Molecular epidemiology of Escherichia coli producing extended-spectrum beta-lactamases isolated in Rome, Italy

Prevalence, serovars, and risk factors associated with the presence of Salmonella in pork sold in public markets in Quito, Ecuador

Background

Salmonella enterica are bacteria that include more than 2,500 serovars. Most of these serovars have been linked to human foodborne illnesses, mainly related to poultry and pigs. Thus, these animals are considered the reservoirs of many Salmonella serovars and strains related to antibiotic resistance. This study aimed to determine the prevalence, serovars, β-lactam resistance genes, and the risk factors associated with Salmonella enterica in pork commercialized in open markets of Quito city.

Methods

For this, 165 pork meat samples were taken from municipal markets in three areas in the city. These samples were microbiologically processed following the ISO 6579-2014 standardized method. The polymerase chain reaction (PCR) test was used to identify Salmonella serotyping and resistance genes. Strains not identified by PCR were typed by the Kauffman White Le Minor scheme. A multivariate analysis was performed to identify risk factors associated with the presence of the microorganism.

Results

Salmonella prevalence in pork was 9.1%. Identified serovars were 4, [5], 12: i:- (53.3%), Infantis (33.3%), and Derby (13.4%). Furthermore, the β-lactam resistance genes bla CTX-M-65 could be identified in three S. infantis isolates. Multivariate analysis showed that temperature (above 8°C) and cutting surfaces (wood) presented significant association values.

Conclusions

In conclusion, pork in traditional markets of Quito is contaminated with Salmonella enterica, whose main serovars pose a public health concern, and shows beta-lactam resistance.

Dominance of ST131, B2, blaCTX-M-15, and papA-papC-kpsMII-uitA among ESBL Escherichia coli isolated from bloodstream infections in Quito, Ecuador: a 10-year surveillance study (2009-2019)

AIMS

This study aimed to examine antibiotic resistance and the epidemiology of extended-spectrum β-lactamases (ESBL)-producing Escherichia coli associated with bloodstream infections over a period of 10 years.

METHODS AND RESULTS

Isolates were collected from January 2009 to December 2019 and those testing for E. coli were included. Antibiotic susceptibility was tested using the VITEK® system. Selected isolates were further characterized by amplification of marker genes (virulence traits, phylogroups, and sequence types). A total of 166 ESBL-producing E. coli were recovered. The blaCTX-M-15 allele was the most abundant. Most of the isolates were resistant to ceftriaxone, cefepime, ceftazidime, ampicillin/sulbactam, piperacillin/tazobactam, and ciprofloxacin. No resistance to carbapenems was registered. More than 80% of bacteria were classified as extraintestinal pathogenic E. coli (ExPEC), and the combination of virulence traits:papA-papC-kpsMII-uitA was the most common. Phylogroup B2 was the most prevalent, and bacteria predominantly belonged to ST131.

CONCLUSIONS

There was an increase in the ExPEC ESBL-E coli in bloodstream infections and the relationship between the isolates found in these infections during these 10 years.

F18:A-:B1 Plasmids Carrying blaCTX-M-55 Are Prevalent among Escherichia coli Isolated from Duck-Fish Polyculture Farms

We determined the prevalence and molecular characteristics of bla_CTX-M-55-positive Escherichia coli (E. coli) isolated from duck-fish polyculture farms in Guangzhou, China. A total of 914 E. coli strains were isolated from 2008 duck and environmental samples (water, soil and plants) collected from four duck fish polyculture farms between 2017 and 2019. Among them, 196 strains were CTX-M-1G-positive strains by PCR, and 177 (90%) bla_CTX-M-1G-producing strains were bla_CTX-M-55-positive. MIC results showed that the 177 bla_CTX-M-55-positive strains were highly resistant to ciprofloxacin, ceftiofur and florfenicol, with antibiotic resistance rates above 95%. Among the 177 strains, 37 strains carrying the F18:A-:B1 plasmid and 10 strains carrying the F33:A-:B- plasmid were selected for further study. Pulse field gel electrophoresis (PFGE) combined with S1-PFGE, Southern hybridization and whole-genome sequencing (WGS) analysis showed that both horizontal transfer and clonal spread contributed to dissemination of the bla_CTX-M-55 gene among the E. coli. bla_CTX-M-55 was located on different F18:A-:B1 plasmids with sizes between ~76 and ~173 kb. In addition, the presence of bla_CTX-M-55 with other resistance genes (e.g., tetA, floR, fosA3, bla_TEM, aadA5 CmlA and InuF) on the same F18:A-:B1 plasmid may result in co-selection of resistance determinants and accelerate the dissemination of bla_CTX-M-55 in E. coli. In summary, the F18:A-:B1 plasmid may play an important role in the transmission of bla_CTX-M-55 in E. coli, and the continuous monitoring of the prevalence and transmission mechanism of bla_CTX-M-55 in duck-fish polyculture farms remains important.

Exploring broilers and native fowls of Andaman and Nicobar Islands as a source of β-lactamase-producing Enterobacteriaceae even with limited anthropogenic activities and docking-based identification of catalytic domains in novel β-lactamase variants

Objectives

The present study was conducted to detect the occurrence of β-lactamase and biofilm-producing Escherichia coli, Salmonella, and Klebsiella in broilers and native fowl reared in the Andaman and Nicobar Islands, India. The study also included molecular docking experiments to confirm the nature of the catalytic domains found in the β-lactamase variants obtained and to reveal the clonal relationship of the isolates with human clinical strains from the database.

Materials and methods

A total of 199 cloacal swabs were collected from five poultry breeds/varieties (broiler, Vanraja, Desi, Nicobari, and layer) in three districts of the Andaman and Nicobar Islands. E. coli, Salmonella enterica, and Klebsiella pneumoniae were isolated by standard techniques and confirmed by PCR. Phenotypical β-lactamase producers were identified by a double-disc test. The genes (bla _CTX, bla _SHV, bla _TEM , and bla _AmpC) were screened, and selected sequences of β-lactamase variants were submitted to DDBJ. Homology modeling, model validation, and active site identification of different β-lactamase variants were done by the SWISS-MODEL. Molecular docking was performed to identify the catalytic domains of the β-lactamase variants. The selected β-lactamase sequences were compared with the Indian ESBL sequences from human clinical strains in NCBI-GenBank.

Results

In total, 425 Enterobacteriaceae strains were isolated from the collected samples. Klebsiella pneumoniae (42.58%) was found to be the most prevalent, followed by Salmonella enterica (30.82%) and E. coli (26.58%). The phenotypical antibiogram of all 425 isolates showed the highest resistance against oxytetracycline (61-76%) and the lowest against gentamicin (15-20%). Phenotypical production of β-lactamase enzymes was observed in 141 (33.38%) isolates. The isolation rate of β-lactamase producing E. coli, Salmonella enterica, and Klebsiella pneumoniae was significantly higher (p < 0.05) in the birds reared in the South Andaman district (25.6, 17.5, and 18.7%, respectively) than in Nicobar (11.5, 7.6, 7.1%, respectively). Genotyping of the β-lactamase-producing isolates revealed the maximum possession of bla _TEM, followed by bla _SHV and bla _{CTX - M}. The nucleotide sequences were found to be similar with bla _{CTX - M-15}, bla _{SHV - 11}, bla _{SHV - 27}, bla _{SHV - 228}, bla _{TEM - 1}, and bla _AmpC in BLAST search. Distribution of studied biofilm-associated genes in Enterobacteriaceae strains from different varieties of the birds revealed that the layer birds had the maximum possession, followed by Vanraja, Desi, broilers, and Nicobari fowls. The phylogenetic analysis of selected sequences revealed a partial clonal relationship with human clinical strains of the Indian subcontinent. Molecular docking depicted the Gibbs free energy release for 10 different macromolecules (proteins) and ligand (antibiotic) complexes, ranging from -8.1 (SHV-27 + cefotaxime) to -7 (TEM-1 + cefotaxime) kcal/mol.

Conclusion and relevance

The study revealed β-lactamase variants circulating in the fowl population of the Andaman and Nicobar Islands (India), even in remote places with low anthropogenic activity. Most of the strains possessed bla _{TEM - 1}, followed by bla _{CTX - M-15}. Possession of bla _{SHV - 11}, bla _{SHV - 27}, and bla _{SHV - 228} in poultry Enterobacteriaceae strains was not reported earlier from any part of the world. The phylogenetic analysis revealed a partial clonal relationship of β-lactamase sequences with the human clinical strains isolated from the Indian subcontinent.

