Liu Xin, Gao Binru, Li Zhuosi, Liang Yingying, Shi Tianqi, Dong Qingli, Chen Min, Wu Huanyu, Zhang Hongzhi
School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, China.
Foods. 2025 Aug 25;14(17):2955. doi: 10.3390/foods14172955.
is a Gram-positive bacterial species that causes listeriosis, a major foodborne disease worldwide. The virulence factor facilitates the invasion of into intestinal epithelial cells expressing E-cadherin receptors. Naturally occurring premature stop codon (PMSC) mutations in have been shown to result in the production of truncated proteins associated with attenuated virulence. Moreover, different strains contain distinct variants. In this study, we first characterized in 546 strains isolated from various foods in Shanghai. The results showed that 36.1% (95% Confidence Interval: 32.0~40.2%) of the food isolates harbored with PMSC, which was found to be associated with clonal complex (CC) types, with the highest proportions observed in CC9 and CC121. To investigate the function of , we first used the dominant CC87 isolated from patients as the test strain and constructed an strain via homologous recombination. Resistance tests and virulence tests showed that while did not affect the resistance of , it significantly influenced cell adhesion and invasiveness. To further explore the function of , we performed virulence tests on five CC-type strains carrying with PMSC and their corresponding strains with intact . We found that the virulence of strains carrying or with PMSC was associated with their CC type. Our preliminary results showed that premature termination of did not significantly affect the adhesion and invasion abilities of low-virulence CC-type strains in Caco-2 cells, but substantially promoted those of high-virulence strains such as CC8 and CC7. In summary, this study preliminarily evaluated the effects of integrity and PMSC mutation variation on the virulence of , providing a foundation for further research on -related pathogenic mechanisms.
是一种革兰氏阳性细菌物种，可引起李斯特菌病，这是一种全球主要的食源性疾病。该毒力因子有助于其侵入表达E-钙粘蛋白受体的肠道上皮细胞。已证明该菌中自然发生的过早终止密码子（PMSC）突变会导致产生与毒力减弱相关的截短蛋白。此外，不同的菌株含有不同的变体。在本研究中，我们首先对从上海各种食品中分离出的546株该菌进行了特征分析。结果表明，36.1%（95%置信区间：32.0~40.2%）的食品分离株携带PMSC，发现其与克隆复合体（CC）类型有关，在CC9和CC121中比例最高。为了研究该基因的功能，我们首先使用从患者中分离出的优势CC87作为测试菌株，并通过同源重组构建了一株该基因突变株。抗性试验和毒力试验表明，该基因突变虽然不影响该菌的抗性，但显著影响其细胞粘附和侵袭能力。为了进一步探索该基因的功能，我们对携带PMSC的5种CC型菌株及其相应的完整基因菌株进行了毒力试验。我们发现携带PMSC的该菌菌株的毒力与其CC类型有关。我们的初步结果表明，该基因的过早终止对低毒力CC型该菌菌株在Caco-2细胞中的粘附和侵袭能力没有显著影响，但对高毒力菌株如CC8和CC7的粘附和侵袭能力有显著促进作用。总之，本研究初步评估了该基因完整性和PMSC突变变异对该菌毒力的影响，为进一步研究该菌相关致病机制奠定了基础。
