvinyltransferase (MurA) of H. pylori. The results indicated that fosfomycin exhibited the highest predicted membrane permeability (membrane ∆G insert = - 37.54 kcal/mol) and binding affinity (docking score = - 5.310 kcal/mol) for H. pylori MurA, compared to other tested antibiotics. The combinations of fosfomycin with these antibiotics exerted synergistic interactions (Fractional inhibitory concentration, FIC index < 1) against the six strains. Importantly, the combinations of fosfomycin with clarithromycin, doxycycline and rifampicin achieved bactericidal effects (reduction ≥ 3.0 Log 10 cfu/ml) against the most resistant H. pylori strain. Notably, these effects increased with presence of metronidazole, which enhanced the activity of the fosfomycin combination with amoxicillin from a weak inhibition to bactericidal effect. This study provides evidence that the combination of fosfomycin with either clarithromycin, amoxicillin, doxycycline, or rifampicin (especially with the presence of metronidazole) could be a promising option for treating MDR H. pylori infection., (© 2022. The Author(s).)

Oral antibiotics remain the therapy of choice for severe bacterial infections; however, antibiotic use disrupts the intestinal microbiota, increasing the risk of colonization by intestinal pathogens. Currently, our understanding of antibiotic-mediated disturbances of the microbiota remains at the level of bacterial families or specific species, and little is known about the effect of antibiotics on potentially beneficial and pathogenic bacteria under the conditions of gut microbiota dysbiosis. Additionally, the question of whether the effects of antibiotics on the gut microbiota are temporary or permanent is controversial. In this study, we used 16S rRNA gene sequencing to evaluate the short- and long-term effects of ampicillin, vancomycin, metronidazole, and neomycin on the murine intestinal microbiota. We found that the changes in the intestinal microbiota reflected the antibiotics' mechanisms of action and that dysbiosis of the intestinal microbiota led to competition between different bacterial communities. In particular, an increase in Enterococcus , which accompanies a decrease in probiotics-related genera such as Lactobacillus , is commonly seen across antibiotic treatments. In addition, we found that these oral antibiotics had long-term negative effects on the intestinal microbiota and promoted the development of antibiotic-resistant bacterial strains. These results indicate that ampicillin, vancomycin, metronidazole, and neomycin have long-term negative effects and can cause irreversible changes in the diversity of the intestinal microbiota, thereby increasing the risk of host disease. IMPORTANCE The intestinal microbiota is a dynamic community of hundreds of millions of microorganisms that play important roles in human health. However, treatment with antibiotics can disrupt the delicate balance of this community, leading to deleterious effects on the host such as inflammation and enhanced susceptibility to infection. To date, most studies of the effects of antibiotic treatment on the microbiota have focused on specific intestinal pathogens and bacterial families. However, few studies have investigated the effects of antibiotic treatment on the relative abundance of probiotic bacteria, pathogenic bacteria, and opportunistic bacterial pathogens in the gut.

Seven new naphthoquinone diglycosides ( 1 - 7 ), three new anthraquinones ( 8 - 10 ), and eight known analogues were obtained from the aerial parts of Mitracarpus hirtus collected from West Africa in a bioassay-guided phytochemical investigation. All isolated compounds were elucidated by comparison with the literature and interpretation of spectroscopic data, and the absolute configurations of the new naphthoquinone diglycosides ( 1 - 10 ) were confirmed by chemical methods and ECD calculations. Notably, compound 1 was found to be the first naphthoquinone diglycoside containing carboxylic acid and isopentenyl side chains isolated from a species in the genus Mitracarpus . Compounds 6 - 18 showed antibacterial activity against multiple Helicobacter pylori strains with MIC values ranging from 0.0625 to 64 μg/mL. Particularly, 1-hydroxybenzoisochromanquinone ( 17 ) and benzo[ g ]isoquinoline-5,10-dione ( 18 ), with MIC values of 0.0625 and 0.125 μg/mL, displayed 32-512-fold higher potencies than a positive control, metronidazole. Compound 18 also demonstrated high antibiofilm activity and killed biofilm-encased Helicobacter pylori cells more effectively than metronidazole.