Occurrence of Extended Spectrum Cephalosporin-, Carbapenem- and Colistin-Resistant Gram-Negative Bacteria in Fresh Vegetables, an Increasing Human Health Concern in Algeria

The aim of this study was to screen for extended spectrum cephalosporin-, carbapenem- and colistin-resistant Gram-negative bacteria in fresh vegetables in Batna, Algeria. A total of 400 samples of fresh vegetables were collected from different retail stores. Samples were immediately subjected to selective isolation, then the representative colonies were identified using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF–MS). Phenotypic and genotypic analyses were carried out in terms of species identification and relative antibiotic resistance. Transferability of the carbapenemase and mcr-bearing plasmids was verified by conjugation. The clonal relationships of carbapenemase and mcr-positive Escherichia coli isolates were studied by multi-locus sequence typing (MLST). Sixty-seven isolates were characterised and were mostly isolated from green leafy vegetables, where the dominant species identified included Citrobacter freundii, Klebsiella pneumoniae, Enterobacter cloacae, Stenotrophomona maltophilia, E. coli and Citrobacter braakii. PCR and sequencing results showed that E. coli was the bacterial species presenting the highest antibiotic resistance level in parallel to bla_TEM (n = 16) and bla_CTX-M-15 (n = 11), which were the most detected genes. Moreover, five isolates carried carbapenemase genes, including the bla_OXA-48 and/or bla_VIM-4 genes. The mcr-1 gene was detected in two E. coli isolates. MLST analysis revealed three different E. coli sequence types: ST101 (n = 1), ST216 (n = 1) and ST2298 (n = 1). Conjugation assays confirmed the transferability of the bla_OXA-48 and mcr-1 genes. In this study we report, for the first time, the detection of the bla_OXA-48 gene in E. coli and C. braakii isolates and the bla_VIM-4 gene in vegetables. To the best of our knowledge, this is the first report on the detection of mcr-1 genes from vegetables in Algeria.

Plasmid Replicon Diversity of Clinical Uropathogenic Escherichia coli Isolates from Riyadh, Saudi Arabia

The aim of this study was to identify and compare the plasmid replicons of clinical uropathogenic Escherichia coli (UPEC) isolates, involving extended spectrum β-lactamase (ESBL)-positive and ESBL-negative, E. coli ST131 and non-ST131 and various ST131 subclones. Plasmid replicon typing on 24 clinical UPEC isolates was carried out using polymerase chain reaction-based replicon typing. A statistical analysis was performed to assess the associations between plasmid replicon types and ESBL carriage, and to evaluate the link between ST131 isolates and high replicon carriage. Eight replicons, I1α, N2, Iγ, X1, FIIS, K, FIA, and FII were detected. The FII was the most common replicon identified here. ESBL-positive E. coli isolates were highly associated with I1α, N2, Iγ, X1, and FIIS replicons, while FIA was present only in ESBL-negative group. ST131 isolates were highly associated with I1α and N2 replicons compared to non-ST131. No link was found between replicon carriage and the number or type of ESBLs in E. coli isolates. The diversity observed in replicon patterns of our clinical E. coli isolates indicates that they might be originated from different sources. The presence of replicons reported previously in animal sources suggests a possible transfer of antimicrobial resistance between animal and human bacterial isolates.

Predominance of genetically diverse ESBL Escherichia coli identified in resistance mapping of Vembanad Lake, the largest fresh-cum-brackishwater lake of India

Antimicrobial resistance (AMR) burden in Escherichia coli along the 90 km stretch of Vembanad Lake, Kerala, India, was assessed. Seventy-seven percent of water samples drawn from 35 different stations of the lake harbored E. coli. Antibiotic susceptibility test performed on 116 E. coli isolates revealed resistance to ≥ one antibiotic with 39 AMR profiles in 81%, multidrug resistance in 30%, and extended spectrum β-lactamase (ESBL) producers in 32%. Of all the 15 antibiotics tested, the probability of isolating cefotaxime-resistant E. coli was the highest (P ≤ 0.05) in the lake. Genetically diverse ESBL types, namely bla_TEM-116, bla_{CTX-M -152}, bla_{CTX-M -27}, bla_{CTX-M -55}, bla_CTX-M-205, and bla_SHV-27, were identified in the lake. This is probably the first report in India for the presence of bla_CTX-M-205 (bla_{CTX-M-group 2}) in the Vembanad Lake. ST11439 and single and double loci variants of ST443 and ST4533 were identified in multilocus sequence typing (MLST). Inc plasmids (B/O, F, W, I1, FIIA, HI1, P-1α, K/B, and N) identified in the lake evidences the resistance transmission potential of the E. coli isolated from the lake. Molecular typing (ERIC-PCR, MLST, and PBRT) delineated diverse E. coli, both between and within the sampling stations. Low multiple antibiotic resistance index (average MAR< 0.2) indicates a lower risk of the lake to the human population, but the occurrence of genetically diverse ESBL E. coli in the Vembanad Lake signals health hazards and necessitates pragmatic control measures.

Extended-Spectrum-β-Lactamase- and AmpC-Producing Escherichia coli in Domestic Dogs: Spread, Characterisation and Associated Risk Factors

In veterinary medicine, the issue of antimicrobial resistance was mainly addressed in food-producing animals (although companion animals also deserve attention). Indeed, these species may be reservoir of resistant microorganisms, such as extended-spectrum β-lactamase and AmpC (ESBL/AmpC)-producing bacteria. Dogs in particular may transmit them to close-contact humans. Overall 266 faecal samples of healthy dogs were microbiologically and molecularly analyzed to investigate ESBL/AmpC-producing Escherichia coli and the effects of host and environmental factors on their spread. A prevalence of 25.9% of ESBL/AmpC-producing E. coli, supported by bla_CTX-M (79.7%), bla_TEM (47.8%), bla_CMY (13%), and bla_SHV (5.8%) gene detection, emerged. Dogs frequenting extra-urban environments showed significantly higher odds of being positive to ESBL/AmpC E. coli (30.2%) compared to urban dogs (16.7%) identifying the environment as a risk factor. About 88.4% of isolates were resistant to cephalosporins, 8.7% to cephalosporins and carbapenems, and 2.9% to cephalosporins, carbapenems, and penicillins. ESBL/AmpC-producing E. coli expressing bla_CMY were significantly more resistant to cefoxitin, cefotaxime/clavulanic acid and ceftazidime/clavulanic acid, highlighting its negative effects. Our results suggest the role of domestic dogs as a maintenance host of ESBL/AmpC-producing E. coli leading to a constant health monitoring. The recorded resistances to carbapenems implies attention and further investigations.

Temporal, Spatial, and Genomic Analyses of Enterobacteriaceae Clinical Antimicrobial Resistance in Companion Animals Reveals Phenotypes and Genotypes of One Health Concern

Background

Antimicrobial resistance (AMR) is a globally important one health threat. The impact of resistant infections on companion animals, and the potential public health implications of such infections, has not been widely explored, largely due to an absence of structured population-level data.

Objectives

We aimed to efficiently capture and repurpose antimicrobial susceptibility test (AST) results data from several veterinary diagnostic laboratories (VDLs) across the United Kingdom to facilitate national companion animal clinical AMR surveillance. We also sought to harness and genotypically characterize isolates of potential AMR importance from these laboratories.

Methods

We summarized AST results for 29,330 canine and 8,279 feline Enterobacteriaceae isolates originating from companion animal clinical practice, performed between April 2016 and July 2018 from four VDLs, with submissions from 2,237 United Kingdom veterinary practice sites.

Results

Escherichia coli (E. coli) was the most commonly isolated Enterobacteriaceae in dogs (69.4% of AST results, 95% confidence interval, CI, 68.7-70.0) and cats (90.5%, CI 89.8-91.3). Multi-drug resistance was reported in 14.1% (CI 13.5-14.8) of canine and 12.0% (CI 11.1-12.9) of feline E. coli isolates. Referral practices were associated with increased E. coli 3rd generation ≤ cephalosporin resistance odds (dogs: odds ratio 2.0, CI 1.2-3.4). We selected 95 E. coli isolates for whole genome analyses, of which seven belonged to sequence type 131, also carrying the plasmid-associated extended spectrum β-lactamase gene bla _{CTX-M- 15}. The plasmid-mediated colistin resistance gene mcr-9 was also identified for the first time in companion animals.

Conclusions

Linking clinical AMR data with genotypic characterization represents an efficient means of identifying important resistance trends in companion animals on a national scale.

