AUTHOR=Hindermann Denise , Gopinath Gopal , Chase Hannah , Negrete Flavia , Althaus Denise , Zurfluh Katrin , Tall Ben D. , Stephan Roger , Nüesch-Inderbinen Magdalena 

TITLE=Salmonella enterica serovar Infantis from Food and Human Infections, Switzerland, 2010–2015: Poultry-Related Multidrug Resistant Clones and an Emerging ESBL Producing Clonal Lineage

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01322

DOI=10.3389/fmicb.2017.01322

ISSN=1664-302X

ABSTRACT=<p><bold>Objectives:</bold> The aim of this study was to characterize a collection of 520 <italic>Salmonella enterica</italic> serovar Infantis strains isolated from food (poultry meat), human infections and environmental sources from the years 2010, 2013 and 2015 in Switzerland.</p><p><bold>Methods:</bold> We performed antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE) analysis on all 520 <italic>S</italic>. Infantis isolates, and whole genome sequencing (WGS) on 32 selected isolates.</p><p><bold>Results:</bold> The majority (74.8%) of the isolates was multidrug resistant (MDR). PFGE analysis revealed that 270 (51.9%) isolates shared an identity of 90%. All isolates subjected to WGS belonged to sequence type (ST) 32 or a double-locus variant thereof (one isolate). Seven (21.9%) of the sequenced isolates were phylogenetically related to the broiler-associated clone B that emerged in Hungary and subsequently spread within and outside of Europe. In addition, three isolates harboring <italic>bla</italic><sub>CTX-M-65</sub> on a predicted large (∼320 kb) plasmid grouped in a distinct cluster.</p><p><bold>Conclusion:</bold> This study documents the presence of the Hungarian clone B and related clones in food and human isolates between 2010 and 2015, and the emergence of a <italic>bla</italic><sub>CTX-M-65</sub> harboring MDR <italic>S</italic>. serovar Infantis lineage.</p>