Background: Increasing prevalence of antibiotic resistance especially to clarithromycin and metronidazole has been observed in Helicobacter pylori (H. pylori)., Aim: To characterize the antimicrobial resistance pattern of H. pylori before and after treatment in a cohort of patients accumulated over a period of 15 years after an unsuccessful eradication treatment had been given comparing sensitivity data from patients with newly diagnosed H. pylori infection. A specific objective was to look for resistance to levofloxacin., Material and Methods: Total of 50 patients newly diagnosed for H. pylori infection treated with omeprazole and amoxicillin/clarithromycin and 42 H pylori treatment-resistant patients treated with omeprazole and amoxicillin/levofloxacin were enrolled in this study. Cultures including antibiotic sensitivity testing were conducted according to standard laboratory routines and thus also in keeping with a European study protocol using E-test gradient strips or disc diffusion methods., Results: Clarithromycin resistance was more frequently observed in the H. pylori resistant group than in newly diagnosed H. pylori group (39% versus 11%). Regarding metronidazole the distribution was 70% versus 38%, and 8% versus 12% were resistant to tetracycline. No resistance was observed for amoxicillin. After re-treatment of patients belonging to the H. pylori treatment-resistant group, just two patient strains were recovered of which one harbored metronidazole resistance. In the group of newly diagnosed H. pylori, seven patients were culture positive by control after treatment. Two and three patient strains showing resistance to clarithromycin and metronidazole, respectively. None of the strains in our material was classified as resistant to amoxicillin and levofloxacin. Whereas 12% was resistant to tetracycline in the newly diagnosed before treatment., Conclusion: Clarithromycin resistance was more frequent in the H. pylori treatment-resistant group than strains from patients with newly diagnosed H. pylori infection. No resistance was observed to amoxicillin and levofloxacin. In such cases Therefore levofloxacin may be used provided in vitro sensitivity testing confirms applicability., Trial Registration: ClinicalTrials.gov identifier: NCT05019586., Competing Interests: There are not any commercial affiliations or competing interests in our study. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Objective: The detection of Helicobacter pylori mutations that result in antimicrobial resistance can serve as a guideline of antimicrobial therapeutics and probably prevent the failure of clinical treatments. Evaluating the potential of Sanger sequencing to identify genetically resistant determinants in Helicobacter pylori clinical isolates will be important., Methods: 180 cultured strains have been tested using agar dilution for antibiotic susceptibility. NCBI BLAST was used to perform genotypic analysis on the sequencing data. Sanger sequencing was evaluated as an alternative method to detect resistant genotypes and susceptibility., Results: By the conventional E-test, resistance to levofloxacin, amoxicillin, metronidazole, and clarithromycin was 67.3%, 15.1%, 96.4%, and 25.5%, respectively. In contrast, tetracycline had no resistance. Resistance to multiple drugs was observed in 8.12% of the strains. The genetic determinants of resistance to CLA was 23s rRNA, the determinants of resistance to amoxicillin was Pbp1, the determinants of resistance to metronidazole was rdxA, and the determinants of resistance to levofloxacin were GyrA and GyrB. However, there was no association of resistance in tetracycline., Conclusion: We found increased rates of metronidazole antibiotic resistance, highlighting the necessity for alternative therapies and periodic evaluation. Sanger sequencing has proved to be highly effective and holds the potential to be implemented in policies catering to local treatments., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Lixia Tian et al.)

Background: Trichomonas vaginalis is the causative agent of a sexually transmitted disease in humans. The virulence of the parasite depends on multiple factors, including the presence of endosymbiotic dsRNA viruses. The presence of Trichomonasviruses (TVV) was associated with more severe genital symptoms, increased proinflammatory host reactions, and modulated parasite sensitivity to metronidazole. However, no efficient antiviral drugs are available against TVV to derive isogenic TVV-positive and TVV-negative cell lines that are essential for investigations of the TVV impact on T. vaginalis biology., Methods: 7-Deaza-2'-C-methyladenosine (7d2CMA) and 2'-C-methylcytidine (2CMC) were used for TVV inhibitory assay. TVV replication was monitored using quantitative reverse transcription PCR (RT qPCR) and western blotting. Modeling of TVV1 RNA-dependent RNA polymerase (RdRp) was performed to visualize the inhibitor-RdRp interaction. Susceptibility to metronidazole was performed under aerobic and anaerobic conditions., Results: We demonstrated that 2CMC but not 7d2CMA is a potent inhibitor of TVV replication. Molecular modeling suggested that the RdRp active site can accommodate 2CMC in the active triphosphate nucleotide form. The effect of 2CMC was shown on strains infected with a single and multiple TVV species. The optimal 2CMC concentration (10 μM) demonstrated strong selectivity for TVVs over trichomonad growth. The presence of TVV has no effect on T. vaginalis metronidazole susceptibility in derived isogenic cell lines., Conclusions: 2CMC acts against TVVs and represents a new inhibitor against Totiviridae viruses. Our isogenic clones are now available for further studies of various aspects of T. vaginalis biology related to TVV infection., Competing Interests: Declaration of competing interest The authors declare no conflict of statement., (Copyright © 2021. Published by Elsevier B.V.)

