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Zidebactam is a novel extended spectrum β-lactamase inhibitor (ESBLI). It's combination with cefepime (WCK 5222) is in phase III clinical studies. Five process impurities were found in zidebactam (1) drug substance using process development through reverse phase high performance liquid chromatography (HPLC) method. To give access to the reference standards for the impurity profile of the drug substance as well as the final product, these process impurities of compound 1, have been synthesized and characterized. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance continues to surmount increasing concern globally, and treatment of difficult‐to‐treat (DTR) Pseudomonas aeruginosa, carbapenem‐resistant (CR) Acinetobacter baumannii (CRAB), and CR Enterobacterales (CRE) remains a challenge for clinicians. Although previously rare, the incidence of multidrug‐resistant (MDR) and CR infections in pediatric patients has increased drastically in the last decade and is associated with increased morbidity and mortality. To combat this issue, 14 novel antibiotics, including three β‐lactam/novel β‐lactamase inhibitor combinations (βL‐βLIs) and two novel β‐lactams (βLs), have received approval from the United States Food and Drug Administration since 2010. Improving clinician understanding of the utility of these novel therapies is imperative to improve judicious decision‐making and prevent societal regression to a pre‐penicillin era. In this review, we summarize the pharmacokinetic/pharmacodynamic (PK/PD) properties, clinical efficacy and safety data, dosing considerations, and subsequent role in therapy for ceftazidime‐avibactam (CAZ‐AVI), meropenem‐vaborbactam (MER‐VAB), imipenem‐cilastatin‐relebactam (IMI‐REL), ceftolozane‐tazobactam (TOL‐TAZ), and cefiderocol in pediatric patients. [ABSTRACT FROM AUTHOR]

Odontogenic infections can be effectively treated through dental care and surgical treatment, and antibiotic therapy remains useful for the treatment of several odontogenic infections. This review conduct a systematic literature comparing the effectiveness of different antibiotics in treating odontogenic infections. This review uses PubMed, SpringerLink, SCOPUS, and Embase databases as the bibliographic resources. Studies with matching keywords were analyzed and filtered using PRISMA guidelines. Thirteen of the 596 studies reviewed were included in this review. The total number of odontogenic infection cases is 4824 cases treated with different antibiotics. The antibiotics discussed in this review are penicillin, penicillin combined with beta-lactamase inhibitors, metronidazole, and clindamycin. The conclusion is penicillin combined with a beta-lactamase inhibitor (ampicillin-sulbactam or amoxicillin/clavulanic acid) is the most effective antibiotic for odontogenic infections treatment. Their combination with metronidazole is not necessary for healthy patients. Patients who are allergic to penicillin can use clindamycin as an alternative antibiotic. [ABSTRACT FROM AUTHOR]

Carbapenem-resistant Acinetobacter baumannii (CRAb) is an urgent public health threat, according to the CDC. This pathogen has few treatment options and causes severe nosocomial infections with > 50% fatality rate. Although previous studies have examined the proteome of CRAb, there have been no focused analyses of dynamic changes to β-lactamase expression that may occur due to drug exposure. Here, we present our initial proteomic study of variation in β-lactamase expression that occurs in CRAb with different β-lactam antibiotics. Briefly, drug resistance to Ab (ATCC 19606) was induced by the administration of various classes of β-lactam antibiotics, and the cell-free supernatant was isolated, concentrated, separated by SDS-PAGE, digested with trypsin, and identified by label-free LC–MS-based quantitative proteomics. Thirteen proteins were identified and evaluated using a 1789 sequence database of Ab β-lactamases from UniProt, the majority of which were Class C β-lactamases (≥ 80%). Importantly, different antibiotics, even those of the same class (e.g. penicillin and amoxicillin), induced non-equivalent responses comprising various isoforms of Class C and D serine-β-lactamases, resulting in unique resistomes. These results open the door to a new approach of analyzing and studying the problem of multi-drug resistance in bacteria that rely strongly on β-lactamase expression. [ABSTRACT FROM AUTHOR]

Background and Aim: The emergence of antimicrobial-resistant bacteria, such as Escherichia coli in milk, is a serious public health concern as milk is considered a complete food and an important part of daily human diet worldwide, including in Bangladesh. However, there have been no reports on the molecular characterization and antibiotic resistance profile of extended-spectrum beta-lactamase (ESBL)-producing E. coli from milk of healthy cows in Bangladesh. Therefore, this study aimed to detect and characterize ESBL-producing E. coli (ESBL-Ec) in milk samples from healthy cows in smallholder dairy farms in Mymensingh district, Bangladesh, and assess the potential risk of consuming this milk. Materials and Methods: A total of 100 milk samples were collected from apparently healthy cows on smallholder dairy farms. Escherichia coli was isolated from the collected samples using standard methods. The detection of ESBL-Ec was performed phenotypically using cultural methods and genotypically by ESBL genetic determinants using multiplex polymerase chain reaction. Antimicrobial susceptibility testing of the ESBL-Ec isolates was performed using the disk diffusion method with 15 common antimicrobials. Results: In this study, out of the 100 samples tested, 70 (70%) were found to be positive for E. coli. Among these, 41 (58.6%) strains were identified as ESBL-producing, both phenotypically and genotypically, with the presence of blaCTX-M, blaTEM, and blaSHV individually or combined (blaCTX-M plus blaTEM plus blaSHV). The antibiogram of these ESBLpositive isolates revealed high resistance against commonly used antibiotics, such as ampicillin, cefotaxime, and gentamicin (100%), azithromycin (88%), oxytetracycline (27%), nalidixic acid, cotrimoxazole/trimethoprim (24%), and streptomycin (22%). In addition, one isolate showed resistance to 4th generation of cephalosporin (cefepime). Most importantly, extensive multidrug resistance was found in many ESBL-Ec isolates. However, the isolates were highly sensitive to drugs such as ceftriaxone (100%) and imipenem (100%). This is the first study to detect ESBL-Ec in raw milk from healthy cows on smallholder dairy farms in Bangladesh. Conclusion: More than 58% of the E. coli isolated from raw milk of healthy cows tested positive for ESBL production and showed resistance to most commonly used antimicrobials which may be alarming for human health. A limitation of our study is that we had a small size of sample collected from one district in Bangladesh. Therefore, a larger sample size covering a wider geographic area, and using multi-locus sequence typing and whole genome sequencing could provide a more comprehensive understanding of the prevalence and characteristics of ESBL-Ec in Bangladesh. [ABSTRACT FROM AUTHOR]

The presence of multidrug-resistant organisms, often known as MDROs, is a significant risk to public health all over the world. Pseudomonas aeruginosa clinical isolates continue to be one of the most researched MDROs; nevertheless, there is a lack of information in Pakistan about the sensitivity of its animal and plant isolates to antipseudomonal drugs. Pseudomonas aeruginosa was isolated from 25 vegetable samples, 25 animal samples, and 50 clinical samples, for a total of 100 samples. Standard biochemical techniques were used to determine the identities of all the isolates. One hundred P. aeruginosa isolates were tested for their susceptibility to seven antipseudomonal drugs via disc diffusion AST, phenotypic detection of ESBL via double disc synergy test (DDST), and plasmid extraction on twenty isolates based on their resistance to two or more classes of antibiotics via alkaline lysis and analysis using Lambda DNA/Hind lll marker. In the overall assay, piperacillin-tazobactam and imipenem had the highest susceptibilities, whereas ceftazidime and carbenicillin had the highest resistances. 15 of 100 isolates 10 vegetable, 3 clinical, and 2 poultry--showed synergy with the beta-lactamase inhibitor, demonstrating ESBL generation by DDST. Plant, poultry, cow, and clinical isolates have plasmids. 6 strains contained 1 plasmid, 5 had 2-4, and 1 had 5. Plasmids are 1-25kbp. ESBL and Plasmids in the isolates reveal diverse resistance mechanisms. Multiple-resistance P. aeruginosa isolates in plants and animals are a public health risk. 6 strains contained 1 plasmid, 5 had 2-4, and 1 had 5. Plasmids are 1-25kbp. ESBL and Plasmids in the isolates reveal diverse resistance mechanisms. Multiple-resistance P. aeruginosa isolates in plants and animals are a public health risk. [ABSTRACT FROM AUTHOR]

