Difference in susceptibility of carbapenem-resistant Klebsiella pneumoniae to tigecycline detected by MTS and instrumental MIC assay / 中国感染控制杂志

ABSTRACT

Objective To explore clinical distribution characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP), analyze enzyme production of strains and verify the in vitro antimicrobial activity of tigecycline.Methods Antimicrobial susceptibility testing results of 53 strains of CRKP isolated from clinical specimens of patients in a hospital from January to December 2015 were analyzed, carbapenemase production of target strains was detected by modified Hodge test, metallo-β-lactamase was detected by EDTA synergy test, minimum inhibitory concentration(MIC) of tigecycline susceptibility testing result detected by instrument was confirmed by MIC test strip(MTS method).Results 53 CRKP strains were mainly isolated from patients in intensive care unit (n=14, 26.42％) and burn unit(n=13, 24.53％);sputum(n=23, 43.40％) and wound secretion(n=15, 28.30％) were the main specimen sources;isolation rate of CRKB was highest in the elderly≥60 years old, 35 strains(66.04％)of CRKP were isolated.CRKP was most sensitive to tigecycline(96.2％).The modified Hodge test showed that 48 strains(90.6％) produced carbapenemases and 15 strains produced metallo-β-lactamase.MICs of tigecycline-resistant strains detected by instrument were all confirmed as susceptibility by MTS.Conclusion CRKP mainly produce carbapenems in this hospital, some strains can produce two types of different β-lactamases;antimicrobial susceptibility testing showed that tigecycline has good antimicrobial activity against CRKP, tigecycline-resistant strains detected by instrument must be confirmed by MTS method.