Detection of drug resistance gene of carbapenem-resistant Klebsiella pneumoniae and molecular epidemiological study / 重庆医学

ABSTRACT

Objective To analyze the drug resistance gene carrying situation of carbapenem-resistant Klebsiella pneumoniae (CRKP) and molecular epidemiological characteristics to provide a reference basis for studying the bacterial drug resistance.Methods A total of 37 clinically isolated strains of CRKP were collect ed from February 2016 to February 2017.The broth microdilution method was used to determine the strain drug susceptibility.The phenotypes of CRKP carbapenemases were detected by using the modified Hodge test and EDTA-imipenem synergistic method.The drug resistance genes of KPC-2,NDM-1 and OXA-48 were detected by PCR.The sequencing and internet comparison were performed for determining the genotype.The multilocus sequence typing (MLST) was adopted to conduct the genetic correlation study on the strains.The evolutionary trees were constructed by using the MEGA software and the genetic relationship was analyzed by using the eBURST software.Results The drug resistance to commonly used antibacterial drugs was over 90％.The KPC-2 gene was detected in all strains,3 strains simultaneously carried the NDM-1 gene,and other genes were negative.In MLST typing,25 strains were ST11,each 2 strains were ST524 and ST789,each 1 strain was ST35,ST29,ST1066 and ST244 respectively.Also a new ST type(2 strians) was confirmed by the PubMlst database and named as ST1792.The ST11 type group and non-ST11 type group had no statistical difference in the aspects of the age,sex,infection route and antibiotics use(P＜0.05).Conclusion Carrying KPC-2 gene is the main cause leading to bacterial resistance to carbapenem and ST11 type is the most popular clone type.