Salmonella Derby is one of the most predominant Salmonella serotypes that seriously threatens food safety. This bacterium can be further differentiated to sub-populations with different population sizes; however, whether and how the S. Derby–gut microbiota interactions affect epidemic patterns of S. Derby sub-populations remain largely unknown. We selected two representative strains, 14T and 14C, which represent rarely distributed and prevalent sub-populations of the S. Derby ST40 group, respectively, to address this question using a mouse model. Effects of oral administration of both strains was monitored for 14 days. Alpha diversity of gut microbiota at early stages of infection (4 h post infection) was higher in 14C-treated mice and lower in 14T-treated mice compared with controls. Strain 14T triggered stronger inflammation responses but with lower pathogen titer in spleen compared with strain 14C at 14 days post infection. Certain known probiotic bacteria that can hinder colonization of Salmonella, such as Bifidobacteriaceae and Akkermansiaceae, exhibited increased relative abundance in 14T-treated mice compared with 14C-treated mice. Our results also demonstrated that Ligilactobacillus strains isolated from gut microbiota showed stronger antagonistic activity against strain 14T compared with strain 14C. We identified how S. Derby infection affected gut microbiota composition, and found that the 14T strain, which represented a rarely distributed S. Derby sub-population, triggered stronger host inflammation responses and gut microbiota disturbance compared with the 14C strain, which represented a prevalent S. Derby sub-population. This study provides novel insights on the impacts of gut microbiota on the epidemic patterns of Salmonella populations.

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密切相关的德比沙门氏菌菌株引发了明显的肠道微生物群改变

德比沙门氏菌是最主要的沙门氏菌血清型之一，严重威胁食品安全。这种细菌可以进一步分化为具有不同种群大小的亚群；然而，S. Derby-肠道微生物群的相互作用是否以及如何影响 S. Derby 亚群的流行模式仍然很大程度上未知。我们选择了两个代表性菌株 14T 和 14C，它们分别代表了 S. Derby ST40 组中很少分布和普遍存在的亚群，以使用小鼠模型解决这个问题。监测两种菌株的口服给药效果14天。与对照组相比，14C 处理的小鼠在感染早期（感染后 4 小时）肠道微生物群的 Alpha 多样性较高，而 14T 处理的小鼠则较低。在感染后 14 天，与菌株 14C 相比，菌株 14T 引发了更强的炎症反应，但脾脏中的病原体滴度更低。与 14C 处理的小鼠相比，某些已知的可以阻碍沙门氏菌定植的益生菌，例如双歧杆菌科和阿克曼氏菌科，在 14T 处理的小鼠中表现出相对丰度增加。我们的研究结果还表明，与菌株 14C 相比，从肠道微生物群中分离出的 Ligilactobacillus 菌株对菌株 14T 表现出更强的拮抗活性。我们确定了 S. Derby 感染如何影响肠道微生物群组成，并发现 14T 菌株代表了一个很少分布的 S. Derby 亚群，与 14C 菌株相比，它引发了更强的宿主炎症反应和肠道微生物群紊乱，14C 菌株代表了一个普遍的S。德比亚人群。这项研究为肠道微生物群对沙门氏菌种群流行模式的影响提供了新的见解。