鲍曼不动杆菌中OXA碳青霉烯酶的表型筛选与PCR检测

Phenotypic screening and PCR detection of OXA carbapenemases in Acinetobacter baumannii

目的了解OXA碳青霉烯酶在暨南大学附属第一医院耐亚胺培南鲍曼不动杆菌中的流行状况,完善OXA碳青霉烯酶的分子流行病学资料。方法采用改良Hodge试验筛选产碳青霉烯酶菌株,多重PCR法检测OXA碳青霉烯酶的编码基因(blaOXA-23-like、blaOXA-24-like、blaOXA-58-like和blaOXA-143),利用生物信息学的方法对OXA亚型进行比对分析并制作分子进化树。结果在157株耐亚胺培南鲍曼不动杆菌中Hodge试验筛选出碳青霉烯酶表型阳性菌株141株,PCR检测结果显示有132株携带OXA-23编码基因,未检测到OXA-24-like、OXA-58-like和OXA-143亚型。结论产OXA-23碳青霉烯酶是该院鲍曼不动杆菌对亚胺培南耐药的主要机制之一。

Objective To determine the prevalence of OXA carbapenemases among imipenem-resistant Acinetobacter baumannii isolated in our hospital, and consummate the molecular epidemiology data of OXA carbapenemases in A. baumannii. Methods The modified Hodge test was used to detect OXA earbapenemases producing isolates, and OXA earbapenemases genetypes were determined by multiplex PCR amplification, including OXA-23-1ike, OXA-24-1ike, OXA-58-1ike and OXA-143 respectively. The genetypes of OXA carbapenemases were analyzed and phylogenetic tree was made by bioinformatics analyzing tools. Results Of the 157 imipenem-resistant A. baumannii, 141 isolates producing OXA carbapenemases were detected by the modified Hodge test. 132 isolates were positive with the primers specific to OXA-23-1ike carbapenemases, while OXA-24-1ike, OXA-58-1ike and OXA-143 carbapenemases were not detected. Conclusion The modified Hodge test could be used to detect OXA carbapenemases producing A. baumannii, and production of OXA-23 carbapenemases is one of the main mecha- nisms of the resistance of A. baumannii to imipenem.