Dissemination Of ESBLs Research Articles

Characterization of antibiotic resistance genes and mobile elements in extended-spectrum β-lactamase-producing Escherichia coli strains isolated from hospitalized patients in Guangdong, China.

This study aimed to investigate the high-resolution phenotypic and genotypic characterization of extended-spectrum β-lactamase (ESBL)-producing E. coli strains isolated from hospitalized patients to explore the resistance genes and mobile genetic elements (MGEs) involved in horizontal dissemination. Between May and September 2021, a total of 216 ESBL-producing E. coli isolates were recovered from multiple departments. The identification of strains was performed using MALDI-TOF mass spectrometry and PCR, while antibiotic susceptibility testing was carried out using the Vitek 2 COMPACT system to determine resistance patterns, while PCR was used to detect different resistance genes and MGEs. In addition, a conjugation assay was performed to investigate the horizontal gene transfer of resistance genes. Selected isolates underwent whole-genome sequencing using the Illumina MiSeq platform. A total of 216 out of 409 E. coli isolates recovered from a tertiary hospital were observed to be ESBL-producing, giving a carriage rate of 52.8%, as determined by phenotypic screening. The most frequent sources of ESBL-producing E. coli isolates were urine (129/216, 59.72%,) and blood (50/216, 23.14%). The most prevalent ESBL genes identified were blaCTX-M (60.18%), blaTEM (40.27%), and blaSHV (18.05%). Three E. coli isolates were found to carry the genes blaNDM, mcr-1, and fosA3 genes. The most prevalent MGEs were IS26 (95.37%), Int (87.03%), and IncFIB (76.85%). Whole-genome sequencing analysis of eight MDR E. coli strains revealed that these isolates belonged to eight different sequence types (STs) and serotypes and were found to harbor multiple plasmid replicons and virulence factors. This study highlights a high incidence of antibiotic resistance genes and MGEs associated with the dissemination of ESBLs and other resistance genes.

A Review of Extended Spectrum β-Lactamases: Definition and Types

Extended-spectrum β-lactamases (ESBLs) are defined as those bacterial enzymes which are capable to hydrolyze most beta-lactam antibiotics, including penicillins, cephalosporins, and the monobactam aztreonam and especially expanded spectrum cephalosporins such as ceftriaxone, cefotaxime, ceftazidime. Worldwide, ESBLs are considered to be a serious threat, especially in hospitalized and immunocompromised patients. There is a growing prevalence and dissemination of ESBLs in bacterial isolates all over the world. Individuals at high risk are those exposed to bacterial species harboring ESBLs as they result in treatment failure in many cases. Thus, there is an urgent need to detect ESBLs producers with the formulation of strategic initiatives that participate in controlling their prevalence and dissemination. The current review aims to illustrate the importance of ESBLs and give a simple definition of their major types emphasizing on their substrate profiles and characteristics.

Satisfactory In Vitro Activity of Ceftolozane-Tazobactam against Carbapenem-Resistant Pseudomonas aeruginosa But Not against Klebsiella pneumoniae Isolates.

Background: Gram-negative rods are one of the most commonly isolated bacteria within human infections. These microorganisms are typically opportunistic pathogens that pose a serious threat to public health due to the possibility of transmission in the human population. Resistance to carbapenems is one of the most important antimicrobial resistance mechanisms amongst them. The aim of this study was to evaluate ceftolozane-tazobactam in vitro activity against carbapenem-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae clinical strains. Information on the antimicrobial activity of this antimicrobial against Gram-negative rods was also supplemented with a brief review of the relevant literature. Methods: The research involved 316 strains of Gram-negative rods: P. aeruginosa-206 and K. pneumoniae-110. Results: Of the tested strains, 86.0% P. aeruginosa and 30.0% K. pneumoniae remained susceptible to ceftolozane-tazobactam. Conclusions: Therefore, ceftolozane-tazobactam might be a good option in the treatment of infections caused by carbapenem-resistant P. aeruginosa strains, including those in ICU patients. Meanwhile, due to dissemination of ESBLs among K. pneumoniae strains, infections with this etiology should not be treated with the ceftolozane-tazobactam combination.

