猪源致病性格氏乳球菌的分离鉴定及毒力基因分析

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中图分类号：S858.285.1 文献标志码：A 文章编号：0366-6964（2025）07-3399-09

Abstract： This study aimed to explore the biological characteristics， drug sensitivity and pathogenicity of Lactococcus garuieae from pig. Suspicious bacteria were isolated from the liver of diseased pig，and then were identified by Gram stained microscopy，matrix asssted laser desorption ionization time-of-flight mass spectrometry （MALDI-TOF MS），16S rRNA gene sequence analysis and sequence analysis. The drug resistance and pathogenicity of isolated strains were explored through drug sensitivity testing and mice infection testing. Related virulence of isolated strain genes were amplified by PCR. Results were as follows： A positive strain of α hemolytic was isolated from the liver of a diseased pig. MALDI-TOF MS，PCR amplification of 16S rRNA gene and phylogenetic tree analysis results showed that the isolated strain was identified as Lactococcus garuieae.The infection test of mice showed that the isolated strain had strong lethality. It can cause swelling of the liver and spleen，severe congestion of the intestines， abdominal cavity，and chest cavity in mice. The drug sensitivity test results showed that the isolated strains were resistant to β -lactam drugs such as penicillin G and ampicillin，as well as erythromycin and lincomycin，and sensitive to other antibiotics. The results of virulence gene testing showed that the isolated strain contains adhesion related genes adhC1， psaA，eno ， $＼iota _ { Ḋ ＼boldsymbol Ḋ p Ḍ Ḍ 1 }$ ， hemolysis related genes hlyl， hly2， hly3，capsule gene cluster formation related genes cgcC， polysaccharide related genes epsA ， epsB ， epsC ！ epsD ，epsL，and other virulence genes nadho， sod， pgm， chp. The Lactococcus garrieae was isolated in this experiment has strong pathogenicity，and its potential risks cannot be ignored as it belongs to zoonotic pathogens. This study provides data reference for the prevention and treatment of clinical infections caused by Lactococcus garvieae.

Keywords： Lactococcus garvieae ; pig; 16S rRNA; drug susceptibility test; virulence gene ∗ Corresponding author：QIAO Hongxing，E-mail：zzmzqhx@163.com

格氏乳球菌（Lactococcusgarvieae）最早是从奶牛乳腺炎病料中分离出来的细菌，最初被归类为格氏链球菌，但后来被重新归类为乳球菌属[]。（剩余13133字）