Construction of serine protease gene mutant and study on pathogenicity of serine protease gene of Entero-coccus faecalis / 中华传染病杂志

ABSTRACT

Objective To construct the serine protease gene(sprE)mutant and to study the pathogenicity of sprE gene of Enterococcus faecalis.Methods Recombinant suicide vector pCQ001 of Enterococcus faecalis with pTX4577,was constructed.Then,created isogenic sprE-deficient mu- tant(*sprE)by allelic replacement was constructed.Moreover,the growth ability and the virulence of the mutant were compared with those of the wide type in vitro and in vivo respectively.A mouse peritonitis model and a rabbit endocarditis model were utilized in the study.Results The *sprE was selected by kanamycin and identified by polymerase chain reaction(PCR),pulsed field gel electropho- resis(PFGE)and Southern blot.The evidences showed that the sprE gene had a major role in helping bacteria to resist the elevated temperature and oxidative stress.The virulence of mutant decreased af- ter sprE gene was knocked out.Conclusions The *sprE of Enterococcus faecalis is constructed suc- cessfully,sprE gene is important in the pathogenesis of Enterococcus faecalis,which probably is a major virulence factor of Enterococcus faecali.