Mechanism of drug resistance of Enterobacter cloacae to carbapenem

Abstract:

Objective：To investigate the mechanism of clincal isolates of carbopenem-resistant Enterobacter cloacae. Methods：Antimi－crobial susceptibility test was done on 21 strains of Enterobacter cloacae by Kirby-Bauer method. The minimal inhibitive concentra－tions（MICs） of these antimicrobial agents were determined by microdosis broth dilution method. A modified Hodge test and Carba NP test were used to detect the presence of carbapenemase. The genotype of KPC，IMP，NDM，VIM，IMI，SPM，OXA-23，OXA-24，OXA-48 and OXA-58 was tested by polymerase chain reaction（PCR）. Results：Clinical isolates of carbapenem-resistant Enterobacter cloacae were multi-drug resistance. The positive rate of modified Hodge test and Carba NP test were 61.9%（13/21），90.5%（19/21），respectively. Carbapenemase genes were positive in 19/21 strains of Enterobacter cloacae by PCR. The positive rate of IMP，KPC and NDM were 23.8%（5/21），9.5%（2/21） and 61.9%（13/21），respectively，in which one strain was both IMP and NDM positive. Conclusion：Production of carbapenemases is the main mechanism of carbapenem-resistant Enterobacter cloacae，which should arouse the attention of stalf in hospital infection-control department.