title: Distribution and Molecular Characterization of Salmonella enterica Hypermutators in Retail Food in China.
abstract: Hypermutable pathogens can easily acquire mutation opportunities, as well as antimicrobial resistance, and are tremendous hazards to food safety and public health. In this study, a total of 96 (7.6%) hypermutators were identified from 1,264 Salmonella isolates recovered from retail foods. Pulsed-field gel electrophoresis analysis indicated that hypermutators were genetically diverse. Amino acid substitution of Val421Phe was detected in MutS in one hypermutator and Val246Ala in 56 other hypermutators, while no mutation in MutS was found among the remaining 39 hypermutators. Hypermutators in Salmonella isolates recovered in 2010 (9.3%) and 2008 (7.7%) were significantly more prevalent than those in 2007 (1.4%). The rate of hypermutators in mutton (22.2%) was significantly higher than that in chicken (7.9%) and pork (4.7%). In Salmonella Leimo isolates (60.0%), hypermutators were most frequently detected, followed by Salmonella Essen (50.0%), Salmonella Indiana (36.6%), Salmonella Kallo (25.0%), Salmonella Heidelberg (23.8%), Salmonella Typhimurium (14.0%), Salmonella Shubra (13.0%), Salmonella Albany (11.1%), Salmonella Agona (7.0%), Salmonella Gueuletapee (6.3%), and Salmonella Enteritidis (1.7%). Salmonella hypermutators in isolates recovered from retail food stored at ambient temperature (15.7%) were significantly more prevalent than those stored in chilled (3.1%) and frozen (5.4%) condition. The overall distributions of mutation frequencies of the 96 hypermutators (selected by rifampin) were from 2.16 × 10(-5) to 4.25 × 10(-1). Mutation frequencies of hypermutators of Salmonella Leimo, Salmonella Essen, Salmonella Kallo, and Salmonella Agona were relative low, while those of Salmonella Typhimurium, Salmonella Indiana, and Salmonella Shubra were extremely high. No significant correlation was found between mutation frequency and antimicrobial resistance of the hypermutators.
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100.
authors.forename: Yin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100.
authors.forename: Chongyang
authors.initials: C
authors.lastname: Liu
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100.
authors.forename: Zengfeng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100; College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi'an, Shaanxi, People's Republic of China, 710062.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Hu
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100.
authors.forename: Chenyang
authors.initials: C
authors.lastname: Cao
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100.
authors.forename: Meili
authors.initials: M
authors.lastname: Xi
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xia
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100. ybwsheng@163.com.
authors.forename: Baowei
authors.initials: B
authors.lastname: Yang
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi, People's Republic of China, 712100.
authors.forename: Jianghong
authors.initials: J
authors.lastname: Meng
mesh_terms: D000818:Animals; D002645:Chickens / Q000382:microbiology; D002681:China; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods; D059022:Food Safety; D008460:Meat / Q000382:microbiology; D009154:Mutation; D012475:Salmonella / Q000235:genetics / Q000302:isolation & purification; D019779:Salmonella enterica / Q000235:genetics*; D012756:Sheep / Q000382:microbiology; D013552:Swine / Q000382:microbiology