Clostridioides difficile is the predominant pathogen responsible for antimicrobial associated diarrhea (AAD) and health care facility-associated infectious diarrhea. The role of C. difficile in China and its impact on public health have gained attention in recent years. Most clinical C. difficile isolates in China belong to multilocus sequence type clade 1 with sequence types (STs) 3, 35 and 54 predominating. Of note, the proportion of C. difficile isolates from clade 4, especially ST37 (PCR ribotype 17), is much higher in China than in other areas. In China, the antimicrobial-resistance profile of C. difficile is similar to that of other countries, demonstrating a higher resistance rate to erythromycin, clindamycin, and fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin). In general, susceptibility to vancomycin and metronidazole of clinical C. difficile in China is high, however, some resistance to metronidazole have recently been reported. Preclinical research on C. difficile in animals in China is limited, and different studies have reported varied isolation rates and antimicrobial resistance profiles. The diverse molecular types of C. difficile in China merit further epidemiological, genomic and evolutionary investigation. While the use of probiotics in preventing C. difficile infection (CDI) have received both support and opposition, the discovery of new probiotics and new formulations are showing promising results in combating the threat posed by CDI., 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 © 2022 Elsevier Ltd. All rights reserved.)

Bacterial vaginosis (BV) is the most common vaginal infection found in women in the world. Due to increasing drug-resistance of virulent pathogen such as Gardnerella vaginalis (G. vaginalis), more than half of BV patients suffer recurrence after antibotics treatment. Here, metastable iron sulfides (mFeS) act in a Gram-dependent manner to kill bacteria, with the ability to counteract resistant G. vaginalis for BV treatment. With screening of iron sulfide minerals, metastable Fe 3 S 4 shows suppressive effect on bacterial growth with an order: Gram-variable G. vaginalis >Gram-negative bacteria>> Gram-positive bacteria. Further studies on mechanism of action (MoA) discover that the polysulfide species released from Fe 3 S 4 selectively permeate bacteria with thin wall and subsequently interrupt energy metabolism by inhibiting glucokinase in glycolysis, and is further synergized by simultaneously released ferrous iron that induces bactericidal damage. Such multiple MoAs enable Fe 3 S 4 to counteract G. vaginalis strains with metronidazole-resistance and persisters in biofilm or intracellular vacuole, without developing new drug resistance and killing probiotic bacteria. The Fe 3 S 4 regimens successfully ameliorate BV with resistant G. vaginalis in mouse models and eliminate pathogens from patients suffering BV. Collectively, mFeS represent an antibacterial alternative with distinct MoA able to treat challenged BV and improve women health., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Introduction: Secnidazole (SEC), newly FDA-approved for trichomoniasis, is a potent 5-nitroimidazole with selective toxicity against various infections. It has been used internationally to treat trichomoniasis, bacterial vaginosis, and other infections for decades. Trichomoniasis is the most common non-viral sexually transmitted infection worldwide and is associated with significant morbidity. In comparison to the only other approved treatments for trichomoniasis in the U.S.-metronidazole and tinidazole-SEC has favorable pharmacokinetics, including a longer half-life, and a lower minimal lethal concentration against Trichomonas vaginalis., Objectives: Provide an updated, comprehensive review of the literature evaluating SEC as a treatment for trichomoniasis in women and men., Methods: We conducted a search to identify existing research on SEC and trichomoniasis. On August 6, 2021, we searched MEDLINE using the terms "secnidazole" and "trichomon.*" We excluded reviews, editorials, case reports, and small case series., Results: We identified 29 articles; 14 of which were included: 5 reported in vitro pharmacologic data on SEC, 6 were observational studies, and 4 were controlled clinical trials (1 observational study also reported in vitro pharmacologic data). Six studies reported data on women only, 1 on men only, and 3 on women and men. These studies showed that SEC-as a single dose or 3-day course-had comparable efficacy to multi-dose metronidazole for treating trichomoniasis in women and men, was generally well tolerated by patients, and had a favorable pharmacokinetic profile. A single 2-g dose of SEC also led to a microbiologic cure rate of 92.2% in the first randomized, double-blind, placebo-controlled study of trichomonas-infected US-based women., Conclusion: SEC is an efficacious and safe treatment for women and men with trichomoniasis. Single-dose administration makes it a favorable treatment option for patients, especially in cases where adherence to other multi-dose treatment regimens could be problematic. Christina A. Muzny and Olivia T. Van Gerwen. Secnidazole for Trichomoniasis in Women and Men. Sex Med Rev 2022;10:255-262., (Copyright © 2022 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.)

