CTX-M-type extended-spectrum beta-lactamases (ESBLs) have shown a high level of global transmission, with limited systematic understanding of their epidemic patterns in China. A comprehensive analysis covering 1974-2023 identified 133 (3.2%) blaCTX-Ms-producing strains among 4146 strains from 25 Chinese cities across 82 genera were performed. Integrating with public database strains (n=431), the study comprised 564 blaCTX-Ms-positive isolates sourced from 19 provinces (1986-2022) including 300 (53.2%) clinical and 228 (40.4%) environmental blaCTX-Ms. The most frequent sources of infection were diarrhea (44%), upper respiratory tract infection (22.2%) and urinary tract infection (14%). Phylogenetic studies indicated CTX-M-1 and CTX-M-9 emerged as the predominant subgroups. Lineages exhibited diverse mutation sites without being restricted by geographical conditions. Ka/Ks ratio distribution varied significantly among lineages (P<0.05). Lineages 1 (L1) and L2 were characterized by neutral or purifying selection, whereas L3 was mainly under purifying selection. Adaptive evolution was noted at different loci within each lineage. The influence of geographic distance on phylogeny varied distinctly across different lineages. Notably, for Lineage L3, there was a remarkably strong correlation observed, which implies that human activities exerted a more substantial influence on genetic distances compared to geography. This research provides valuable insights into the epidemiology, genotypic diversity, and evolutionary traits of blaCTX-Ms in China, supporting health risk assessment for early warning systems.

Efficient analysis of active ingredient in complex natural products is crucial for drug discovery, but developing a simple method for this is challenging. The discovery of drugs against bacterial resistance is urgent because drug-resistant bacteria produce β-lactamases, which inactivate antibiotics and increase infection risks, particularly the AmpC β-lactamase. Here, an integrated analytical model based on colorimetric sensing and magnetic nanoparticles (MNPs) affinity chromatography was developed for screening AmpC β-lactamase inhibitors. A paper-based colorimetric microdevice was designed for rapid identification of inhibitors in complex samples. Magnetic nanoparticles affinity was then utilized to capture, isolate and identify the active ingredient by immobilized enzyme technology. This comprehensive analytical model greatly improves the efficiency and accuracy of inhibitor screening compared to other screening methods. Finally, the method was applied to screen AmpC β-lactamase activity inhibitors from five natural medicines. As a result, epicatechin gallate, a potential active component of AmpC β-lactamase, was successfully identified from Rhodiola rosea L. After thorough integration with in vitro antibacterial assays, the activity of the screened compounds was further substantiated. Their binding was further explored by molecular docking and molecular dynamics simulations. Consequently, potential AmpC β-lactamase inhibitors are rapidly and precisely captured from complex natural products by this method, which will offer novel insights into the screening of enzyme inhibitors within natural products.

Ceftriaxone-resistant Enterobacterales remain a public health threat; contemporary data investigating their molecular epidemiology are limited. Five hundred consecutive ceftriaxone-resistant (MIC ≥ 4 µg/mL) Enterobacterales bloodstream isolates were collected between 2018 and 2022 from three Maryland hospitals. Broth microdilution confirmed antibiotic susceptibilities. Whole-genome sequencing identified extended-spectrum β-lactamase (ESBL) and ampC genes both in bacterial chromosomes (c-ampC) and on plasmids (p-ampC). Mutations in promoter or attenuator regions of the Escherichia coli c-ampC gene (i.e., blaEC gene) with the potential to result in ampC derepression were investigated. The presence of ESBL or ampC genes was confirmed in 497 (99.4%) isolates. Two hundred seventy-nine (55.8%) isolates had both ESBL and ampC genes. ESBL families were identified among 398 (80%) patients: blaCTX-M (n = 370), blaSHV (n = 17), blaOXY (n = 14), and blaVEB (n = 5). Ceftriaxone-resistant Enterobacterales species carrying ESBL genes included the following: E. coli (67%), Klebsiella pneumoniae (24%), Klebsiella oxytoca (4%), Proteus mirabilis (2%), Enterobacter cloacae complex (2%), Klebsiella aerogenes (1%), Providencia stuartii (<1%), and Serratia marcescens (<1%). c-ampC genes were identified in 374 (75%) of the 500 isolates. Only 7% of E. coli isolates with mutations in the promoter or attenuator region of the c-ampC gene exhibited resistance to cefoxitin, a proxy for increased AmpC production. Two p-ampC genes were confirmed in 25 (5%) of the 500 isolates: blaCMY-59 (72%) and blaDHA-1 (28%; confined to E. coli [92%] and K. pneumoniae [8%]). Until comprehensive β-lactamase molecular testing is available, the species-specific prevalence of ESBL and ampC genes in ceftriaxone-resistant Enterobacterales should be considered to promote effective albeit judicious antibiotic prescribing. Mutations in promoter or attenuator regions of the E. coli c-ampC gene do not appear to contribute significantly to increased AmpC production in this species.

Due to the widespread use of broad-spectrum antibiotics, the problem of antibiotic resistance has become an increasingly serious global threat. One of the key mechanisms of Escherichia coli resistance to beta-lactam antibiotics is the production of beta-lactamase enzymes, which poses a dilemma for clinicians in selecting antibiotics when faced with resistant bacterial infections. However, research on the reversal of bacterial resistance is limited.

This study involved the preparation of Iris tectorum extract and detection of its effects on antibiotics sensitivity, extended-spectrum beta-lactamase (ESBL) gene expression, and histidine kinase phosphorylation levels in β-lactam antibiotic-resistant Escherichia coli. Additionally, analyses of the active ingredients of Iris tectorum extract were conducted with a liquid chromatography-mass spectrometer, and the binding sites were predicted by molecular docking.

Iris tectorum extract could restore the sensitivity of Escherichia coli to beta-lactam antibiotics and reduce the expression levels of ESBL genes and histidine phosphorylation levels. The active ingredients of Iris tectorum extract may be irigenin and tectorigenin, and these two small molecules could bind to histidine kinase to inhibit phosphorylation.

Iris tectorum extract may serve as an antibiotic adjuvant, restoring the sensitivity of antibiotic-resistant bacteria by inhibiting histidine kinase phosphorylation, thereby alleviating the problem of Escherichia coli resistance to β-lactam antibiotics.

The study aimed to review the beta-lactamase resistance genes detected in Enterobacterales from humans, animals, and the environment in the United States.

We conducted a comprehensive search on PubMed, Web of Science, and Google Scholar for articles reporting beta-lactamase genes in the United States from 1981 to 22 April 2022, following the PRISMA protocol. Studies were evaluated based on predefined eligibility criteria, and both qualitative and quantitative analyses were conducted on the selected studies.

Of the 335 articles, a total of 169 different beta-lactamase genes, including narrow-spectrum, extended-spectrum, AmpC, and carbapenemase have been detected and reported in the United States, with human (137), animal (53), and environment (47). 22 genes (blaCMY-2, blaCTX-M-(1, 2, 9, 14, 15, 27, 32, 65), blaFOX-5, blaIMP-27, blaKPC-2, blaNDM-(1, 5), blaOXA-(1, 48), blaPSE-1, blaSHV-(1, 12), blaTEM-(1, 1A, 1B)) have been reported across animals, humans, and environment. Notably, blaCTX-M-15 was prevalent in E. coli isolates, with an overall pooled proportion of 10.7 %, varying between animals (8.6 %), humans (13.1 %), and the environment (0.8 %). Similarly, blaCMY-2 in E. coli isolates had an overall pooled proportion of 10.6 %, with distinctions in proportion among animals (1.6 %), humans (41.3 %), and the environment (16.2 %). The sequence type (ST131) was detected as the predominant, mainly associated with the blaCTX-M-15, with a pooled proportion of 56.9 %, varying from 14.3 % to 90 % across studies.

