AUTHOR=Holohan Niamh , Wallat Maximilian , Hai Yen Luu Thi , Clark Eleanor , Truong Duong Thi Quy , Xuan Sinh Dang , Vu Hue Thi Kim , Van Truong Dung , Tran Huy Hoang , Nguyen-Viet Hung , Unger Fred , Thi Thanh Dang Son , Stabler Richard A. 

TITLE=Analysis of Antimicrobial Resistance in Non-typhoidal Salmonella Collected From Pork Retail Outlets and Slaughterhouses in Vietnam Using Whole Genome Sequencing

JOURNAL=Frontiers in Veterinary Science

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.816279

DOI=10.3389/fvets.2022.816279

ISSN=2297-1769

ABSTRACT=<p>Non-typhoidal <italic>salmonella</italic> (TS) remains a significant health burden worldwide. In Vietnam, pork accounts for 70% of the total meat consumed, and contamination with <italic>Salmonella</italic> is high. High levels of antimicrobial resistance (AMR) have emerged among porcine NTS and of particular concern is the emergence of colistin resistance, a “last defense” antibioic against multi-drug resistant (MDR) Gram-negative pathogens. This study aimed to investigate the antibiotic susceptibility of 69 NTS isolates collected from the pork retail outlets and slaughterhouses in Vietnam during 2014 a nd 2018/19. Phenotypic testing and whole genome sequencing was used to assess the serotype and AMR gene profiles of the 69 NTS isolates. Seventeen different serotypes were identified, of which <italic>S. enterica</italic> subsp <italic>enterica</italic> serotype Typhimurium was the most common followed by <italic>S</italic>. ser. Rissen, <italic>S</italic>. ser. London, <italic>S</italic>. ser. Anatum, and <italic>S</italic>. ser. Derby. Phenotype AMR was common with 41 (59.4%) isolates deemed MDR. MDR strains were most common in slaughterhouses (83%) and supermarkets (75%) and lowest in traditional markets (38%) and convenience stores (40%). Colistin resistance was identified in 18 strains (15 resistant, three intermediate) with <italic>mcr-1</italic> identified in seven isolates (<italic>S</italic>. ser. Meleagridis, <italic>S</italic>. Rissen, <italic>S</italic>. Derby) and <italic>mcr-3</italic> in two isolates (<italic>S</italic>. Typhimurium). This includes the first <italic>mcr</italic> positive <italic>S</italic>. Meleagridis to our knowledge. Surprisingly, boutique stores had high levels (60%) of MDR isolates including 5/20 isolates with <italic>mcr</italic>-1. This study demonstrates that pork from modern retail stores classed as supermarkets or boutique (with pork claiming to be high quality, traceable, environmentally friendly marketed toward higher income consumers) still contained NTS with high levels of AMR.</p>