耐亚胺培南鲍曼不动杆菌碳青霉烯酶基因研究

Detection of carbapenemases genes in imipenem-resistant Acinetobacter baumannii

目的了解本地区耐亚胺培南鲍曼不动杆菌(IRAB)的耐药特征以及D类和B类碳青霉烯酶基因的流行状况。方法收集广东省2家三甲医院临床分离的耐亚胺培南鲍曼不动杆菌70株,采用K-B纸片法进行药敏试验;设计合成D类和B类碳青霉烯酶的引物序列进行PCR扩增和测序分析;热不对称PCR法检测侧翼序列。结果 70株耐亚胺培南鲍曼不动杆菌对13种抗生素的耐药率都在84.29%以上,共有3株鲍曼不动杆菌检出OXA-58-like,60株检出OXA-51-like,23株检出OXA-23-like,4株检出OXA-24-like,另有1株检出了NDM-1基因;NDM-1上游存在ISAba125插入序列。结论鲍曼不动杆菌耐药情况严重,本地区鲍曼不动杆菌D类碳青霉烯酶基因的分布以OXA-23-like为主,同时检测出B类碳青霉烯酶NDM-1,需密切监测。

Objective To study the drug resistance and Class D and Class B carbapenemas genotypes of imipenem-resistant Acinetobacter baumannii （IRAB）. Methods Seventy non- repetitive isolates of IRAB were collected from two tertiary hospitals of Guangdong, and the drug sensitive test was carried out by Kirby-Bauer method recommended by CLSI （2010）. Class D and Class B β-lactamase genes were detected by PCR, and thermal asymmetric interlaced PCR was performed to determine the flanking sequences. Results All isolates showed very high resistance （ 〉84.29% ） to 13 common antibiotics. PCR and sequencing results showed that 3 strains possessed the OXA-58-1ike gene, 60 strains possessed the OXA-51-like gene, 23 strains produced the OXA-23-like gene, 4 strains possessed the OXA-24-1ike gene and 1 strains possessed NDM-1 gene. The insert sequence ISAba125 was found in the upstream of NDM-1 gene. Conclusion The total antibiotic resistance of A. baumannii was serious, and the genetypes of Class D carbapenemas were mainly OXA-23-1ike, and the New Delhi metallo -β-lactamase （NDM-1 ）-encoding gene was belong to Class B carbapenemas was also detected in the local A. baumannii.