This study highlights the distribution of beta-lactamases in the United States, essential for understanding One Health and the molecular epidemiology of key beta-lactamases, especially extended-spectrum beta-lactamases and carbapenemases.

Currently, antimicrobial agents are widely used in both animals and agriculture, causing the crisis of multidrug-resistant (MDR) bacteria. In this study we surveyed for 4 important antimicrobial-resistant bacteria: extended-spectrum β-lactamase (ESBL)-producing Escherichia coli, Klebsiella pneumoniae and Salmonella spp., and methicillin-resistant Staphylococcus aureus (MRSA) from the environment around chicken and pig farms.

Forty-four soils, 44 water and 15 bootstrap samples were collected from upstream and downstream of the riverside close to 22 animal farms in 2020 (9 farms) and 2023 (13 farms). The samples were cultured in appropriate media and isolated colonies were further identified. Antimicrobial susceptibility and ESBL production were tested by disk diffusion method except for colistin susceptibility determined by broth disk elution test. Common resistance genes were tested by polymerase chain reaction (PCR) methods.

A total of 123 E. coli (n = 59) and Klebsiella species (n = 64) were identified and 25 isolates of them were MDR; 21 and 4 isolates from the downstream and upstream areas respectively. In addition, 13 isolates were ESBL producers, of which 12 isolates were from the downstream area. The most common ESBL gene among both organisms was blaCTX-M, whereas colistin resistance gene, mcr-1, was found in 2 E. coli isolates. Salmonella spp. and MRSA were not isolated from any sample.

Antimicrobial-resistant bacteria were found in the environment around the animal farms especially from the downstream area, suggesting the urgent need of judicious use of antimicrobial agents in animal farms.

This study aimed to identify the aetiological spectrum, seasonal distribution and antimicrobial resistance patterns of diarrhoeal diseases in Bhutan.

The study used a cross-sectional, retrospective analysis of secondary data gathered through a passive, hospital-based sentinel surveillance for diarrhoeal disease across 12 hospitals, representing Bhutan's demographically diverse regions.

A total of 3429 participants' data of all age groups who presented with diarrhoea at sentinel hospitals between 1 January 1 2016 and 31 December 2022 were analysed.

Diarrhoeagenic Escherichia coli (DEC), Shigella, Salmonella and Aeromonas spp. were predominant bacterial pathogens, while Rotavirus, Astrovirus and Norovirus were the leading viral pathogens. Coinfections were observed in 195 cases. Children under nine were significantly affected than the other age groups. Seasonal trends revealed that bacterial pathogen incidence peaked during the summer/monsoon season, viral pathogens were more common in winter and spring, and parasites persisted year-round. Among the antibiotics tested, gentamicin, chloramphenicol, ceftriaxone and tetracycline exhibited high efficacy, with susceptibility rates of 93.4%, 87.2%, 81.5% and 69.5%, respectively. Conversely, high resistance rates were observed for amoxicillin (80.3%), ampicillin (77.4%) and nalidixic acid (69.5%). Multidrug resistance was prevalent, with β-lactamase production contributing to resistance rates of 80.7% to penicillin and 65.4% to fluoroquinolones groups. Cephalosporin resistance was also notable, with rates of 34.4% for cephalexin, 40.0% for cefazolin and 16.9% for ceftriaxone.

DEC and Rotavirus were identified as the leading causes of diarrhoea, with significant resistance patterns observed in common bacterial isolates. These findings underscore the need for DEC screening in paediatric cases and emphasise the need for sustained antimicrobial resistance surveillance.

Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in dairy farm wastewater represents a significant threat to environmental and public health due to the dissemination of antibiotic-resistance genes. This study investigates the molecular profiles of ESBL-producing E. coli isolates harboring bla CTX-M, bla TEM, and bla SHV genes from dairy farm wastewater in East Java, Indonesia.

Wastewater samples (n = 342) were collected from six major dairy regions in East Java: Pasuruan, Malang, Tulungagung, Blitar, Batu, and Kediri. The samples underwent bacterial isolation, identification, and ESBL phenotypic screening using the double-disk synergy test (DDST). Molecular genotyping of bla CTX-M, bla TEM, and bla SHV was conducted using a polymerase chain reaction.

Of the samples, 69.30% (237/342) tested positive for E. coli, with 32.91% (78/237) identified as ESBL producers through DDST. Molecular genotyping confirmed ESBL genes in 28.20% (22/78) of the isolates. The genotypic distribution was 77.2% (17/22) bla TEM, 4.5% (1/22) bla CTX-M, 9.0% (2/22) bla TEM + bla SHV, and 9.0% (2/22) bla TEM + bla CTX-M. These findings highlight the dominance of bla TEM and the presence of multi-gene combinations in East Java's dairy farm wastewater.

The identified molecular profiles underscore dairy farm wastewater as a critical reservoir for antibiotic resistance genes, particularly bla TEM. Addressing this issue necessitates stringent antimicrobial use policies, improved wastewater management, and enhanced biosecurity measures. These findings support a One Health approach to mitigate environmental and public health risks associated with AMR.

Despite clinical relevance, commercially available molecular tools for accurate β-lactamase detection are limited. In this study, we evaluated the performance of the ARM-DⓇ Kit, β-Lactamase, a commercially available multiplex PCR assay designed to detect nine β-lactamase genes, including the five major plasmid-mediated carbapenemases, ESBL and AmpC genes circulating in the United States.

A diverse collection of 113 Gram-negative isolates, including 42 with multiple β-lactamases genes, was selected from the U.S. Centers for Disease Control and Prevention (CDC) & Food and Drug Administration (FDA) Antimicrobial Resistance Isolate Bank, to represent the most frequently detected bacterial species carrying plasmid-mediated β-lactam resistance genes.

Results were compared with whole genome sequence data. Of 164 β-lactamase gene targets with 49 unique variants, all were detected correctly without any cross-reactivity. The sensitivity and specificity were 100% (164/164) and 99.9% (852/853), respectively.

The ARM-DⓇ Kit, β-Lactamase detected a wide range of β-lactamase genotypes at a low upfront cost. The Streck assay represents a suitable, comprehensive tool for the detection of key β-lactamase resistance genes of public health concern in the United States.

To determine the etiological agents responsible for acute pneumonia in puppies in China, this study utilized bronchoalveolar lavage (BAL) fluid extraction to enable the isolation, culture, biochemical identification, and 16S rRNA PCR amplification of the pathogens. Following preliminary identification, the pathogens underwent analysis for antibiotic resistance phenotypes and resistance genes. Additionally, the study examined the presence of virulence genes, conducted multilocus sequence typing (MLST), and performed whole-genome sequencing (WGS). The findings revealed that all four isolated pathogens were characterized as extraintestinal pathogenic Escherichia coli (ExPEC). The examined ExPEC strains demonstrated resistance to cephalosporins, tetracyclines, and penicillins, while remaining susceptible to aminoglycosides, beta-lactamase inhibitors, carbapenems, chloramphenicols, and sulfonamides. An analysis of virulence genes identified the presence of eight genes, namely CNF-I, fyuA, fimC, papC, ompA, fimH, irp2, and iroN, which are implicated in their invasiveness and potential to inflict tissue damage. The MLST analysis revealed that all ExPEC strains were classified under either sequence type ST131 (Achtman database) or ST43 (Pasteur database). The study further determined that these strains were absent in the kennel's drinking water source, thereby ruling out water contamination as a potential factor in the emergence of ST131-type ExPEC. This study offers a theoretical framework and empirical evidence for elucidating the potential pathogenic mechanisms and clinical therapeutic strategies of ExPEC in the etiology of acute pneumonia in puppies.

