青岛地区重症监护病房分离的鲍曼不动杆菌耐药特征及碳青霉烯酶基因型的研究

摘要

目的 对重症监护病房(ICU)临床分离的鲍曼不动杆菌的耐药特征及碳青霉烯酶基因型进行研究,为临床诊治提供依据.方法 回顾性研究.收集2013年1月至2014年1月青岛地区3所三级甲等综合性医院重症监护病房(ICU)分离的非重复鲍曼不动杆菌90株.VITEK2-compact微生物鉴定系统进行细菌鉴定试验;K-B琼脂纸片扩散法进行药敏试验;对筛选出的32株亚胺培南耐药鲍曼不动杆菌聚合酶链反应(PCR)检测OXA-23、OXA-24、OXA-51、OXA-58、KPC-2、IMP、VIM7种碳青霉烯酶基因,并对PCR产物进行测序;采用卡方(χ2)检验对耐药率进行比较.结果 3家医院ICU分离的90株鲍曼不动杆菌临床分离株中共鉴定出多重耐药鲍曼不动杆菌(MDRAB)55株,泛耐药鲍曼不动杆菌(PDRAB)16株,检出率分别为61.11%和17.78%;32株亚胺培南耐药鲍曼不动杆菌除对头孢哌酮/舒巴坦、多黏菌素B的耐药率较低外,对其他药物的耐药率均在85%以上;亚胺培南耐药组与亚胺培南敏感组菌株对9种药物的耐药率差异均有统计学意义(P≤0.05).PCR扩增结果显示32株扩增出OXA-51基因,28株扩增出OXA-23基因,3株扩增出VIM基因,检出率分别为100%、87.50%和9.38%,OXA-24、OXA-58、KPC-2及IMP均未检出;PCR产物测序表明与Genbank相关基因同源性为100%.结论 青岛地区重症监护病房鲍曼不动杆菌耐药情况严重,尤其是亚胺培南耐药鲍曼不动杆菌,几乎对绝大多数临床常用药都不敏感.碳青霉烯酶基因的存在和其产生的碳青霉烯酶是青岛地区亚胺培南耐药鲍曼不动杆菌对碳青霉烯类药物耐药的重要机制之一,其基因型主要为OXA-23.%Objective To investigate antibiotics resistant characteristics and carbapenemases genotype of Acinetobacter baumannii in Intensive Care Unit (ICU),so as to provide theoretical basis for clinical prevention and treatment.Methods Retrospective study was made on 90 non-duplicated clinical isolates of Acinetobacter baumannii,which were collected From January 2013 to January 2014 in three tertiary hospitals of Qingdao.All strains were identified by VITEK2 automated microbiology analyzer;K-B method was used to do drug susceptibility test;polymerase chain reaction (PCR) was used to amplify the OXA-23,OXA-24,OXA-51,OXA-58,KPC-2,VIM,IMP genes,and the positive products of genes were sequenced;the chi-square test was used to compare the difference of the resistance rates.Results The detection rate of multi-drug resistant A.baumannii (MDRAB)and Pan-drug resistant A.baumannii (PDRAB)was 61.11% (55/90) and 17.78% (16/90).In the 32 strains of imipenem-resistant Acinetobacter baumannii,the resistant rates to Cefoperazone/sulbactam,Polymyxin B was lower,while the resistant rates to other drugs tested were more than 85%.The difference of the resistance rates to 9 drugs between imipenem resistant group and Imipenem sensitive group were statistically significant (P≤0.05).PCR result showed: 32 strains detected OXA-51 gene,28 strains detected OXA-23 gene,and 3 strains detected VIM gene,the detection rates of which were 100%,87.50% and 9.38% respectively.All strains were not detected OXA-24,OXA-58,KPC-2 and IMP genes.The sequenced results were absolutely homology with the corresponding genes in genbank.Conclusions The resistance of A.baumannii in ICU is serious in this region,especially imipenem-resistant A.baumannii,which were nearly no-sensitive to most of the drugs commonly used in clinical.The gene existence of carbapenemase and carbapenemase producing is one of the main resistance mechanism of Acinetobacter baumannii to carbapenem antibiotics.OXA-23 was the major genotypes in this region.