Serichantalergs Oralak, Wassanarungroj Patcharawalai, Khemnu Nuanpan, Poly Frédéric, Guerry Patricia, Bodhidatta Ladaporn, Crawford John, Swierczewski Brett
1Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
2Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD USA.
Gut Pathog. 2020 Apr 9;12:18. doi: 10.1186/s13099-020-00357-6. eCollection 2020.
() is one of the most common bacteria responsible for human gastroenteritis worldwide. The mode of human transmission is foodborne infections due to consumption of contaminated food, especially poultry. Type 6 secretion systems (T6SS) were described recently as virulence mechanisms. Furthermore, infection sequelae associated with neurological disorders like Guillain-Barré (GBS) and Miller Fisher (MF) syndromes can become serious health problems in some patients after gastroenteritis. Our objective was to determine the distribution of these virulence genes among isolated from stool of human diarrhea.
A total of 524 strains from travelers and pediatric cases of acute diarrhea in Thailand were selected for this study. All isolates belonged to one of 20 known capsule types and all were assayed by PCR for T6SS, a hemolysin co-regulated protein () gene, and GBS-associated genes (, , and ) which are involved in sialic acid production in the lipooligosaccharide (LOS) cores of . The distribution of these genes are summarized and discussed.
Of all isolates with these 20 capsule types identified, 328 (62.6%) were positive for , ranging from 29.2 to 100% among 10 capsule types. The GBS-associated LOS genes were detected among 14 capsule type isolates with 24.4% and 23.3% of isolates possessed either or all three genes (, and ), which were classified as LOS classes A and B whereas 9.2% of isolates possessing were classified as LOS class C. The isolates of LOS A, B, and C together accounted for 56.9% of the isolates among 14 different capsule types while 31.1% of all isolates did not possess any GBS-associated genes. No significant difference was detected from isolates possessing GBS-associated LOS genes among travelers and children, but changes between those with were significant (p < 0.05).
Our results suggested a high diversity of and GBS-associated LOS genes among capsule types of isolated from Thailand.
（）是全球人类肠胃炎最常见的致病菌之一。人类传播途径是食用受污染食物，尤其是家禽导致的食源性感染。6型分泌系统（T6SS）最近被描述为一种毒力机制。此外，在一些肠胃炎患者中，与格林-巴利综合征（GBS）和米勒-费雪综合征（MF）等神经系统疾病相关的感染后遗症可能会成为严重的健康问题。我们的目标是确定从人类腹泻粪便中分离出的这些毒力基因的分布情况。
本研究共选取了泰国旅行者和儿童急性腹泻病例中的524株（）菌株。所有分离株属于20种已知荚膜类型之一，并且全部通过PCR检测T6SS、溶血素共调节蛋白（）基因以及与GBS相关的基因（、、和），这些基因参与了（）脂寡糖（LOS）核心中唾液酸的产生。总结并讨论了这些基因的分布情况。
在鉴定出的这20种荚膜类型的所有分离株中，328株（62.6%）的（）呈阳性，在10种荚膜类型中，阳性率从29.2%到100%不等。在14种荚膜类型的分离株中检测到了与GBS相关的LOS基因，24.4%的（）分离株拥有或全部三个基因（、和），这些被归类为LOS A类和B类，而9.2%拥有的（）分离株被归类为LOS C类。LOS A、B和C类的（）分离株在14种不同荚膜类型的分离株中占56.9%，而所有（）分离株中有31.1%不拥有任何与GBS相关的基因。在旅行者和儿童中拥有与GBS相关LOS基因的（）分离株之间未检测到显著差异，但拥有（）的分离株之间的差异具有统计学意义（p < 0.05）。
我们的结果表明，从泰国分离出的（）荚膜类型中，（）和与GBS相关的LOS基因具有高度多样性。