Simple Summary: The scientific community has recently turned its interest to wildlife, including birds, as a potential marker of environmental antimicrobial resistance. The aim of this work was to investigate the antimicrobial susceptibility of 100 commensal Escherichia coli strains isolated from wild birds admitted to the Veterinary Teaching Hospital of Perugia (Central Italy) and the possible presence of extended-spectrum beta-lactamase (ESBL)-producing E. coli and Salmonella spp. Antimicrobials have been selected on the basis of their relevance for public health. The majority of the birds investigated were nocturnal and diurnal raptors and came from "WildUmbria", a wildlife rescue centre in Central Italy. The initial clinical assessment revealed injuries mainly due to traumatic events. The E. coli isolates displayed significant resistance (p < 0.001) to ampicillin (85%) and amoxicillin/clavulanic acid (47%), which are widely used in veterinary and human medicine. Resistance to ciprofloxacin, cefotaxime, and ceftazidime showed values of 18%, 17% and 15%, respectively. Eight out of the hundred E. coli isolates (8%) were ESBL and seven displayed a multidrug resistance profile. Salmonella spp. was not isolated. Resistance to beta-lactams in all multidrug-resistant E. coli, including the presence of third-generation cephalosporins, highlights the need to increase wildlife monitoring studies to assess the potential risk to public health. The role of wildlife, including birds, in antimicrobial resistance is nowadays a speculative topic for the scientific community as they could be spreaders/sources of antimicrobial resistance genes. In this respect, we aimed to investigate the antimicrobial susceptibility of 100 commensal Escherichia coli strains, isolated from wild birds from an Umbrian rescue centre and admitted to the Veterinary Teaching Hospital of Perugia (Central Italy) mainly for traumatic injuries. The possible presence of Salmonella spp. and ESBL-producing E. coli was also estimated. The highest prevalence of resistance was observed for ampicillin (85%) and amoxicillin/clavulanic acid (47%), probably due to their extensive use in human and veterinary medicine. Seventeen out of the one hundred E. coli isolates (17%) displayed a multidrug-resistance profile, including the beta-lactam category, with the most common resistance patterns to three or four classes of antibiotics. Resistance to ciprofloxacin, cefotaxime and ceftazidime exhibited values of 18%, 17% and 15%, respectively. Eight out of the hundred E. coli isolates (8%) were ESBL and seven showed multidrug resistance profiles. Salmonella spp. was not isolated. Resistance to third-generation cephalosporins, also detected in long-distance migratory birds, suggests the need for monitoring studies to define the role of wild birds in antimicrobial resistance circuits. [ABSTRACT FROM AUTHOR]

This talk describes common features of zombie trials using various examples including a detailed case study about Artemisia tea infusions in the treatment of Malaria [2]. B ACT-001 b B New JAK inhibitor safety data in 2023 b P. Vergne Salle SP 1 sp and T. Loupret SP 2 sp SP 1 sp I CHU de Limoges Equipe Pereine UR 22722, Limoges, France; i SP 2 sp I CHU de Limoges, Limoges, France i B Explain what has changed the practice: b JAK inhibitors represent a new treatment group, synthetic targeted therapies, whose efficacy has been demonstrated in numerous indications: rheumatoid arthritis, psoriatic arthritis, spondyloarthritis, juvenile arthritis, atopic dermatitis, alopecia areata, and ulcerative colitis. But could the fact of thinking about the treatment on a daily basis be a key factor leading the patients to be more involved in the care? Safety data in patients having rheumatoid arthritis based on observational studies are available. [Extracted from the article]

The fungal natural product aspergillomarasmine A (AMA) has been identified as a noncompetitive inhibitor of New Delhi metallo-β-lactamase-1 (NDM-1) that inhibits by removing ZnII from the active-site. The nonselective metal-chelating properties and difficult synthesis and derivatization of AMA have hindered the development of this scaffold into a potent and selective inhibitor of NDM-1. Iminodiacetic acid (IDA) has been identified as the metal-binding pharmacophore (MBP) core of AMA that can be leveraged for inhibitor development. Herein, we report the use of IDA for fragment-based drug discovery (FBDD) of NDM-1 inhibitors. IDA (IC50 =120 μM) was developed into inhibitor 23 f (IC50 =8.6 μM, Ki =2.6 μM), which formed a ternary complex with NDM-1, as evidenced by protein thermal-shift and native-state electrospray ionization mass spectrometry (ESI-MS) experiments. Combining mechanistic analysis with inhibitor derivatization, the use of IDA as an alternative AMA scaffold for NDM-1 inhibitor development is detailed.

Background: Multiple-choice, true-false, completion, matching, oral presentation type questions have been used as an evaluation criterion in medical education for many years. Although not as old as other question types, performance evaluation and portfolio-like assessment types, can be called alternative evaluation, have been used for a considerable time. While summative assessment maintains its importance in medical education, the value of formative assessment is gradually increasing. In this research, the use of Diagnostic Branched Tree (DBT), which is used both as a diagnostic and feedback tool, in pharmacology education was examined. Methods: The study was conducted on 165 students (112 DBT, 53 non-DBT) on the 3rd year of undergraduate medical education. 16 DBTs prepared by the researchers were used as data collection tool. Year 3 first committee was elected for implementation. DBTs were prepared according to the pharmacology learning objectives within the committee. Descriptive statistics, correlation and comparison analyzes were used in the analysis of the data. Results: DBTs with the most wrong exits are DBTs entitled phase studies, metabolism, types of antagonism, dose-response relationship, affinity and intrinsic activity, G-protein coupled receptors, receptor types, penicillins and cephalosporins. When each question in the DBTs is examined separately, it is seen that most of the students could not answer the questions correctly regarding phase studies, drugs that cause cytochrome enzyme inhibition, elimination kinetics, chemical antagonism definition, gradual and quantal dose response curves, intrinsic activity and inverse agonist definitions, important characteristics of endogenous ligands, changes in the cell as a result of G-protein activation, ionotropic receptor examples, mechanism of action of beta-lactamase inhibitors, excretion mechanism of penicillins, differences of cephalosporins according to generations. As a result of the correlation analysis, the correlation value calculated between the DBT total score and the pharmacology total score in the committee exam. The comparisons showed that the average score of the pharmacology questions in the committee exam of the students who participated in the DBT activity was higher than the students who did not participate. Conclusions: The study concluded that DBTs are a candidate for an effective diagnostic and feedback tool. Although this result was supported by research at different educational levels, support could not be shown in medical education due to the lack of DBT research in medical education. Future research on DBTs in medical education may strengthen or refute our research results. In our study, receiving feedback with DBT had a positive effect on the success of the pharmacology education. [ABSTRACT FROM AUTHOR]

Simple Summary: Direct and indirect exposure of antibiotics to pet animals has been shown to play a role in the transmission of antimicrobial-resistant bacteria. Our study from the United Arab Emirates found that a public health relevant antibiotic-resistant strain of Escherichia coli (E. coli) bacteria is present in fecal swabs sampled from many healthy pet cats and dogs. The strain, known as extended-spectrum β-lactamases resistant (ESBL-R) E. coli, is resistant to many commonly used antibiotics, making it difficult to treat if it causes an infection. We found that 23.65% of the animals tested had ESBL-R E. coli. The bacteria were most commonly found in pets that had access to water in ditches and puddles. The study also found that 91% of the bacteria samples were multidrug resistant, meaning that they were resistant to multiple types of antibiotics. The findings from this study call for veterinarians to develop surveillance programs to monitor ESBL-R E. coli in pets and to reduce the risk of transmission to humans and the environment. Extended-spectrum β-lactamases resistant (ESBL-R) Escherichia coli (E. coli) has been reported from healthy and sick pets. However, data from Middle Eastern countries, including the United Arab Emirates (UAE), are minimal. This study provides the first evidence of ESBL-R E. coli carriage among pets in the UAE. A total of 148 rectal swabs were collected from domestic cats (n = 122) and dogs (n = 26) attending five animal clinics in the UAE. Samples were cultured directly onto selective agar, and suspected colonies were confirmed as ESBL-producing using phenotypic and molecular methods. Confirmed isolates were screened for their phenotypic resistance to twelve antimicrobial agents using the Kirby Bauer method. The owners of the pets completed a questionnaire at the time of sampling, and the data were used to identify risk factors. ESBL-R E. coli was detected in rectal swabs of 35 out of 148 animals (23.65%) (95% confidence interval [CI]: 17.06–31.32). Multivariable logistic regression analysis identified cats and dogs with access to water in ditches and puddles as 3.71 (p-value = 0.020) times more likely to be positive to ESBL-R E. coli than those without access to open water sources. Ciprofloxacin resistance was evident in 57.14% (44/77) of the ESBL-R E. coli isolates. The percentage of resistance to azithromycin and cefepime was 12.99% (10/77) and 48.05% (37/77), respectively. The blaCTX-M gene was detected in 82% of the PCR-screened isolates (n = 50). Multidrug resistance (MDR) phenotypes were evident in 91% (70/77) of the isolates. In conclusion, ESBL-R E. coli was detected at a noticeable rate among healthy pet cats and dogs in the UAE, and the majority are MDR to clinically important antimicrobials such as fluoroquinolones and 3rd and 4th generation cephalosporins. Our results call for strengthening antimicrobial stewardship among companion animal veterinarians in the UAE to reduce the potential transmission of ESBL-R E. coli between pets, humans, and urban environments. [ABSTRACT FROM AUTHOR]

