Conjugative IncFI plasmids carrying CTX-M-15 among Escherichia coli ESBL producing isolates at a University hospital in Germany

<p>Abstract</p> <p>Background</p> <p>Multi-drug-resistant, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, constitute an emerging public-health concern. Little data on the molecular epidemiology of ESBL producing <it>Escherichia coli </it>is available in Germany. Here we describe the prevalence and molecular epidemiology of ESBL producing-<it>Escherichia coli </it>isolates at a German University hospital.</p> <p>Methods</p> <p>We analysed 63 non-duplicate clinical ESBL isolates obtained over an 8-month period using PCR and sequence-based ESBL allele typing, plasmid replicon typing, phylogenetic group typing. Pulsed-field gel electrophoresis (PFGE) based genotyping and plasmid profiling was performed, as well as confirmatory DNA-based hybridization assays.</p> <p>Results</p> <p>Examination of the 63 <it>Escherichia coli </it>isolates revealed an almost equal distribution among the <it>E. coli </it>phylogenetic groups A, B1, B2 and D. High prevalence (36/63) of the CTX-M-15 gene was observed and an analysis of PFGE-based patterns revealed the presence of this CTX-M allele in multiple clones. Resistance to cefotaxime was a transferable trait and a commonly occurring 145.5 kb conjugative IncFI plasmid was detected in 65% of <it>E. coli </it>carrying the CTX-M-15 allele. The rate of transferable antibiotic resistances for GM, SXT, TET, GM-SXT-TET, SXT-TET and GM-TET was 33%, 61%, 61%, 27%, 44% and 11%, respectively. The remaining strains did not have a common IncFI plasmid but harboured transferable IncFI plasmids with sizes that ranged from 97 to 242.5 kb.</p> <p>Conclusion</p> <p>Our data demonstrate the presence of IncFI plasmids within the prevailing <it>E. coli </it>population in a hospital setting and suggest that the dissemination of CTX-M-15 allele is associated to lateral transfer of these well-adapted, conjugative IncFI plasmids among various <it>E. coli </it>genotypes.</p