Genomic characterization of ESBL-producing Salmonella Thompson isolates harboring mcr-9 from dead chick embryos in China

The emergence and dissemination of the extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae harbouring antimicrobial resistance (AMR) genes has diminished the potential options for treating multidrug-resistant (MDR) bacterial infections. Until now, numerous studies reported the spreading of critical plasmid-borne AMR genes from different sources worldwide. While the knowledge on the occurrence of the plasmid-borne AMR genes, especially mcr genes in the dead chick embryos, remains obscure. A retrospective study was conducted to detect the presence of the mcr genes in forty-five Salmonella enterica isolates recovered from 2139 dead chick embryo samples, from breeding chicken hatcheries in Henan, China. Using multiplex PCR, we found only four isolates out of the forty-five were mcr-9-positive. These four isolates were found to be MDR, ESBL- producing and showed resistance to 10 antimicrobial drugs. Additionally, mcr-9 harbouring plasmids were successfully transferred into Escherichia coli (E. coli) J53 by conjugation and the mcr-9 gene was confirmed by PCR. We also found that the transconjugants exhibited higher MICs for ampicillin, gentamycin and colistin than the recipient. Whole-genome sequence analysis showed that the four isolates belonged to Salmonella Thompson ST26 and harboured IncHI2 plasmid replicon. Furthermore, the mcr-9 harbouring plasmids were reconstructed using in silico tools and found to be carried other AMR genes (blaDHA-1 and qnrB4). The studied isolates carried the typical virulence factors from Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2), in addition to pef and csg operons which are important in host adhesion and biofilm formation. The mgtC gene, which is involved in phagocytosis, has also been identified. Together, the increase in the phenotypic resistance of the transconjugants and the plasmid in silico reconstruction analysis confirmed that the corresponding resistance genes might be located together on the same plasmid. To track the potential phylogenomic relations of our detected ESBL S. Thompson isolates, we constructed a phylogenomic tree with available ESBL S. Thompson genomes (n = 26) that were reported worldwide. The studied isolates were independently clustered together with four other Chinese isolates of food origin in one clade, providing strong evidence of a potential recent and wide dissemination of ESBL S. Thompson across the food chain in China. In conclusion, we report the detection of four highly virulent ESBL-producing S. Thompson ST26 isolates harbouring mcr-9 gene obtained from dead chick embryos in Henan, China.

Fecal Microbiome Features Associated with Extended-Spectrum β-Lactamase-Producing Enterobacterales Carriage in Dairy Heifers.

Simple SummaryExtended-spectrum β-lactamases (ESBLs) are a growing public health threat in terms of antimicrobial resistance (AMR), and one key human exposure point is through livestock and the food supply. Many factors can contribute to livestock carrying ESBLs, including feeding patterns, crowdedness, and the microbiome (bacterial ecosystem) of the animal. In this study, we observed that heifers from farms feeding calves with pooled colostrum had higher rates of ESBL carriage. Several genera of bacteria also differed between ESBL carriers and noncarriers. This study provides some potential directions for future research regarding ESBL carriage in heifers.Extended-spectrum β-lactamases (ESBLs) are a growing public health threat, and one key human exposure point is through livestock and the food supply. Understanding microbiome factors associated with fecal ESBL carriage can help detect and ideally assist with controlling and preventing ESBL dissemination among livestock. The objective of this study was to investigate the diversity and composition of the heifer fecal microbiota in ESBL-producing Enterobacterales (ESBL-PE) carriers and noncarriers. A total of 59 fecal samples were collected from replacement heifers between 12 and 18 months old from eight dairy farms in central Israel. Genomic DNA was extracted, and 16S rRNA amplicon sequencing was performed (Illumina short reads), focusing on a comparison between 33 ESBL-PE carriers (55.9%) and 26 (44.1%) noncarriers. Samples were analyzed and compared using QIIME2 (DADA2 pipeline and taxonomic assignment with SILVA database) and associated R packages for alpha and beta diversity and taxonomic abundances. Alpha diversity (Shannon diversity) and beta diversity (unweighted UniFrac) showed no significant difference between ESBL-PE carriers and noncarriers. Heifers from farms feeding calves with pooled colostrum had higher ESBL-PE carriage rates than heifers from farms feeding with individual mother colostrum (p < 0.001). Taxonomical abundance analysis revealed that the most common bacterial phyla were Bacteroidetes (44%) and Firmicutes (38%). There was no significant difference in taxonomic composition between ESBL-PE carriers and noncarriers at the phylum and genus levels. However, LEfSe biomarker discovery analysis identified several genera which were significantly different between carriers and noncarriers. For example, Prevotellacaea, Bacteroides, Rikenellaceae, and uncultured Bacteroidales were more abundant in ESBL carriers than noncarriers. Some aspects of microbiota composition differ between ESBL carriers and noncarriers in dairy heifers, specifically the abundance of certain genera. Feeding with pooled colostrum may play a role in that assembly. These could potentially serve as markers of ESBL-PE carriage. However, further research is needed to determine whether these observed differences have a significant impact on colonization with ESBL-PE.