Empirically prescribed standard dosing regimens of antibacterial agents may result in insufficient or excess plasma concentrations with persistently poor clinical outcomes, especially for patients in intensive care units (ICUs). Therapeutic drug monitoring (TDM) of antibacterial agents can guide dose adjustments to benefit patients. In this study, we developed a robust, sensitive, and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) platform for the quantification of 14 antibacterial and antifungal agents (beta-lactams piperacillin, cefoperazone, and meropenem; beta-lactamase inhibitors tazobactam and sulbactam; antifungal agents fluconazole, caspofungin, posaconazole, and voriconazole; and daptomycin, vancomycin, teicoplanin, linezolid, and tigecycline) that can be used for patients with severe infection. This assay requires only 100 µL of serum with rapid protein precipitation. Chromatographic analysis was performed using a Waters Acquity UPLC C8 column. Three stable isotope-labeled antibacterial agents and one analogue were used as internal standards. Calibration curves ranged from 0.1-100 μg/mL, 0.1-50 μg/mL, and 0.3-100 μg/mL for different drugs, and all correlation coefficients were greater than 0.9085. Intra- and inter-day imprecision and inaccuracy values were below 15%. After validation, this new method was successfully employed for TDM in routine practice. [ABSTRACT FROM AUTHOR]

CTX-M β-lactamases are a widespread source of resistance to β-lactam antibiotics in Gram-negative bacteria. These enzymes readily hydrolyze penicillins and cephalosporins, including oxyimino-cephalosporins such as cefotaxime. To investigate the preference of CTX-M enzymes for cephalosporins, we examined eleven active-site residues in the CTX-M-14 β-lactamase model system by alanine mutagenesis to assess the contribution of the residues to catalysis and specificity for the hydrolysis of the penicillin, ampicillin, and the cephalosporins cephalothin and cefotaxime. Key active site residues for class A β-lactamases, including Lys73, Ser130, Asn132, Lys234, Thr216, and Thr235, contribute significantly to substrate binding and catalysis of penicillin and cephalosporin substrates in that alanine substitutions decrease both kcat and kcat/KM. A second group of residues, including Asn104, Tyr105, Asn106, Thr215, and Thr216, contribute only to substrate binding, with the substitutions decreasing only kcat/KM. Importantly, calculating the average effect of a substitution across the 11 activesite residues shows that the most significant impact is on cefotaxime hydrolysis while ampicillin hydrolysis is least affected, suggesting the active site is highly optimized for cefotaxime catalysis. Furthermore, we determined X-ray crystal structures for the apo-enzymes of the mutants N106A, S130A, N132A, N170A, T215A, and T235A. Surprisingly, in the structures of some mutants, particularly N106A and T235A, the changes in structure propagate from the site of substitution to other regions of the active site, suggesting that the impact of substitutions is due to more widespread changes in structure and illustrating the interconnected nature of the active site. [ABSTRACT FROM AUTHOR]

Background: Animal husbandry practices in different livestock production systems and increased livestock–wildlife interactions are thought to be primary drivers of antimicrobial resistance (AMR) in Arid and Semi‐Arid Lands (ASALs). Despite a tenfold increase in the camel population within the last decade, paired with widespread use of camel products, there is a lack of comprehensive information concerning beta‐lactamase‐producing Escherichia coli (E. coli) within these production systems. Objectives: Our study sought to establish an AMR profile and to identify and characterise emerging beta‐lactamase‐producing E. coli isolated from faecal samples obtained from camel herds in Northern Kenya. Methods: The antimicrobial susceptibility profiles of E. coli isolates were established using the disk diffusion method, with beta‐lactamase (bla) gene PCR product sequencing performed for phylogenetic grouping and genetic diversity assessments. Results: Here we show, among the recovered E. coli isolates (n = 123), the highest level of resistance was observed for cefaclor at 28.5% of isolates, followed by cefotaxime at 16.3% and ampicillin at 9.7%. Moreover, extended‐spectrum beta‐lactamase (ESBL)‐producing E. coli harbouring the blaCTX‐M‐15 or blaCTX‐M‐27 genes were detected in 3.3% of total samples, and are associated with phylogenetic groups B1, B2 and D. Multiple variants of non‐ESBL blaTEM genes were detected, the majority of which were the blaTEM‐1 and blaTEM‐116 genes. Conclusions: Findings from this study shed light on the increased occurrence of ESBL‐ and non‐ESBL‐encoding gene variants in E. coli isolates with demonstrated multidrug resistant phenotypes. This study highlights the need for an expanded One Health approach to understanding AMR transmission dynamics, drivers of AMR development, and appropriate practices for antimicrobial stewardship in camel production systems within ASALs. [ABSTRACT FROM AUTHOR]

Urinary tract infections (UTIs) are predominantly caused by uropathogenic Escherichia coli (E. coli). There is rapid increase in antimicrobial resistance in UTIs, also declared as a serious health threat by World Health Organization (WHO). Present study was designed to investigate the antimicrobial resistance status with specific focus on ESBLs and carbapenemases in local uropathogenic E. coli (UPEC) isolates. E. coli isolates were characterized from patients of all ages visiting diagnostic laboratories for urine examination. Demographic data was also recorded for each patient. Antibiograms were developed to observe antibiotic resistance in UPEC using Kirby Bauer disc diffusion technique. Double Disc Synergy test (DDST) was used for phenotypic ESBL test. ESBLs and carbapenemases genes were detected in UPEC using PCR. The PCR results were confirmed by sequencing. The UPEC isolates under study exhibited 78%, 77%, 74%, 72% and 55% resistance against cefotaxime, amoxicillin, erythromycin, ceftriaxone and cefixime, respectively. Resistance against colistin and meropenem was observed in 64% and 34% isolates, respectively. Phenotypic DDST identified 48% isolates as ESBLs producers. Genotypic characterization identified 70%, 74.4% and 49% prevalence of CTXM-1, TEM-1 and CTXM-15 genes respectively. One isolate was observed exhibiting co-existence of all ESBL genes. TEM-1 + CTXM-1 and TEM-1 + CTXM-1 + CTXM-15 + OXA-1 gene patterns were dominant among ESBLs. For carbapenem-resistance, 14% isolates indicated the presence of KPC whereas GES and VIM was detected in 7% and 3.4% isolates, respectively. In conclusion, our results present a high prevalence of extensively drug resistant UPEC isolates with a considerable percentage of ESBL producers. These findings propose the need of continuous surveillance for antimicrobial resistance and targeted antimicrobial therapy. [ABSTRACT FROM AUTHOR]

The objective of this work was to characterize reference bacteria strains, belonging to the genus Bacillus and species of correlated genera, by simplified morphological and biochemical methods. The morphological characterization is based on the aspects of the colonies, as well as cytomorphology of the species, by optical and scanning microscopy. For biochemical characterization, the sensitivity test to antimicrobials by disk-diffusion is performed. Moreover, the strains were characterized by extracting intracellular proteins. Characteristics such as shape, color, and consistency of the colonies, in addition to the type of spore and production of protein crystals were determinants for the morphological characterization of these species. The antibiogram revealed high resistance to ß-lactam group antibiotics, in species of Bacillus cereus s.l group. In Bacillus subtilis s.l. group there was high susceptibility to antibiograms, mainly for species of B. subtilis. The protein profile provided specific protein patterns for some species, mainly bands of 130 e 65 kDa for B. thuringiensis, 140 e 130 kDa for Lysinibacillus sphaericus, and 115 kDa for Brevibacillus laterosporus. Our results showed that the morphological and biochemical characterizations, provided a simple identification, with easy interpretation, and low cost. [ABSTRACT FROM AUTHOR]

Objectives To elucidate the role of a novel carbapenem-hydrolysing class D β-lactamase (RAD-1) from Riemerella anatipestifer. Methods We applied WGS and bioinformatic analysis to screen putative β-lactamase genes in R. anatipestifer SCVM0004. A putative class D β-lactamase gene was cloned into pET24a and transferred into Escherichia coli BL21 (DE3) for antibiotic susceptibility determination and protein purification. Meanwhile, the purified native protein was used to determine the enzymatic activities. Results A class D β-lactamase, RAD-1, was identified in the genome of R. anatipestifer SCVM0004. It was distinct from all characterized class D β-lactamases (≤42% amino acid sequence identity). Searching in GenBank showed that bla RAD-1 was widely disseminated among R. anatipestifer. Genomic environment analysis indicated that the chromosomal structures of bla RAD-1-located regions were relatively conserved. Expression of RAD-1 in E. coli results in elevated MICs for various β-lactam antibiotics, including penicillins, extended-spectrum cephalosporins, a monobactam and carbapenems. Moreover, kinetic analysis of purified RAD-1 revealed: (i) high-level activity against penicillins; (ii) highest affinity for carbapenems; (iii) moderate hydrolysis of extended-spectrum cephalosporins and a monobactam; and (iv) no activity for oxacillin and cefoxitin. Conclusions This study identified a novel chromosomally located class D carbapenemase RAD-1 (Bush–Jacoby functional group 2def) in R. anatipestifer SCVM0004. Moreover, bioinformatic analysis confirmed that the RAD-1 was widely prevalent and conserved in R. anatipestifer. [ABSTRACT FROM AUTHOR]

