AUTHOR=Zurfluh Katrin , Wang Juan , Klumpp Jochen , Nüesch-Inderbinen Magdalena , Fanning Seamus , Stephan Roger 

TITLE=Vertical transmission of highly similar blaCTX-M-1-harbouring IncI1 plasmids in Escherichia coli with different MLST types in the poultry production pyramid

JOURNAL=Frontiers in Microbiology

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2014.00519

DOI=10.3389/fmicb.2014.00519

ISSN=1664-302X

ABSTRACT=<p><bold>Objectives</bold>: The purpose of this study was to characterize sets of extended-spectrum β-lactamases (ESBL)-producing <italic>Enterobacteriaceae</italic> collected longitudinally from different flocks of broiler breeders, meconium of 1-day-old broilers from theses breeder flocks, as well as from these broiler flocks before slaughter.</p><p><bold>Methods</bold>: Five sets of ESBL-producing <italic>Escherichia coli</italic> were studied by multi-locus sequence typing (MLST), phylogenetic grouping, PCR-based replicon typing and resistance profiling. The <italic>bla</italic><sub>CTX-M-1</sub>-harboring plasmids of one set (pHV295.1, pHV114.1, and pHV292.1) were fully sequenced and subjected to comparative analysis.</p><p><bold>Results</bold>: Eleven different MLST sequence types (ST) were identified with ST1056 the predominant one, isolated in all five sets either on the broiler breeder or meconium level. Plasmid sequencing revealed that <italic>bla</italic><sub>CTX-M-1</sub> was carried by highly similar IncI1/ST3 plasmids that were 105 076 bp, 110 997 bp, and 117 269 bp in size, respectively.</p><p><bold>Conclusions</bold>: The fact that genetically similar IncI1/ST3 plasmids were found in ESBL-producing <italic>E. coli</italic> of different MLST types isolated at the different levels in the broiler production pyramid provides strong evidence for a vertical transmission of these plasmids from a common source (nucleus poultry flocks).</p>