红霉素体外诱导猪链球菌耐药机制研究

Study of Mechanism on Inductive Resistance against Erythromycin in Streptococcus suis in Vitro

关键词:  猪链球菌  红霉素  体外  诱导耐药  

Key words:  Streptococcus suis  erythromycin  in vitro  inductive resistance  

摘要:

2004年在病猪体内分离到一株猪链球菌，通过平板扩散法和微量稀释法药敏试验表明这株链球菌对红霉素敏感。采用这株猪链球菌用于体外诱导试验。在低浓度药物组第165代和高浓度药物组第180代的菌液对红霉素MIC值均达到中介水平。它们的耐药表型均为内在型，而且都扩增到了ermB耐药基因。其中180代菌的23S rRNA碱基A1387G位发生突变；对于核糖体蛋白L4，165代菌在T104C、A585G和A633G位发生突变，180代菌在A283G和T651G位发生突变；对于核糖体蛋白L22，165代和180代菌液都在C109A 和T468A位发生突变，并且165代菌还在G426A位发生突变。这些碱基的突变可能是引起猪链球菌对红霉素的耐药机制之一。

Abstract:

A Streptococcus suis strain was isolated in 2004 from diseased pig.It was susceptible to erythromycin by disk diffusion and tube dilution test.It was applied to inductive resistance test against erythromycin in vitro.165th passage of S.suis in low concentration drug group and 180th passage of S.suis in high concentration drug group were intermediate resistance against erythromycin.Their phenotypes of resistance were both cMLSB resiatance phenotype.ErmB resistance gene were detected from the 165th and 180th strains of S.suis. 23S rRNA gene of 180th strain was mutated at position of A2387G. 165th strain was mutated at position T104C,A585G and A633G in ribosomal protein L4.180th strain was mutated at position A283G and T651G in ribosomal protein L4.165th and 180th strains were both mutated at position C109A and T468A,165th strain was also mutated at position G426A in ribosomal protein L22. All those mutative genes maybe a mechanism of S.suis against erythromycin.