Background: The occurrence of extended spectrum beta-lactamase (ESBL) producing bacteria such as Escherichia coli has increasingly become recognized beyond hospital settings. Resistance to other types of antibiotics limits treatment options while the existence of such bacteria among humans, animals, and the environment is suggestive of potential zoonotic and reverse-zoonotic transmission. This study aimed to establish the antibiotic susceptibility profiles of the ESBL-producing Escherichia coli (ESBL-EC) from human, animal, and environmental isolates obtained among farming households within Wakiso district using a One Health approach. Methods: A total of 100 ESBL-EC isolates from humans 35/100 (35%), animals 56/100 (56%), and the environment 9/100 (9%) were tested for susceptibility to 11 antibiotics. This was done using the Kirby-Bauer disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Data were analyzed in STATA ver. 16 and graphs were drawn in Microsoft excel ver. 10. Results: Most of the ESBL-EC isolates (98%) were resistant to more than two antibiotics. ESBL-EC isolates were most susceptible to meropenem (MEM) (88.0%), and imipenem (82.0%) followed by gentamicin (72%). ESBL-EC isolates from humans were most susceptible to meropenem (MEM) followed by imipenem (IPM)> gentamicin (CN)> ciprofloxacin (CIP). Animal samples were more susceptible to MEM, IPM, and CN but were highly resistant to cefotaxime (CTX)> cefepime (FEP)>other antibiotics. Multidrug resistance (MDR) was mostly reported among households keeping goats under intensive husbandry practices. Seven percent of the isolates exhibited carbapenem resistance while 22% showed aminoglycoside resistance. Similar resistance patterns among humans, animals, and environmental samples were also reported. Conclusion: Our study provides baseline information on non-hospital-based MDR caused by ESBL-EC using a One Health approach. ESBL-EC isolates were prevalent among apparently healthy community members, animals, and their environment. It is important to conduct more One Health approach studies to generate evidence on the drivers, resistance patterns, and transmission of ESBL-producing organisms at the human-animal-environmental interface. [ABSTRACT FROM AUTHOR]

The lack of effective therapeutics against emerging multi-drug resistant strains of Mycobacterium tuberculosis (Mtb) prompts the identification of novel antituberculosis targets. The essential nature of the peptidoglycan (PG) layer of the mycobacterial cell wall, which features several distinctive modifications, such as the N-glycolylation of muramic acid and the amidation of D-iso-glutamate, makes it a target of particular interest. To understand their role in susceptibility to beta-lactams and in the modulation of host-pathogen interactions, the genes encoding the enzymes responsible for these PG modifications (namH and murT/ gatD, respectively) were silenced in the model organism Mycobacterium smegmatis using CRISPR interference (CRISPRi). Although beta-lactams are not included in TB-therapy, their combination with beta-lactamase inhibitors is a prospective strategy to treat MDR-TB. To uncover synergistic effects between the action of beta-lactams and the depletion of these PG modifications, knockdown mutants were also constructed in strains lacking the major beta-lactamase of M. smegmatis BlaS, PM965 (M. smegmatis ΔblaS1) and PM979 (M. smegmatis ΔblaS1 ΔnamH). The phenotyping assays affirmed the essentiality of the amidation of D-iso-glutamate to the survival of mycobacteria, as opposed to the N-glycolylation of muramic acid. The qRT-PCR assays confirmed the successful repression of the target genes, along with few polar effects and differential knockdown level depending on PAM strength and target site. Both PG modifications were found to contribute to beta-lactam resistance. While the amidation of D-iso-glutamate impacted cefotaxime and isoniazid resistance, the N-glycolylation of muramic acid substantially promoted resistance to the tested beta-lactams. Their simultaneous depletion provoked synergistic reductions in beta-lactam MICs. Moreover, the depletion of these PG modifications promoted a significantly faster bacilli killing by J774 macrophages. Whole-genome sequencing revealed that these PG modifications are highly conserved in a set of 172 clinical strains of Mtb, demonstrating their potential as therapeutic targets against TB. Our results support the development of new therapeutic agents targeting these distinctive mycobacterial PG modifications. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance, especially carbapenem resistance, poses a serious threat to global public health. Here, a carbapenem-resistant Comamonasaquatica isolate SCLZS63 was recovered from hospital sewage. Whole-genome sequencing showed that SCLZS63 has a 4,048,791-bp circular chromosome and three plasmids. The carbapenemase gene blaAFM-1 is located on the 143,067-bp untypable plasmid p1_SCLZS63, which is a novel type of plasmid with two multidrug-resistant (MDR) regions. Notably, a novel class A serine β-lactamase gene, blaCAE-1, coexists with blaAFM-1 in the mosaic MDR2 region. Cloning assay showed that CAE-1 confers resistance to ampicillin, piperacillin, cefazolin, cefuroxime, and ceftriaxone, and elevates the MIC of ampicillin-sulbactam two-fold in Escherichia coli DH5α, suggesting that CAE-1 functions as a broad-spectrum β-lactamase. Amino acid sequences analysis suggested that blaCAE-1 may originate from Comamonadaceae. The blaAFM-1 in p1_SCLZS63 is located in a conserved structure of ISCR29-ΔgroL-blaAFM-1-ble-ΔtrpF-ΔISCR27-msrB-msrA-yfcG-corA. Comprehensive analysis of the blaAFM-bearing sequences revealed important roles of ISCR29 and ΔISCR27 in the mobilization and truncation of the core module of blaAFM alleles, respectively. The diverse passenger contents of class 1 integrons flanking the blaAFM core module make the complexity of genetic contexts for blaAFM. In conclusion, this study reveals that Comamonas may act as an important reservoir for antibiotics-resistance genes and plasmids in the environment. Continuous monitoring for the environmental emergence of antimicrobial-resistant bacteria is needed to control the spread of antimicrobial resistance. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen with a great ability to adapt to stress, in particular, to the selective pressure of antibiotics in the hospital environment. This pathogen constitutes a real public health concern, especially in low- and middle-income countries. In Cameroon, little is known about the drug resistance patterns of Pseudomonas aeruginosa. This study sought to determine the prevalence of Pseudomonas aeruginosa strains producing carbapenemases in six health facilities in the center, littoral, and west regions of Cameroon. An analytical cross-sectional study was conducted over a four-month period from July to October 2021. All Pseudomonas aeruginosa or suspected strains isolated from pathological products at the bacteriology laboratory of different health facilities were systematically collected and underwent a re-identification. After growing on cetrimide agar and successfully subculturing on nutrient agar, an oxidase test was performed on pure colonies, followed by biochemical identification (API 20NE system) of the bacterial suspension (0.5McFarland standard). Drug susceptibility testing for the detection of extended-spectrum beta-lactamases of overproduced inducible cephalosporinases and carbapenemases was performed according to adequate standard procedures. Of the 468 isolates collected, 347 (74.14%) were confirmed Pseudomonas aeruginosa after re-identification, of which 34.49% (120/347) produced inducible cephalosporinases (CAZR and C/TS) and 32.26% (112/347) extended-spectrum beta-lactamases. The prevalence of carbapenemase-producing P. aeruginosa (IMPR and C/TR) was 25.07% (87/347), with 17.24% (15/87) class A and 82.76% (72/87) class B. A high rate of resistance to penicillin (piperacillin: 70.58% and ticarcillin: 60.24%) was observed. We also noted a 34.49% resistance to ceftazidime, 30.22% to imipenem against 37.02% to meropenem, and 25.1% to ceftolozane/tazobactam (C/T). These strains also exhibited 79.57% resistance to quinolones and about 26% to aminoglycoside families. Multivariate analysis revealed that carbapenemase-producing Pseudomonas aeruginosa-related infections were significantly associated with hospitalization (p = 0.04), maternity (p = 0.03), surgery (p = 0.04), and intensive care wards (p = 0.04). This study highlighted a high burden of resistant strains of carbapenemase-producing Pseudomonas aeruginosa. Surveillance should be intensified to prevent the dissemination and spread of these strains. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the pharmacokinetic (PK) exposure and clinical toxicity for three beta-lactams: cefotaxime, piperacillin/tazobactam, and meropenem, depending on two lengths of infusion: continuous and intermittent, in critically ill children. This single center observational prospective study was conducted in a pediatric intensive care unit. All hospitalized children who had one measured plasma concentration of the investigated antibiotics were included. Plasma antibiotic concentrations were interpreted by a pharmacologist, using a Bayesian approach based on previously published population pharmacokinetic models in critically ill children. Exposure was considered optimal, low, or high according to the PK target 100% fT> 4 × MIC and a trough concentration below the toxic concentration (50 mg.L−1 for cefotaxime, 150 mg.L−1 for piperacillin, and 44 mg.L−1 for meropenem). Between May 2019 and January 2020, 80 patients were included and received 106 antibiotic courses: 74 (70%) were administered in intermittent infusion (II) and 32 (30%) in continuous infusion (CI). Compared to II, CI provided more optimal PK exposure (n = 22/32, 69% for CI versus n = 35/74, 47% for II, OR 1.2, 95%CI 1.01–1.5, p = 0.04), less underexposure (n = 4/32, 13% for CI versus n = 36/74, 49% for II, OR 0.7, 95%CI 0.6–0.84, p < 0.001), and more overexposure (n = 6/32, 19% for CI versus n = 3/74, 4% for II, OR 1.2, 95%CI 1.03–1.3, p = 0.01). Five adverse events have been reported during the study period, although none has been attributed to beta-lactam treatment. Conclusion: CI provided a higher probability to attain an optimal PK target compared to II, but also a higher risk for overexposure. Regular therapeutic drug monitoring is recommended in critically ill children receiving beta-lactams, regardless of the length of infusion. What is Known: • Since beta-lactams are time-dependent antibiotics, the probability to attain the pharmacokinetic target is higher with continuous infusion compared to that with intermittent infusion. • In daily practice, continuous or extended infusions are rarely used despite recent guidelines, and toxicity is hardly reported. What is New: • Continuous infusion provided a higher probability to attain an optimal pharmacokinetic target compared to intermittent infusion, but also a higher risk of overexposure. • Regular therapeutic drug monitoring is recommended in critically ill children receiving beta-lactams, regardless of the length of infusion. [ABSTRACT FROM AUTHOR]

