无菌体液中碳青霉烯类耐药鲍曼不动杆菌的临床分布特征及耐药机制研究

Clinical Distribution and Resistance Mechanism of Carbapenem-resistant Acinetobacter Baumannii from Abacterial Body Fluid

目的研究我院2011-2012年临床无菌体液培养分离出的碳青霉烯类耐药鲍曼不动杆菌的临床分布及耐药机制,为临床合理选用抗菌药物提供依据。方法收集无菌体液中分离出的95株碳青霉烯类耐药鲍曼不动杆菌,进行标本种类和来源病区的统计分析,菌株分布及药敏结果用WHONET 5.6软件进行分析;使用PCR检测β-内酰胺酶基因(OXA、IMP、VIM、NDM等)及外排泵编码基因(Ade A、Ade B、Ade C、Ade S、Ade R)的携带情况。结果 2011-2012年我院无菌体液中共分离鲍曼不动杆菌124株,其中碳青霉烯类耐药鲍曼不动杆菌95株,构成比为76.6%。分离的鲍曼不动杆菌主要来自血液标本,占75.8%,其次为脑脊液,占22.1%;分布科室主要为重症监护、烧伤科和儿科。碳青霉烯类耐药鲍曼不动杆菌对多数抗菌药物耐药率达到90%以上,仅对多粘菌素B、阿米卡星和米诺环素具有较高敏感性。95株碳青霉烯类耐药鲍曼不动杆菌,全部检出携带OXA-23、OXA-51基因,而OXA-24、OXA-58、IMP-1、IMP-2、NDM-1等耐药基因全为阴性;Ade ABC外排泵耐药基因及调控基因阳性率均大于85.0%,其中Ade A,Ade B,Ade C三种耐药基因检出率分别为97.5%、96%、97%,调控基因Ade S、Ade R检出率分别为85%、88%。结论我院感染患者无菌体液标本碳青霉烯类耐药鲍曼不动杆菌检出率以血液标本最多,其次为脑脊液标本。该菌株普遍耐药,多黏菌素B、米诺环素和阿米卡星可作为治疗的首选药物。OXA-23和OXA-51基因及Ade ABC外排泵相关耐药基因和调节基因的高表达是其耐碳青霉烯类抗生素及多重耐药的主要原因。

Objective To investigate the clinical distribution and drug resistance methanism of carbapenem-resistant Acinetobacter Baumannii(CRAB)isolated from abacterial body fluid in the our hospital from 2011 to 2012 and to provide the basis for reasonably selecting antibiotics.MethodsThe automatic detection machine of VITEK-2 compact was used for identification of bacteria as well as the drug susceptibility of the bacteria was performed by using disc agar diffusion(K-B method). WHONET5.6 PCR techniques were used to detect carbapenemase production-related resistance gene type OXA-51,OXA-23,OXA-24,OXA-58,IMP-1, IMP-2,NDM-1;AdeABC drugs outside efflux pump genes,AdeA,AdeB,AdeC and regulate gene AdeS,AdeR.Results From 2011 to 2012,124 strains of AB from abacterial body fluid were detected in our hospital and 95 strains were carbapenem-resistant Acinetobacter baumanii(CRAB),which accounted for 76.6%. A total of 75.8% isolates were from the blood and 22.1% isolates were from the csf.The CRAB was mainly isolated from the department of intensive care unit(ICU),burn department and pediatrics department. Drug resistances of CRAB to most antibiotics were over 90%. CRAB had a high sensitivity to polymyxin B,amikacin and minocycline. Of 95 multi-drug resistant strains,all detected OXA-23,OXA-51 gene positive while OXA-24, OXA-58,IMP-1,IMP-2,NDM-1 resistance gene negative. Five kinds AdeABC efflux pump resistance gene positive rate was greater than 85% and AdeA,AdeB,AdeC had positive detection rate reached 97.5%,96%, 97% while AdeS,AdeR genes positive detection rate reached 85%,88%.Conclusion CRAB had a high detection rate in infected patient abacterial body fluid in our hospital.The strains had widespread resistance. The polymyxinB,Minomycin and amikacin with considerable antibacterial activities may be the choices for carbapenem-resistant Acinetobacter Baumannii. OXA-23,OXA-51 and AdeABC efflux pump genes with much higher detection rate of resistant strains genes are the main causes of resistance to carbapenems. susceptible strains and multi-drug resistance.