耐亚胺培南鲍曼不动杆菌碳青霉烯酶基因分析

The carbapenemase genotype of imipenem-resistant Acinetobacter baumannii isolates

目的研究我院耐亚胺培南鲍曼不动杆菌(IRAB)的耐药性与碳青霉烯酶基因型。方法收集我院耐亚胺培南鲍曼不动杆菌35株,K-B法和E-test法测定对常用抗菌药物的敏感性,采用改良Hodge试验和乙二胺四乙酸(EDTA)协同试验检测耐亚胺培南不动杆菌产碳青霉烯酶和金属β-内酰胺酶情况,聚合酶链反应(PCR)检测其碳青霉烯酶基因OXA-23、OXA-24、OXA-58I、MP、VIM。结果 35株耐亚胺培南鲍曼不动杆菌对β-内酰胺类、部分氨基糖苷类、喹诺酮类及磺胺类抗菌药物均有很高耐药率(>70%),仅对阿米卡星、头孢哌酮/舒巴坦和多粘菌素B有较高的敏感性(>70%),35株耐亚胺培南鲍曼不动杆菌均产碳青霉烯酶,未检测到金属β-内酰胺酶,全部检测到OXA-23型基因,未检测到OXA-24、OXA-58I、MP、VIM型基因。结论耐亚胺培南鲍曼不动杆菌耐药相当严重;产OXA-23型碳青霉烯酶是我院鲍曼不动杆菌对亚胺培南耐药的主要原因。

Aim To study the resistance and carbapenemase gcnotype of imipenem-resistant Acinetobacter baumannii （IRAB）isolates in our hospital. Methods Thirty-five non-repetitive isolates of IRAB were collected. The drug resistance was detected by Kirby-Bauer test and E-test. The modified Hodge and the ethylenediaminetetraacetic acid （EDTA）-disk synergy test were performed for screening carbapenemase and metallo-β-lactamase production. PCR was performed to determine OXA-23,OXA-24,OXA-58,IMP and VIM carbapenemase gene. Results All isolates showed very high resistance （〉70%） to common antimicrobia] agents concluding β-1actams, a part of anainoglycosides, quinolones, sulfa drugs, and high susceptibility （〉70%）to amikacin, sulperazon and polymyxin B. All of the 35 isolates （100%） showed positive results in the modified Hodge test and negative results in the EDTA-disk synergy test. They all （100%） possessed the encoding gene for an OXA-23 carbapenemase. Conclusion The resistance of IRAB was very serous. OXA-23 gene are the most popular carbapenemase coding genes in our hospital .