Molecular Characteristics and Antimicrobial Susceptibility Profiles of Clinical Isolates in Shanghai, China.

PURPOSE

To investigate molecular characteristics and antimicrobial susceptibility profiles of clinical isolates of in Shanghai, China.

METHODS

isolates were collected in a university-affiliated hospital in 2012-2015 and 2017-2018. They were re-identified to species level by 16S rRNA gene and species-specific gene sequencing. Antimicrobial susceptibility testing, screening for metallo-beta-lactamase production, identification of antimicrobial resistance genes and pulsed-field gel electrophoresis (PFGE) were performed.

RESULTS

Among 52 isolates, was the most prevalent species (67.3%), followed by (26.9%). High carriage rates of , and genes were consistent with the poor in vitro activity of most β-lactams including carbapenems. Nevertheless, β-lactamase inhibitors increased susceptibility rates significantly for cefoperazone and piperacillin. Susceptibility rates for minocycline, tigecycline, rifampin and levofloxacin were 100%, 78.8%, 76.9% and 71.2%, respectively. Ser83Ile or Ser83Arg substitution in the DNA gyrase A unit was associated with resistance to fluoroquinolones. MIC/MIC values of vancomycin and linezolid were 16/16 mg/L and 16/32 mg/L, respectively. Molecular typing showed twenty-one different types of PFGE and more than one indistinguishable isolates were observed in each of the eight subtypes.

CONCLUSION

Tetracyclines, tigecycline, β-lactam/β-lactamase inhibitor combinations, rifampin and fluoroquinolones demonstrated high rates of in vitro activity against clinical isolates of . Both genetic diversity and clonality were observed from this health-care facility. Our report provides potential alternative treatment options for infections.