梅州地区临床分离耐碳氢霉烯类鲍曼不动杆菌的耐药机制及分子流行病学研究

目的 了解梅州地区临床分离的耐碳青霉烯类鲍曼不动杆菌的耐药性，探讨其耐药机制及分子流行病学特征。方法 收集梅州地区5所医院2012年1～12月临床分离的非重复耐碳青霉烯类鲍曼不动杆菌210株，采用K-B法检测药敏性，改良Hodge试验筛选耐碳青霉烯表型，PCR扩增IMP、VIM、OXA-23、OXA-24、OXA-51和OXA-58型碳氢霉烯酶基因，并测序。应用ERIC-PCR分型及同源性分析。结果 药敏结果显示，17种药物除多粘菌素B耐药率为0.48%外，其他药敏耐药率都高于60%；改良Hodge试验阳性菌株163株(77.62%)。扩增结果显示Bla-OXA-51的检出率为最高为94.29%(198/210)，Bla-OXA-23的检出率次之为78.57%(165/210)，Bla-VIM的检出率为4.29%(9/210)，Bla-IMP、Bla-OXA-24、Bla-OXA-58均未被检出。210株菌株分为7个ERIC基因型，其中A型97株，B型44株，H型25株，为主要的流行克隆株。结论 梅州地区临床分离的耐碳青霉烯类鲍曼不动杆菌耐药十分严重；产OXA-51、OXA-23和VIM型碳氢霉烯酶是本地区鲍曼不动杆菌对碳青霉烯类药物耐药的重要机制，且耐碳青霉烯类鲍曼不动杆菌存在克隆的流行。

Resistance mechanism and molecular epidemiological characteristics of isolated clinically carbapenem-resistant Acinetobacter baumannii in Meizhou,China

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 .