Antimicrobial resistance (AMR) poses a severe global health threat, yet the transmission pathways of AMR within communal public environments, where humans and animals interact, remain poorly explored. This study investigated AMR risk pathways, prevalence, and seasonality of extended-spectrum β-lactamase (ESBL) producing E. coli and K. pneumoniae, and observed practices contributing to environmental contamination within urban, peri-urban, and rural Malawi. Using the SaniPath tool, in August 2020, transect walks across three Malawian study sites identified potential AMR exposure pathways, including drains, standing water, soil, and areas of communal hand contact. Subsequently, from September-2020 to August-2021, 1440 environmental samples were collected at critical points along exposure routes (n = 40/month from each site). These underwent microbiological analysis using chromogenic agar techniques to detect the presence of ESBL E. coli and ESBL K. pneumoniae. Results showed the highest ESBL prevalence in urban environments (68.1 %, 95%CI = 0.64-0.72, p < 0.001) with a higher ESBL presence seen in drains (58.8 %, 95%CI = 055-0.62, p < 0.001) and soil (54.1 %, 95%CI = 0.46-0.62, p < 0.001) compared to other pathways. Environmental contamination was attributed to unavailability and poor condition of sanitation and hygiene infrastructure based on key informant interviews with community leaders (n = 9) and confirmed by independent observation. ESBL prevalence varied between seasons (χ2 (2,N = 1440) = 10.89, p = 0.004), with the highest in the hot-dry period (55.8 % (n = 201)). Prevalence also increased with increased rainfall (for ESBL E.coli). We highlight that community environments are likely to be a crucial component in AMR transmission, evident in the abundance of ESBL bacteria in identified exposure pathways. Additionally, poor sanitation infrastructure and practices coupled with seasonal dynamics further affect the presence of ESBLs in communal environments. Therefore, a context appropriate whole system approach that tackles infrastructure and behavioural factors, supported by effective surveillance is required to impact AMR and a range of aligned development challenges in these settings.

Urinary tract infections (UTIs) are the second most common infection, affecting 150 million people each year worldwide. Enterobacteriaceae species expressing extended-spectrum β-lactamases (ESBLs) are on the rise across the globe and are becoming a severe problem in the therapeutic management of clinical cases of urinary tract infection. Knowledge of the prevalence and antibiogram profile of such isolates is essential to develop an appropriate treatment methodology. This study aimed to investigate the prevalence of Enterobacteriaceae isolates exhibiting ESBL and their selective oral antibiogram profile at the district general hospital, Polonnaruwa.

A total of 4386 urine specimens received to the Microbiology Laboratory during the study period. Among them, 1081 (24.6%) showed positive results for urine culture while 200/1081 specimens showed ESBL isolates. Out of the selected 200 specimen's majority (67.5%) of samples received from the In-Patient Department. There were 200 patients and reported that 115 (57.5%) were females and 85 (42.5%) were males. The majority (51%) of the patients belong to the age group of 55-74 years. Among the ESBLs positive specimens, the majority 74.5% (n = 149) identified organisms were E. coli followed by Klebsiella spp.17.5% (n = 35), Enterobacteriaceae 7% (n = 14) and only1% (n = 2) isolate of Proteus spp. Mecillinam (87.92%) and Nitrofurantoin (83.2%) showed higher effectiveness against E. coli. Nitrofurantoin showed the highest effectiveness against Klebsiella spp. (40%), other Enterobacteriaceae spp. (100%). Proteus spp. showed 100% effectiveness and resistance respectively against Ciprofloxacin, Cotrimoxazole and Nitrofurantoin.

The most predominant ESBLs producing uro-pathogen was the E. coli in the study setting and E. coli had higher sensitivity rate against Mecillinam. Among currently used oral antibiotics Nitrofurantoin was the best choice for UTIs caused by ESBL producers.

Extended-spectrum β-lactamases (ESBLs) are β-lactamase enzymes produced by Gram-negative bacterial pathogens that harbor the ESBL genes. In addition, most ESBL genes are plasmid-mediated and usually encode a broader spectrum of antimicrobial resistance, especially to penicillins, first-generation, second-generation, and third-generation cephalosporins, as well as monobactam, such as aztreonam. Escherichia coli has become an opportunistic pathogen, especially in poultry, and has been implicated in zoonotic diseases that can be transmitted to humans, resulting in public health problems. Poultry can act as carriers of ESBL-producing E. coli (ESBL-EC) bacteria to humans through poultry meat that is contaminated by waste products, feces, and excretions. The ESBL gene CTX-M type was identified as the main cause of infection in humans and was detected in poultry as a cause of infection accompanied by clinical symptoms. Several studies have also shown a link between E. coli and ESBL gene transfer from birds to humans. Controlling the spread of ESBL-EC involves maintaining the cleanliness of poultry products, especially meat, and eliminating contaminant sources from poultry. Likewise, maintaining the environmental cleanliness of poultry slaughterhouses and poultry farms must be taken as a precautionary measure to curtail the increasing spread of ESBL-EC into the environment. This review aimed to explain the spread of ESBL-producing E. coli in poultry.

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae are associated with serious antimicrobial-resistant infections in Canadians. Humans are exposed to ESBL-producing Enterobacteriaceae through many interconnected pathways. To better protect Canadians, it is important to generate an understanding of which sources and activities contribute most to ESBL exposure and infection pathways in Canada.

The aims of this scoping review were to thematically describe factors potentially associated with ESBL-producing Enterobacteriaceae colonization, carriage and/or infection in humans from countries with a very high human development index and describe the study characteristics.

Four databases (PubMed, CAB Direct, Web of Science, EBSCOhost) were searched to retrieve potentially relevant studies. Articles were screened for inclusion, and factors were identified, grouped thematically and described.

The review identified 381 relevant articles. Factors were grouped into 13 themes: antimicrobial use, animals, comorbidities and symptoms, community, demographics, diet and substance use, health care, household, occupation, prior ESBL colonization/carriage/infection, residential care, travel, and other. The most common themes reported were demographics, health care, antibiotic use and comorbidities and symptoms. Most articles reported factors in hospital settings (86%) and evaluated factors for ESBL-producing Enterobacteriaceae infections (52%).

This scoping review provided valuable information about which factor themes have been well described (e.g., health care) and which have been explored less frequently (e.g., diet or animal contact). Themes identified spanned human, animal and environmental contexts and settings, supporting the need for a diversity of perspectives and a multisectoral approach to mitigating exposure to antimicrobial resistance.

