糖尿病足分离的铜绿假单胞菌对氨基糖苷类抗生素耐药机制探讨

Study on aminoglycoside antibiotics resistance of Pseudomonas aeruginosa isolated from diabetic foot infections

目的分析糖尿病足溃疡感染(DFI)铜绿假单胞菌(PA)的临床特点及对氨基糖苷类抗生素(Am An)耐药的表型和基因型。方法采集本院209例DFI患者感染部位的细菌学报告及药敏结果,筛选出41株PA菌株,以聚合酶链反应(PCR)检测Am An修饰酶基因aac(3′)-Ⅱ、aac(6′)-Ⅰb、aac(6′)-Ⅱ、ant(2′′)-Ⅰ、ant(3′′)-Ⅰ及aac(3′)-Ⅰ,结合患者的临床资料和耐药报告,对耐药基因型及耐药表型进行相关分析。结果 DFI患者创面分离出的致病菌以革兰阳性(G+)菌为主(51.67%);PA的总检出率为19.62%,且是革兰阴性菌(G-)的首位致病菌(47.67%)。PA组患者溃疡面积≥4 cm2的比例高于非PA组和G+组,差异有统计学意义;与G+组相比,PA组患者缺血性溃疡、骨髓炎的发生率均较高,患者临床特点及溃疡深度评分(SAD评分)、超敏C反应蛋白增高,差异均有统计学意义。30株PA对Am An耐药(73.17%);耐药基因检出最多的为ant(3′′)-Ⅰ(65.85%),aac(3′)-Ⅰ未检出。结论 DFI患者PA检出率较高,且多见于溃疡面积较大、溃疡较深及缺血严重的患者中;PA对Am An的耐药现象较为严重;ant(3′′)-Ⅰ是检出的最常见的耐药基因。

Objective To investigate the clinical features, phenotypes and genotypes of Pseudomonas aeruginosa（PA）strains isolated from patients with diabetic foot infection（DFI） resisting to aminoglycosides antibiotics（Am An）. Methods The clinical profiles of 209 DFI patients hospitalized in the Tianjin Metabolic Diseases Hospital were collected and ana-lyzed. Forty-one PA strains were identified, and their antibiotic resistance profiles were obtained. The DNAs of PA isolateswere extracted and applied to amplifications for several aminoglycosides modifying enzyme genes, including aac（3′）-Ⅰ, aac（3′）-Ⅱ, aac（6′）-Ⅰb, aac（6′）-Ⅱ, ant（2″）-Ⅰand ant（3″）-Ⅰ by PCR method. Combining with the clinical features and theantibiotic resistance profiles, the relationship between genotypes and phenotypes of the PA strains was analyzed. Results Gram positive bacteria（G＋） were the majority of the pathogen with 51.67% detection rate. The total detection rate of PA was19.62%, listed as the top one pathogenic bacterium among gram negative bacteria（47.67%）. There was significant differencein the ratio of ulcer area≥4 cm2 between PA group and non-PA group and G＋group. There were significantly higher inci-dence rate of ischemic ulcer and osteomyelitis in PA group than those of G＋group. There were higher clinical characteristicsand ulcer depth（SAD） score, and increased hypersensitive C-reactive protein in PA group than those of G＋group. Therewere 30 strains of PA being resistant to Am An（73.17%）. The predominant drug resistance gene to Am An was ant（3″）-Ⅰ（65.85%）, and aac（3′）-Ⅰgene was not found from all PA isolates. Conclusion The detection rate of PA isolated from DFIpatients was higher, and patients were with the characteristics of larger, deeper and severe ischemia of ulcer area. The phe-nomenon of PA resistant to Am An was more serious, and ant（3″）-Ⅰgene identified from PA isolates was the most commonresistance gene identified to Am An.