In the present study, we demonstrated the synthesis of nanosized molecularly imprinted polymer (nanoMIP) particles via a miniemulsion polymerization strategy for the selective recognition of Penicillin G element, a β-lactam antibiotic (PenG-nanoMIP). The PenG-nanoMIP probe was developed by the mixture of functional monomer, methacrylic acid (MAA) and crosslinking agent, ethylene glycol dimethacrylate (EGDMA). The pre-polymerization of monomer-template mixture was emulsified into miniemulsion via sonication where the PenG-nanoMIP particles were obtained with an average diameter of 60–70 nm. Also, various MIPs were formed by taking different combinations of monomer to crosslinker and among all, the MIP formed with a ratio of 6:24 was chosen as the optimum formulation. In addition, the PenG-nanoMIP probe has been characterized thoroughly for the surface functionality (FTIR), morphological changes (FESEM-EDX), and particles diameter. Finally, the batch rebinding tests via UV–Vis were conducted to investigate that the PenG-nanoMIP 2 has the greatest binding capacity with 4.37 mg/g as compared to PenG-nanoMIP 1 and PenG-nanoMIP 3 having the binding capacities of 3.33 mg/g and 3.62 mg/g respectively. Based on the analysis, it can be suggested that PenG-nanoMIP 2 has offered the highest binding and selectivity for PenG. [ABSTRACT FROM AUTHOR]

The aims of the present study were to detect Escherichia coli in chicken distributed in Birjand, to investigate the prevalence of ESBL and AmpC beta-lactamases producers among them, and to identify their antibiotic resistance patterns. The study was conducted on 150 chicken samples, and the antimicrobial susceptibility patterns were determined by the Kirby–Bauer disk diffusion method. Phenotypic identification of ESBL and AmpC was performed by the combined disk test (CDT). The specific genes of ESBL and AmpC beta-lactamases were detected using two multiplex PCR (m-PCR) assays. According to our results, 116 out of 150 chicken samples were contaminated with E. coli. Moreover, the highest resistance of E. coli isolates was observed to trimethoprim/sulfamethoxazole (46%), ampicillin (40%), and amoxicillin (29.33%). In the molecular confirmation step, among 17 (11.33%) beta-lactamase producers, five samples contained the blaCTX-M14 gene (3.33%), two samples contained blaDHA (1.33%) and blaCTX-M3 gene (1.33%), and just one sample carried blaCMY-2 gene (0.66%). The blaSHV and blaTEM genes were not detected in any strains isolated from the chicken samples. This study showed the contamination of chicken with antibiotic-resistant E. coli. Therefore, it is recommended that veterinarians be more precautious in prescribing antibiotics. [ABSTRACT FROM AUTHOR]

The emergence of bacteria resistant to beta-lactam/beta-lactamase inhibitor combinations is insufficiently studied, wherein the role of the inoculum effect (IE) in decreased efficacy is unclear. To address these issues, 5-day treatments with doripenem and doripenem/relebactam combination at different ratios of the agents were simulated in a hollow-fiber dynamic model against carbapenemase-producing K. pneumoniae at standard and high inocula. Minimal inhibitory concentrations (MICs) of doripenem alone and in the presence of relebactam at two inocula were determined. Combination MICs were tested using traditional (fixed relebactam concentration) and pharmacokinetic-based approach (fixed doripenem-to-relebactam concentration ratio equal to the therapeutic 24-h area under the concentration-time curve (AUC) ratio). In all experiments, resistant subpopulations were noted, but combined simulations reduced their numbers. With doripenem, the IE was apparent for both K. pneumoniae isolates in combined treatments for one strain. The pharmacokinetic-based approach to combination MIC estimation compared to traditional showed stronger correlation between DOSE/MIC and emergence of resistance. These results support (1) the constraint of relebactam combined with doripenem against the emergence of resistance and IE; (2) the applicability of a pharmacokinetic-based approach to estimate carbapenem MICs in the presence of an inhibitor to predict the IE and to describe the patterns of resistance occurrence.

Gram-negative pathogens expressing serine β-lactamases (SBLs) and metallo-β-lactamases (MBLs), especially those with carbapenemase activity, threaten the clinical utility of almost all β-lactam antibiotics. Here we describe the discovery of a heteroaryl phosphonate scaffold that exhibits noncovalent cross-class inhibition of representative carbapenemases, specifically the SBL KPC-2 and the MBLs NDM-1 and VIM-2. The most potent lead, compound 16, exhibited low nM to low μM inhibition of KPC-2, NDM-1, and VIM-2. Compound 16 potentiated imipenem efficacy against resistant clinical and laboratory bacterial strains expressing carbapenemases while showing some cytotoxicity toward human HEK293T cells only at concentrations above 100 μg/mL. Complex structures with KPC-2, NDM-1, and VIM-2 demonstrate how these inhibitors achieve high binding affinity to both enzyme classes. These findings provide a structurally and mechanistically new scaffold for drug discovery targeting multidrug resistant Gram-negative pathogens and more generally highlight the active site features of carbapenemases that can be leveraged for lead discovery.

New Delhi metallo-β-lactamase-1 (NDM-1) poses an immediate threat to our most effective and widely prescribed drugs, the β-lactam-containing class of antibiotics. There are no clinically relevant inhibitors to combat NDM-1, despite significant efforts toward their development. Inhibitors that use a carboxylic acid motif for binding the ZnII ions in the active site of NDM-1 make up a large portion of the >500 inhibitors reported to date. New and structurally diverse scaffolds for inhibitor development are needed urgently. Herein we report the isosteric replacement of one carboxylate group of dipicolinic acid (DPA) to obtain DPA isosteres with good inhibitory activity against NDM-1 (and related metallo-β-lactamases, IMP-1 and VIM-2). It was determined that the choice of carboxylate isostere influences both the potency of NDM-1 inhibition and the mechanism of action. Additionally, we show that an isostere with a metal-stripping mechanism can be re-engineered into an inhibitor that favors ternary complex formation. This work provides a roadmap for future isosteric replacement of routinely used metal binding motifs (i.e., carboxylic acids) for the generation of new entities in NDM-1 inhibitor design and development.

