OmpA基因表达与鲍曼不动杆菌耐药的相关性

The correlation between OmpA expression and drug resistance of Acinetobacter baumannii

目的分析鲍曼不动杆菌(Acinetobacter baumannii,AB)OmpA基因缺失株(△OmpA)和OmpA基因补救株(+OmpA)药物敏感性的差异,探讨临床株鲍曼不动杆菌OmpA mRNA表达水平与耐药的相关性,明确OmpA在鲍曼不动杆菌耐药中的作用。方法采用定点诱变技术构建ATCC17978 OmpA基因缺失株及补救株。收集福建医科大学附属龙岩第一医院2020年9月—2020年12月期间AB菌感染的住院患者40例,分离并培养各AB菌株。荧光定量PCR检测临床株鲍曼不动杆菌OmpA mRNA表达水平,MIC法检测各菌株药物敏感性,药敏结果依据美国CLSI 2018判断标准判别。结果OmpA基因缺失导致菌株在阿米卡星、头孢吡肟、莫西沙西、亚胺培南、哌拉西林/他唑巴坦等几种抗生素中表现得更为敏感。本研究选择非耐药临床菌株和多重耐药临床菌株各20株。其中,对阿米卡星耐药18株,不耐药22株;头孢吡肟耐药20株,不耐药20株;对亚胺培南耐药19株,不耐药21株;对哌拉西林他唑巴坦耐药20株,不耐药20株。同时,多重耐药株鲍曼不动杆菌OmpA mRNA表达水平显著高于非耐药株(P<0.05)。结论OmpA的缺失可显著降低阿米卡星、头孢吡肟、莫西沙西、亚胺培南、哌拉西林他唑巴坦等5类抗生素的最低抑菌浓度。OmpA mRNA高表达是本机构临床株鲍曼不动杆菌发生耐药的主要因素之一。对本机构临床菌株OmpA mRNA表达水平的监测或可有效预测菌株耐药性,掌握本机构内耐药菌株的流行动态,有效指导临床抗感染治疗和院感防控。

Objective To analyze the differences in drug sensitivity between the OmpA gene deletion strain and the OmpA gene recovery strain,to explore the correlation between OmpA mRNA expression level and drug resistance of Acinetobacter baumannii clinical isolates,and to definitude the role of OmpA in drug resistance of A.baumannii.Methods ATCC17978 OmpA gene deletion and recovery strains were constructed by site-directed mutagenesis technology.Samples from 40 patients with infections of A.baumannii were collected at Fujian Longyan First Hospital from September 2020 to December 2020,then isolated and cultured the A.baumannii strains from clinical specimens.Fluorescence quantitative PCR was used to detect the OmpA mRNA expression level of clinical A.baumannii strains,and the sensibility test of 40 A.baumannii was determined by microdilution quantitative minimum inhibitory concentration(MIC)method,the American Clinical&Laboratory Standards Institute(CLSI)2018 judgment standard was used to determine the drug sensitivity of A.baumannii strains.Results Deletion of the ompA gene led to decreased MICs of amikacin,cefepime,moxixaxil,imipenem,and piperacillin/tazobactam.In this study,20 non-resistant clinical strains and 20 multi-drug resistant clinical strains were selected.Among them,18 were resistant to amikacin and 22 were not resistant;20 were resistant to cefepime and 20 were not resistant;19 were resistant to imipenem and 21 were not resistant;20 strains of piracillin and tazobactam were resistant and 20 were non-resistant.And the expression level of OmpA mRNA in multi-drug resistant A.baumannii strains was significantly higher than that in non-drug resistant strains(P<0.05).Conclusion The deletion of OmpA gene led to decreased MICs of amikacin,cefepime,moxixaxil,imipenem,and piperacillin/tazobactam.And the high expression of OmpA mRNA is a main factor for the drug resistance in the clinical isolates of A.baumannii in this institution.To monitor the OmpA mRNA expression level of A.baumannii clinical isolates can effectively predict the drug resistance of the strains,keep abreast of the epidemic dynamics about drug-resistant strains,effectively guide rational use of antibiotics in clinical treatment and hospital infection prevention.