Xiao Lisheng, Nie Zihan, Zhuang Deyi, Zhou Yufeng, Zhu Weiwei
Fujian Key Laboratory of Neonatal Diseases, Xiamen Key Laboratory of Neonatal Diseases, Xiamen Children's Hospital (Children's Hospital of Fudan University at Xiamen), Xiamen, China.
State Key Laboratory of Vaccines for Infectious Diseases, Xiang-An Biomedicine Laboratory, National Innovation Platform for Industry-Education Integration in Vaccine Research, Department of Laboratory Medicine, School of Public Health, Xiamen University, Xiamen, China.
Front Cell Infect Microbiol. 2025 Aug 22;15:1643224. doi: 10.3389/fcimb.2025.1643224. eCollection 2025.
infections represent a significant public health concern. Despite their clinical relevance, the genetic determinants underlying bacterial fitness and virulence remain incompletely characterized. In this study, we systematically identified genes involved in host adaptation by generating a transposon mutant library and integrating a infection model with transposon sequencing (Tn-seq) technology. This approach yielded a comprehensive dataset of adaptation-deficient genes in the hypervirulent strain ATCC 43816. Using homologous recombination, we constructed gene deletion mutants of the carbohydrate phosphotransferase system enzyme I (PtsI) and the putative prolyl endopeptidase (GM2628), and verified their key roles in fitness and virulence through both and assays. In particular, defects exhibited lower dissemination and virulence in a murine pneumonia model, which cross-validates that the virulence determinants identified by the model are conserved across hosts. Our findings provide gene-level insights for the development of novel strategies to combat infections and indicate that is a cost-effective mammalian alternative for investigating bacterial pathogenicity. Going beyond the general knowledge that hypermucoviscosity (HMV) mediates high virulence, we observed that deficits in and led to HMV while decreasing virulence. This exemplifies that HMV does not always directly correlate with virulence, challenging its role as a virulence marker and underscoring the need for further investigation into non-HMV-mediated virulence mechanisms.
感染是一个重大的公共卫生问题。尽管感染具有临床相关性，但细菌适应性和毒力背后的遗传决定因素仍未完全明确。在本研究中，我们通过构建转座子突变体文库，并将感染模型与转座子测序（Tn-seq）技术相结合，系统地鉴定了参与宿主适应的基因。这种方法产生了高毒力菌株ATCC 43816中适应缺陷基因的综合数据集。利用同源重组，我们构建了碳水化合物磷酸转移酶系统酶I（PtsI）和假定的脯氨酰内肽酶（GM2628）的基因缺失突变体，并通过体内和体外试验验证了它们在细菌适应性和毒力中的关键作用。特别是，ptsI缺陷在小鼠肺炎模型中表现出较低的传播和毒力，这进一步证实了通过该模型鉴定的毒力决定因素在不同宿主中具有保守性。我们的研究结果为开发对抗感染的新策略提供了基因层面的见解，并表明该模型是研究细菌致病性的一种经济有效的哺乳动物替代模型。除了高黏液性（HMV）介导高毒力这一普遍认知外，我们观察到ptsI和GM2628缺陷导致HMV，同时毒力降低。这表明HMV并不总是与毒力直接相关，对其作为毒力标志物的作用提出了挑战，并强调需要进一步研究非HMV介导的毒力机制。
