化脓隐秘杆菌毒力基因nanH和nanP检测及与β-内酰胺类抗生素耐药相关性分析

化脓隐秘杆菌是位于动物黏膜表面的一种革兰氏阳性菌，常引起多种动物如牛、羊、猪等动物多种器官的化脓性感染。化脓隐秘杆菌毒力基因的表达是研究其致病机制的关键，分析化脓隐秘杆菌的耐药表型与毒力基因之间的相关性，对化脓隐秘杆菌耐药机制的研究具有重要意义。本研究从患有临床型奶牛子宫内膜炎的奶牛分离得到化脓隐秘杆菌，采用琼脂平板法测定化脓隐秘杆菌对12种β-内酰胺类抗生素的MIC值，分析化脓隐秘杆菌对β-内酰胺类抗生素的耐药表型；并对化脓隐秘杆菌的毒力基因nanP和nanH进行克隆，分析其基因及编码氨基酸同源性；并通过荧光定量PCR的方法测定不同耐药表型的化脓隐秘杆菌毒力基因nanP和nanH mRNA的表达量的差异，以检测化脓隐秘杆菌耐药表型与毒力基因nanP和nanH之间的相关性。

Arcanobacterium pyogenes is a commensal on the mucous membranes of the upper respiratory and urogenital tracts of cattle, sheep, swine and other domestic animals, and it is often the cause of diseases such as metritis, mastitis, liver abscessation and pneumonia. As an opportunistic pathogen in economic livestock, it is crucial to investigate the expressions of virulence factors during the establishment of endometritis, and it is of importance to study the correlation between antibiotics resistance and virulence expression in preventing the emergence of bacteria with resistance and virulence factor. In this study, the MICs of Arcanobacterium pyogenes isolated from dairy cows with endometritis, against beta-lactam antibiotics were measured by disk diffusion in Mueller-Hinton agar to investigate its antibiotics resistant spectrum. The virulence factors nanH and nanP was amplified by PCR to analyse homology of gene. The fluorescent quantitative PCR was selected to investigate the expressions of nanH and nanP mRNA in Arcanobacterium pyogenes at different antibiotics resistant levels, which is aimed to study on the correlation between antibiotics resistance and two virulence factors, nanH and nanP, in Arcanobacterium pyogenes.