AUTHOR=Schwan Carla L. , Lomonaco Sara , Bastos Leonardo M. , Cook Peter W. , Maher Joshua , Trinetta Valentina , Bhullar Manreet , Phebus Randall K. , Gragg Sara , Kastner Justin , Vipham Jessie L. 

TITLE=Genotypic and Phenotypic Characterization of Antimicrobial Resistance Profiles in Non-typhoidal Salmonella enterica Strains Isolated From Cambodian Informal Markets

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.711472

DOI=10.3389/fmicb.2021.711472

ISSN=1664-302X

ABSTRACT=<p>Non-typhoidal <italic>Salmonella enterica</italic> is a pathogen of global importance, particularly in low and middle-income countries (LMICs). The presence of antimicrobial resistant (AMR) strains in market environments poses a serious health threat to consumers. In this study we identified and characterized the genotypic and phenotypic AMR profiles of 81 environmental <italic>S. enterica</italic> strains isolated from samples from informal markets in Cambodia in 2018–2019. AMR genotypes were retrieved from the NCBI Pathogen Detection website (<ext-link ext-link-type="uri" xlink:href="https://www.ncbi.nlm.nih.gov/pathogens/" xmlns:xlink="http://www.w3.org/1999/xlink">https://www.ncbi.nlm.nih.gov/pathogens/</ext-link>) and using ResFinder (<ext-link ext-link-type="uri" xlink:href="https://cge.cbs.dtu.dk/services/" xmlns:xlink="http://www.w3.org/1999/xlink">https://cge.cbs.dtu.dk/services/</ext-link>) <italic>Salmonella</italic> pathogenicity islands (SPIs) were identified with SPIFinder (<ext-link ext-link-type="uri" xlink:href="https://cge.cbs.dtu.dk/services/" xmlns:xlink="http://www.w3.org/1999/xlink">https://cge.cbs.dtu.dk/services/</ext-link>). Susceptibility testing was performed by broth microdilution according to the Clinical and Laboratory Standards Institute (CLSI) standard guidelines M100-S22 using the National Antimicrobial Resistance Monitoring System (NARMS) Sensititre Gram Negative plate. A total of 17 unique AMR genes were detected in 53% (43/81) of the isolates, including those encoding tetracycline, beta-lactam, sulfonamide, quinolone, aminoglycoside, phenicol, and trimethoprim resistance. A total of 10 SPIs (SPI-1, 3–5, 8, 9, 12–14, and centisome 63 [C63PI]) were detected in 59 isolates. C63PI, an iron transport system in SPI-1, was observed in 56% of the isolates (<italic>n</italic> = 46). SPI-1, SPI-4, and SPI-9 were present in 13, 2, and 5% of the isolates, respectively. The most common phenotypic resistances were observed to tetracycline (47%; <italic>n</italic> = 38), ampicillin (37%; <italic>n</italic> = 30), streptomycin (20%; <italic>n</italic> = 16), chloramphenicol (17%; <italic>n</italic> = 14), and trimethoprim-sulfamethoxazole (16%; <italic>n</italic> = 13). This study contributes to understanding the AMR genes present in <italic>S. enterica</italic> isolates from informal markets in Cambodia, as well as support domestic epidemiological investigations of multidrug resistance (MDR) profiles.</p>