BackgroundOvercoming β-lactam resistance in pathogens such as Pseudomonas aeruginosa is a major clinical challenge. Rapid molecular diagnostics (RMDs) have the potential to inform selection of empiric therapy in patients infected by P. aeruginosa.MethodsIn this study, we used a heterogeneous collection of 197 P. aeruginosa that included multidrug-resistant isolates to determine whether 2 representative RMDs (Acuitas Resistome test and VERIGENE gram-negative blood culture test) could identify susceptibility to 2 newer β-lactam/β-lactamase inhibitor (BL-BLI) combinations, ceftazidime/avibactam (CZA) and ceftolozane/tazobactam (TOL/TAZO).ResultsWe found that the studied RMD platforms were able to correctly identify BL-BLI susceptibility (susceptibility sensitivity, 100%; 95% confidence interval [CI], 97%, 100%) for both BLs-BLIs. However, their ability to detect resistance to these BLs-BLIs was lower (resistance sensitivity, 66%; 95% CI, 52%, 78% for TOL/TAZO and 33%; 95% CI, 20%, 49% for CZA).ConclusionsThe diagnostic platforms studied showed the most potential in scenarios where a resistance gene was detected or in scenarios where a resistance gene was not detected and the prevalence of resistance to TOL/TAZO or CZA is known to be low. Clinicians need to be mindful of the benefits and risks that result from empiric treatment decisions that are based on resistance gene detection in P. aeruginosa, acknowledging that such decisions are impacted by the prevalence of resistance, which varies temporally and geographically.

Despite intense interest in expanding chemical space, libraries containing hundreds-of-millions to billions of diverse molecules have remained inaccessible. Here we investigate structure-based docking of 170 million make-on-demand compounds from 130 well-characterized reactions. The resulting library is diverse, representing over 10.7 million scaffolds that are otherwise unavailable. For each compound in the library, docking against AmpC β-lactamase (AmpC) and the D4 dopamine receptor were simulated. From the top-ranking molecules, 44 and 549 compounds were synthesized and tested for interactions with AmpC and the D4 dopamine receptor, respectively. We found a phenolate inhibitor of AmpC, which revealed a group of inhibitors without known precedent. This molecule was optimized to 77 nM, which places it among the most potent non-covalent AmpC inhibitors known. Crystal structures of this and other AmpC inhibitors confirmed the docking predictions. Against the D4 dopamine receptor, hit rates fell almost monotonically with docking score, and a hit-rate versus score curve predicted that the library contained 453,000 ligands for the D4 dopamine receptor. Of 81 new chemotypes discovered, 30 showed submicromolar activity, including a 180-pM subtype-selective agonist of the D4 dopamine receptor.

Objectives: Carbapenemase-producing Enterobacterales (CPE) represent a serious threat for human health being frequently resistant to most of available antibiotics classes. Recently, ceftazidime/avibactam (CAZ/AVI) has been approved for treatment of infections by Gram-negative bacteria, including class A CPE (including KPC-producing K. pneumoniae). Following CAZ/AVI commercialization, resistance to this combination has been reported. The aim of this study was to evaluate the prevalence of CAZ/AVI resistance among carbapenem-resistant K. pneumoniae(CR-Kp) isolates recovered from bloodstream infections (BSI) and hospital-acquired pneumonia (HAP), representative of the contemporary southern Italy epidemiology, during the first pandemic wave of SARS-CoV-2. Methods: From Jan...20-Jun...20, 4 Laboratories, collected all consecutive, non-replicated CR-Kp from BSIs and HAPs. All isolates were subjected to i) MALDI-ToF identification; ii) antimicrobial susceptibility testing by microdilution method. CAZ/AVI resistant (CAZ/AVI-R) isolates were screened for presence of most common carbapenemase genes and subjected to whole genome sequencing for characterization. Results: A total of 89 isolates were collected. The majority of strains retained susceptibility to colistin, gentamicin and amikacin. Three strains (3/89, 3,4%) were CAZ/AVI-R (MIC range 16/4-64/4 mg/L). Among CAZ/AVI-R, one was KPC-type producer (an ST101) while the remaining where NDM-type and VIM-type producers and belonged to ST147, and ST45, respectively. Conclusion: During the pandemic period, in southern Italy, CAZ/AVI resistance remained infrequent but high-risk Klebsiella pneumoniae epidemic clones, producing the KPC-31 variant and class B carbapenamases were reported from some of the included centers.

The article discusses a comprehensive review of pharmacokinetic/pharmacodynamic (PK/PD) targets for β-lactamase inhibitors. The review found that the efficacy of β-lactamase inhibitors varies between different non-clinical experiments due to factors such as the dose and dosing regimen of the β-lactam partner and the characteristics of the target pathogen. The article suggests that the use of standard PK/PD indices for β-lactam/β-lactamase inhibitor combinations may be flawed and recommends alternative data analysis methods to improve dose and dosing regimen selection. These methods include calculating 'instantaneous' values and using mechanistic or semi-mechanistic PK/PD modeling. [Extracted from the article]

Background: Pathogenic Escherichia coli are an important cause of bacterial infections in both humans and pigs and many of antimicrobials are used for the treatment of E. coli infection. The objective of this study was to investigate the characteristics and relationship between humans and pigs regarding third-generation cephalosporin resistance and CMY-2-producing E. coli in Korea. Results: All 103 third-generation cephalosporin-resistant E. coli isolates showed multidrug resistance. Also, except for β-lactam/β-lactamase inhibitor combinations, all antimicrobials resistant rates were higher in pigs than in humans. A total of 36 isolates (humans: five isolates; pigs: 31 isolates) were positive for the CMY-2-encoding genes and thirty-two (88.9%) isolates detected class 1 integrons with 10 different gene cassette arrangements, and only 1 isolate detected a class 2 integron. The most common virulence genes in pigs were LT (71.0%), F18 (51.6%), and STb (51.6%), while stx2 (80.0%) was the most frequently detected gene in humans. Stx2 gene was also detected in pigs (6.5%). Interestingly, 36 CMY-2-producing E. coli isolates showed a high diversity of sequence types (ST), and ST88 was present in E. coli from both pigs (11 isolates) and humans (one isolate). Conclusion: Our findings suggest that a critical need for comprehensive surveillance of third-generation cephalosporin resistance is necessary to preserve the usefulness of third-generation cephalosporins in both humans and pigs. [ABSTRACT FROM AUTHOR]

Data on Point Prevalence Surveys (PPSs) in India are limited yet. We report findings of a PPS conducted in a core "National Antimicrobial Consumption Network site" under National Centre for Disease Control - WHO project "Point prevalence survey of antimicrobial consumption at healthcare facilities." A cross-sectional survey was conducted as per the "WHO methodology for PPS on antibiotic use in hospitals" in a tertiary care hospital in India in December 2021. Data were collected using predesigned and pretested questionnaire in separate hospital, ward, and patient forms. Eight hundred two inpatients (excluding ICUs) were covered out of whom 299 (37.3%) were on antibiotics with 11.7% receiving 3 or more antibiotics. Surgical prophylaxis (SP) (42.5%) and community acquired infections (32.8%) were the most common indications for antibiotic use. Of the patients, 92.5% received SP for more than 24 hrs. Most commonly prescribed antibiotics were penicillins with beta-lactamase inhibitors (22.3%). Of the total antibiotic prescriptions, 81.5% were from WHO essential medicines list and 12% from "not recommended" WHO AWaRe classification. Of the antibiotic prescriptions, 84.6% were parenteral. Few prescriptions complied with standard treatment guidelines (1.9%), documented indication for antibiotic use (11.6%), and stop/review date (4.4%) in notes. Double anaerobic cover accounted for 6.8% of the total prescriptions. Some identified areas for improvement were: formulation of hospital antibiotic guidelines, promoting culture of sending cultures, improvement in surgical antibiotic prophylaxis, decreasing use of antibiotic combinations and double anaerobic cover, fostering IV to oral switch of antibiotics, and ensuring effective communication among health care workers by documenting adequate information in medical notes. [ABSTRACT FROM AUTHOR]

The issue of increasing resistance to antibiotics in recent years has become an important problem all over the world. Our aim is to determine the antimicrobial resistance profile and Extended Spectrum Beta-Lactamase (ESBL) rates in Klebsiella spp isolates to prevent the gradual increase in multi-resistant isolates as a result of unconscious antibiotic use thereby contributing to the faster effective treatment of infections. A total of 100 Klebsiella spp were isolated and identified from various clinical specimens. Antibiotic susceptibility tests were performed using the Kirby-Bauer method. The presence of extended-spectrum beta-lactamases (ESBL) was detected using the Double Disc Synergy Test (DDST) and E-test methods. The rates of ESBL-producing strains were 46.1% in 6 K. oxytoca and 56.3% in 49 K. pneumoniae. These strains were found to be 38% in 38 adult patients and 17% in 17 pediatric patients, and this difference was statistically significant (p <0.05). The ESBL rate was 31% in 31 male patients and 24% in 24 female patients, and this difference was not statistically significant (p>0.05). This rate was found to be high in patients hospitalized in the pediatric service and intensive care unit. 67 out of 100 strains were found to be suspicious for ESBL by Disk Diffusion Test (DDT). DDST and E-tests were applied as confirmatory tests. The sensitivity of the DDST and E tests was 100%. Screening for ESBL in Klebsiella spp and other members of Enterobacteriaceae isolates is necessary to reduce further selection and spread of these increasingly broad-spectrum antimicrobial-resistant enteric pathogens. [ABSTRACT FROM AUTHOR]