Determination of incompatibility group plasmids and copy number of the bla NDM-1 gene in carbapenem-resistant Klebsiella pneumoniae strains recovered from different hospitals in Kerman, Iran

Introduction. New Delhi metallo-β-lactamase (NDM)-producing Klebsiella pneumoniae has become a serious global health concern.Hypothesis/Gap Statement. Due to the high genetic diversity among NDM-positive K. pneumoniae, we need further surveillance and studies to better understand the relationships between them. In addition, the coexistence of several plasmid replicon types in NDM-positive K. pneumoniae may affect the copy number of bla _NDM, the MIC level to antibiotics, as well as increasing the chance of horizontal gene transfer.Aim. The aim of this study was to determine incompatible plasmid groups and copy numbers of bla _NDM, and to investigate the genetic relationship of 37 NDM-positive K. pneumoniae in Kerman, Iran.Methodology. The bla _NDM-1 gene was detected and confirmed by PCR-sequencing. The plasmid replicon types were determined by PCR-based replicon typing (PBRT) and the copy number of bla _NDM-1 was determined by quantitaive real time-PCR (qPCR). Random amplified polymorphic DNA (RAPD)-PCR typing was used to detect genetic relationships between the strains.Results. In this study, 10 different replicon types, including Frep [n=25 (67.5 %)], FIIAs [n=11 (29.7 %)], FIA [n=5 (13.5 %)], FIB [n=3 (8.1 %)], I1-Iγ [n=2 (5.4 %)], L/M [n=7 (18.9 %)], A/C [n=7 (18.9 %)], Y [n=3 (8.1 %)], P [n=1 (2.7 %)] and FIC [n=1 (2.7 %)] were reported. The copy numbers of the bla _NDM-1 gene varied from 30.00 to 5.0×10⁶ and no statistically significant correlation was observed between a rise of the MIC to imipenem and the copy numbers of bla _NDM-1 (P>0.05). According to RAPD typing results, 35 strains were divided into five clusters, while two strains were non-typeable.Conclusion. The spread of NDM-1-producing K. pneumoniae strains that carry several plasmid replicon types increases the chance of horizontal transfer of antibiotic resistance genes in hospital settings. In this study, 10 different replicon types were identified. We could not find any relationship between the increase of MIC levels to imipenem and the copy numbers of bla _NDM-1. Therefore, due to the identification of different replicon types in this study, the type and genetic characteristics of bla _NDM-1-carrying plasmids, and other factors such as antibiotic selective pressure, probably affect the copy number of bla _NDM-1 and change the MIC level to imipenem.

Identification and characterization of a spreadable IncI1 plasmid harbouring a blaCTX-M-15 gene in an Italian human isolate of Salmonella serovar Napoli

Salmonella enterica subsp. enterica serovar Napoli (S. Napoli) ranks among the top serovars causing human infections in Italy, although not common in other European countries. Isolates are generally pan-susceptible or resistant to aminoglycosides only, however data on antimicrobial resistance genes in strains of S. Napoli are limited. Recently an isolate encoding resistance to third generation cephalosporins was reported. This study aimed to characterize plasmid-encoded cephalosporin resistance due to the bla_CTX-M-15 gene in a human S. Napoli isolate in Italy, and to investigate plasmid stability over time. S. Napoli 16/174478 was confirmed to be ESBL-producing. The bla_CTX-M-15 gene was shown to be located on an IncI1α plasmid of 90,272 bp (50.03 GC%) encoding for 107 coding sequences (CDS). The plasmid was successfully transferred by conjugation to an E. coli 1816 recipient strain (conjugation frequency 3.9 × 10^-2 transconjugants per donor). Transconjugants were confirmed to carry the IncI1α plasmid, and to be ESBL-producing strains as well. Moreover, transconjugant colonies maintained the plasmid for up to 10 passages. The identification of S. Napoli isolates able to produce ESBLs is of great concern, as this pathogen is frequently associated with invasive infections and a higher risk of bacteraemia, and its reservoir has not yet been clearly identified.

Molecularly defined extraintestinal pathogenic Escherichia coli status predicts virulence in a murine sepsis model better than does virotype, individual virulence genes, or clonal subset among E. coli ST131 isolates

BACKGROUND

Escherichia coli ST131, mainly its H30 clade, is the leading cause of extraintestinal E. coli infections but its correlates of virulence are undefined.

MATERIALS AND METHODS

We tested in a murine sepsis model 84 ST131 isolates that differed by country of origin (Spain vs. USA), clonal subset, resistance markers, and virulence genes (VGs). Virulence outcomes, including illness severity score (ISS) and "killer" status (>80% mouse lethality), were compared statistically with clonal subset, individual and combined VGs, molecularly defined extraintestinal and uropathogenic E. coli (ExPEC, UPEC) status, and country of origin.

RESULTS

Virulence varied widely by strain. Univariable correlates of median ISS and percent "killer" (outcomes if variable present vs. absent) included pap (ISS, 4.4 vs. 3.8; "killer", 71% vs. 46%), kpsMII (4.1 vs. 2.3; 59% vs. 25%), K2/K100 (4.4 vs. 3.2; 77% vs. 41%), ExPEC (4.2 vs. 2.2; 62% vs. 17%), Spanish origin (4.3 vs. 3.1; 65% vs. 36%), and H30R1 subset (2.5 vs. 4.1; 35% vs. 59%). With multivariable adjustment, ExPEC status was the only consistently significantly predictive variable.

CONCLUSION

Within ST131 the strongest predictor of experimental virulence was molecularly defined ExPEC status. Clonal subsets seemed to behave differently in the murine sepsis model by country of origin.

Genomic Epidemiology of Salmonella Infantis in Ecuador: From Poultry Farms to Human Infections

Salmonella enterica is one of the most important foodborne pathogens around the world. In the last years, S. enterica serovar Infantis has become an important emerging pathogen in many countries, often as multidrug resistant clones. To understand the importance of S. enterica in the broiler industry in Ecuador, we performed a study based on phenotypic and WGS data of isolates from poultry farms, chicken carcasses and humans. We showed a high prevalence of S. enterica in poultry farms (41.4%) and chicken carcasses (55.5%), but a low prevalence (1.98%) in human samples. S. Infantis was shown to be the most prevalent serovar with a 98.2, 97.8, and 50% in farms, foods, and humans, respectively, presenting multidrug resistant patterns. All sequenced S. Infantis isolates belonged to ST32. For the first time, a pESI-related megaplasmid was identified in Ecuadorian samples. This plasmid contains genes of antimicrobial resistance, virulence factors, and environmental stress tolerance. Genomic analysis showed a low divergence of S. Infantis strains in the three analyzed components. The results from this study provide important information about genetic elements that may help understand the molecular epidemiology of S. Infantis in Ecuador.

Occurrence and Characteristics of the Extended-spectrum Beta-lactamase-producing Enterobacterale in a Hospital Setting

Objectives:

Infectious diseases caused by ESBL-producing Enterobacterale are an emerging problem worldwide, which increase hospital costs, empirical treatment failure, together with rates of morbidity and mortality. The aims of this study were to determine the antibiotic-resistant patterns and the frequency of blaTEM, blaCTX-M and blaSHV genes among Enterobacterale.

Methods:

A total of 239 non-repeated clinical isolates of the Enterobacterale family, including 202 (84.5%) Escherichia coli and Klebsiella pneumoniae 25 (12.3%) were collected. Identification and susceptibility tests were carried out on 60 (25.9%) ESBL phenotypes using biomérieux VITEK® 2 compact system. Isolates showing ESBL positivity by the phenotypic method were all screened for blaTEM, blaCTX-M and blaSHV genes by PCR.

Results:

The prevalence of ESBL-producing Enterobacterale isolates was found to be 25.9%. These ESBL-producing isolates displayed an increasing rate of resistance for aminopenicillins (ampicillin) (96.3%), followed by piperacillin-tazobactam (54.2%), amoxicillin/clavulanic acid (45.8), the cephalosporin groups, ceftriaxone (52.4%), ceftazidime (46.7%), and fluoroquinolone (ciprofloxacin) (42.7%). Both the organisms showed a higher susceptibility to the carbapenems (Imipenem) and aminoglycosides (Amikacin). Out of the 62 ESBL positive isolates, 11 (17.7%) carried the TEM gene, 22 (35.5%) carried the CTX-M gene alone, 8 (12.9%) carried both TEM and CTX-M genes, 1(1.6%) carried both SHV and CTX-M genes, and 20 (32.3%) carried the TEM, SHV, and CTX-M genes. SHV gene alone was not reported in any of the isolates.

Conclusion:

The study indicated a moderate occurrence of ESBL-producing Enterobacterale with CTX-M being the most dominant gene. The co-existence of all three genes on many occasions suggested the carriage of multiple plasmids with three resistance genes that might pose a serious epidemiological, clinical and public health threat.