Bacterial resistance to β-lactams is mainly attributed to CTX-M-type extended-spectrum β-lactamases (ESBLs). However, the predominant sequence type (ST) of blaCTX-M-carrying Escherichia coli (blaCTX-M-Ec) in chickens, an important food animal, in China and its contribution to human β-lactam resistance are not investigated. In this study, approximately 1808 chicken-derived strains collected from 10 provinces from 2012 to 2020 were screened for blaCTX-M-Ec, and 222 blaCTX-M-Ec were identified. Antimicrobial susceptibility tests, whole genome sequencing and conjugation experiment were performed. All quality-controlled 136 chicken-derived blaCTX-M-Ec and 1193 human-derived blaCTX-M-Ec genomes were downloaded from NCBI and EnteroBase to comprehensively analyze the prevalence of blaCTX-M-Ec in China. blaCTX-M-55 (153/358, 42.7% in chicken isolates; 312/1193, 26.2% in human isolates) and blaCTX-M-14 (92/358, 25.7% in chicken isolates; 450/1193, 37.7% in human isolates) were dominant in blaCTX-M-Ec. The STs of blaCTX-M-Ec were diverse and scattered, with ST155 (n = 21) and ST152 (n = 120) being the most abundant in chicken- and human-derived isolates, respectively. Few examples indicated that chicken- and human-derived blaCTX-M-Ec have 10 or less core genome single nucleotide polymorphisms (cgSNPs). Genetic environment analysis indicated that ISEcp1, IS26 and IS903B were closely associated with blaCTX-M transfer. The almost identical pc61-55 and pM-64-1161 indicated the possibility of plasmid-mediated transmission of blaCTX-M between humans and chickens. Although the genomes of most blaCTX-M-Ec isolated from chickens and humans were quite different, the prevalence and genetic environment of blaCTX-M variants in both hosts were convergent. CTX-M-mediated resistance is more likely to spread through horizontal gene transmission than bacterial clones.

The purpose of this study was to determine if orangutans (Pongo spp.) living in captivity at a zoo in Wisconsin were colonized with antimicrobial-resistant bacteria and, if found, to identify underlying genetic mechanisms contributing to their resistant phenotypes. We hypothesize that since antimicrobial-resistant bacteria are so prevalent within humans, the animals could also be carriers of such strains given the daily contact between the animals and the zoo staff that care for them. To test this theory, fecal samples from two orangutans were examined for resistant bacteria by inoculation on HardyCHROM™ ESBL and HardyCHROM™ CRE agars. Isolates were identified using MALDI-TOF mass spectrometry and antimicrobial susceptibility testing was performed using a Microscan autoSCAN-4 System. An isolate was selected for additional characterization, including whole genome sequencing (WGS). Using the Type (Strain) Genome Server (TYGS) the bacterium was identified as Escherichia coli. The sequence type identified was (ST/phylogenetic group/β-lactamase): ST6448/B1/CTX-M-55.

Rectal swabs of 104 patients who underwent abdominal surgery were screened for ESBL producers. Sequence types (STs) and resistance genes were identified by whole-genome sequencing of 46 isolates from 17 patients. All but seven isolates were assigned to recognized STs. While 18 ESBL-producing E. coli (EPEC) strains were of unique STs, ESBL-producing K. pneumoniae (EPKP) strains were mainly ST14 or ST15. Eight patients harboured strains of the same ST before and after abdominal surgery. The most prevalent resistant genes in E. coli were blaEC (69.57%), blaCTX-M (65.22%), and blaTEM (36.95%), while blaSHV was present in only K. pneumoniae (41.30%). Overall, genes encoding β-lactamases of classes A (blaCTX-M, blaTEM, blaZ), C (blaSHV, blaMIR, and blaDHA), and D (blaOXA) were identified, the most prevalent variants being blaCTX-M-15, blaTEM-1B, blaSHV-28, and blaOXA-1. Interestingly, blaCMY-2, the most common pAmpC β-lactamase genes reported worldwide, and mobile colistin resistance genes, mcr-10-1, were also identified. The presence of blaCMY-2 and mcr-10-1 is concerning as they may constitute a potentially high risk of pan-resistant post-surgical infections. It is imperative that healthcare professionals monitor intra-abdominal surgical site infections rigorously to prevent transmission of faecal ESBL carriage in high-risk patients.

Klebsiella pneumoniae is a Gram-negative bacterium that colonizes the gastrointestinal tract and nasopharynx with many being linked to nosocomial infections. Extended-spectrum β-lactamases (ESBL)-producing and carbapenem-resistant K. pneumoniae is recognized by the World Health Organization (WHO) as a critical public health concern. In this study, whole-genome sequencing (WGS) - based analysis was performed to understand the molecular epidemiology of multi-drug resistant Klebsiella spp. clinical isolates. Genome comparison, multi-locus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and whole-genome-SNP-based phylogenetic analysis (wg-SNP) were used for in-depth molecular characterization. in silico typing was used to determine the resistance genes, virulence factors, Inc. groups, and capsular types. All except one isolate were non-susceptible to meropenem and 89% were non-susceptible to ertapenem and imipenem. blaNDM, blaOXA-48, and blaKPC were the detected carbapenemases with blaNDM-1 found in half of the sequenced genomes. Resistance to colistin was detected in one isolate and was linked to several genetic alterations in crrB, pmrB, and pmrC genes. The most common plasmid type was IncFIB followed by IncR, and the Type 3 fimbriae, encoded by the mrkABCDF operon, was conserved among all isolates. The most common sequence- (ST) and K-type detected were ST147 and K64. The prevelance and the genomic relatedness of ST147 isolates, as shown by the data from SNP-based phylogenetic analysis, PFGE, and genomic clustering, may be an outbreak marker. However, this can only be validated through a more comprehensive study encompassing a wider sampling scheme and over an extended timeframe.

The spread of ESBL-producing Escherichia coli has constantly increased in both clinical and community infections. Actually, the main ESBL reported is the CTX-M family, which is widely disseminated between the Enterobacteriaceae family. The epidemiology of the CTX-M family shows the CTX-M-15 variant dominating worldwide, followed by CTX-M-14 and CTX-M-27. The specific ESBL-producing E. coli clones included mainly the sequence types ST131, ST405, and ST648. In this report, we present the molecular characterization of ESBL-producing E. coli clinical isolates from eight hospitals in Mexico. From a collection of 66 isolates, 39 (59%) were identified as blaCTX-M-14 and blaCTX-M-27 belonging to the group CTX-M-9. We identified 25 (38%) isolates, producing blaCTX-M-28 belonging to the group CTX-M-1. blaCTX-M-2 and blaTEM-55 were identified in one isolate, respectively. Fourteen isolates (21%) were positive for blaCTX-M-14 (13%) and blaCTX-M-28 (7.3%) that were selected for further analyses; the antimicrobial susceptibility showed resistance to ampicillin (> 256 µg/mL), cefotaxime (> 256 µg/mL), cefepime (> 64 µg/mL), and ceftazidime (16 µg/mL). The ResFinder analysis showed the presence of the antimicrobial resistance genes aacA4, aadA5, aac(3)lla, sul1, dfrA17, tet(A), cmlA1, and blaTEM-1B. PlasmidFinder analysis identified in all the isolates the replicons IncFIB, which were confirmed by PCR replicon typing. The MLST analysis identified isolates belonging to ST131, ST167, ST405, and ST648. The ISEcp1B genetic element was found at 250 pb upstream of blaCTX-M-14 and flanked by the IS903 genetic element at 35 pb downstream. The IS1380-like element ISEc9 family transposase was identified at 250 pb upstream of blaCTX-M-14 and flanked downstream by the IS5/IS1182 at 80 pb. Our study highlights the significant prevalence of CTX-M-14 and CTX-M-28 enzymes as the second-most common ESBL-producing E. coli among isolates in Mexican hospitals. The identification of specific sequence types in different regions provides valuable insights into the correlation between ESBL and E. coli strains. This contribution to understanding their epidemiology and potential transmission routes is crucial for developing effective strategies to mitigate the spread of ESBL-producing E. coli in healthcare settings.

Carbapenem is recommended as one of the first-line regimens for ventilator-associated pneumonia (VAP), but no recent systematic review has fully investigated its efficacy. This systematic review aims to evaluate the efficacy of carbapenem compared with non-carbapenem for VAP treatment.

We performed a systematic review and meta-analysis of studies comparing the efficacy and the safety between carbapenem and non-carbapenem with activity to Pseudomonas aeruginosa in the treatment for VAP. The main outcome was mortality, and the additional outcomes were the clinical cure of pneumonia, length of intensive care unit stay, recurrence, adverse effects, and the development of resistant bacteria. This study was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.