Correlation of multi-drug resistance integron genes, blaESBL carriage of Extended-spectrum β-lactamas producing clinical isolates from equine with respiratory disorders

The present study was aimed to identify phenotypical and genotypic antimicrobial characterization of clinical isolates obtained from equine with respiratory disorders in Egypt, as well as the correlation between the β-lactamases and integron genes in clinical isolates. Thirty two clinical isolates were identified as K.pneumoneae (15 isolates); P.aeruginosa (8 isolates); S.zooepidemicus (3 isolates) and S.equi (6 isolates). All isolates showed resistance to more than 3 classes of antibiotic and were considered as multidrug resistance isolates (MRD isolates), K. pneumoneae harbor ctx-M genes and shv-1 gene in highest rate (53.3% and 60% respectively). P.aeruginosa isolates harbor ctx-M genes and shv-1 gene (20% and 33.3% respectively) while S.equi and S.zooepidemicus harbor only ctx-M genes (33.3% and 20% respectively), tem-1 gene was observed in S. equi (66.7%) followed by K,pneumoneae (33.3%) and absent in P.aeruginosa. Significant correlation or association of intI genes with ctx-M genes in K. pneumoneae, P.aeruginosa and streptococcus species was observed, while it was significant with shv-1 in K.pneumoneae and streptococcus species. The significance was at p&lt;0.05. It was concluded that the detection of integrons in most of the bacterial isolates promoters the phenomenon of in depth resistance because of these mobile genetic elements therefore the detection of those mobile gene cassettes in equine may be a keystone of multidrug resistance. Companion animals predominantly contain bla-ctx-M clusters, which might be animal origin, causing quick changes in drug-resistance epidemiology. ctx-M-1 and shv-1 also are commonly found among human pathogens signifying a standard clonal heredity and a possible ESBL dissemination source in farm and livestock.

Emergence and Spread of Different ESBL-Producing Salmonella enterica Serovars in Hospitalized Horses Sharing a Highly Transferable IncM2 CTX-M-3-Encoding Plasmid.

Salmonella enterica is a major causative pathogen of human and animal gastroenteritis. Antibiotic resistant strains have emerged due to the production of extended-spectrum β-lactamases (ESBLs) posing a major health concern. With the increasing reports on ESBL-producing Enterobacterales that colonize companion animals, we aimed to investigate ESBL dissemination among ESBL-producing Salmonella enterica (ESBL-S) in hospitalized horses. We prospectively collected ESBL-S isolates from hospitalized horses in a Veterinary-Teaching Hospital during Dec 2015–Dec 2017. Selection criteria for ESBL-S were white colonies on CHROMagarESBL plates and an ESBL phenotypic confirmation. Salmonella enterica serovars were determined using the Kaufmann-White-Le-Minor serological scheme. ESBL-encoding plasmids were purified, transformed and compared using restriction fragment length polymorphism (RFLP). Whole genome sequencing (Illumina and MinION platforms) were performed for detailed phylogenetic and plasmid analyses. Twelve ESBL-S were included in this study. Molecular investigation and Sequence Read Archive (SRA) meta-analysis revealed the presence of three unique Salmonella enterica serovars, Cerro, Havana and Liverpool, all reported for the first time in horses. PFGE revealed the clonal spread of S. Cerro between seven horses. All twelve isolates carried blaCTX–M–3 and showed an identical multidrug resistance profile with co-resistance to trimethoprim/sulfamethoxazole and to aminoglycosides. Plasmid RFLP proved the inter-serovar horizontal spread of a single blaCTX–M–3-encoding plasmid. Complete sequence of a representative plasmid (S. Havana strain 373.3.1), designated pSEIL-3 was a -86.4 Kb IncM2 plasmid, that encoded nine antibiotic resistance genes. pSEIL-3 was virtually identical to pCTX-M3 from Citrobacter freundii, and showed high identity (>95%) to six other blaCTX–M–3 or blaNDM–1 IncM2 broad host range plasmids from various Enterobacterales of human origin. Using a specific six gene-based multiplex PCR, we detected pSEIL-3 in various Enterobacterales species that co-colonized the horses’ gut. Together, our findings show the alarming emergence of ESBL-S in hospitalized horses associated with gut shedding and foal morbidity and mortality. We demonstrated the dissemination of CTX-M-3 ESBL among different Salmonella enterica serovars due to transmission of a broad host range plasmid. This report highlights horses as a zoonotic reservoir for ESBL-S, including highly transmissible plasmids that may represent a ‘One-Health’ hazard. This risk calls for the implementation of infection control measures to monitor and control the spread of ESBL-S in hospitalized horses.

Wide Spread of bla CTX-M-9/mcr-9 IncHI2/ST1 Plasmids and CTX-M-9-Producing Escherichia coli and Enterobacter cloacae in Rescued Wild Animals.

Wildlife has recently been pinpointed as one of the drivers of dissemination of genes conferring resistances to clinically important antimicrobials. The presence of both extended-spectrum beta-lactamase- (ESBL) and carbapenemase-encoding genes has notably been reported in wild birds, that can act as sentinels of antimicrobial resistance (AMR) contamination but also as long-distance spreaders in case of migratory birds. Here, 424 wild birds brought to a rescue center in France were sampled over a 6-month period. These birds encompassed 62 different sedentary or migratory species. A further 16 wild mammals present in the center were also investigated. No carbapenemase-producer was found, but we identified a surprisingly high proportion (24.1%) of ESBL-positive isolates. A total of 144 non-duplicate isolates were collected, including Escherichia coli (n = 88), Enterobacter cloacae (n = 51), and Citrobacter freundii (n = 5), of which 123 carried the blaCTX–M–9 gene. PFGE, phylogroup, and MLST revealed the presence of a limited number of ESBL-positive clones circulating in these animals, all presenting multiple associated resistances. Next-generation sequencing on a subset of isolates, followed by Southern blot hybridization, showed the wide dissemination of an IncHI2/ST1 plasmid carrying the blaCTX–M–9, blaSHV–12 and mcr-9 genes. In all, our results undoubtedly reflect cross transmissions of ESC-resistance (ESC-R) Enterobacteriaceae within the rescue center – similarly to nosocomial spreads observed at hospital, rather than the true bacterial flora of birds. We also showed that the spread of ESC-R in this rescue center did not only rely on clonal but also on a highly successful plasmidic transmission. Since most animals are intended to get back to nature after a few days or weeks, this is obviously an issue with regard to ESBL dissemination in natural environments.

Risk factors of community-onset extended-spectrum β-lactamase Escherichia coli and Klebsiella pneumoniae bacteraemia: an 11-year population-based case–control–control study in Denmark

ObjectivesTo investigate and explore temporal changes in risk factors of community-onset extended-spectrum β-lactamase (ESBL) Escherichia coli and Klebsiella pneumoniae bacteraemia in a region with low antibiotic resistance. MethodsPopulation-based case–control study including 223 cases hospitalized with a first-time community-onset ESBL-producing E. coli and K. pneumoniae bacteraemia, 2214 non-ESBL E. coli and K. pneumoniae bacteraemia controls, and 2228 population controls in the North Denmark Region between 2007 and 2017. We used a conditional logistic regression to compute crude and adjusted (age, gender and co-morbidity) odds ratios (aORs) and 95% CIs of risk factors and compared selected risk factors between 2007–2011 and 2016–2017. ResultsSeveral conventional risk factors of ESBL E. coli or K. pneumoniae were identified compared with the population controls. Compared with the non-ESBL controls, use of fluoroquinolones (aOR 3.56, 95% CI 2.52–5.05), three or more admissions within the recent year (aOR 2.18, 95% CI 1.45–3.28), three or more antibiotic prescriptions within 15–365 days before the admission (aOR 2.18, 95% CI 1.53–3.10), male sex (aOR 2.01, 95% CI 1.50–2.69), admission within 1–91 days (aOR 1.84, 95% CI 1.37–2.48) and antibiotic within 15–91 days (aOR 1.82, 95% CI 1.37–2.42) inferred the highest risk. Assessment of temporal dynamics between 2007–2011 and 2016–2017 revealed a slight reduction in risk factors associated with direct health-care contact (e.g. hospital admission). ConclusionsRecent and frequent hospitalization, and exposure to antibiotics, especially use of fluoroquinolones, appeared to be associated specifically with ESBL production, and focus and interventions should be directed towards these areas. Our results indicated a dissemination of ESBLs into the community.

Horizontal Plasmid Transfer among Klebsiella pneumoniae Isolates Is the Key Factor for Dissemination of Extended-Spectrum β-Lactamases among Children in Tanzania.