Aims: We described the presence of Helicobacter pylori (HP) and estimated the prevalence of primary and secondary resistance using molecular detection in gastric biopsies of Ecuadorian patients., Methods and Results: 66.7% (238/357) of the patients demonstrated the presence of HP using CerTest qPCR. Of these, 69.79% (104/149) were without previous HP eradication treatment and 64.42% (134/208) with prior HP eradication treatment. The mutation-associated resistance rate for clarithromycin was 33.64% (primary resistance) and 32.82% (secondary resistance), whereas that in levofloxacin the primary and secondary resistance was 37.38% and 42%, respectively. For tetracycline and rifabutin, primary and secondary resistance was 0%. Primary and secondary resistance for metronidazole and amoxicillin could not be evaluated by genotypic methods (PCR and sequencing)., Conclusions: The analysis of mutations in gyrA, 23S rRNA and 16S rRNA is useful to detect bacterial resistance as a guide for eradication therapy following failure of the first-line regimen., Significance and Impact of the Study: This study carried out in an Ecuadorian population indicates that the resistance of HP to first-line antibiotics is high, which may contribute to the high rates of treatment failure, and other treatment alternatives should be considered., (© 2021 The Society for Applied Microbiology.)

In view of the rising incidence of Anaerobic bacteremia(AB), the use of anaerobic blood culture bottles have been recommended in addition to the aerobic blood culture bottles. The need to perform antimicrobial susceptibility testing(AST) for anaerobes has become mandatory owing to increasing metronidazole resistance. The frequency of AB following large bowel surgery and the metronidazole susceptibility for members of the Bacteroides fragilis group were determined. The incidence of AB was found to be 16%. Seventeen obligate anaerobes were isolated in total, of which B. fragilis was the most common. Two of twelve isolates of B. fragilis were resistant to metronidazole., (Copyright © 2022 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

Background: Infections with Bacteroides fragilis are routinely treated with metronidazole, a 5-nitroimidazole antibiotic that is active against most anaerobic microorganisms. Metronidazole has remained a reliable treatment option, but resistance does occur, including in B. fragilis., Objectives: In this study we tested whether haemin, a growth supplement for B. fragilis in vivo and in vitro, had an influence on the susceptibility of resistant B. fragilis strains to metronidazole. We further tested whether haemin-deprived B. fragilis would be more susceptible to oxygen and oxidative stress. Metronidazole has been described to cause oxidative stress, which we argued would be exacerbated in haemin-deprived B. fragilis because the bacteria harness haemin, and the iron released from it, in antioxidant enzymes such as catalase and superoxide dismutase., Methods: Haemin was omitted from growth media and the effect on metronidazole susceptibility was monitored in susceptible and resistant B. fragilis strains. Further, haemin-deprived B. fragilis were tested for resistance to aeration and hydrogen peroxide and the capacity for the removal of oxygen., Results: Omission of haemin from the growth medium rendered metronidazole-resistant B. fragilis strains, including an MDR isolate from the UK, highly susceptible to metronidazole. Haemin deprivation further rendered B. fragilis highly susceptible to oxygen, which was further exacerbated in resistant strains. B. fragilis was incapable of scavenging oxygen when haemin was omitted., Conclusions: We propose that haemin deprivation overrules resistance mechanisms by rendering B. fragilis hypersusceptible to metronidazole due to a compromised antioxidant defence. Monitoring of haemin concentrations is imperative when conducting metronidazole susceptibility testing in B. fragilis., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.)

