Faculty of Life Science and Technology, Kunming University of Science and Technologygrid.218292.2, Yunnan, Kunming, China.
Microbiol Spectr. 2022 Oct 26;10(5):e0112822. doi: 10.1128/spectrum.01128-22. Epub 2022 Oct 10.
Streptococcus agalactiae is a common pathogen in aquaculture that disrupts the balance of the intestinal microbiota and threatens fish health, causing enormous losses to the aquaculture industry. In this study, we isolated and screened a Lactococcus lactis () strain with antibacterial effect against S. agalactiae and used it as a potential probiotic to explore its therapeutic effect on zebrafish (Danio rerio) infected with S. agalactiae. This study divided zebrafish into 3 groups: control group, injected with phosphate-buffered saline; infection group, injected with S. agalactiae; and treatment group, treated with after S. agalactiae injection. Then, the 16S rRNA gene sequences of the intestinal microbiota of these 3 groups were sequenced using Illumina high-throughput sequencing technology. The results showed that the relative abundance of intestinal bacteria was significantly decreased in the infection group, and a high relative abundance of S. agalactiae was observed. The relative abundance of the intestinal microbiota was increased in the treatment group, with a decrease in the relative abundance of S. agalactiae compared to that in the control group. In the Cluster of Orthologous Groups of proteins function classification, the relative abundance of each biological function in the infection group was significantly lower than that of the control and treatment groups, showing that has a positive therapeutic effect on zebrafish infected with S. agalactiae. This study provides a foundation for exploring the pathogenic mechanism of S. agalactiae on fish and their intestinal symbionts, and also presents a new approach for the treatment of S. agalactiae infections in fish aquaculture systems. L. lactis () with a bacteriostatic effect against S. agalactiae was isolated from tilapia intestinal tracts. S. agalactiae infection significantly reduced the relative abundance of intestinal bacteria and various physiological functions in zebrafish intestines. demonstrated infection and subsequent therapeutic effects on the S. agalactiae infection in the zebrafish intestine. Therefore, the potential probiotic can be considered as a therapeutic treatment for S. agalactiae infections in aquaculture, which can reduce the use of antibiotics and help maintain fish health.
无乳链球菌是水产养殖中的一种常见病原体，它会破坏肠道微生物群落的平衡，威胁鱼类健康，给水产养殖业造成巨大损失。在本研究中，我们从罗非鱼肠道中分离筛选到一株具有抗无乳链球菌作用的乳酸乳球菌（），并将其作为一种潜在的益生菌，用于探索其对感染无乳链球菌的斑马鱼的治疗效果。本研究将斑马鱼分为 3 组：对照组，注射磷酸盐缓冲液；感染组，注射无乳链球菌；治疗组，在注射无乳链球菌后用处理。然后，使用 Illumina 高通量测序技术对这 3 组肠道微生物群落的 16S rRNA 基因序列进行测序。结果表明，感染组肠道细菌的相对丰度显著降低，且观察到无乳链球菌的相对丰度较高。治疗组肠道微生物群落的相对丰度增加，与对照组相比，无乳链球菌的相对丰度降低。在蛋白功能分类的同源基因簇中，感染组的每个生物功能的相对丰度均明显低于对照组和治疗组，表明对感染无乳链球菌的斑马鱼具有积极的治疗效果。本研究为探索无乳链球菌对鱼类及其肠道共生菌的致病机制提供了依据，也为鱼类水产养殖系统中无乳链球菌感染的治疗提供了新方法。从罗非鱼肠道中分离到一株具有抑菌作用的乳酸乳球菌（）。无乳链球菌感染显著降低了斑马鱼肠道中细菌的相对丰度和各种生理功能。证明了在斑马鱼肠道中对无乳链球菌感染的感染和后续治疗作用。因此，潜在的益生菌可以被视为水产养殖中无乳链球菌感染的治疗方法，它可以减少抗生素的使用，有助于维持鱼类健康。
