Extended-spectrum B-lactamase producing Enterobacteriaceae: diagnostics and epidemiology

Kluytmans, J.A.J.W. [Promotor]Savelkoul, P.H.M. [Promotor

Extended-Spectrum beta-Lactamase-Producing Escherichia coli From Retail Chicken Meat and Humans: Comparison of Strains, Plasmids, Resistance Genes, and Virulence Factors

BACKGROUND: The worldwide prevalence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae is increasing rapidly both in hospitals and in the community. A connection between ESBL-producing bacteria in food animals, retail meat, and humans has been suggested. We previously reported on the genetic composition of a collection of ESBL-producing Escherichia coli (ESBL-EC) from chicken meat and humans from a restricted geographic area. Now, we have extended the analysis with plasmid replicons, virulence factors, and highly discriminatory genomic profiling methods. METHODS: One hundred forty-five ESBL-EC isolates from retail chicken meat, human rectal carriers, and blood cultures were analyzed using multilocus sequence typing, phylotyping, ESBL genes, plasmid replicons, virulence genes, amplified fragment length polymorphism (AFLP), and pulsed-field gel electrophoresis (PFGE). RESULTS: Three source groups overlapped substantially when their genetic composition was compared. A combined analysis using all variables yielded the highest resolution (Wilks lambda [Lambda]: 0.08). Still, a prediction model based on the combined data classified 40% of the human isolates as chicken meat isolates. AFLP and PFGE showed that the isolates from humans and chicken meat could not be segregated and identified 1 perfect match between humans and chicken meat. CONCLUSIONS: We found significant genetic similarities among ESBL-EC isolates from chicken meat and humans according to mobile resistance elements, virulence genes, and genomic backbone. Therefore, chicken meat is a likely contributor to the recent emergence of ESBL-EC in human infections in the study region. This raises serious food safety questions regarding the abundant presence of ESBL-EC in chicken meat

Extended-spectrum β-lactamase producing Klebsiella spp. in chicken meat and humans: a comparison of typing methods

AbstractRecently, chicken meat was identified as a plausible source of extended-spectrum β-lactamase (ESBL) -producing Escherichia coli in humans. We investigated the relatedness of ESBL-producing Klebsiella spp. in chicken meat and humans. Furthermore, we tested the performance of SpectraCell RA® (River Diagnostics), a new typing method based on Raman spectroscopy, in comparison with multilocus sequence typing (MLST) for Klebsiella pneumoniae. Twenty-seven phenotypically and genotypically confirmed ESBL-producing Klebsiella spp. isolates were typed with MLST and SpectraCell RA. The isolates derived from chicken meat, human rectal swabs and clinical blood cultures. In the 22 ESBL-producing K. pneumoniae isolates, CTX-M15 was the predominant genotype, found in five isolates of human origin and in one chicken meat isolate. With MLST, 16 different STs were found, including five new STs. Comparing the results of SpectraCell RA with MLST, we found a sensitivity of 70.0% and a specificity of 81.8% for the new SpectraCell RA typing method. Therefore, we conclude that SpectraCell RA is not a suitable typing method when evaluating relationships of ESBL-producing Klebsiella spp. at the population level. Although no clustering was found with isolates of chicken meat and human origin containing the same ESBL genes, MLST showed no clustering into distinctive clones of isolates from chicken meat and human origin. More studies are needed to elucidate the role of chicken meat in the rise of ESBL-producing Klebsiella spp. in humans

Third-generation cephalosporin and carbapenem resistance in Streptococcus mitis/oralis. Results from a nationwide registry in the Netherlands

Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc