Resistance mechanism and molecular epidemiological characteristics of isolated clinically carbapenem-resistant Acinetobacter baumannii in Meizhou, China / 中国人兽共患病学报

ABSTRACT

In order to survey antibiotic resistance of clinical isolates carbapenem-resistant A cinetobacter baumannii in Meizhou and to investigate resistance mechanism and molecular epidemiological characteristics ,a total of 210 non-duplicated clinical isolates of carbapenem-resistant Acinetobacter baumannii from January 2012 to December 2012 were collected .The K-B disk diffusion method was applied for the drug-susceptibility test ,a modified Hodge test was used for the screening of carbapen-emase ,PCR was used to amplify carbapenemase genes (including IMP ,VIM ,OXA-23 ,OXA-24 ,OXA-51 and OXA-58) ,and the positive products were sequenced .Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) was used for DNA typing and test of homology .Our results on the percentage of strains resistant for antibiotics tested were higher than 60% except for polymyxin B was 0 .48% .There were 163 positive strains by the modified Hodge test ,accounting for 77 .62% .OXA-51 gene was identified in 198 strains (94 .29% ) ,OXA-23 in 165 strains (78 .57% ) ,and VIM in 9 strains (4 .29% ) ,OXA-24 ,OXA-58 and IMP gene was not identified by PCR amplification .Seven genomic types were included in the 210 carbapenem-resistant Acinetobacter baumannii .The major prevalence types were Type A (97 strains) ,Type B (44 strains) and Type H (25 strains) . In conclusion ,multiple drug resistance of clinically isolated carbapenem-resistant A cinetobacter baumannii is a serious problem in Meizhou .Production of OXA-51 ,OXA-23 and IMP carbapenemases is an important mechanism of resistance to carbapenem antibiotics ,and there is prevalence of the same clones in these carbapenem-resistant strains .