Gene detection of vancomycin-resistant Enterococcus isolated from a teaching hospital in Shanghai / 中华检验医学杂志

ABSTRACT

Objective To investigate the prevalence of VRE in Huashan hospital of Shanghai from 2007 to 2009, and to examine the molecular characteristics of the VRE isolates.Methods A total of 890 non-repetive clinical isolates of Enterococcus were screened by the agar screening method ( ADSP method).Broth dilution susceptibility test was performed to determine the antimicrobial susceptibility of Enterococcus isolates to vancomycin and teicoplanin.The resistant genes and virulent genes of VRE isolates were investigated by PCR and sequencing methods.VRE isolates were classified by MLST and six isolates of VRE from 2007 to 2008 were analyzed by PFGE.Results Thirteen VRE isolates were identified by ADSP method and broth dilution susceptibility test. Six of them were resistant to vancomycin but sensitive to teicoplanin ( vancomycin MICs were from 64 to 256 μg/ml).The sequencing data of PCR products indicated these isolates might harbor a potential novel vancomycin resistant gene, which was different from the one reported in previous studies. The rest 7 isolates harbored vanA gene. The MICs of these isolates to vancomycin and teicoplanin were 32 - 64 μg/ml and 16 - 32 μg/ml, respectively.MLST results revealed 4 STs were identified in 13 VRE isolates.Eleven isolates belonged to clonal complexes(CC) 17.The positive rates of esp gene and hyl gene were 69.2% and 30.8%, respectively.Conclusions This study suggests that the most common VRE clone in Huashan Hospital was CC17.A potentially novel vancomycin resistance gene was identified, and further work needs to be done to investgate the function and the location of this novel gene.