鲍氏不动杆菌blaOXA-23基因定位及其临床意义

Genetic Supports of blaOXA-23 in Acinetobacter baumannii and Their Clinical Significance

目的研究鲍氏不动杆菌blaOXA-23的基因背景,探讨不动杆菌属耐药性产生与抗菌药物使用的关系。方法连续筛选法获得耐亚胺培南鲍氏不动杆菌;PCR检测碳青酶烯酶基因;ERIC-PCR研究菌株遗传相关性;质粒接合实验及blaOXA-23杂交等研究OXA-23基因定位。结果24株中筛选出10株耐药菌,其中有6株检测到blaOXA-23基因;且菌株呈多克隆特点;DNA杂交发现blaOXA-23与整合子无关。结论blaOXA-23可存在于对亚胺培南敏感的不动杆菌属中;抗菌药物选择压力强化了blaOXA-23阳性菌的种群优势,导致耐药性产生;提示应合理应用此类抗菌药物。

OBJECTIVE To study the genetic supports of OXA-23 in Acinetobacter baumannii isolates and investigate the relationship between imipenem resistance acquiring and use of antibiotics.METHODS Consecutive selection of the 24 highly susceptive A.baumannii clinical isolates by imipenem was carried out.Genes of carbapenemases were detected by PCR and the colonial relationship of these isolates was evaluated by ERIC-PCR.Plasmids conjugation experiments and blaOXA-23 hybridization were performed to explore the gene location of blaOXA-23.RESULTS From all 24 susceptible A.baumannii isolates 10 were selected,including 6 multi-colonial blaOXA23 harboring strains.Plasmid conjugation experiments and Southern blotting experiments demonstrated that blaOXA-23 was not associated with integrons.CONCLUSIONS BlaOXA-23 may exist in a certain subset of apparently carbapenem sensitive Acinetobacter strains.When under consecutive selective pressure,bacteria harboring blaOXA-23 become the predominant group and subsequently the antibiotics resistance properties appear.It highlights the reasonable use of this category of antibiotics.