Of the initial 1,730 publications, 9 randomized control trials were enrolled. In the meta-analysis, no difference was observed between the carbapenem and non-carbapenem regimens in improving mortality (odds ratio, 0.83; 95 % confidence interval (CI) 0.67-1.02). While the carbapenem regimen was superior to the non-carbapenem regimen in studies reporting the resolution of pneumonia (odds ratio, 1.09; 95 % CI 1.01-1.17), the effectiveness of carbapenem treatment was not evident in studies assessing the other outcomes.

Carbapenem might have no superiority in survival when treating VAP. Moreover, non-carbapenem antibiotics with activities to P. aeruginosa have a potential option to avoid inducing carbapenem-resistant pathogens.

We evaluated gut carriage of extended spectrum beta lactamase producing Enterobacteriaceae (ESBL-E) in southeastern U.S. residents without recent in-patient healthcare exposure. Study enrollment was January 2021-February 2022 in Athens, Georgia, U.S. and included a diverse population of 505 adults plus 50 child participants (age 0-5). Based on culture-based screening of stool samples, 4.5% of 555 participants carried ESBL-Es. This is slightly higher than reported in studies conducted 2012-2015, which found carriage rates of 2.5-3.9% in healthy U.S. residents. All ESBL-E confirmed isolates (n=25) were identified as Escherichia coli. Isolates belonged to 11 sequence types, with 48% classified as ST131. Ninety six percent of ESBL-E isolates carried a blaCTX-M gene. Isolated ESBL-Es frequently carried virulence genes as well as multiple classes of antibiotic resistance genes. Long-term colonization was common, with 64% of ESBL-E positive participants testing positive when rescreened three months later. One participant yielded isolates belonging to two different E. coli sequence types that carried blaCTX-M-1 genes on near-identical plasmids, suggesting intra-gut plasmid transfer. Isolation of E. coli on media without antibiotics revealed that ESBL-E. coli typically made up a minor fraction of the overall gut E. coli population, although in some cases they were the dominant strain. ESBL-E carriage was not associated with a significantly different stool microbiome composition. However, some microbial taxa were differentially abundant in ESBL-E carriers. Together, these results suggest that a small subpopulation of US residents are long-term, asymptomatic carriers of ESBL-Es, and may serve as an important reservoir for community spread of these ESBL genes.

The horizontal gene transfer events are the major contributors to the current spread of CTX-M-encoding genes, the most common extended-spectrum β-lactamase (ESBL), and many clinically crucial antimicrobial resistance (AMR) genes. This study presents evidence of the critical role of IS26 transposable element for the mobility of bla CTX-M gene among Escherichia coli isolates from children and domestic animals in the community. We suggest that the nucleotide sequences of IS26-bla CTX-M could be used to study bla CTX-M transmission between humans, domestic animals, and the environment, because understanding of the dissemination patterns of AMR genes is critical to implement effective measures to slow down the dissemination of these clinically important genes.

Background: Antimicrobial resistance (AR) has led to increasing human and animal morbidity and mortality and negative consequences for the environment. AR among Escherichia coli (EC) is on the rise, with serious concerns about extended-spectrum β-lactamase-producing E. coli (ESBL-EC). In the Galápagos Islands, where antimicrobials are available without a prescription, growing demands for food production can drive antimicrobial use. Food producing animals are at the interface of wildlife and environmental health on the smallest human-inhabited Galápagos Island, Floreana. We sought to determine if ESBL-EC were present in Floreana Island farm animal species and nearby wildlife and the relatedness of ESBL-EC isolates identified. Materials and Methods: During July 4-5, 2022, we visited 8 multispecies farms, representing 75% of food-producing animal production on Floreana, and collected 227 fecal samples from farm animals and wildlife. Each sample was plated on MacConkey agar supplemented with cefotaxime (4 μg/mL). Results: ESBL-EC was isolated from 20 (9%) fecal samples collected from pigs (N = 10), chickens (N = 6), wildlife (N = 3), and dog (N = 1). All ESBL-EC isolates were from samples taken at three (38%) of the eight farms. Fifteen (75%) of the ESBL-EC isolates were from a single farm. All ESBL-EC isolates were multidrug resistant. The most prevalent ESBL genes belonged to the blaCTX-M group. Among the typeable isolates from the farm with the largest proportion of ESBL-EC isolates (N = 14), we observed nine unique pulsed-field gel electrophoresis (PFGE) patterns, with identical patterns present across pig and chicken isolates. PFGE patterns in the three farms with ESBL-EC isolates were different. Conclusions: These results lend support for future routine AR monitoring activities at the livestock-wildlife interface in Galápagos to characterize potential interspecies transmission of AR bacteria and AR genes in this unique protected ecosystem, and the related human, animal, and environmental health impacts, and to formulate interventions to reduce AR spread in this setting.

Extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae infection is a serious global threat. ESBLs target 3rd generation cephalosporin antibiotics, the most commonly prescribed medicine for gram-negative bacterial infections. As bacteria are prone to develop resistance against market-available ESBL inhibitors, finding a novel and effective inhibitor has become mandatory. Among ESBL, the worldwide reported two enzymes, CTX-M-15 and CTX-M-3, are selected for the present study. CTX-M-3 protein was modeled, and two thousand phyto-compounds were virtually screened against both proteins. After filtering through docking and pharmacokinetic properties, four phyto-compounds (catechin gallate, silibinin, luteolin, uvaol) were further selected for intermolecular contact analysis and molecular dynamics (MD) simulation. MD trajectory analysis results were compared, revealing that both catechin gallate and silibinin had a stabilizing effect against both proteins. Silibinin having the lowest docking score, also displayed the lowest MIC (128 µg/mL) against the bacterial strains. Silibinin was also reported to have synergistic activity with cefotaxime and proved to have bactericidal effect. Nitrocefin assay confirmed that silibinin could inhibit beta-lactamase enzyme only in living cells, unlike clavulanic acid. Thus the present study validated the CTX-M inhibitory activity of silibinin both in silico and in vitro and suggested its promotion for further studies as a potential lead. The present study adopted a protocol through the culmination of bioinformatics and microbiological analyses, which will help future researchers identify more potential leads and design new effective drugs.Communicated by Ramaswamy H. Sarma.

Urinary tract infections caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL-E. coli) may occur as outbreaks due to common-source exposures. Yet, it is currently unknown if they cluster geographically as would be expected as part of an outbreak.

We collected electronic health record data on all patients living in San Francisco with culture-documented community-onset E. coli bacteriuria in a safety-net public healthcare system from January 2014 to March 2020 (diagnosed < 48 h after hospital admission or in outpatient clinical settings without a hospitalization in the past 90 days). We assessed the presence of spatial clusters of (1) ESBL-E. coli bacteriuria episodes, and (2) individuals with any ESBL-E. coli bacteriuria episode, with Global and Local Moran's I. We evaluated differences in prevalence of bacteriuria recurrence by ESBL-production by Poisson regression.

Out of 4,304 unique individuals, we identified spatial clusters of ESBL-E. coli bacteriuria episodes (n = 461) compared to non-ESBL-E. coli bacteriuria episodes (n = 5477; Global Moran's p < 0.001). Spatial clusters of individuals with any bacteriuria caused by ESBL-E. coli were not identified (p = 0.43). Bacteriuria recurrence was more likely to occur with ESBL-E. coli (odds ratio [OR] 2.78, 95% confidence interval [95% CI] 2.10, 3.66, p < 0.001), particularly after an initial ESBL-E. coli bacteriuria episode (OR 2.27, 95% CI 1.82, 2.83, p < 0.001).