It is widely accepted that production of biofilm is a protective mechanism against various type of stressors, including exposure to antibiotics. However, the impact of this structure on the spread of antibiotic resistance in Helicobacter pylori is still poorly understood. Therefore, the aim of the current research was to determine the relationship between biofilm formation and antibiotic resistance of H. pylori . The study was carried out on 24 clinical strains with different resistance profiles (antibiotic-sensitive, mono-resistant, double-resistant and multidrug-resistant) against clarithromycin (CLR), metronidazole (MTZ) and levofloxacin (LEV). Using static conditions and a crystal violet staining method, a strong correlation was observed between biofilm formation and resistance to CLR but not MTZ or LEV. Based on the obtained results, three the strongest and three the weakest biofilm producers were selected and directed for a set of microfluidic experiments performed in the Bioflux system combined with fluorescence microscopy. Under continuous flow conditions, it was observed that strong biofilm producers formed twice as much of biofilm and created significantly more eDNA and in particular proteins within the biofilm matrix when compared to weak biofilm producers. Additionally, it was noticed that strong biofilm producers had higher tendency for autoaggregation and presented morphostructural differences (a greater cellular packing, shorter cells and a higher amount of both OMVs and flagella) in relation to weak biofilm counterparts. In conclusion, resistance to CLR in clinical H. pylori strains was associated with a broad array of phenotypical features translating to the ability of strong biofilm formation., 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 © 2022 Krzyżek, Migdał, Grande and Gościniak.)

In order to test an effective biopolymer scaffold in promoting the growth of human dental pulp stem cells (HDPSCs), mesoporous silica @ hydrogel (MSN@Gel) nanocomposites are invented as a new type of biopolymer scaffold for HDPSCs proliferation in this paper. The expression levels of alkaline phosphatase (ALP), dentin matrix protein 1 (DMP1), and dentin sialophosphoprotein (DSPP) are significantly increased in the MSN@Gel group so as to better repair damaged dentin. In order to inhibit the proliferation of bacteria in the dental pulp, metronidazole (MTR) is loaded into MSN. The study found that MSN could effectively prolong the half-life of MTR by 1.75 times, and the viability of HDPSCs could be better maintained in the MSN-MTR@Gel group so as to better promote its proliferation to repair pulpitis. However, with the increase of the MTR concentration, its proliferation effect on HDPSCs decreased gradually, and the proliferation effect is the best in 10  μ mol/L. Therefore, the MSN-MTR@Gel scaffold is expected to become an effective method for pulpitis therapy in the future., Competing Interests: The authors declare no competing interests., (Copyright © 2022 Wei Wang et al.)

BackgroundBacterial vaginosis (BV) causes genital inflammation and increases HIV risk, whereas a vaginal microbiota dominated by Lactobacillus species is associated with immune quiescence and relative HIV protection. BV treatment reduces genital inflammation, but it is unclear whether this reduction is driven by a decrease in BV-associated bacteria or an increase in Lactobacillus species.METHODSTo evaluate the short-term effect of standard BV treatment on genital immunology and the vaginal microbiota, vaginal swabs were collected immediately before and after metronidazole treatment for BV and analyzed with multiplex ELISA, metagenomic sequencing, and quantitative PCR.RESULTSTopical metronidazole treatment rapidly reduced vaginal levels of proinflammatory cytokines, chemokines, and soluble immune markers of epithelial barrier disruption. Although the vaginal microbiota shifted to dominance by L. iners or L. jensenii, this proportional shift was primarily driven by a 2 to 4 log10-fold reduction in BV-associated bacteria absolute abundance. BV treatment induced no change in the absolute abundance of L. crispatus or L. iners and only minor (<1 log10-fold) increases in L. gasseri and L. jensenii that were not independently associated with reduced inflammation in multivariable models.CONCLUSIONThe genital immune benefits that are associated with Lactobacillus dominance after BV treatment were not directly attributable to an absolute increase in lactobacilli, but rather to the loss of BV-associated bacteria.Trial REGISTRATIONParticipants were recruited as part of a randomized controlled trial (ClinicalTrials.gov NCT02766023) from 2016 to 2019.FUNDINGCanadian Institutes of Health Research (PJT-156123) and the National Institute of Allergy and Infectious Diseases (HHSN2722013000141 and HHSN27200007).