Increased knowledge about the role of horizontal gene transfer is key to improve our understanding of the spread of antimicrobial resistance (AMR) in human populations. We therefore studied the dissemination of the blaCTX-M-15 extended-spectrum-β-lactamase (ESBL) gene in Klebsiella pneumoniae isolates obtained from stool samples from hospitalized children and healthy controls below 2 years of age in Dar es Salaam, Tanzania, from August 2010 to July 2011. We performed Illumina whole-genome sequencing (WGS) to characterize resistance genes, multilocus sequence type (MLST), plasmid incompatibility group (Inc), and plasmid MLST of 128 isolates of K. pneumoniae with blaCTX-M-15 recovered from both healthy and hospitalized children. We assessed the phylogenetic relationship using single nucleotide polymorphism (SNP)-based analysis and resolved the sequences of five reference plasmids by Oxford Nanopore technology to investigate plasmid dissemination. The WGS analyses revealed the presence of a blaCTX-M-15-positive IncFIIK5/IncR plasmid with a highly conserved backbone in 70% (90/128) of the isolates. This plasmid, harboring genes encoding resistance to most β-lactams, aminoglycosides, trimethoprim-sulfamethoxazole, and chloramphenicol, was present in phylogenetically very diverse K. pneumoniae strains (48 different MLSTs) carried by both hospitalized and healthy children. Our data strongly suggest widespread horizontal transfer of this ESBL-carrying plasmid both in hospitals and in the general population.IMPORTANCE Horizontal spread of plasmids carrying multiple resistance genes is considered an important mechanism behind the global health problem caused by multidrug-resistant bacteria. Nevertheless, knowledge about spread of plasmids in a community is limited. Our detailed molecular analyses of K. pneumoniae isolated from hospitalized and healthy children in Tanzania disclosed an epidemic spread of a resistance plasmid. In this study population, we revealed horizontal plasmid transfer among K. pneumoniae as the key factor for dissemination of ESBLs. Traditional outbreak investigation and surveillance focus on the spread of bacterial clones, and short-read sequencing can result in erroneous plasmid composition. Our approach using long-read sequencing reveals horizontal gene transfer of antimicrobial resistance, and therefore has a potential impact on outbreak investigations and approaches to limit spread of AMR.

High level detection of extended spectrum beta-lactamase gene encoding Enterobacteriaceae in public toilets in Abeokuta, Nigeria

Increasing reports of the pandemic nature of extended spectrum β-lactamase (ESBL) producing bacteria in clinical infections called for more surveillance to identify possible sources of infection. This study examined the dissemination of ESBL producing Enterobacteriaceae in hospital and public toilet facilities in Abeokuta. Swab samples were collected from toilet seats, door handles, toilet bowls and flush handles. Detection of ESBL producing isolates was done using double disc test. Presence of ESBL gene was done using multiplex PCR. Overall, ESBL-producing bacteria was detected in 44 (27.5%) out of 160 samples. ESBL-producing bacteria were detected at significantly higher rate )p<0.001) in hospital toilets than in community toilets. Isolates were identified as Klebsiella pneumoniae (n=25), Klebsiella oxytoca (n=2), Citrobacter freundii (n=6), Citrobacter youngae (n=3), Escherichia coli (n=5), Enterobacter cloacae (n=2) and Enterobacter kobei (n=1). . Analysis for the presence of ESBL gene showed that all the isolates harboured the blaCTX-M- gene while blaTEM and blaSHV were detected in six and two isolates respectively. All the ESBL-producing isolates demonstrated resistance to at least three different classes of antimicrobials. The study showed that public toilets could serve as sources for nosocomial and community transmission of ESBL-producing bacteria in the environment.

Fecal Carriage of Extended-Spectrum-β-Lactamase/AmpC-Producing Escherichia coli in Horses.

A nationwide study on the occurrence of extended-spectrum β-lactamase (ESBL)/AmpC in nonhospitalized horses in the Netherlands was performed. Molecular characterization was done, and questionnaires were analyzed to identify factors associated with carriage. In total, 796 horse owners were approached; 281 of these submitted a fecal sample from their horse(s), resulting in 362 samples. All samples were cultured qualitatively in Luria-Bertani (LB) broth and subsequently on MacConkey agar, both supplemented with 1 mg/liter cefotaxime (LB+ and MC+). Positive samples were subsequently cultured quantitatively on MC+. Initial extended-spectrum-β-lactamase (ESBL)/AmpC screening was performed by PCR, followed by whole-genome sequencing on selected strains. Associations between ESBL/AmpC carriage and questionnaire items were analyzed using a univariate generalized estimating equation (GEE) regression analysis, followed by a multiple GEE model for relevant factors. In total, 39 of 362 samples (11%) were determined to be positive for ESBL/AmpC. blaCTX-M-1-carrying isolates were obtained from 77% of positive samples (n = 30). Other ESBL/AmpC genes observed included blaCTX-M-2, blaCTX-M-14, blaCTX-M-15, blaCTX-M-32, blaSHV-12, blaCMY-2, and blaACT-10 A high association between the presence of blaCTX-M-1 and IncHI1 plasmids was observed (46% of samples; n = 18). Based on core genome analysis (n = 48 isolates), six Escherichia coli clusters were identified, three of which represented 80% of the isolates. A negative association between ESBL/AmpC carriage and horses being in contact with other horses at a different site was observed. The presence of a dog on the premises and housing in a more densely human-populated region were positively associated.IMPORTANCE Extended-spectrum β-lactamases (ESBLs) are widespread in human and animal populations and in the environment. Many different ESBL variants exist. The dissemination of ESBLs within and between populations and the environment is also largely influenced by genetic mobile elements (e.g., plasmids) that facilitate spread of these ESBLs. In order to identify potential attributable ESBL sources for, e.g., the human population, it is important to identify the different ESBL variants, the bacteria carrying them, and the potential risk factors for ESBL carriage from other potential sources. This nationwide study focuses on ESBL carriage in the open horse population and investigated the molecular characteristics, geographical distribution throughout the Netherlands, and potential risk factors for fecal ESBL carriage in horses. These data can be used for future attribution studies in order to reduce potential transmission of ESBL-producing bacteria between sources.