Novel Insights and Features of the NDM-5-Producing Escherichia coli Sequence Type 167 High-Risk Clone

Escherichia coli sequence type 167 (ST167), producing the metallo beta-lactamase NDM-5, has been isolated as a colonizer of patients recovered at the University Hospital Policlinico Umberto I of Rome. Phylogenesis and comparative analysis of the genomes of these strains were performed against 343 ST167 genomes available from the EnteroBase database. These analyses revealed that resistance plasmids, integrative conjugative elements (ICEs), carrying the yersiniabactin virulence trait and capsular synthesis gene clusters had variable compositions and distributions within different strains of the ST167 clone. A novel capsular synthesis gene cluster, highly similar to the K48 cluster previously described only for Klebsiella pneumoniae, was identified in phylogenetically related strains of the ST167 clone.IMPORTANCE Global dissemination of some E. coli high-risk clones has been described in the last decades. The most widespread was the ST131 clone, associated with extended-spectrum-beta-lactamase (ESBL) production. Genomics of ST131 demonstrated that one clade within the ST emerged in the early 2000s, followed by a rapid, global expansion. The E. coli ST167 clone is emerging throughout the world, being frequently reported for its association with carbapenem resistance. Our study shows that virulence features are differently represented within the ST167 population. One clade shows the K48 capsular synthesis gene cluster of K. pneumoniae, not previously described for E. coli, and is populated by NDM-5-producing strains. The combination of resistance and virulence may sustain the global expansion of this specific ST167 clade.

Detection of two simultaneous outbreaks of Klebsiella pneumoniae coproducing OXA-48 and NDM-1 carbapenemases in a tertiary-care hospital in Valencia, Spain

Klebsiella pneumoniae is one of the most common hospital-acquired Gram-negative pathogens. During the last decade, the emergence of strains with reduced susceptibility or resistance to carbapenems is becoming a therapeutic challenge. This study takes place after the isolation of 14 strains of carbapenem-resistant K. pneumoniae with similar susceptibility patterns and carriage of OXA-48 and NDM-1 carbapenemases genes. Fourteen patients were found to be colonized (faecal carriage) and/or infected by two different clones of carbapenemase-coproducing K. pneumoniae during a 1-year period of time. Some of the patients had shared a hospital ward and continued to be colonized several months after the outbreak.

High quantities of multidrug-resistant Escherichia coli are present in the Machángara urban river in Quito, Ecuador

Urban river pollution by multidrug-resistant (MDR) bacteria constitutes an important public health concern. Epidemiologically important strains of MDR Escherichia coli transmissible at the human-animal-environment interfaces are especially worrying. Quantifying and characterizing MDR E. coli at a molecular level is thus imperative for understanding its epidemiology in natural environments and its role in the spread of resistance in precise geographical areas. Cefotaxime-resistant E. coli was characterized along the watercourse of the major urban river in Quito. Our results showed high quantities of cefotaxime-resistant E. coli (2.7 × 10³-5.4 × 10⁵ CFU/100 mL). The antimicrobial resistance index (ARI) revealed the exposure of the river to antibiotic contamination, and the multiple antibiotic resistance index indicated a high risk of contamination. The bla_CTX-M-15 gene was the most prevalent in our samples. Isolates also had class 1 integrons carrying aminoglycoside-modifying enzymes and folate pathway inhibitors. The isolates belonged to phylogroups A, B1 and D. Clonal complex 10 was found to be the most prevalent (ST10, ST44 and ST 167), followed by ST162, ST394 and ST46. Our study provides a warning about the high potential of the major urban river in Quito for spreading the epidemiologically important MDR E. coli.

Trends in the serovar and antimicrobial resistance in clinical isolates of Salmonella enterica from cattle and pigs between 2002 and 2016 in Japan

AIMS

Given the significance of Salmonella enterica in both human and animal health, and a recent global dissemination of Salmonella 4,[5],12:i:-, changes in the prevalent serovars and antimicrobial resistance in clinical isolates of Salmonella from cattle and pigs were investigated in Japan.

METHODS AND RESULTS

The serovars and antimicrobial susceptibilities of 1605 Salmonella enterica isolated from cattle (n = 894) and swine (n = 711) between 2002 and 2016 were examined. The most common serovar among all samples was Salmonella Typhimurium. However, its monophasic variant with antigenic structure S. 4,[5],12:i:-, which was first detected in cattle in 2006 and swine in 2010, has been rapidly increasing in incidence and resistance. Resistance rates to cefotaxime and ciprofloxacin were generally low (<10% in the cattle isolates and <5% in the swine isolates); however, isolates resistant to more than five antimicrobials, which often include these antimicrobials, were recently detected in Salmonella Dublin, S. 4,[5],12:i:-, S. Typhimurium, Salmonella Newport, Salmonella Choleraesuis and Salmonella 6,7:c:-. Among them, two S. 4,[5],12:i:- isolates possessed extended-spectrum β-lactamase-encoding genes; bla_SHV-12 or bla_CTX-M-55 , respectively, while all the five S. Typhimurium isolates possessed AmpC-type β-lactamase gene of bla_CMY-2 .

CONCLUSIONS

S. 4,[5],12:i:- has been rapidly increasing and exhibiting a remarkable change in antimicrobial resistance in Japan. Considering certain serovars are characterized by multidrug resistance including medically important antimicrobials, continuous monitoring and appropriate measures are required to protect public health and veterinary husbandry.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study presents a trend in the serovars and antimicrobial resistance in clinical isolates of Salmonella from cattle and pigs in Japan, and showed that there were certain types of Salmonella serovars depending on the animal origin which needs more attention.

Genotypic validation of extended-spectrum β-lactamase and virulence factors in multidrug resistance Klebsiella pneumoniae in an Indian hospital

The emergence of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae has been increasing rapidly across the world. The presence of virulence factors in ESBL producers further adds to the pathogenicity and severity of infection, which often complicate empirical therapy and sometimes result in treatment failures. In the present study, 227 non-repeated clinical isolates of K. pneumoniae obtained from different clinical specimens from a tertiary care hospital in India were analyzed to detect the genes responsible for ESBL production (blaTEM, blaCTX-M, and blaSHV), virulence (fimH-1, mrkD, entB, irp-1), and capsule production (K1-K2). Phenotypically identified 72 ESBL producing K. pneumoniae isolates were further subjected to PCR based genotypic analysis but only 20 were found to have at least one of the ESBL producing genes. blaTEM was the most predominant gene (100%), followed by blaSHV (90%), and blaCTX-M (85%). Similarly, the most common virulence genes were fimH-1 (70%), entB (65%), markD (55%), irp-1 (25%), K1 (25%), and K2 (20%). REP-PCR profile separated them into five major clusters (I-V), indicating the existing heterogeneity among the isolates. The resistance profile data obtained from the present study can serve as the information base to understand the infection pattern prevailing in the hospital and for physicians to recommend suitable antibiotics for the patients.

Comparative Genomics of Antibiotic-Resistant Uropathogens Implicates Three Routes for Recurrence of Urinary Tract Infections

The rise of antimicrobial resistance in uropathogens has complicated the management of urinary tract infections (UTIs), particularly in patients who are afflicted by recurrent episodes of UTIs. Antimicrobial-resistant (AR) uropathogens persistently colonizing individuals at asymptomatic time points have been implicated in the pathophysiology of UTIs. The dynamics of uropathogen persistence following the resolution of symptomatic disease are, however, mostly unclear. To further our understanding, we determined longitudinal AR uropathogen carriage and clonal persistence of uropathogenic Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae isolates in the intestinal and urinary tracts of patients affected by recurrent and nonrecurrent UTIs. Clonal tracking of isolates in consecutively collected urine and fecal specimens indicated repeated transmission of uropathogens between the urinary tract and their intestinal reservoir. Our results further implicate three independent routes of recurrence of UTIs: (i) following an intestinal bloom of uropathogenic bacteria and subsequent bladder colonization, (ii) reinfection of the urinary tract from an external source, and (iii) bacterial persistence within the urinary tract. Taken together, our observation of clonal persistence following UTIs and uropathogen transmission between the intestinal and urinary tracts warrants further investigations into the connection between the intestinal microbiome and recurrent UTIs.IMPORTANCE The increasing antimicrobial resistance of uropathogens is challenging the continued efficacy of empiric antibiotic therapy for UTIs, which are among the most frequent bacterial infections worldwide. It has been suggested that drug-resistant uropathogens could persist in the intestine after the resolution of UTI and cause recurrences following periurethral contamination. A better understanding of the transmission dynamics between the intestinal and urinary tracts, combined with phenotypic characterization of the uropathogen populations in both habitats, could inform prudent therapies designed to overcome the rising resistance of uropathogens. Here, we integrate genomic surveillance with clinical microbiology to show that drug-resistant clones persist within and are readily transmitted between the intestinal and urinary tracts of patients affected by recurrent and nonrecurrent UTIs. Thus, our results advocate for understanding persistent intestinal uropathogen colonization as part of the pathophysiology of UTIs, particularly in patients affected by recurrent episodes of symptomatic disease.