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The asymmetric synthesis of methyl or pentyloxy N, O-bicyclic ?-butyrolactone lactams, 6-aminocyclohex- 3-ene-1,2-diol (an oseltamivir precursor) and ß-hydroxy lactam tripeptide, starting from (-)-(1S,2S)-1- azido-2-hydroxycyclohexene is hereby described. Synthetic transformations in the developed protocols include a linear relay of reduction/protection of the azide, allylic hydroxylation, alcoholysis, oxidative cleavage promoting lactonization/lactamization sequences and methylation. This route provides a simple synthetic pathway towards necine alkaloid derivatives, the antiviral drug oseltamivir (Tamiflu) and peptides incorporating rigid lactam units for foldamer synthesis thus extending the usefulness of our previously reported asymmetric synthetic methodology. [ABSTRACT FROM AUTHOR]

As antimicrobial resistance continues to grow, one of the biggest threats includes the members of the Enterobacterales order presenting with carbapenem resistance (CRE). Meropenem-vaborbactam, along with other beta-lactam/beta-lactamase agents, has been developed to help combat this growing concern and is currently approved to treat complicated urinary tract infections (cUTI), as well as acute pyelonephritis (AP), in the USA. Vaborbactam is a novel beta-lactamase inhibitor designed specifically to optimize and restore the activity of meropenem against resistant Enterobacterales. Vaborbactam inhibits a number of beta-lactamases, including in vitro activity against extended-spectrum beta-lactamases (ESBL) and the Klebsiella pneumoniae carbapenemase (KPC) group. KPC represents one of the most clinically relevant carbapenemase in the USA, accounting for the majority of carbapenemase-producing CRE. Meropenem-vaborbactam has been studied in the two Phase 3, noninferiority trials, TANGO I and TANGO II. TANGO I compared meropenem-vaborbactam against piperacillin-tazobactam in patients with cUTIs and was found to be noninferior for overall success and microbial eradication. TANGO II expanded to other disease states (bacteremia, hospital-acquired/ventilator-associated bacterial pneumonia [HAP/VAP], complicated intra-abdominal infection [cIAI], cUTI/AP) and was found to be noninferior against best available therapy (BAT) with respect to clinical cure at the end of treatment and the test of cure. Meropenem-vaborbactam maintained the established safety profile of meropenem alone, with headache as the most common adverse event in both phase 3 studies. Overall, clinical efficacy has been demonstrated and suggests the use of meropenem-vaborbactam for the treatment of cUTI is an option. [ABSTRACT FROM AUTHOR]

Limited data is available on the prevalence of ESBL genes in the STEC isolates of ruminant origin. This study investigated the molecular prevalence of ESBL-encoding genes (blaCTX-M, blaTEM, blaSHV and blaOXA) and AMR of 58 STEC isolates recovered from cattle (n = 32), sheep and goats (n = 26). In the current study, ESBL genes were identified by the molecular technique. Moreover phenotypic AMR was tested by disc diffusion method against six antibiotics, namely amoxicillin-clavulanic acid, tetracycline, neomycin, florfenicol, enrofloxacin, and sulfamethoxazole-trimethoprim. Phylogenetic groups were also determined by a PCR scheme. Isolates were categorized into five phylogroups of (A, B1, C, D, and E), with B1 being the most prevalent phylogenetic group (43; 74.1%). Statistical analysis revealed a significant association between phylogroup D and small ruminants (sheep and goats, p = 0.014). Moreover, the highest rates of antimicrobial resistance were related to tetracycline (25.9%) and neomycin (22.4%). Isolates resistant to tetracycline (p = 0.001), trimethoprim-sulfamethoxazole (p = 0.013) and neomycin (p = 0.00) were significantly prevalent among strains recovered from cattle. In addition, the majority of multidrug-resistant strains also had a significant distribution among cattle isolates (p = 0.001). In the current study, the prevalence of ESBL positive STEC was 12.06% (7/58). Genes blaCTX-M and blaTEM were detected separately and in combination in bovine isolates. However, only one STEC strain of small ruminants harbored blaTEM. In conclusion, it seems that cattle isolates are notable sources of different AMR traits which could be a threat to veterinary sections, public health and food hygiene, in particular. [ABSTRACT FROM AUTHOR]

Objective: Raw milk is an important source of nutrients. Therefore, today, there is a great demand for raw milk consumption. The positive side of milk consumption on growth and development cannot be ignored, but unfortunately, pathogens in raw milk are always potential public health risks for transmission pathogens. Bacteria such as Enterobacteriaceae in normal flora can cause serious problems due to their extended-spectrum beta-lactamase (ESBL) production. These bacteria and their resistance genes have been reported in raw milk. In this matter, the aim of the study is to determine the status of blaCTX-M-1, blaCTXM-2, blaTEM and blaSHV genes responsible for the production of ESBL enzyme in Escherichia coli and Klebsiella spp. strains to identify risk factors in raw milk consumption and to gain an understanding of the epidemiology of these resistant strains. Materials and methods: A total of different 50 raw milk samples were collected and subjected to phenotypic microbiological analysis and Real-time PCR targeting blaCTX-M-1, blaCTX-M-2, blaTEM and blaSHV genes. In the phenotypic analyses, suspicious isolates were identified by classical microbiological methods and antibiotic resistance profiles were revealed. Results: These results indicated that raw milk is a potential reservoir for ESBL producing E. Coli, Klebsiella spp. strains are obviously significant. And It was determined that CTX-M-basedESBL genes are predominant in ESBL production. Conclusion: The present study revealed that raw milk is epidemiologically involved in the transmission of ESBL genes. Raw milk could be distributed to ESBL genes widely and is consumed in Şanlıurfa. [ABSTRACT FROM AUTHOR]

Pasteurella multocida, a Gram-negative, penicillin-sensitive coccobacillus that is frequently a member of the normal respiratory microbiota of different animals, remains a clinically important pathogen with the ability to cause severe disease. Few case reports have involved P. multocida infections without animal bites. Moreover, few reports have identified P. multocida as the causative agent of septic shock, which usually occurs in patients with cirrhosis and/or immunocompromised patients. To our knowledge, a human submandibular salivary gland abscess caused by P. multocida has not been reported. Pasteurella spp. are resistant to benzylpenicillin, and human isolates of betalactamase-producing resistant strains of P. multocida resistant have also been documented. The noteworthy findings of the current study were as follows: (i) the combination of ceftriaxone and ciprofloxacin successfully treated two patients infected with P. multocida; (ii) the first reported case of a septicemic patient with no history of animal bites and a submandibular P. multocida infection; and (iii) an immunocompetent patient in septic shock due to a P. multocida systemic infection. [ABSTRACT FROM AUTHOR]

AmpC β-lactamases are enzymes that are resistant to β-lactams, such as penicillin and cephalosporin, but not cefoxitin and cefotetan. this study was conducted to characterize AmpC β-lactamases in Enterobacteriaceae. this study included 200 cephalosporin-resistant Gram-negative isolates recovered from different samples between January 2015 and December 2016. the isolates were subjected to phenotypic tests, and those that tested positive were further analyzed by PCR for six AmpC genotypes: ACC, DHA, FOX, Cit, MOX, and eBC. Among the 200 strains, 32% (64) were positive for AmpC β-lactamases by different phenotypic methods. the target genotypes were detected in 20 (10%) of the isolates. Pus was the predominant source of AmpC isolates. Klebsiella pneumoniae (55%) was the most common producer of AmpC β-lactamase. Cit-FOX was the predominant gene type. As there is variation in the prevalence of AmpC β-lactamases in different geographic regions, periodic surveillance and measures to control infection can prevent the spread of these genes. [ABSTRACT FROM AUTHOR]

Background: Broad-spectrum antibiotic resistance genes are one of the most common developing resistance genes worldwide. Accordingly, it is of paramount importance to study the extended-spectrum beta-lactamase genes to report them to physicians to select the most appropriate treatment. Objectives: This study aimed to detect three genes of ESBL such as TEM, AmpC, and KPC simultaneously. Methods: Primers were designed for ESBL genes such as TEM, AmpC, and KPC with Genscript software. In this study, control-positive genes were used for the PCR set-up. Fifty isolates of Escherichia coli isolated in the Baqiyatallah Hospital were confirmed and checked by Multiplex PCR. Results: This study revealed that TEM, AmpC, and KPC primers could detect positive control genes. The sensitivity and specificity of the multiplex PCR technique for these genes were 0.001 ng and 100%, respectively. Conclusions: This study revealed that a Multiplex PCR with a sensitivity of 0.001 ng and 100% specificity can detect ESBL genes precisely. Accordingly, the rapid and precise detection of the antibiotic resistance genes and the recommendation of an appropriate treatment pattern can decrease the distribution of antibiotic resistance occurrence and economic cost. [ABSTRACT FROM AUTHOR]

