Research on drug resistant genes and genotypes of carbapenem-resistant Klebsiella pneumoniae

Abstract

Objective To investigate the drug resistant genes and genotypes of carbapenem-resistant Klebsiella pneumoniae in Tianjin First Center Hospital. Methods A total of 52 strains of carbapenem-non-susceptible Klebsiella pneumoniae were collected from 2012 to 2015. The MICs of antimicrobial drugs were detected using agar dilution methods. Phenotypes of carbapenemases were screened using modified Hodge test. Drug resistant genes were detected by multiplex-PCR assay. Multilocus sequence typing (MLST) was used to determine the genotypes and homology of these carbapenem-resistant Klebsiella pneumoniae strains. Results Susceptibility of antimicrobial agents indicated that all these strains with multiple drug resistance. The resistance rate to piperacillin/tazobactam, ceftriaxone, ceftazidime, cefepime, aztreonam imipenem, meropenem was 100%(52/52). The resistance rate of ST11 type to amikacin was 93.5%(43/46), ciprofloxacin was 97.8%(45/46), levofloxacin was 97.8%(45/46), compound sulfamethoxazole was 17.4%(8/46), tigecycline was 0. The resistance rate of ST101 type to amikacin was 3/3, ciprofloxacin was 2/3, levofloxacin was 3/3, compound sulfamethoxazole was 3/3, tigecycline was 0. The resistance rate of ST709 type to amikacin was 1/1, ciprofloxacin was 1/1, levofloxacin was 1/1, compound sulfamethoxazole was 1/1, tigecycline was 0. The resistance rate of ST1393 type to amikacin was 1/1, ciprofloxacin was 1/1, levofloxacin was 1/1, compound sulfamethoxazole was 1/1, tigecycline was 0. The resistance rate of ST2068 type to amikacin was 1/1, ciprofloxacin was 1/1, levofloxacin was 1/1, compound sulfamethoxazole was 1/1, tigecycline was 0. PCR results showed that 43 isolates were blaKPC-2 positive and 5 isolates were blaOXA-48 positive, 1 isolate was blaDNM-1 positive. There were 46 strains of ST11 type. The 43 strains of Klebsiella pneumoniae producing KPC-2 type carbapenemase were all ST11. While among 5 strains of Klebsiella pneumoniae carrying OXA-48 carbapenem resistant gene, 3 strains were ST101, 1 was ST709, 1 was ST1393. One strain of Klebsiella pneumoniae harboring DNM-1 type carbapenemase was ST2068. Conclusions Drug resistant genes of carbapenem-resistant Klebsiella pneumoniae were KPC-2 dominant, OXA-48 and DNM-1 were sporadical; the genotype was mainly ST11 by MLST in the hospital.The research provided effective basic and reference for the hospital infection t control.(Chin J Lab Med, 2016, 39: 701-704) Key words: Klebsiella pneumoniae; Carbapenems; Drug resistance, bacterial; Bacterial proteins; beta-Lactamases; Multilocus sequence typing