Emergence of ESBL-producing Escherichia coli ST131-C1-M27 clade colonizing patients in Europe.

The ST131 Escherichia coli clone is associated with the global dissemination of ESBLs. It has been hypothesized that ST131 could take advantage of better colonizing abilities. However, the data on colonization prevalence of ESBL-ST131 in European hospitals are scarce. To assess the prevalence of the ST131 clone and its microbiological characteristics among colonizing ESBL-producing E. coli (ESBL-Ec) from hospitalized patients in four European hospitals (Berlin, Geneva, Madrid and Utrecht) during the R-GNOSIS study. ESBL-Ec isolates (n = 688) were obtained from rectal swabs of hospitalized patients from March 2014 to February 2015 using selective media. The ST131 clone and its subclones were sought using PCR and positive isolates were further studied. blaESBL genes were characterized (PCR and sequencing), antibiotic susceptibility testing was performed, clonal relationships were studied by PFGE and fimH allele and O type (PCR) were assessed. ST131 prevalence was 20.5% (141/688); C1/H30R1 isolates were significantly more prevalent in Geneva (49%) and C2/H30Rx in Madrid (67%). C1/H30R1 isolates showed less resistance to amikacin than C2/H30Rx (4% versus 35%) and all were susceptible to penicillin/inhibitor combinations. CTX-M-15 was the most common enzyme (49%) followed by CTX-M-27 (27%). C1/H30R1 isolates were significantly associated with CTX-M-27 (72%) and all of these isolates belonged to the C1-M27 clade. Moreover, C2/H30Rx isolates and CTX-M-15 were also significantly related (88%). The predominance of C2/H30Rx-CTX-M-15 in Madrid and C1/H30R1-CTX-M-27 in Geneva demonstrates a changing epidemiology of ESBLs in Europe caused by ST131 subclones; in particular, the emergence of the C1-M27 clade in Europe.

Environmental adaptation and vertical dissemination of ESBL-/pAmpC-producing Escherichia coli in an integrated broiler production chain in the absence of an antibiotic treatment.

SummaryHigh prevalence numbers of extended‐spectrum beta‐lactamase‐ (ESBL‐)/plasmid‐mediated AmpC beta‐lactamase‐ (pAmpC‐) producing Escherichia coli in broiler chicken and their distribution along the broiler production chain is an ongoing problem in food production. We, therefore, investigated resistant isolates along the broiler production chain to determine whether there is a constantly occurring direct vertical transmission of the ESBL‐/pAmpC‐producing E. coli from the parent flocks to their offspring or not. We, furthermore, analysed the isolates concerning the occurrence of virulence factors and their ability to form biofilms to estimate their potential to effectively colonize broiler chickens and/or persist and survive in the environment of the broiler production facilities. Using whole genome sequencing, we could show that ESBL‐/pAmpC‐producing E. coli were likely transferred in a step‐wise process along the broiler production chain but not directly from the parent flock to the fattening flock with every single batch of offspring chickens. Additionally, resistant E. coli strains showing an extraintestinal pathogenic genotype as well as high numbers of virulence‐associated genes including the production of curli fibres and cellulose have high capabilities to persist and spread in the broiler production chain.