Multidrug-resistant Escherichia coli isolated from canine faeces in a public park in Quito, Ecuador

OBJECTIVES

This study focused on estimating the prevalence of extended-spectrum β-lactamases (ESBLs), plasmid-mediated AmpC β-lactamases, carbapenemases and MCR-1-producing Escherichia coli in canine faeces from a public park in Quito, Ecuador.

METHODS

Phenotypic and genotypic characterisation of E. coli isolated from 50 canine faecal samples recovered from a city park in Quito was performed. In addition, a multiple choice survey was conducted among 50 dog owners.

RESULTS

Of the 50 faecal samples, 20 (40.0%) presented E. coli resistant to ceftriaxone. Moreover, 23 E. coli isolates were recovered for further analysis. All of the isolates showed as multidrug-resistant (MDR) phenotype (resistant to three or more antibiotic families). Resistance to carbapenems, tigecycline and amikacin was not observed. No major clonal relatedness was observed among the resistant isolates. The ESBL genes bla_CTX-M-15, bla_CTX-M-55 and bla_CTX-M-65 were the most common. Two isolates harboured the bla_CMY-2 gene and one isolate harboured both mcr-1 and bla_CTX-M-65. Statistical analysis showed that older people were more conscious of collecting and disposing of dog faeces than subjects aged <35 years (P < 0.05).

CONCLUSION

The finding of MDR E. coli in dog faeces in a city park in Ecuador illustrates the importance of analysing canine faeces in public settings (e.g. parks, playgrounds) as part of surveillance programmes for MDR E. coli. In addition, this research might be a sentinel sampling method to gain a better understanding of community sources of antibiotic-resistant Enterobacteriaceae at human-animal-environment interfaces.

Characterization of cefotaxime resistant Escherichia coli isolated from broiler farms in Ecuador

Antimicrobial resistance (AR) is a worldwide concern. Up to a 160% increase in antibiotic usage in food animals is expected in Latin American countries. The poultry industry is an increasingly important segment of food production and contributor to AR. The objective of this study was to evaluate the prevalence, AR patterns and the characterization of relevant resistance genes in Extended Spectrum β-lactamases (ESBL) and AmpC-producing E. coli from large poultry farms in Ecuador. Sampling was performed from June 2013 to July 2014 in 6 slaughterhouses that slaughter broilers from 115 farms totaling 384 flocks. Each sample of collected caeca was streaked onto TBX agar supplemented with cefotaxime (3 mg/l). In total, 176 isolates were analyzed for AR patterns by the disk diffusion method and for blaCTX-M, blaTEM, blaCMY, blaSHV, blaKPC, and mcr-1 by PCR and sequencing. ESBL and AmpC E. coli were found in 362 flocks (94.3%) from 112 farms (97.4%). We found that 98.3% of the cefotaxime-resistant isolates were multi-resistant to antibiotics. Low resistance was observed for ertapenem and nitrofurantoin. The most prevalent ESBL genes were the ones belonging to the blaCTX-M group (90.9%), specifically the blaCTX-M-65, blaCTX-M-55 and blaCTX-M-3 alleles. Most of the AmpC strains presented the blaCMY-2 gene. Three isolates showed the mcr-1 gene. Poultry production systems represent a hotspot for AR in Ecuador, possibly mediated by the extensive use of antibiotics. Monitoring this sector in national and regional plans of AR surveillance should therefore be considered.

Occurrence, genotypes and antimicrobial susceptibility of Salmonella collected from the broiler production chain within an integrated poultry company

Salmonella is a common foodborne pathogen in the poultry production systems. Its presence in this food industry is determined by the fact that it can survive and pass throughout the different steps in the poultry production. In this study we aimed to study the occurrence, genotypes and antimicrobial resistance of Salmonella collected from the broiler production chain within an integrated poultry company. Three hundred fourteen samples were collected in the feeding plant, farms and the slaughterhouse. Samples were cultured for Salmonella isolation according to the ISO6579/Amd 1. Isolates were further typed by Kauffmann-White scheme and pulse field gel electrophoresis (PFGE). Antimicrobial resistance to 11 antimicrobials was studied by disk diffusion tests and sequencing of ESBL genes. From the collected samples 70 (22%) were found to be Salmonella positive. The lowest Salmonella rates were found in feed samples while in farm and slaughterhouse samples Salmonella presence ranged from 5% to 88%. S. Infantis was the most common serotype (94%, 66/70). PFGE demonstrated that isolates belonged to 11 genotypes. Some genotypes were continuously identified throughout the production chain. 97% of the isolates showed resistance to at least one antimicrobial. Moreover, all S. Infantis isolates and one auto-agglutinable isolate showed resistance to at least 6 antimicrobials. 30 and 8 isolates were positive to bla_CTX-M-65 and bla_CTX-M-14 genes respectively. No bla_KPC resistance genes were identified in any isolate. This study highlights the predominance of S. Infantis in the integrated poultry company. Genotypes showed that cross-contamination between stages of poultry production can occur, stressing the importance of implementing good hygiene practices in every level of the production. Moreover, multidrug resistance patterns and the presence of important ESBL genes have public health implications that need to be deeply discussed with a one health approach.

Characterization of a multidrug-resistant Klebsiella pneumoniae ST607-K25 clone responsible for a nosocomial outbreak in a neonatal intensive care unit

PURPOSE

Multidrug-resistant Klebsiella pneumoniae strains are regularly involved in hospital outbreaks. This study describes an ESBL-producing K. pneumoniae clone (ST607-K25) responsible for a nosocomial outbreak in a neonatal intensive care unit.

METHODOLOGY

Fourteen strains isolated from 13 patients were included. Antimicrobial susceptibility testing was performed by the agar diffusion method. A clonal link was first investigated by fingerprinting (ERIC-PCR and REP-PCR) then confirmed by MLST. Characterization was performed by molecular detection and identification of several drug resistance and virulence determinants.

RESULTS

All strains expressed the same antibiotype, combining ESBL production, fluoroquinolones and aminoglycoside resistance, except for one which remained susceptible to fluoroquinolones. Fingerprinting methods confirmed the clonal link and MLST identified a ST607 clone. Molecular investigations revealed: (I) genes encoding for two narrow-spectrum beta-lactamases (SHV-1 and TEM-1) and an ESBL (CTX-M-15); (II) absence of any chromosomal mutation in quinolone resistance-determining- regions (QRDR) of gyrA/gyrB and parC/parE genes; (III) genes encoding for three plasmid-mediated quinolone-resistance (PMQR) determinants: oqxAB (14/14), aac(6')-Ib-cr (14/14) and qnrB (13/14); (IV) production of a K25 capsule; and (V) carriage of three genes encoding for virulence factors: mrkD (type 3 fimbriae) (14/14), ybts (yersiniabactin) (12/14) and entB (enterobactin) (14/14).

CONCLUSION

We described a multidrug-resistant Kp ST607 clone responsible for a nosocomial outbreak in vulnerable and premature newborns. Molecular investigations allowed us to identify several resistance factors responsible for ESBL production (CTX-M-15) and quinolone resistance (three PMQR determinants). The detection of a gene (ybtS) belonging to the high-pathogenicity island yersiniabactin could partly explain its high colonization and diffusion potential.

Genomic Characterization of Extended-Spectrum Cephalosporin-Resistant Salmonella enterica in the Colombian Poultry Chain

Salmonella enterica serovars have been isolated from Colombian broilers and broiler meat. The aim of this study was to investigate the diversity of ESBL/pAmpC genes in extended-spectrum cephalosporin resistant Salmonella enterica and the phylogeny of ESBL/pAmpC-carrying Salmonella using Whole Genome Sequencing (WGS). A total of 260 cefotaxime resistant Salmonella isolates, obtained between 2008 and 2013 from broiler farms, slaughterhouses and retail, were included. Isolates were screened by PCR for ESBL/pAmpC genes. Gene and plasmid subtyping and strain Multi Locus Sequence Typing was performed in silico for a selection of fully sequenced isolates. Core-genome-based analyses were performed per ST encountered. bla CMY-2-like was carried in 168 isolates, 52 carried bla CTX-M-2 group, 7 bla SHV, 5 a combination of bla CMY-2-like-bla SHV and 3 a combination of bla CMY-2-like-bla CTX-M-2 group. In 25 isolates no ESBL/pAmpC genes that were screened for were found. WGS characterization of 36 selected strains showed plasmid-encoded bla CMY-2 in 21, bla CTX-M-165 in 11 and bla SHV-12 in 7 strains. These genes were mostly carried on IncI1/ST12, IncQ1, and IncI1/ST231 plasmids, respectively. Finally, 17 strains belonged to S. Heidelberg ST15, 16 to S. Paratyphi B variant Java ST28, 1 to S. Enteritidis ST11, 1 to S. Kentucky ST152 and 1 to S. Albany ST292. Phylogenetic comparisons with publicly available genomes showed separate clustering of Colombian S. Heidelberg and S. Paratyphi B var. Java. In conclusion, resistance to extended-spectrum cephalosporins in Salmonella from Colombian poultry is mainly encoded by bla CMY-2 and bla CTX-M-165 genes. These genes are mostly associated with IncI1/ST12 and IncQ1 plasmids, respectively. Evolutionary divergence is observed between Colombian S. Heidelberg and S. Paratyphi B var. Java and those from other countries.