We found spatial clusters of ESBL-E. coli bacteriuria episodes. However, this was partly explained by clustering within individuals more than between individuals, as having an ESBL-E. coli bacteriuria was associated with recurrence with ESBL-E. coli. These findings may help better tailor clinical treatment of patients with recurrent urinary tract infections after an initial episode caused by ESBL-E. coli.

Klebsiella pneumoniae carbapenemase-2 (KPC-2) presents a clinical threat as this β-lactamase confers resistance to carbapenems. Recent variants of KPC-2 in clinical isolates contribute to concerning resistance phenotypes. Klebsiella pneumoniae expressing KPC-2 D179Y acquired resistance to the ceftazidime/avibactam combination affecting both the β-lactam and the β-lactamase inhibitor yet has lowered minimum inhibitory concentrations for all other β-lactams tested. Furthermore, Klebsiella pneumoniae expressing the KPC-2 D179N variant also manifested resistance to ceftazidime/avibactam yet retained its ability to confer resistance to carbapenems although significantly reduced. This structural study focuses on the inhibition of KPC-2 D179N by avibactam and relebactam and expands our previous analysis that examined ceftazidime resistance conferred by D179N and D179Y variants. Crystal structures of KPC-2 D179N soaked with avibactam and co-crystallized with relebactam were determined. The complex with avibactam reveals avibactam making several hydrogen bonds, including with the deacylation water held in place by Ω loop. These results could explain why the KPC-2 D179Y variant, which has a disordered Ω loop, has a decreased affinity for avibactam. The relebactam KPC-2 D179N complex revealed a new orientation of the diazabicyclooctane (DBO) intermediate with the scaffold piperidine ring rotated ~150° from the standard DBO orientation. The density shows relebactam to be desulfated and present as an imine-hydrolysis intermediate not previously observed. The tetrahedral imine moiety of relebactam interacts with the deacylation water. The rotated relebactam orientation and deacylation water interaction could potentially contribute to KPC-mediated DBO fragmentation. These results elucidate important differences that could aid in the design of novel β-lactamase inhibitors.

Antibiotic resistance in uropathogens has increased substantially and severely affected treatment of urinary tract infections (UTIs). Lately, some new formulations, including meropenem/vaborbactam (MEV), ceftazidime/avibactam (CZA), and ceftolozane/tazobactam (C/T) have been introduced to treat infections caused by drug-resistant pathogens. This study was designed to screen Enterobacteriales isolates from UTI patients and to assess their antimicrobial resistance pattern, particularly against the mentioned (new) antibiotics. Phenotypic screening of extended-spectrum β-lactamase (ESBL) and carbapenem resistance was followed by inhibitor-based assays to detect K. pneumoniae carbapenemase (KPC), metallo-β-lactamase (MBL), and class D oxacillinases (OXA). Among 289 Enterobacteriales, E. coli (66.4%) was the most predominant pathogen, followed by K. pneumoniae (13.8%) and P. mirabilis (8.3%). The isolates showed higher resistance to penicillins and cephalosporins (70-87%) than to non-β-lactam antimicrobials (33.2-41.5%). NDM production was a common feature among carbapenem-resistant (CR) isolates, followed by KPC and OXA. ESBL producers were susceptible to the tested new antibiotics, but NDM-positive isolates appeared resistant to these combinations. KPC-producers showed resistance to only C/T. ESBLs and carbapenemase encoding genes were located on plasmids and most of the genes were successfully transferred to recipient cells. This study revealed that MEV and CZA had significant activity against ESBL and KPC producers.

This study compared the efficacy of flomoxef with other β-lactam antibiotics against extended-spectrum β-lactamases (ESBL)-producing bacteria of clinical relevance. First, the prevalence and β-lactamase genotypes of ESBL-producing strains among Escherichia coli and Klebsiella pneumoniae isolates collected in Japan from 2004 to 2018 were investigated. High MIC90 values (>64 µg/mL) of ceftriaxone, cefepime, and ceftazidime and low MIC90 values (≤0.06-2 µg/mL) of flomoxef, cefmetazole, and meropenem against both species were observed. Second, a chemostat model was used to analyze the efficacy of humanized regimens of three oxacephem/cephamycin antibiotics (flomoxef, cefmetazole, cefoxitin) and two other antibiotics (meropenem and piperacillin/tazobactam) in suppressing the growth of five ESBL-producing E. coli and two K. pneumoniae strains. Flomoxef, piperacillin/tazobactam, and meropenem showed good bactericidal effects with >4 log10 CFU/mL reduction without bacterial regrowth at 24 h even when the MIC of test isolates was >MIC90. Cefmetazole and cefoxitin resulted in regrowth of test isolates with MIC ≥MIC90 at 24 h. Cefmetazole, cefoxitin, flomoxef, and meropenem showed increased MICs for regrown samples. A clear relationship between the proportion of time that the free drug concentration exceeded the MIC (%fT>MIC) and antibiotic efficacy was found for flomoxef, cefoxitin, and cefmetazole, and flomoxef had the highest %fT>MIC, whereas discrepancies between Clinical and Laboratory Standards Institute breakpoint and bactericidal activity were observed for cefmetazole. Flomoxef was effective in preventing the growth of all ESBL-producing strains, even those with an MIC eight times the MIC90. Thus, flomoxef may be a good alternative to meropenem in context of carbapenems sparing stewardship.

In recent years, blaCTX-M-55-positive Escherichia coli has been widely reported in multiple locations with an increasing trend in prevalence, yet few studies have comprehensively analyzed the transmission characteristics and epidemiological patterns of blaCTX-M-55-positive E. coli. Here, we constructed a blaCTX-M-55-positive E. coli global genomic data set as completely as possible and explored the epidemiology and potential impact of blaCTX-M-55-positive E. coli on a global scale by high-resolution bioinformatics methods. The results show that blaCTX-M-55-positive E. coli has spread widely worldwide, especially in Asia, with the rich sequence typing (ST) diversity and high proportion of auxiliary genome occupancy indicating a high degree of openness. The phylogenetic tree suggests that blaCTX-M-55-positive E. coli is frequently clonally transmitted between the three human-animal environments and often cotransmitted with fosA, mcr, blaNDM, and tet(X). The stable presence of InclI1 and InclI2 in different hosts from different sources suggests that this part of the plasmid drives the widespread transmission of blaCTX-M-55-positive E. coli. We inductively clustered all blaCTX-M-55 flanking environmental gene structures and obtained five types. Notably, "ISEcp1-blaCTX-M-55-orf477-(Tn2)" and "IS26(IS15DI)-hp-hp-blaCTX-M-55-orf477-hp-blaTEM-IS26-hp-IS26-Tn2" are dominant in "humans" and in "animals and related foods," respectively. Overall, our findings highlight the importance of whole-genome sequencing-based surveillance in exploring the transmission and evolution of blaCTX-M-55-positive E. coli in the context of "One Health," and they serve as a reminder to strengthen the surveillance of blaCTX-M-55-positive E. coli in order to address the potential risk of future large outbreaks. IMPORTANCE CTX-M-55 was first discovered in Thailand in 2004, and today, this enzyme is the most common CTX-M subtype in E. coli of animal origin in China. Thus, blaCTX-M-55-positive E. coli getting widely spread is a growing public health problem. Although prevalence surveys of blaCTX-M-55-positive E. coli in different hosts have been widely reported in recent years, they remain insufficient in "One Health" context and from a global comprehensive perspective. Here, we constructed a genomic database of 2144 blaCTX-M-55-positive E. coli and used bioinformatics methods to resolve the spread and evolution of blaCTX-M-55-positive E. coli. The results suggest a potential risk of rapid transmission of blaCTX-M-55-positive E. coli and that long-term continuous surveillance of blaCTX-M-55-positive E. coli should be emphasized.

