The pagC gene is ubiquitously distributed in Salmonella, but there is limited information regarding its function. Pullorum disease (PD) is a septicemic disease caused by Salmonella Pullorum, which also harbors the pagC gene. In this study, we constructed an S. Pullorum pagC gene deletion strain and its complemented strain. First, we confirmed that the pagC gene does not participate in bacterial growth regulation or environmental pH adaptation. Interestingly, the results of subsequent analyses indicated that the pagC gene defect led to increased bacterial colonization in the intestine (especially in the cecum) and increased biofilm formation, while the number of outer-membrane vesicles (OMVs) in the bacterial culture decreased. Purified OMVs were able to reduce S. Pullorum biofilm formation in vitro. In addition, the results of a mass spectrometry analysis of purified OMVs indicated that some enzymes harbored by OMVs may be involved in biofilm degradation. Based on these results, we conclude that deletion of the pagC gene leads to reduced S. Pullorum OMVs production, which subsequently promotes biofilm stability, increases bacterial colonization in the intestine, and potentially inhibits the switch from sessile to planktonic growth.

pagC基因普遍存在于沙门氏菌中，但有关其功能的信息有限。鸡白痢（PD）是由沙门氏菌引起的败血病，它也带有pagC基因。在这项研究中，我们构造了一个S。鸡白痢pagC基因缺失菌株及其互补菌株。首先，我们确认pagC基因不参与细菌生长调节或环境pH适应。有趣的是，随后的分析结果表明，pagC基因缺陷导致肠道内细菌定植增加（尤其是盲肠）和生物膜形成增加，而细菌培养物中外膜囊泡（OMV）的数量减少。纯化的OMV能够减少体外的P. Pullorum生物膜形成。此外，纯化的OMV的质谱分析结果表明，OMV所携带的某些酶可能与生物膜降解有关。根据这些结果，我们得出结论，删除pagC基因会导致S降低。 Pullorum OMVs的产生随后可促进生物膜的稳定性，增加肠道细菌的定殖，并可能抑制从无柄生长向浮游生长的转变。