Dynamics of cefotaxime resistant Escherichia coli in broilers in the first week of life

Extended-spectrum beta-lactamase producing E. coli (ESBL-E) are wide spread among broilers, with the highest prevalence among individual birds at broiler production farms. Previous research describes low prevalences among individual birds at arrival at the farm (below 30%), and a rapid increase up to 100% within the first week. Our goal was to investigate whether this rapid increase was due to latent contamination of ESBL-E or to contamination at the broiler farm. Two broiler groups, one hatched at a conventional hatchery and the other individually hatched in an ESBL-free environment, were housed individually in an experimental ESBL-free environment. A third group was hatched at a conventional hatchery and kept at a conventional broiler farm. The birds were sampled daily during the first week after hatch and tested for the presence of ESBL-E. In addition ESBL-E presence in eggs that were not incubated was investigated. All birds and eggs came from one ESBL-E positive parent flock. ESBL/AmpC genes, plasmids and E. coli sequence types were determined for a selection of isolates. ESBL-E was never found in the two groups kept in the ESBL-free experimental environment or in the sampled eggs, whereas all broilers sampled at the conventional farm became positive for ESBL-E within three days. One dominant E. coli strain (ST88) carrying bla_CTX-M-1 gene on an IncI1/pST3 plasmid was found in parent and broiler samples. We conclude that the rapid increase in ESBL-E prevalence in the first week of life is not caused by a latent contamination of the majority of birds at arrival, but that this increase must be caused by other factors.

Investigation of Extended-Spectrum and AmpC β-Lactamase-Producing Enterobacteriaceae from Retail Seafood in Berlin, Germany

Retail seafood in Berlin, Germany, was investigated to detect the prevalence and quantitative load of Enterobacteriaceae that produce extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase (AmpC). A total of 160 raw seafood samples were screened for the presence of these bacteria using MacConkey agar supplemented with 1 mg/L cefotaxime after nonselective enrichment. Isolated species were subsequently identified using matrix-assisted laser desorption-ionization time-of-flight analysis. ESBL and AmpC production was tested by the disk diffusion method, and ESBL and AmpC genes were characterized using real-time and conventional PCR assays with DNA sequencing. Spread plating was used for quantification of ESBL- and AmpC-producing Enterobacteriaceae. Overall, these bacteria were detected in 21.3% of seafood samples (34 of 160 samples) with prevalences of 22.5 and 20% for shrimp and bivalves, respectively. Of the positive samples, 91.2% contained an ESBL- or AmpC-producing Enterobacteriaceae load of <100 CFU/g (lower detection limit), and 8.8% contained 100 to 1,000 CFU/g. Among the 45 Enterobacteriaceae isolates, Klebsiella pneumoniae (13 isolates) and Escherichia coli (12 isolates) were the predominant species. ESBL and AmpC genes were detected in 33 isolates, with the majority of isolates harboring bla_CTX-M (27.3%), bla_CMY (21.2%), or bla_DHA (21.2%). Our study highlights the hazard associated with seafood containing ESBL- and AmpC-producing Enterobacteriaceae in Germany. Even though the contamination levels were low, the high prevalence of ESBL- and AmpC-producing Enterobacteriaceae in seafood might be of concern to public health because of the potential transmission of these bacteria from seafood to humans through the food chain.

Distribution of extended-spectrum β-lactam, quinolone and carbapenem resistance genes, and genetic diversity among uropathogenic Escherichia coli isolates in Tehran, Iran

OBJECTIVES

Antimicrobial resistance among uropathogenic Escherichia coli (UPEC) is increasing. The aim of this study was to evaluate antimicrobial resistance in UPEC isolates and its correlation with virulence factors.

METHODS

A total of 120 E. coli isolates were collected from patients with urinary tract infection in Tehran, Iran. Biofilm formation and antimicrobial susceptibility were determined by phenotypic tests. The combination disk diffusion test and modified Hodge test (MHT) were performed for phenotypic detection of extended-spectrum β-lactamases (ESBLs) and carbapenemases, respectively. PCR was used for the detection of virulence genes, ESBL-encoding genes, and quinolone (qnr) and carbapenem resistance genes. Pulsed-field gel electrophoresis (PFGE) was performed to explore the genetic relatedness among isolates.

RESULTS

Most isolates exhibited biofilm formation, and different frequencies of virulence genes were observed. There was a high rate of resistance, especially multidrug resistance, to most of the antimicrobial agents tested. Phenotypically, 67.5% of the isolates produced an ESBL and were resistant to different antimicrobial classes. In total, 83.3% of the isolates harboured ESBL genes, especially bla_TEM and bla_CTX-M, and 32.5% were positive for the quinolone resistance genes qnrS and qnrB. All isolates were negative for carbapenemases by the MHT and PCR. These results indicate the association between the presence of various virulence genes and antimicrobial susceptibility. PFGE analysis showed that there was great clonal diversity among the selected isolates, with 17 isolates divided into five clusters.

CONCLUSIONS

These results indicate that the high antimicrobial resistance among UPEC isolates is alarming and requires urgent attention.

Prevalence of TEM, SHV, and CTX-M genes of extended-spectrum β-lactamase-producing Escherichia coli strains isolated from urinary tract infections in adults

Urinary tract infections (UTIs) are one of the major sources of widespread infectious diseases in the community as well as in the hospitals which increase the cause of morbidity and mortality. Prevalence of extended-spectrum-β-lactamase (ESBL)-producing uropathogenic E. coli isolates has been found to be increased rapidly across the world. The present study was undertaken to find out the frequency of bla _TEM, bla _CTX-M, and bla _SHV genes among E. coli isolates from UTI and detect their sensitivity pattern. A total of 112 non-repeated E. coli isolates obtained from urine samples of UTI diagnosed patients were included in this study. Antibiotic susceptibility test was done by disc diffusion method. Seventy seven (68.75%) isolates were MDR and tested for ESBL. ESBL-positive isolates were screened for bla _TEM, bla _CTX-M, and bla _SHV genes by monoplex PCR (polymerase chain reaction). Among 46 ESBL-producing E. coli isolates, 8.69% harboured all the three bla genes. The bla _TEM was the predominant (93.47%) gene followed by bla _CTX-M (82.6%) and bla _SHV (4.34%). It can be concluded that the prevalence of MDR (multidrug resistance) ESBL-producing E. coli appears to be high and the highest identified gene was bla _TEM. The knowledge of resistance pattern can help physician's select suitable empirical antibiotic regimens, so that antibiotics showing high-resistance pattern can be avoided.

Detection of emerging antibiotic resistance in bacteria isolated from subclinical mastitis in cattle in West Bengal

AIM

The aim of this work was to detect antibiotic resistance in Gram-negative bacteria isolated from subclinical mastitis in cattle in West Bengal.

MATERIALS AND METHODS

The milk samples were collected from the cattle suffering with subclinical mastitis in West Bengal. The milk samples were inoculated into the nutrient broth and incubated at 37°C. On the next day, the growth was transferred into nutrient agar and MacConkey agar. All the pure cultures obtained from nutrient agar slant were subjected to Gram-staining and standard biochemical tests. All the bacterial isolates were tested in vitro for their sensitivity to different antibiotics commonly used in veterinary practices. All Gram-negative isolates including positive control were subjected to polymerase chain reaction (PCR) for detection of bla_CTX-M, bla_TEM, bla_SHV, bla_VIM, tetA, tetB, tetC, and tetM genes considered for extended-spectrum β-lactamase (ESBL), metallo-β-lactamase, and tetracycline resistance.