Extended spectrum beta-lactamase and metallo beta-lactamase production among Escherichia coli and Klebsiella pneumoniae isolated from different clinical samples in a tertiary care hospital in Kathmandu, Nepal

BackgroundExtended spectrum beta-lactamase (ESBL) and metallo beta-lactamase (MBL) production in Klebsiella pneumoniae and Escherichia coli are the commonest modes of drug resistance among these commonly isolated bacteria from clinical specimens. So the main purpose of our study was to determine the burden of ESBL and MBL production in E. coli and K. pneumoniae isolated from clinical samples. Further, the antimicrobial susceptibility patterns of E. coli and K. pneumoniae were also determined.MethodsA cross-sectional study was conducted at Om Hospital and Research Centre, Kathmandu, Nepal by using the E. coli and K. pneumoniae isolated from different clinical samples (urine, pus, body fluids, sputum, blood) from May 2015 to December 2015. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion technique. Extended spectrum beta-lactamase production was detected by combined disc method using ceftazidime and ceftazidime/clavulanic acid discs and cefotaxime and cefotaxime/clavulanic acid discs. Similarly, metallo beta-lactamase production was detected by combined disc assay using imipenem and imipenem/ethylenediaminetetracetate discs. Bacteria showing resistance to at least three different classes of antibiotics were considered multidrug resistant (MDR).ResultsOf total 1568 different clinical samples processed, 268 (17.1%) samples were culture positive. Among which, E. coli and K. pneumoniae were isolated from 138 (51.5%) and 39 (14.6%) samples respectively. Of the total isolates 61 (34.5%) were ESBL producers and 7 (4%) isolates were found to be MBL producers. High rates of ESBL production (35.9%) was noted among the clinical isolates from outpatients, however no MBL producing strains were isolated from outpatients. Among 138 E. coli and 39 K. pneumoniae, 73 (52.9%) E. coli and 23 (59%) K. pneumoniae were multidrug resistant. The lowest rates of resistance was seen toward imipenem followed by piperacillin/tazobactam, amikacin and cefoperazone/sulbactam.ConclusionsHigh rate of ESBL production was found in the E. coli and K. pneumoniae isolated from outpatients suggesting the dissemination of ESBL producing isolates in community. This is very serious issue and can’t be neglected. Regular monitoring of rates of ESBL and MBL production along with multidrug resistance among clinical isolates is very necessary.

Characteristics of Transmissible CTX-M- and CMY-Type β-Lactamase-Producing Escherichia coli Isolates Collected from Pig and Chicken Farms in South Korea.

The rapid dissemination of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has significantly contributed to public health hazard globally. A total of 281 E. coli strains recovered from pigs and chickens between 2009 and 2015 in South Korea were analyzed for ESBL production. ESBL phenotypes were recognized in 14 E. coli isolates; ten and three ESBLproducing isolates carried only blaCTX-M and blaCMY genes, respectively, and one isolate harbored both genes. The predominant CTX-M and CMY types were CTX-M-15 (n = 8) and CMY-2 (n = 3). We also detected ESBL-producing isolates harboring blaCTX-M-65, blaCTX-M-14, blaCMY-6, blaDHA-1, and blaTEM-1 genes. All ESBL-producing isolates showed resistance to the extent of the fourth generation cephalosporins, along with multidrug resistance. CTX-M-15- producing isolates showed higher MIC values than CTX-M-14- and CTX-M-65-producing isolates. The blaCTX-M and blaCMY genes have the potential to be transferable. The spreading of blaCMY and blaCTX-M genes was arbitrated mainly v ia F rep a nd I ncI1 plasmids. Our i solates showed clonal diversity in PFGE analysis. This is the first report of E. coli isolates carrying blaCMY-6 in chicken from South Korea. The emergence of CMY-6 ESBLs in a population of poultry suggests that extensive screening with long-term surveillance is necessary to prevent the dissemination of ESBL from chicken to human.

Clonal Diversity of ESBL-Producing Escherichia coli Isolated from Environmental, Human and Food Samples.

This study presents a comprehensive approach of a clonal diversity analysis of 448 Extended-spectrum β-lactamase (ESBL)-producing E. coli isolated from environmental, human and food samples in Spain. The phenotypic confirmation of ESBL production was performed by disc diffusion and microdilution methods, while Polymerase Chain Reaction (PCR) and sequencing were used for the molecular characterization of β-lactamase genes (blaCTX-M, blaSHV, blaTEM, blaOXA). Clonal relationship of isolates was determined by multi-locus sequence typing (MLST). Multidrug resistant strains were present in all the studied niches, with percentages above 50.0%. The most prevalent β-lactamase genes were blaCTXM-14 (26%) and blaCTXM-1 (21.4%), followed by blaSHV-12, blaCTX-M-15 and blaTEM-42. MLST isolates were grouped into 26 clonal complexes (CC) and 177 different sequence types (ST) were detected. Despite the high clonal diversity observed, CC10 was the prevalent and the only CC detected in all niches, while other complexes as CC131 were mainly associated to human isolates. The observed prevalence and diversity of these resistant bacteria across the different environments encourages a One Health approach to prevent and control ESBL dissemination between environment and consumers.