Antimicrobial drugs have been noticed to have reduce activity effective due to upsurge witnessed in resistance of microbes. To deal with viewpoint of such a circumstance, we must seek ways to prevent it or atleast mitigate its effects in order to provide its activity against the microbes. Hence, novel antimicrobials are the one of the most promising solution for ending antimicrobial resistance. Furthermore, due to the less development of newer antimicrobials in recent years, the only way to combat microbial resistance are various synergistic approaches of exploring antimicrobial drug combinations. This combination's efficacy is due to a synergistic chemical that re-sensitizes the resistant microbial strain. It has been observed that classes of β-lactamases inhibitors, efflux pump inhibitors and membrane permeabilizers are of particular relevance, since they can break resistance to the most commonly used antimicrobials. This review explains the readers that how these synergistic combinations can help to reduce or eliminate the microbial resistance supported with clinical evidence. [ABSTRACT FROM AUTHOR]

The role of β-lactamases in reduced susceptibility or resistance to cefiderocol has been supported by recent reports. The purpose of this study was to investigate the in vitro impact of clinically available β-lactamase inhibitors on cefiderocol activity against characterized carbapenemase-producing Gram-negative isolates. A collection of 39 well-characterized Gram-negative isolates obtained from various clinical sources and countries were included. Cefiderocol antimicrobial susceptibility was evaluated via reference broth microdilution. The chequerboard microdilution method and time–kill assays were used to determine the synergy of tazobactam, avibactam, vaborbactam and relebactam in combination with cefiderocol. MICs of cefiderocol presented a 4- to 256-fold reduction against Klebsiella pneumoniae carbapenemase (KPC)-producing Gram-negative isolates (predominantly K. pneumoniae) when avibactam, vaborbactam and relebactam were combined individually. Notably, the KPC-inhibitors led to a 4- to 32-fold reduction in cefiderocol MICs in the four cefiderocol-resistant KPC-producing K. pneumoniae isolates, showing restoration of cefiderocol susceptibility (MIC ≤ 2 mg/L) in ten out of twelve cases. Tazobactam led to a 4- to 64-fold decrease in cefiderocol MICs only in K. pneumoniae strains harbouring blaKPC-41, blaKPC-31, blaKPC-53 and blaKPC-66. The synergistic effect of all serine-β-lactamase inhibitors on cefiderocol activity was also shown in OXA-48-like-producing Enterobacterales strains. Conversely, a combination of β-lactamases inhibitors with cefiderocol was not synergistic with all OXA-23-like-producing strains and most metallo-β-lactamases producers. In conclusion, the addition of clinically available serine β-lactamase inhibitors to cefiderocol might represent an important development in the formulation to increase its spectrum and therapeutic efficacy, and to limit in vivo resistance emergence. [ABSTRACT FROM AUTHOR]

OBJECTiVE: To examine antibiotic use in long-term care residents at a VA skilled nursing facility. DESiGN: Quality improvement project. SETTiNG: Long-term care residents admitted to the Community Living Center of a Midwestern VA medical center. PATiENTS: Inclusion criteria were long-term care residents admitted to the VA skilled nursing facility who were prescribed an oral (including via percutaneous endoscopic gastrostomy tube) antibiotic from January 1, 2018, to December 31, 2018. Residents were excluded if they were admitted for hospice care, rehabilitation, or short-term skilled nursing. Residents were also excluded if they were on intravenous or topical antibiotics. RESULTS: Fifty-six unique antibiotic courses consisting of 13 different antibiotics were evaluated. Median days of therapy per 1,000 resident days was 39.7 overall, for quarter 1 was 51, quarter 2 was 42, quarter 3 was 49.3, and quarter 4 was 17.5. Average antibiotic days of therapy was 7.6 days. Fluoroquinolones comprised 26.8% of the courses, followed by beta-lactamase inhibitors at 25%. Of the 56 courses, 85.7% were found to have appropriate dose/frequency, while 73.2% had appropriate duration. No reports of Clostridioides difficile infection were noted. Thirty-one antibiotic courses had cultures obtained, of which 29 did not deescalate therapy. Of these, 5 (17.2%) were indicated for de-escalation. CONCLUSiON: Antibiotic use in this skilled nursing facility have opportunities for intervention, including reducing fluoroquinolone use, optimizing de-escalation, and shortening days of therapy. The implementation of an antimicrobial stewardship monitoring program within the long-term care setting could assist in maximizing therapy while reducing antibiotic exposure. [ABSTRACT FROM AUTHOR]

Cefiderocol (CFDC) is a novel, broad-spectrum siderophore cephalosporin with potential activity against multi-drug (MDR) and extensively drug-resistant (XDR) Enterobacterales, including carbapenem-resistant strains. We assessed the in vitro susceptibility to CFDC of MDR, and XDR E. coli isolates derived from clinical samples of hospitalized patients. Disk diffusion (DD) and MIC (minimum inhibitory concentration) test strip (MTS) methods were used. The results were interpreted based on EUCAST (version 12.0 2022) recommendations. Among all E. coli isolates, 98 (94.2%) and 99 (95.2%) were susceptible to CFDC when the DD and MTS methods were used, respectively (MIC range: <0.016–4 µg/mL, MIC50: 0.19 µg/mL, MIC90: 0.75 µg/mL). With the DD and MTS methods, all (MIC range: 0.016–2 µg/mL, MIC50: 0.19 µg/mL, MIC90: 0.75 µg/mL) but three (96.6%) ESBL-positive isolates were susceptible to CFDC. Out of all the metallo-beta-lactamase-positive E. coli isolates (MIC range: 0.016–4 µg/mL, MIC50: 0.5 µg/mL, MIC90: 1.5 µg/mL), 16.7% were resistant to CFDC with the DD method, while 11.1% were resistant to CFDC when the MTS method was used. CFDC is a novel therapeutic option against MDR and XDR E. coli isolates and is promising in the treatment of carbapenem-resistant E. coli strains, also for those carrying Verona integron-encoded metallo-beta-lactamases, when new beta-lactam-beta-lactamase inhibitors cannot be used. [ABSTRACT FROM AUTHOR]

• Three Chlamydia psittaci strains were isolated from psittacosis patients in China. • A core genome multilocus sequence typing method for C. psittaci was constructed. • Using the developed method, the new isolates were classified as a new variant. • Treatment with doxycycline appeared to be effective to treat these patients. • Our study expanded the catalog of underrepresented and diverse C. psittaci genomes. From January 2022 to November 2022, sporadic psittacosis occurred in Lishui city, China. The patients were presented with fever, cough, and pulmonary infiltration. Their clinical symptoms were not relieved after receiving cephalosporin, penicillin, beta-lactamase inhibitors, and quinolones. Metagenomic next-generation sequencing of bronchoalveolar lavage fluid samples from the patients revealed Chlamydia psittaci infection. Then, three C. psittaci strains were isolated from the patients. Their whole genome sequences (WGSs) were obtained, and a core genome multilocus sequence typing (cgMLST) method was developed to study the population structure of C. psittaci. Using the constructed cgMLST method, 72 WGSs were divided into four related groups and ten sub-clusters. The Lishui strains formed a unique population of C. psittaci , which might represent a new variant of C. psittaci. In vitro antimicrobial susceptibility testing suggested that the Lishui strains were sensitive to tetracycline, macrolides, quinolones, and no drug-resistance was observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A dual-response probe to rapid detection of β-lactam-resistant bacteria is developed. • The probe simultaneously exhibits near-infrared fluorescence and photoacoustics signals. • A portable photoacoustics PA device for detecting β-lactamase is constructed. Early identification of antimicrobial-resistant (AMR) bacteria is of great significance to guide the use of drugs and reduce the risk of AMR infection. One of the main reasons for AMR resistance to antibiotic therapy is the production of β-lactamase that decomposes antibiotics. Accurate and rapid detection of β-lactamase is crucial o deal with bacterial resistance. Herein, a dual-modal probe with near-infrared fluorescence (NIRF) and photoacoustics (PA) to rapid detection of β-lactamases (TEM-1) and β-lactam-resistant bacteria (BLRB) was ingeniously designed and developed. The NIRF and PA signal of CyPA-L can be fully turned on after 7 min of incubation of CyPA-L with TEM-1, and also showed high selectivity for TEM-1 among multiple interfering analytes. Notably, a portable PA device with immediate detection (POCT) capability was developed to detect β-lactamase and BLRB through PA signaling of CyPA-L. The design of probe and facile device will provide a new way for the diagnosis and symptomatic treatment of early drug-resistant bacteria. [ABSTRACT FROM AUTHOR]