Nanyang Technological University Food Technology Centre (NAFTEC), Nanyang Technological University (NTU), Singapore
Title of the talk: Whole Genome DNA Sequence Analysis of Salmonella enterica isolated from the fecal material of swine and chicken in the Southeast region of Vietnam
Extensive antimicrobial usage in agricultural animal production contributes to the development and spread of antimicrobial resistant pathogens in both animals and humans, posing a significant threat to public health. In Vietnam, 70% of the antimicrobials that are used in animals are antibiotics. However, no data on antibiotic use in agriculture are available and little is known on the genetic diversity and antimicrobial resistance (AMR) profile of non-typhoidal Salmonella enterica (NTS) from animals, which can be spread from animals to humans through food chain and direct contact with animals shedding Salmonella. This study aimed to compare the genetic diversity and AMR profiles of NTS that were isolated from the fecal material of swine and chicken in the Southeast region of Vietnam. A total of 76 cecal Salmonella enterica isolates from chicken (n=29) and swine (n=47) were selected for the study. All isolates were tested for phenotypic antibiotic resistance to 10 drugs from 6 classes and were also subjected to whole genome sequencing. The AMR genes, serovar types, replicon sequences, genome and plasmid sequence types of these isolates were identified in their assembled genomes by ResFinder, SeqSero, PlasmidFinder and Multi-Locus Sequence Typing. The most common phenotypic resistances for both chicken and swine were beta-lactam and tetracycline. On the contrary, resistance to fluoroquinolone and colistin were more common in chicken isolates whereas resistance to aminoglycoside and phenicol were more common in swine isolates. All isolates had at least one resistance gene, and the maximum number of resistance genes seen is twenty-two and they were found in one Kentucky (ST198) chicken isolate. Enteritidis of ST11 (n=12) was the most common serovar in chicken whereas Typhimurium of ST34 (n=27) was the most common serovar in swine. Our study reflects distinct epidemiology of NTS colonization and AMR in chicken and swine in the the Southeast region of Vietnam and demonstrates the value of using whole genome sequencing in understanding the genetic diversity of NTS at a greater resolution.
Disclaimer: The analysis is still ongoing and preliminary findings are reported here.
Moon Tay is currently working as a Research Fellow in NTU Food Technology Centre (NAFTEC), under Prof Jorgen Schlundt. She received her Bachelor of Science (Hons.) Degree in Biological Sciences from NTU in 2009 and her Ph.D in Integrated Biology and Medicine from Duke-NUS Medical School in 2015. Prior to joining NAFTEC, Moon worked as Research Fellow in Prof Mary Chan’s multidisciplinary research group that aims to develop new antimicrobial polymers, which are less likely to evoke resistance as compared to antibiotics and yet, can effectively kill bacteria and with low toxicity to mammalian cells. Moon’s current research is focused on using next generation sequencing to detect emergence and spread of antimicrobial resistance genes across the food chain and evaluating the potential of next generation sequencing in improving food safety through a lab-based One Health approach.