Emergence of blaCTX-M-15, blaTEM-169 and blaPER-1 extended-spectrum β-lactamase genes among different Salmonella enterica serovars from human faecal samples

Background: Broad-spectrum β-lactams are used for empirical therapy of severe infections with non-typhoid Salmonella serotypes; however, activities of these drugs against the strains producing different β-lactamase is not so clear. This study investigated the prevalence of β-lactamase genes among isolates of S. enterica serovars from human faecal samples and determined their diversity in activity against different β-lactams.Methods: Antimicrobial resistance of faecal isolates of S. enterica to extended-spectrum cephalosporins was analysed and MIC values were determined for the strains presenting extended-spectrum β-lactamases (ESBLs) phenotypes. The β-lactamase genes were identified by PCR and sequencing. β-lactamase activity of the Salmonella strains exhibiting ESBL phenotype was detected by biological, iodometric, spectrophotometry and nitrocefin assays.Results: Out of 202 S. enterica isolates, ESBLs phenotype was detected among 3.4% (7/202) of the strains. blaTEM-1 and blaCTX-M-15 were among the frequent β-lactamase genes. Detection of blaTEM-169 in S. enterica serovar Typhimurium and S. enterica serovar Bredeney and blaPER-1 in S. enterica serovar Infantis was a new finding in this experiment. Location of blaCTX-M-15/blaTEM-169/blaPER-1 genes on plasmid was confirmed in a transformation experiment. While crude extracts of the enzymes from each strain showed higher activity against cephalothin and cefotaxime, the lowest activity was detected against ceftazidime. The greatest synergistic activity was seen in a strain of S. enterica that carried blaCTX-M-15 and blaPER-1 genes compared with those presenting blaCTX-M-15/blaTEM-169 or blaCTX-M-15/blaTEM-1 genotypes.Conclusions: The results show dissemination of ESBLs encoding genes and their combined activity among different serovars of S. enterica that are a threat for future treatment options.

Quantitative evaluation of extended-spectrum β-lactamase-producing Escherichia coli strains in the wastewater of a French teaching hospital and relation to patient strain.

BackgroundExtended-spectrum β-lactamase-producing Escherichia coli has become ubiquitous and has been reported in diverse ecosystems. We evaluated the potential impact of post-acute and long-term healthcare activities on the environment by quantifying ESBL-producing Enterobacteriaceae in wastewaters of a French geriatric hospital.MethodsWe collected wastewater specimens representative of one-day efflux immediately before the connection with the municipal sewer pipe. The sample was processed following two different methods: dilution-filtration method and concentration method and was screened for ESBL-producing Enterobacteriaceae using selective media. ESBL E. coli strains were quantified, screened for ESBL genes and compared with ESBL strains isolated from patients present in the building at the time of wastewater collection, using molecular methods.ResultsSix distinct environmental ESBL E. coli clusters were identified, two of them related to patient strains. The concentrations in hospital wastewater of these strains ranged from 2.5 × 104 to 106 UFC/L.ConclusionsOur results demonstrate that the presence of ESBL E. coli patients leads to a dissemination of ESBL E. coli in the environment and highlights the need to improve excreta and wastewater policy in hospitals.

BlaCTX-M-15 carried by IncF-type plasmids is the dominant ESBL gene in Escherichia coli and Klebsiella pneumoniae at a hospital in Ghana

Escherichia coli and Klebsiella pneumoniae producing extended-spectrum β-lactamases (ESBLs) are among the most multidrug-resistant pathogens in hospitals and are spreading worldwide. Horizontal gene transfer and spread of high-risk clones are involved in ESBL dissemination. Investigation of the resistance phenotypes of 101 consecutive clinical E. coli (n=58) and K. pneumoniae (n=43) isolated at the Komfo Anokye Teaching Hospital in Ghana over 3months revealed 63 (62%) with an ESBL phenotype. All 63 had a blaCTX-M gene, and sequence analysis showed that 62 of these were blaCTX-M-15. blaCTX-M-15 was linked to ISEcp1 and orf477Δ in all isolates, and most isolates also carried blaTEM, aac(3)-II, aacA4cr, and/or blaOXA-30 genes on IncF plasmids. XbaI/pulsed-field electrophoresis showed heterogeneity among isolates of both species, suggesting that blaCTX-M-15 dissemination is caused by horizontal gene transfer rather than clonal spread of these species in Ghana.