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Engineering >> 2022, Volume 15, Issue 8 doi: 10.1016/j.eng.2022.05.006

Genomic Epidemiology of ST34 Monophasic Salmonella enterica Serovar Typhimurium from Clinical Patients from 2008 to 2017 in Henan, China

a Henan Center for Disease Control and Prevention, Zhengzhou 450016, China
b Key Laboratory of Food Safety Risk Assessment & China National Center for Food Safety Risk Assessment, National Health Commission of the People’s Republic of China,
Beijing 100021, China
c Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University,
Yangzhou 225009, China
d Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
e Department of Food Science, National Institutes for Food and Drug Control, Beijing 100050, China
f Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin D04 N2E5, Ireland

Received:2022-03-13 Revised:2022-05-04 Accepted: 2022-05-15 Available online:2022-05-29

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Salmonella enterica serovar 4,[5],12:i:- (S. 4,[5],12:i:-) is a monophasic variant of Salmonella enterica serovar Typhimurium that has emerged as a global serovar causing public health concern. To date, the epidemiology and genomic characterization of this pathogen in China have not been well described. We investigated the prevalence, antimicrobial resistance (AMR) phenotypes, and population genomics of sequence type 34 (ST34) S. 4,[5],12:i:- among cases of human salmonellosis in Henan Province, China. A total of 100 ST34 S. 4,[5],12:i:- isolates were studied from 2008 to 2017 and found mostly resistant to ampicillin (AMP), streptomycin (STR), sulfonamides (SUL), and tetracycline (TET) (ASSuT). Bayesian phylogenetic analysis demonstrated that isolates identified in China were mostly related to the European lineage and evolved into two major clades with different resistance genes and plasmid profiles. Notably, clade 1 showed a significantly higher rate of mutations in gyrA and plasmid-mediated quinolone resistance genes. The carrying of the resistance-containing region (encoding R-type ASSuT), including blaTEM-1B (conferring resistance to AMP), strAB (STR), sul2 (SUL), and tet(B) (TET) inserted into the fljBA operon, was responsible for most of the monophasic variants in clade 2. IncHI2 plasmids were the dominant multi-drug resistance mobile genetic elements accounting for the transmission of acquired resistance genes in this serovar, and these were more prevalent in clade 1. Our findings highlighted the increasing prevalence of multi-drug resistant S. 4,[5],12:i:- in China, along with the differential characteristics of resistance gene acquisition among various lineages. Based on our data, control measures are required to address the spread of this zoonotic pathogen. Further owing to its potential origin in food-producing animals, a "One Health" approach, should be implemented to support surveillance whilst informing interventional strategies.



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