The spread of extended-spectrum beta-lactamases (ESBLs) in nosocomial and community-acquired enterobacteria is an important challenge for clinicians due to the limited therapeutic options for infections that are caused by these organisms. Here, we developed a panel of ESBL coding genes, evaluated the abundance and prevalence of ESBL encoding genes in patients undergoing H. pylori eradication therapy, and summarized the effects of eradication therapy on functional profiles of the gut microbiome. To assess the repertoire of known beta lactamase (BL) genes, they were divided into clusters according to their evolutionary relation. Primers were designed for amplification of cluster marker regions, and the efficiency of this amplification panel was assessed in 120 fecal samples acquired from 60 patients undergoing H. pylori eradication therapy. In addition, fecal samples from an additional 30 patients were used to validate the detection efficiency of the developed ESBL panel. The presence for majority of targeted clusters was confirmed by NGS of amplification products. Metagenomic sequencing revealed that the abundance of ESBL genes within the pool of microorganisms was very low. The global relative abundances of the ESBL-coding gene clusters did not differ significantly among treatment states. However, at the level of each cluster, classical ESBL producers such as Klebsiella sp. for blaOXY (p = 0.0076), Acinetobacter sp. for blaADC (p = 0.02297) and others, differed significantly with a tendency to decrease compared to the pre- and post-eradication states. Only 13 clusters were common across all three datasets, suggesting a patient-specific distribution profile of ESBL-coding genes. The number of AMR genes detected in the post-eradication state was higher than that in the pre-eradication state, which could be attributed, at least in part, to the therapy. This study demonstrated that the ESBL screening panel was effective in targeting ESBL-coding gene clusters from bacterial DNA and that minor differences exist in the abundance and prevalence of ESBL-coding gene levels before and after eradication therapy.

The proliferation of antibiotic-resistant bacteria and antimicrobial resistance is a pressing public health challenge because of their possible transfer to humans via contact with polluted water sources. In this study, three freshwater resources were assessed for important physicochemical characteristics as well as heterotrophic and coliform bacteria and as potential reservoirs for extended-spectrum beta-lactamase (ESBL) strains. The physicochemical characteristics ranged from 7.0 to 8.3; 25 to 30 °C, 0.4 to 93 mg/L, 0.53 to 8.80 mg/L and 53 to 240 mg/L for pH, temperature, dissolved oxygen (DO), biological oxygen demand (BOD₅) and total dissolved solids, respectively. The physicochemical characteristics mostly align with guidelines except for the DO and BOD₅ in some instances. Seventy-six (76) Aeromonas hydrophila and 65 Escherichia coli O157: H7 isolates were identified by preliminary biochemical analysis and PCR from the three sites. Among these, A. hydrophila displayed higher frequencies of antimicrobial resistance, with all 76 (100%) isolates completely resistant to cefuroxime and cefotaxime and with MARI ≥ 0.61. The test isolates showed more than 80% resistance against five of the ten test antimicrobials, with resistance against cefixime, a cephalosporin antibiotic being the highest at 95% (134/141). The frequency of the detection of the resistance genes in the A. hydrophila isolates generally ranged between 0% (bla_SHV) and 26.3% (bla_CTX-M), while the frequency of detection among the E. coli O157:H7 isolates ranged between 4.6% (bla_CTX-M) and 58.4% (bla_TEM). Our findings indicate that the distribution of antibiotic-resistant bacteria with diverse ESBL-producing capabilities and virulence genes in freshwater sources potentially threatens public health and the environment.

Several studies have reported an increased frequency of colonization and/or infection with antibiotic-resistant bacteria (ARB) during the COVID-19 pandemic. Extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) are a group of bacteria with intrinsic resistance to multiple antibiotics, including penicillins, cephalosporins, and monobactams. These pathogens are easy to spread and can cause difficult-to-treat infections. Here, we summarize the available evidence on the impact of the COVID-19 pandemic on infections caused by ESBL-PE. Using specific criteria and keywords, we searched PubMed, MEDLINE, and EMBASE for articles published up to 30 March 2023 on potential changes in the epidemiology of ESBL-E since the beginning of the COVID-19 pandemic. We identified eight studies that documented the impact of COVID-19 on ESBL-E. Five studies were focused on assessing the frequency of ESBL-PE in patient-derived specimens, and three studies investigated the epidemiological aspects of ESBL-PE infections in the context of the COVID-19 pandemic. Some of the studies that were focused on patient specimens reported a decrease in ESBL-PE positivity during the pandemic, whereas the three studies that involved patient data (1829 patients in total) reported a higher incidence of ESBL-PE infections in patients hospitalized for COVID-19 compared with those with other conditions. There are limited data on the real impact of the COVID-19 pandemic on the epidemiology of ESBL-PE infections; however, patient-derived data suggest that the pandemic has exacerbated the spread of these pathogens.

Aztreonam-avibactam, eravacycline, and cefoselis are three novel antimicrobial agents for the treatment of serious infections caused by Gram-negative bacteria. We evaluated the in vitro activities of the above-mentioned three antimicrobial agents against clinical Enterobacterales isolates. A total of 1,202 Enterobacterales isolates, including 10 genera or species, were collected from 26 hospitals that cover seven regions of China. The susceptibilities of the 30 antimicrobial agents were interpreted based on the combination of U.S. Food and Drug Administration and Clinical and Laboratory Standards Institute guidelines. The results indicated that all Enterobacterales isolates showed high susceptibility to aztreonam-avibactam (98.25%), eravacycline (85.69%), and cefoselis (62.73%). The first two antimicrobial agents also demonstrated potent activities against multidrug-resistant and carbapenem-resistant Enterobacterales independent of antimicrobial resistance mechanisms. The rates of susceptibility to aztreonam-avibactam, eravacycline, and cefoselis were lowest in Morganella spp. (84.42%), Proteus spp. (33.65%), and Escherichia coli (40.14%), respectively. In general, the lower rates of susceptibility to eravacycline and cefoselis were in the older inpatient group. The strains isolated from urinary tract exhibited the lowest rate of susceptibility (78.97%) to eravacycline, and the lowest rate of susceptibility (45.83%) to cefoselis was observed in nervous system specimens. The strains isolated from intensive care unit (ICU) wards showed significantly reduced susceptibility to cefoselis compared with those isolated from non-ICU wards. The MIC values of aztreonam-avibactam and ceftazidime-avibactam have poor consistency (weighted kappa = 0.243), as did eravacycline and tigecycline (weighted kappa = 0.478). Cefoselis and cefepime showed highly similar activities against Enterobacterales (weighted kappa = 0.801). Our results support the clinical development of aztreonam-avibactam, eravacycline, and cefoselis to treat infections caused by Enterobacterales. IMPORTANCE Infections caused by multidrug-resistant (MDR) Enterobacterales, especially carbapenem-resistant Enterobacterales (CRE), have been a challenging clinical problem due to the limited therapeutic options. Therefore, the need to develop novel antimicrobial agents and evaluate their activities against Enterobacterales in vitro is urgent. Our results show that the novel antimicrobial agents aztreonam-avibactam and eravacycline retain activities against MDR and CRE isolates, including carbapenemase producers and non-carbapenemase producers. Further analysis combined with clinical information on the strains tested revealed that no significant differences were observed in susceptibility rates of strains with different demographic parameters to aztreonam-avibactam. Age, specimen source, and department were associated with the susceptibility of strains to eravacycline and cefoselis (P ≤ 0.01). Compared with ceftazidime-avibactam, aztreonam-avibactam has its advantages and limitations against Enterobacterales. The potent activity of eravacycline against Enterobacterales was higher than that of tigecycline. Cefoselis and cefepime showed a highly consistent activity against Enterobacterales.