RESULTS

In total, 50 Gram-negative organisms (Escherichia coli, Proteus, Pseudomonas, Klebsiella, and Enterobacter) were isolated from milk samples of subclinical mastitis infected cattle. Among these Gram-negative isolates, 48% (24/50) were found either ESBL producing or tetracycline resistant. Out of total 50 Gram-negative isolates, bla_CTX-M was detected in 18 (36%) isolates, and 6 (12%) harbored bla_TEM genes in PCR. None of the isolates carried bla_SHV genes. Further, in this study, 5 (10%) isolates harbored tet(A) gene, and 8 (16%) isolates carried tet(B) gene. No tet(C) gene was detected from the isolates.

CONCLUSION

This study showed emerging trend of antibiotic-resistant Gram-negative bacteria associated with subclinical mastitis in cattle in West Bengal, India.

Diversity, virulence, and antimicrobial resistance of the KPC-producing Klebsiella pneumoniae ST307 clone

The global spread of Klebsiella pneumoniae producing Klebsiella pneumoniae carbapenemase (KPC) has been mainly associated with the dissemination of high-risk clones. In the last decade, hospital outbreaks involving KPC-producing K. pneumoniae have been predominantly attributed to isolates belonging to clonal group (CG) 258. However, results of recent epidemiological analysis indicate that KPC-producing sequence type (ST) 307, is emerging in different parts of the world and is a candidate to become a prevalent high-risk clone in the near future. Here we show that the ST307 genome encodes genetic features that may provide an advantage in adaptation to the hospital environment and the human host. Sequence analysis revealed novel plasmid-located virulence factors, including a cluster for glycogen synthesis. Glycogen production is considered to be one of the possible adaptive responses to long-term survival and growth in environments outside the host. Chromosomally-encoded virulence traits in the clone comprised fimbriae, an integrative conjugative element carrying the yersiniabactin siderophore, and two different capsular loci. Compared with the ST258 clone, capsulated ST307 isolates showed higher resistance to complement-mediated killing. The acquired genetic features identified in the genome of this new emerging clone may contribute to increased persistence of ST307 in the hospital environment and shed light on its potential epidemiological success.

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates collected from diseased food-producing animals in the GERM-Vet monitoring program 2008-2014

The aim of this study was to identify extended-spectrum β-lactamase (ESBL)-producing Escherichia coli collected from diseased food-producing animals in Germany. A total of 6849 E. coli isolates, collected from diseased cattle, pigs and poultry in the German national monitoring program GERM-Vet (2008-2014), were characterized by antimicrobial susceptibility testing and screened for the ESBL phenotype. ESBL genes were identified by PCR and sequencing. The isolates were further characterized by PCR-based phylotyping. The 419/6849 (6.1%) ESBL-producers identified included 324/2896 (11.2%) isolates from cattle, 75/1562 (4.8%) from pigs and 20/2391 (0.8%) from poultry. The ESBL genes detected were: bla_CTX-M-1 (69.9%), bla_CTX-M-15 (13.6%), bla_CTX-M-14 (11.7%), bla_TEM-52 (1.9%), bla_SHV-12 (1.4%), bla_CTX-M-3 (1.0%), and bla_CTX-M-2 (0.5%). The phylogroup A was the dominant phylogroup (57.0%) followed by phylogroups D (23.4%), B1 (17.9%), and B2 (1.7%). Bovine isolates belonged predominantly to the phylogroups A and D, whereas the porcine and avian isolates mainly belonged to A and B1. The majority of the ESBL-producing isolates found in each phylogroup were from animals suffering from gastrointestinal infections. In 399/419 isolates (95.2%), additional resistance to non-β-lactam antibiotics was seen. Multidrug-resistance [resistance to aminoglycosides, fluoro(quinolones), sulphonamides, tetracyclines, and trimethoprim] was seen in 369/419 (88.1%) isolates, which may facilitate the co-selection of ESBL genes, when located on the same mobile genetic element as the others resistance genes, and may compromise the therapeutic options.

EXTENDED-SPECTRUM BETA-LACTAMASE-PRODUCING ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE ISOLATES FROM THE URINE OF DOGS AND CATS SUSPECTED OF URINARY TRACT INFECTION IN A VETERINARY TEACHING HOSPITAL

Extended-spectrum [Formula: see text]-lactamase (ESBL)-producing microorganisms often cause severe infections; they have only limited therapeutic alternatives and have emerged in both human and veterinary medicine. Companion animals have prolonged contact with humans and could serve as a reservoir for ESBL strains. Information regarding ESBL producers in companion animals is rather limited compared to that regarding humans. Therefore, the objective of this study was to screen for ESBL producers in Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis in urine samples collected from dogs and cats in which urinary tract infection was suspected in a veterinary teaching hospital in Taipei, Taiwan. In addition, bla genes, multilocus sequence typing (MLST) analysis, and antibiotic susceptibility testing were performed on these ESBL producers. From December 2011 to March 2013, disc tests of cefotaxime and ceftazidime, with and without clavulanic acid, were performed on 60 E. coli, 22 [Formula: see text]. pneumoniae, and 18 P. mirabilis samples isolated from urine; 2 E. coli and 5 K. pneumoniae samples with the ESBL phenotype were identified. CTX-M-15 was the most frequently found bla gene. CTX-M-14, SHV-11, SHV-12, and SHV-28 were also identified. MLST analysis did not detect a predominant ST type in either E. coli or [Formula: see text]. pneumoniae; nonetheless, K. pneumoniae ST15 and ST11, which are zoonotic agents of public health concern, were detected in our study. All ESBL-producing bacteria exhibited a multidrug-resistant phenotype. The occurrence of ESBL-producing E. coli and K. pneumoniae in companion animals underscores the importance of ESBL screening and epidemiological study in veterinary hospitals.

Quantitative assessment of faecal shedding of β-lactam-resistant Escherichia coli and enterococci in dogs

Quantitative data on faecal shedding of antimicrobial resistant bacteria are crucial to assess the risk of transmission from dogs to other animals as well as humans. In this study we investigated prevalence and concentrations of β-lactam-resistant Escherichia coli and enterococci in the faeces of 108 dogs presenting at a veterinary hospital in Denmark. The dogs had not been treated with antimicrobials for 4 weeks prior to the study. Total E. coli and enterococci were quantified by counts on MacConkey and Slanetz-Bartley, respectively. Resistant E. coli and enterococci were counted on the same media containing relevant antibiotic concentrations, followed by species identification using MALDI-TOF. Ampicillin- and cefotaxime-resistant E. coli were detected in 40% and 8% of the dogs, respectively, whereas approximately 15% carried ampicillin-resistant enterococci, mainly Enterococcus faecium. In the faeces of the carriers, the proportion of resistant strains in the total bacterial species population was on average 15% for both ampicillin-resistant E. coli (median faecal load 3.2×10(4)cfu/g) and E. faecium (5.8×10(2) cfu/g), and 4.6% for cefotaxime-resistant E. coli (8.6×10(3) cfu/g). Cefotaxime resistance was associated with the presence of blaCTX-M-1 (n=4), blaCMY-2 (n=4) or multiple mutations in the promoter and coding region of chromosomal ampC (n=1). Altogether the results indicate that the risks of zoonotic transmission of β-lactam-resistant bacteria via human exposure to canine faeces greatly vary amongst individual dogs and are influenced by unidentified factors other than recent antimicrobial use.

Characterization of human uropathogenic ESBL-producing Escherichia coli in the Czech Republic: spread of CTX-M-27-producing strains in a university hospital

AIMS

The purpose of this study was to characterize the extended-spectrum β-lactamase (ESBL)-producing uropathogenic Escherichia coli (UPEC) strains isolated in the South Moravia region of the Czech Republic.

RESULTS

Out of 109 ESBL-producing UPEC isolates, the CTX-M-15-producing E. coli O25b-ST131 was detected in 55 (50.5%) and the CTX-M-27-producing E. coli O25b-ST131 in 40 isolates (36.7%). Most isolates were distributed among three pulsed-field gel electrophoresis clusters and were characterized by low variability relative to antibiotic resistance patterns, in E. coli phylogroups and by the prevalence of virulence and bacteriocin determinants. Despite this, 14 groups of identical isolates (comprising a total of 41 isolates) were identified when all tested parameters of E. coli were combined.

CONCLUSIONS

Since the occurrence of E. coli B2-O25b-ST131 CTX-M-27 was only recently described in Asia, the frequent isolation of this lineage among patients in South Moravia suggests an efficient transfer of this clone from Asian countries. The limited variability of detected parameters of ESBL-producing UPEC strains is consistent with a common origin of the analyzed isolates, in which there is an ongoing process of genetic diversification.