Objective: Description of the changing patterns of antibiotic resistance in Helicobacter pylori infection in the Netherlands., Design: Retrospective database study using the Dutch infectious disease surveillance information system-antibiotic resistance (ISIS-AR)., Method: In the ISIS-AR database antibiotic resistance data are reported by 46 microbiologic laboratories in the Netherlands. For the present study, data from 16 centres were used with a 10 year period of reporting H. pylori resistance data, from 1 January 2010 till 1 January 2020, for amoxycillin, levofloxacin, claritrhromycin, tetracyclin and metronidazole., Results: In 2019 Antimicrobial resistance rates in the Netherlands were 1% for tetracycline, 5% for amoxycillin, 23%% for levofloxacin, 46% for metronidazole and 47% for clarithromycin. The combined resistance rate for clarithromycin and metronidazole was 29%. Significantly higher resistance rates were found in female patients for amoxycillin (8% vs 1%), clarithromycin (53% vs 38%) and metronidazole (52% vs 38%). From 2010 to 2019, a significant rise in resistance rates was found for amoxycillin (0% - 5%), clarithromycin (7% - 40%), metronidazole (14% - 45%) and for the clarithromycin and metronidazole combination (2% - 29%)., Conclusion: There was an important rise in antibiotic resistance rates in H. pylori in the Netherlands. For optimal H. pylori treatment bismuth-based therapies should become available again in the Netherlands. Treatment of H. pylori should be based on the individual antibiotic resistance profile and be in concordance with the principles of antibiotic stewardship. Guidelines for treatment of H. pylori in the Netherlands should be adapted and have a better correlation with International guidelines and best practices.

The retinal pigment epithelium (RPE) resides at the back of the eye and performs functions essential for maintaining the health and integrity of adjacent retinal and vascular tissues. At present, the limited reparative capacity of mammalian RPE, which is restricted to small injuries, has hindered progress to understanding in vivo RPE regenerative processes. Here, a detailed methodology is provided to facilitate the study of in vivo RPE repair utilizing the zebrafish, a vertebrate model capable of robust tissue regeneration. This protocol describes a transgenic nitroreductase/metronidazole (NTR/MTZ)-mediated injury paradigm (rpe65a:nfsB-eGFP), which results in ablation of the central two-thirds of the RPE after 24 h treatment with MTZ, with subsequent tissue recovery. Focus is placed on RPE ablations in larval zebrafish and methods for testing the effects of pharmacological compounds on RPE regeneration are also outlined. Generation and validation of RpEGEN, a MATLAB script created to automate quantification of RPE regeneration based on pigmentation, is also discussed. Beyond active RPE repair mechanisms, this protocol can be expanded to studies of RPE degeneration and injury responses as well as the effects of RPE damage on adjacent retinal and vascular tissues, among other cellular and molecular processes. This zebrafish system holds significant promise in identifying genes, networks, and processes that drive RPE regeneration and RPE disease-related mechanisms, with the long-term goal of applying this knowledge to mammalian systems and, ultimately, toward therapeutic development.

Trichomoniasis is the most common non-viral sexually transmitted infection worldwide and it may have serious consequences, especially for women. Currently, 5-nitroimidazole drugs are the treatment of choice for trichomoniasis, although presenting adverse effects and reported cases of drug resistance. Metabolites isolated from marine fungi have attracted considerable attention due to their unique chemical structures with diverse biological activities, including antiprotozoal activity. In this study, we showed the anti-Trichomonas vaginalis activity of fractions obtained from marine fungi and the chemical composition of the most active fraction was determined. Ethyl acetate fractions of the fungus Aspergillus niger (EAE03) and Trichoderma harzianum/Hypocrea lixii complex (EAE09) were active against T. vaginalis. These samples, EAE03 and EAE09, were also effective against the fresh clinical isolate metronidazole-resistant TV-LACM2R, presenting MIC values of 2.0 mg/mL and 1.0 mg/mL, respectively. The same MIC values were found against ATCC 30,236 T. vaginalis isolate. In vitro cytotoxicity revealed only the fraction named EAE03 with no cytotoxic effect; however, the active fractions did not promote a significant hemolytic effect after 1-h incubation. Already, the in vivo toxicity evaluation using Galleria mellonella larvae demonstrated that none of the tested samples caused a reduction in animal survival. The fraction EAE03 was followed for purification steps and analyzed by LC-DAD-MS. Eleven compounds were annotated, including butyrolactone, butanolide, and atromentin. Overall, the range of activities reported confirms the potential of marine fungi to produce bioactive molecules., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)