With extended-spectrum β-lactamases (ESBLs) and CTX-M enzymes being on the rise, antimicrobial treatment of enterobacterial infections is becoming more and more challenging. Our study aimed at a molecular characterization of phenotypically ESBL-positive E. coli strains obtained from blood cultures of patients of the University Hospital of Leipzig (UKL), Germany. The presence of CMY-2, CTX-M-14 and CTX-M-15 was investigated using Streck ARM-D Kit (Streck, USA). Real-time amplifications were performed by QIAGEN Rotor-Gene Q MDx Thermocycler (QIAGEN, Thermo Fisher Scientific, USA). Antibiograms as well as epidemiological data were evaluated. Among 117 cases, 74.4% of the isolates showed a resistance to ciprofloxacin, piperacillin and ceftazidime or cefotaxime while being susceptible to imipenem/meropenem. The proportion of ciprofloxacin resistance was significantly higher than the proportion of ciprofloxacin susceptibility. At least one of the investigated genes was detected in 93.1% of the blood culture E. coli isolates: CTX-M-15 (66.7%), CTX-M-14 (25.6%) or the plasmid-mediated ampC gene CMY-2 (3.4%). 2.6% were tested positive for two resistance genes. 94 of the corresponding stool specimens tested positive for ESBL producing E. coli (94/112, 83.9%). 79 (79/94, 84%) E. coli strains found in the stool samples matched with the respective patient's blood culture isolate phenotypically (MALDI-TOF, antibiogram). The distribution of resistance genes was in accordance with recent studies in Germany as well as worldwide. This study provides indications of an endogenous focus of infection and emphasize the importance of screening programs for high-risk patients.

Urinary tract infections caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL-E. coli) may occur as outbreaks due to common-source exposures. Yet, it is currently unknown if they cluster geographically as would be expected as part of an outbreak.

We collected electronic health record data on all patients living in San Francisco with culture-documented community-onset E. coli bacteriuria in a safety-net public healthcare system from January 2014 to March 2020 (diagnosed < 48 hours after hospital admission or in outpatient clinical settings without a hospitalization in the past 90 days). We assessed the presence of spatial clusters of (1) ESBL-E. coli bacteriuria episodes, and (2) individuals with any ESBL-E. coli bacteriuria episode, with Global and Local Moran's I. We evaluated differences in prevalence of bacteriuria recurrence by ESBL-production by Poisson regression.

Out of 4,304 unique individuals, we identified spatial clusters of ESBL-E. coli bacteriuria episodes (n = 461) compared to non-ESBL-E. coli bacteriuria episodes (n = 5477; Global Moran's p < 0.001). Spatial clusters of individuals with any bacteriuria caused by ESBL-E. coli were not identified (p = 0.43). Bacteriuria recurrence was more likely to occur with ESBL-E. coli (odds ratio [OR] 2.78, 95% confidence interval [95% CI] 2.10, 3.66, p < 0.001), particularly after an initial ESBL-E. coli bacteriuria episode (OR 2.27, 95% CI 1.82, 2.83, p < 0.001).

We found spatial clusters of ESBL-E. coli bacteriuria episodes. However, this was partly explained by clustering within individuals more than between individuals, as having an ESBL-E. coli bacteriuria was associated with recurrence with ESBL-E. coli.

Antimicrobial resistance (AMR) is one of the top ten global health threats, and current surveillance programs rarely monitor it outside healthcare settings. This limits our ability to understand and manage the spread of AMR. Wastewater testing has the potential to simply, reliably and continuously survey trends in AMR outside the healthcare settings, as it captures biological material from the entire community. To establish and evaluate such a surveillance, we monitored wastewater for four clinically significant pathogens across the urban area of Greater Sydney, Australia. Untreated wastewater from 25 wastewater treatment plants (WWTPs) covering distinct catchment regions of 5.2 million residents was sampled between 2017 and 2019. Isolates for extended-spectrum β-lactamases-producing Enterobacteriaceae (ESBL-E) were consistently detected, suggesting its endemicity in the community. Isolates for carbapenem-resistant Enterobacteriaceae (CRE), vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA) were only occasionally detected. The flow normalized relative (FNR) ESBL-E load was positively correlated with the proportion of the population between 19 and 50 years of age, completion of vocational education and the average length of hospital stay. Collectively, these variables explained only a third of the variance of the FNR ESBL-E load, indicating further, yet-unidentified factors as a contributor to the distribution. About half of the variation in the FNR CRE load was explained by the average length of hospital stay, showing healthcare-related drivers. Interestingly, variation in the FNR VRE load was not correlated to healthcare-related parameters but to the number of schools per 10,000 population. Our study provides insight into how routine wastewater surveillance can be used to understand the factors driving the distribution of AMR in an urban community. Such information can help to manage and mitigate the emergence and spread of AMR in important human pathogens.

The increase in multidrug-resistant microorganisms that produce extended-spectrum β-lactamases (ESBLs) and carbapenemases is a serious problem worldwide. Recently, matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) has been used for the rapid detection of antibiotic-resistant bacteria. The objective of this study was to establish a method to detect ESBL-producing Escherichia coli by monitoring the hydrolyzation of cefotaxime (CTX) using MALDI-TOF MS. According to the ratio of the peak intensity of CTX and hydrolyzed-CTX-related compounds, the ESBL-producing strains could be clearly distinguished after 15 min of incubation. Moreover, the minimum inhibitory concentration (MIC) values for E. coli were 8 μg/mL and lower than 4 μg/mL, which could be distinguished after 30 min and 60 min of incubation, respectively. The enzymatic activity was determined using the difference in the signal intensity of the hydrolyzed CTX at 370 Da for the ESBL-producing strains incubated with or without clavulanate. The ESBL-producing strains with low enzymatic activity or bla_CTX-M genes could be detected by monitoring the hydrolyzed CTX. These results show that this method can rapidly detect high-sensitivity ESBL-producing E. coli.

Few studies have addressed drug resistance of Enterobacterales in rural communities in developing countries. This study aimed to determine the coexistence of extended-spectrum β-lactamase (ESBL) and carbapenemase genes in Escherichia coli and Klebsiella pneumoniae strains carrying the mcr-1 gene in rural communities in Ecuador from healthy humans and their backyard animals. Sixty-two strains, thirty E. coli and thirty-two K. pneumoniae strains carrying the mcr-1 gene were selected from a previous study. PCR were performed for the presence of ESBLs and carbapenemase genes. The strains were further characterized, and the genetic relationship was studied with multi-locus sequencing typing (MLST) of seven housekeeping genes. Fifty-nine of the sixty-two mcr-1 isolates (95%) harbored at least on β-lactam resistance gene. The most prevalent ESBL genes were the bla_TEM genes (present in in 80% of the E. coli strains) and the bla_SHV gene (present in 84% of the K. pneumoniae strains). MSLT analysis revealed 28 different sequence types (ST); 15 for E. coli and 12 for K. pneumoniae, with most ST never described in humans and animals. The coexistence of mcr-1 and β-lactams resistant genes in E. coli and K. pneumoniae strains is alarming and threatens the efficacy of last-resort antibiotics. Our findings highlight backyard animals as a reservoir of mcr-1/β-lactams resistant genes.

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.