Characterization of multidrug-resistant, qnrB2-positive and extended-spectrum-b-lactamase-producing Salmonella Concord and Salmonella Senftenberg isolates

Objectives: To characterize plasmids and resistance genes of multidrug-resistant (MDR) Salmonella Senftenberg and Salmonella Concord isolated from patients in the Netherlands. Methods: The resistance genes of four MDR Salmonella isolates (three Salmonella Concord and one Salmonella Senftenberg) were identified by miniaturized microarray, PCR and sequencing. Plasmids were characterized by S1 nuclease-PFGE and PCR-based replicon typing (PBRT). Linkage between plasmids and genes was determined by conjugation experiments and microarray analysis. The genetic relationship between the three Salmonella Concord isolates was determined by XbaI-PFGE. Results: A large variety of resistance genes was detected, including qnrB2 and the b-lactamase genes bla TEM-1 and bla SHV-12 in all isolates; moreover all Salmonella Concord isolates also harboured bla CTX-M-15 . Salmonella Senftenberg harboured a large IncHI2 plasmid. The three Salmonella Concord isolates harboured two large plasmids typed as IncHI2 and IncA/C. Conclusions: We detected the first plasmid-mediated MDR Salmonella isolates in the Netherlands harbouring both qnr and extended-spectrum b-lactamase (ESBL) genes. In Salmonella Senftenberg one large plasmid (IncHI2) and in Salmonella Concord two large plasmids (IncHI2 and IncA/C) were responsible for the multidrug resistance

Comparative Analysis of ESBL-Positive Escherichia coli isolates from Animals and Humans from the UK, the Netherlands and Germany

The putative virulence and antimicrobial resistance gene contents of extended spectrum β-lactamase (ESBL)-positive E. coli (n=629) isolated between 2005 and 2009 from humans, animals and animal food products in Germany, The Netherlands and the UK were compared using a microarray approach to test the suitability of this approach with regard to determining their similarities. A selection of isolates (n=313) were also analysed by multilocus sequence typing (MLST). Isolates harbouring blaCTX-M-group-1 dominated (66%, n=418) and originated from both animals and cases of human infections in all three countries; 23% (n=144) of all isolates contained both blaCTX-M-group-1 and blaOXA-1-like genes, predominantly from humans (n=127) and UK cattle (n=15). The antimicrobial resistance and virulence gene profiles of this collection of isolates were highly diverse. A substantial number of human isolates (32%, n=87) did not share more than 40% similarity (based on the Jaccard coefficient) with animal isolates. A further 43% of human isolates from the three countries (n=117) were at least 40% similar to each other and to five isolates from UK cattle and one each from Dutch chicken meat and a German dog; the members of this group usually harboured genes such as mph(A), mrx, aac(6’)-Ib, catB3, blaOXA-1-like and blaCTX-M-group-1. forty-four per cent of the MLST-typed isolates in this group belonged to ST131 (n=18) and 22% to ST405 (n=9), all from humans. Among animal isolates subjected to MLST (n=258), only 1.2% (n=3) were more than 70% similar to human isolates in gene profiles and shared the same MLST clonal complex with the corresponding human isolates. The results suggest that minimising human-to-human transmission is essential to control the spread of ESBL-positive E. coli in humans

Samenvatting ESBL-Attributieanalyse (ESBLAT) : Op zoek naar de bronnen van antibioticaresistentie bij de mens

Samenvatting over een project rondom ESBL's. Doelstellingen waren: vaststellen wat de bijdrage is van alle ESBL-reservoirs aan het dragerschap en infecties bij mensen en vaststellen wat de transmissieroutes zijn vanuit deze reservoirs naar de (geïnfecteerde) mens

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 blaCTX-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.</p

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 blaCTX-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.</p

qnrB19 Gene Bracketed by IS26 on a 40-Kilobase IncR Plasmid from an Escherichia coli Isolate from a Veal Calf ▿

qnrB19 genes have been reported in Escherichia coli, Escherichia hermannii, Salmonella enterica, and Klebsiella spp., located on IncN, IncL/M (human isolates), and ColE-like (both human and chicken isolates) plasmids (2, 6, 8, 9, 11, 13, 14, 16). This study describes the characterization of the genetic environment of a plasmid-mediated qnrB19 gene identified in E. coli isolated from a veal calf in the Netherlands

Dynamics of CMY-2 producing E. coli in a broiler parent flock

<p>Extended-spectrum β-lactamase and plasmid mediated AmpC β-lactamase (ESBL/pAmpC) producing bacteria are resistant to Extended Spectrum Cephalosporins (ESC), and are present in all levels of the broiler production chain. We determined the prevalence, concentration, and persistence of ESBL/pAmpC-Escherichia coli in a broiler parent flock during the rearing and laying period. One-day old chickens were housed in four separate pens. Until week 33 no antibiotics or coccidiostatics were used. During rearing 57 chickens in each pen (n = 228), and in the laying period two groups of 33 chickens were individually sampled (n = 66). Environmental samples were taken from week 16 onwards. ESBL/pAmpC-E. coli presence was determined by selective culturing. In the samples of week 16–19 the concentration of ESBL/pAmpC-E. coli was determined. All ESC-resistant isolates found were positive for pAmpC gene bla_CMY-2 located on IncA/C plasmids, in several E. coli MLST types. CMY-2-E. coli prevalence decreased from 91% (95%CI 86–94%) at day 7 (week 1) to 0% (95%CI 0–5%) in week 21. However, CMY-2-E. coli remained present in the environmental samples during the whole study. CMY-2-E. coli concentration varied between detection limit (&lt;10^3) and 2·10^4 cfu/g faeces. The sharp reduction of CMY-2-E. coli in this broiler parent flock in absence of antibiotics suggests a selective disadvantage of bla_CMY-2 on IncA/C plasmids on animal level. The underlying mechanism should be studied further as this may provide new insights on how to reduce ESBL/pAmpC prevalence and transmission in the broiler production chain.</p

Dynamics of CMY-2 producing E. coli in a broiler parent flock

Extended-spectrum β-lactamase and plasmid mediated AmpC β-lactamase (ESBL/pAmpC) producing bacteria are resistant to Extended Spectrum Cephalosporins (ESC), and are present in all levels of the broiler production chain. We determined the prevalence, concentration, and persistence of ESBL/pAmpC-Escherichia coli in a broiler parent flock during the rearing and laying period. One-day old chickens were housed in four separate pens. Until week 33 no antibiotics or coccidiostatics were used. During rearing 57 chickens in each pen (n = 228), and in the laying period two groups of 33 chickens were individually sampled (n = 66). Environmental samples were taken from week 16 onwards. ESBL/pAmpC-E. coli presence was determined by selective culturing. In the samples of week 16–19 the concentration of ESBL/pAmpC-E. coli was determined. All ESC-resistant isolates found were positive for pAmpC gene blaCMY-2 located on IncA/C plasmids, in several E. coli MLST types. CMY-2-E. coli prevalence decreased from 91% (95%CI 86–94%) at day 7 (week 1) to 0% (95%CI 0–5%) in week 21. However, CMY-2-E. coli remained present in the environmental samples during the whole study. CMY-2-E. coli concentration varied between detection limit