Sarichai Phinitphong, Buddhasiri Songphon, Walters Georgia E, Khantawa Banyong, Kaewsakhorn Thattawan, Chantarasakha Kanittha, Tepaamorndech Surapun, Thiennimitr Parameth
Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Department of Biology, Health and Medicine, University of Manchester, Manchester, UK.
Microbiol Immunol. 2020 Oct;64(10):679-693. doi: 10.1111/1348-0421.12837. Epub 2020 Sep 30.
Salmonella enterica serovar Typhimurium (S. Typhimurium [STM]) is a leading cause of nontyphoidal salmonellosis (NTS) worldwide. The pathogenesis of NTS has been studied extensively using a streptomycin-pretreated mouse colitis model with the limited numbers of laboratory STM strains. However, the pathogenicity of the clinically isolated STM (STMC) strains endemic in Thailand in mice has not been explored. The aim of this study was to compare the pathogenicity of STMC strains collected from Northern Thailand with the laboratory STM (IR715) in mice. Five STMC isolates were obtained from the stool cultures of patients with acute NTS admitted to Maharaj Nakorn Chiang Mai Hospital in 2016 and 2017. Detection of virulence genes and sequence type (ST) of the strains was performed. Female C57BL/6 mice were pretreated with streptomycin sulfate 1 day prior to oral infection with STM. On Day 4 postinfection, mice were euthanized, and tissues were collected to analyze the bacterial numbers, tissue inflammation, and cecal histopathological score. We found that all five STMC strains are ST34 and conferred the same or reduced pathogenicity compared with that of IR715 in mice. A strain-specific effect of ST34 on mouse gut colonization was also observed. Thailand STM ST34 exhibited a significant attenuated systemic infection in mice possibly due to the lack of spvABC-containing virulence plasmid.
肠炎沙门氏菌鼠伤寒血清型（鼠伤寒沙门氏菌[STM]）是全球非伤寒型沙门氏菌病（NTS）的主要病因。使用链霉素预处理的小鼠结肠炎模型，对数量有限的实验室STM菌株进行了广泛研究，以探究NTS的发病机制。然而，泰国流行的临床分离STM（STMC）菌株在小鼠中的致病性尚未得到探索。本研究的目的是比较从泰国北部收集的STMC菌株与实验室STM（IR715）在小鼠中的致病性。从2016年和2017年入住清迈玛哈拉吉医院的急性NTS患者的粪便培养物中获得了5株STMC分离株。对这些菌株的毒力基因和序列类型（ST）进行了检测。雌性C57BL/6小鼠在口服感染STM前1天用硫酸链霉素进行预处理。感染后第4天，对小鼠实施安乐死，并收集组织以分析细菌数量、组织炎症和盲肠组织病理学评分。我们发现，所有5株STMC菌株均为ST34，与IR715相比，它们在小鼠中的致病性相同或降低。还观察到ST34对小鼠肠道定植的菌株特异性影响。泰国STM ST34在小鼠中表现出明显减弱的全身感染，这可能是由于缺乏含spvABC的毒力质粒。
