Genotyping and detection of virulence genes for methicillin-resistant and-sensitive Staphylococcus aureus / 中国感染与化疗杂志

ABSTRACT

Objective To elucidate the difference between methicillin-resistant Staphylococcus aureus (MRSA)and methicillin-sensitive S.aureus (MSSA)in terms of genotypes and distribution of virulence genes with the clinical strains isolated from Hohhot,and explore the relationship between the changing resistance of S.aureus and the virulence transition.Methods Pulsed field gel electrophoresis (PFGE)and multi locus sequence typing (MLST)methods were employed to do molecular typing for 30 MRSA strains and 30 MSSA strains isolated from inpatients in Hohhot,Inner Mongolia.PCR method was used to profile the distribution of virulence genes among these strains.Results PFGE typing results showed that 60 S.aureus strains were classified into 19 major types.MSSA strains belonged to 16 types,mainly types I and H.MRSA strains mainly belonged to types of K and M.Among the 20 strains with different PFGE types,MRSA strains were mainly identified as ST-239 type.but the prevalence of sec ,seg ,sei,sem,sen,seo,fnbB ,ebpS and cap 5 was higher in MSSA strains than in MRSA strains (P<0.05).Conclusions The clinical strains of S .aureus isolated from Hohhot showed diverse genotyping features.ST-239 was the major PFGE type of MRSA strains.The prevalence of virulence genes was higher in MSSA strains than in MRSA strains. Characteristic cluster is found for specific virulence genes.The results also suggest that acquisition of specific antibiotic resistance may be associated with change of specific virulence feature in S.aureus.