Prevalence and characterization of extended-spectrum-β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in ready-to-eat vegetables

The objective of this investigation was to determine the prevalence and characteristics of extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae in ready-to-eat (RTE) vegetables. A total of 189 RTE vegetable samples (91 sprouts and 98 mixed salads) were collected in a retail market in South Korea from October 2012 to February 2013. The prevalence of ESBL-producing E. coli and K. pneumoniae was 10.1%. Of these, 94.7% were from the sprout samples. All isolates were resistant to cefotaxime, and many of the ESBL producers were also resistant to non-β-lactam antibiotics, including gentamicin, trimethoprim/sulfamethoxazole, and ciprofloxacin (73.7%, 63.2%, and 26.3% respectively). TEM-1, SHV-1, -2, -11, -12, -27, -28 and -61, and CTX-M-14, -15 and -55 β-lactamases were detected alone or in combination. The genetic platforms of all CTX-M producing isolates were ISEcp1-blaCTX-M-orf477 and ISEcp1-blaCTX-M-IS903 in CTX-M groups 1 and 9, respectively. To our knowledge, this is the first report of the prevalence and characterization of ESBL-producing E. coli and K. pneumoniae isolated from RTE vegetables. The results of this study indicate that RTE vegetables, sprouts, in particular, may play a role in spreading antimicrobial resistant bacteria and ESBL genes to humans.

Fatal sepsis by Klebsiella pneumoniae in a patient with systemic lupus erythematosus: the importance of postmortem microbiological examination for the ex post diagnosis of infection

The utility of postmortem microbiology has continuously been a topic of controversy. The present study describes a case of fatal sepsis in a patient with systemic lupus erythematosus. Postmortem culture and genotyping analyses allowed us to identify Klebsiella pneumoniae as the cause of sepsis, revealing the inadequateness of antimicrobial therapy.

A novel plasmid carrying blaCTX-M-15 identified in commensal Escherichia coli from healthy pregnant women in Ibadan, Nigeria

The aim of this study was to investigate the molecular characteristics of commensal Escherichia coli producing extended-spectrum β-lactamases and showing fluoroquinolone resistance circulating in a healthy population in Ibadan, Nigeria. In total, 101 faecal samples from healthy pregnant women on the day of admission to hospital were collected and plated on eosin-methylene blue agar supplemented with cefotaxime. Genotyping demonstrated the presence of the bla_CTX-M-15 gene in all of the cefotaxime-resistant isolates (n=32), and there was circulation of prevalent clones. The aac(6')-Ib-cr, qnrS1, qepA1 and qnrB1 genes were identified in several strains. A novel plasmid supporting the spread of the bla_CTX-M-15, bla_TEM-1 and qnrS1 genes was identified in these isolates by complete DNA sequencing.

Degenerate primer MOB typing of multiresistant clinical isolates of E. coli uncovers new plasmid backbones

Degenerate Primer MOB Typing is a PCR-based protocol for the classification of γ-proteobacterial transmissible plasmids in five phylogenetic relaxase MOB families. It was applied to a multiresistant E. coli collection, previously characterized by PCR-based replicon-typing, in order to compare both methods. Plasmids from 32 clinical isolates of multiresistant E. coli (19 extended spectrum beta-lactamase producers and 13 non producers) and their transconjugants were analyzed. A total of 95 relaxases were detected, at least one per isolate, underscoring the high potential of these strains for antibiotic-resistance transmission. MOBP12 and MOBF12 plasmids were the most abundant. Most MOB subfamilies detected were present in both subsets of the collection, indicating a shared mobilome among multiresistant E. coli. The plasmid profile obtained by both methods was compared, which provided useful data upon which decisions related to the implementation of detection methods in the clinic could be based. The phylogenetic depth at which replicon and MOB-typing classify plasmids is different. While replicon-typing aims at plasmid replication regions with non-degenerate primers, MOB-typing classifies plasmids into relaxase subfamilies using degenerate primers. As a result, MOB-typing provides a deeper phylogenetic depth than replicon-typing and new plasmid groups are uncovered. Significantly, MOB typing identified 17 plasmids and an integrative and conjugative element, which were not detected by replicon-typing. Four of these backbones were different from previously reported elements.

Phenotypic and molecular characterization of extended-spectrum beta-lactamase-producing Escherichia coli in Bangladesh

Background

Resistance to cephalosporins in Enterobacteriaceae is mainly due to the production of extended-spectrum beta-lactamase (ESBL). Little is known about ESBL-producing bacteria in Bangladesh. Therefore, the study presents results of phenotypic and molecular characterization of ESBL-producing Escherichia coli from hospitals in Bangladesh.

Methods

A total of 339 E. coli isolated from patients with urinary tract and wound infections attending three different medical hospitals in urban and rural areas of Bangladesh between 2003–2007 were screened for ESBL-production by the double disk diffusion test. Isolates with ESBL-phenotype were further characterized by antibiotic susceptibility testing, PCR and sequencing of different β-lactamase and virulence genes, serotyping, and XbaI-macrorestriction followed by pulsed-field gel electrophoresis (PFGE).

Results

We identified 40 E. coli with ESBL phenotype. These isolates were resistant to ceftriaxone, ceftazidime, cefotaxime, aztreonam, cefepime, and nalidixic acid but remained susceptible to imipenem. All but one isolate were additionally resistant to ciprofloxacin, and 3 isolates were resistant to cefoxitin. ESBL genes of blaCTX-M-1-group were detected in all isolates; blaTEM-type and blaOXA-1-type genes were detected in 33 (82.5%) and 19 (47.5%) isolates, respectively. Virulence genes that are present in diarrhoeagenic E. coli were not found. Class-1 integron was present in 20 (50%) isolates. All the ESBL-producing E. coli isolates harbored plasmids ranging between 1.1 and 120 MDa. PFGE-typing revealed 26 different pulsotypes, but identical pulsotype showed 6 isolates of serotype O25:H4.

Conclusion

The prevalence of multidrug-resistant ESBL-producing E. coli isolates appears to be high and the majority of the isolates were positive for bla_CTX-M. Although there was genetic heterogeneity among isolates, presence of a cluster of isolates belonging to serotype O25:H4 indicates dissemination of the pandemic uropathogenic E. coli clone in Bangladesh.

High prevalence of ST131 among CTX-M-producing Escherichia coli from community-acquired infections, in the Czech Republic

A total of 2,683 nonrepetitive Escherichia coli isolates were collected from microbiological laboratories covering all regions of the Czech Republic, during April 2011. Antimicrobial susceptibility patterns of E. coli were assessed. All 38 cefotaxime-resistant (CTX-R) isolates were found to be extended-spectrum β-lactamase (ESBL)-positive by the double-disc synergy test. Thirty-two of those isolates produced enzymes of CTX-M-1 family, five of CTX-M-9 family, and one isolate both CTX-M types. Genotyping by multilocus sequence typing classified all ESBL-producing isolates into 13 sequence types (STs). ST131 was the most prevalent and was exclusively correlated with E. coli belonging to the more-virulent phylogroup B2. blaCTX-M-15 and blaCTX-M-9-like genes were mainly carried by plasmids belonging to the IncF group, while replicon I1 was predominant among CTX-M-1-encoding plasmids. Additionally, 63% of the ESBL-producing isolates were also resistant to ciprofloxacin. Sequence analysis of quinolone resistance-determining regions of gyrA and parC revealed the presence of amino acid substitutions in 22 out of 23 ciprofloxacin-resistant isolates. The acc(6')-Ib-cr and qnrB1 plasmid-mediated quinolone resistance genes were also detected in some of the isolates. This is the first report on the emergence and spread of CTX-M-producing E. coli in the community of the Czech Republic, indicating the high prevalence of ST131 clone among CTX-M producers.

Differences in extended-spectrum beta-lactamase producing Escherichia coli virulence factor genes in the Baltic Sea region

The aim of this study was to compare the prevalence of different virulence factor (VF) genes in extended-spectrum beta-lactamase (ESBL) producing Escherichia coli strains isolated from the Baltic Sea region. A total of 432 strains of phenotypically ESBL positive E. coli were collected from 20 institutions located in Estonia, Latvia, Lithuania, and the region of St. Petersburg in Russia from January to May 2012 and analyzed for phylogenetic group and prevalence of 23 VF genes. The strains were collected from clinical material (urine, blood, wound, and respiratory tract). Bacterial isolates were compared according to phylogenetic group, clinical material, and geographical origin. Most of the VF genes were concentrated within phylogenetic group B2 and/or D. When comparing strains isolated from different countries, it was found that strains originating from Estonia and Latvia belonged mainly to group B2 and strains from Lithuania and Russia mainly to groups B2 and D. The P-fimbrial adhesin gene papEF was more prevalent in Russian strains, colicin gene cvaC in Lithuanian strains, and capsular gene kpsMTII in Latvian strains; serum resistant gene traT was less prevalent in Estonian strains. The regional differences of VF genes remained statistically significant after taking into account the phylogenetic distribution in the countries.