AUTHOR=Zhou Min , Li Xiaofang , Hou Wenfu , Wang Hongxun , Paoli George C. , Shi Xianming 

TITLE=Incidence and Characterization of Salmonella Isolates From Raw Meat Products Sold at Small Markets in Hubei Province, China

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.02265

DOI=10.3389/fmicb.2019.02265

ISSN=1664-302X

ABSTRACT=<p><italic>Salmonella</italic> is a leading cause of foodborne disease and is often associated with the consumption of foods of animal origin. In this study, sixty-six <italic>Salmonella</italic> isolates were obtained from 631 raw meat samples purchased at small retail suppliers in Hubei Province, China. The most prevalent <italic>Salmonella</italic> serotypes were Thompson (18.2%) and Agona (13.6%). Frequent antimicrobial resistance was observed for the sulfonamides (43.9%), tetracycline (43.9%), and the β-lactams amoxicillin and ampicillin (36.4% for each). Interestingly, a high incidence of resistance to cephazolin was observed in strains of the most common serotype, <italic>S.</italic> Thompson. Class I integrons were found in 27.3% (18/66) of the isolates and five of these integrons contained different gene cassettes (<italic>aacA4C-arr-3-dfr2, dfrA12-aadA21, aadA2, dfrA12-aadA2, dfr17-aadA5</italic>). Additional antimicrobial resistance genes, including <italic>bla</italic><sub>TEM–1</sub>, <italic>bla</italic><sub>CTX–M–65</sub>, <italic>bla</italic><sub>CTX–M–15</sub>, <italic>qnrB</italic>, and <italic>qnrS</italic>, were also identified among these <italic>Salmonella</italic> isolates. Results of replicon typing and conjugation experiments revealed that an integron with <italic>qnrB</italic> and <italic>bla</italic><sub>CTX–M–15</sub> genes was present on incH12 mobile plasmid in <italic>S.</italic> Thompson strain. Multilocus sequence typing (MLST) analysis revealed 32 sequence types, indicating that these isolates were phenotypically and genetically diverse, among which ST26 (18.2%) and ST541 (12.1%) were the predominant sequence types. The integrons, along with multiple antimicrobial resistance genes on mobile plasmids, are likely contributors to the dissemination of multidrug resistance in <italic>Salmonella</italic>.</p>