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

【摘要】 目的 通过对天津地区糖尿病足感染主要革兰氏阴性致病菌，铜绿假单胞菌（PA）对氨基糖苷类抗生素耐药的表型和基因型分析，旨在指导临床抗生素用药的选择，减少耐药菌株的增加。方法 采集本院209例糖尿病足溃疡患者的细菌学报告以及药敏结果，筛选出41株PA菌株，萃取菌株DNA后，以聚合酶链反应（PCR）检测氨基糖苷类修饰酶aac (3’)-Ⅱ、aac (6’) -Ⅰb、aac (6’) -Ⅱ、ant (2″) -Ⅰ、ant (3″) -Ⅰ及aac (3’) -Ⅰ，结合所选患者的临床资料和对耐药报告，对耐药基因型及耐药表型的进行相关分析。结果 结果显示，糖尿病足溃疡创面分离出的致病菌以革兰氏阳性（G+）菌为主，为51.67%；PA的总检出率为19.62%，是革兰氏阴性菌（G-）的首位致病菌；在感染较深、较重创面中PA的检出率明显增高；感染PA患者的溃疡面积明显高于感染其他G-菌和G+菌患者。PA菌株对所检测的氨基糖苷类抗菌素的耐药率高达73.17，检出氨基糖苷类修饰酶基因最多的为ant (3″) -Ⅰ（65.85%），aac (3’) -Ⅱ，aac(6’) -Ⅱ，aac (6’)-Ⅰb及ant (2″) -Ⅰ分别为63.41%，48.78%，12.2%及7.32%，aac(3’)-Ⅰ未检出。结论 研究提示在创面较深较大、感染较重的创面PA感染几率大；氨基糖苷类抗菌素的耐药现象非常严重； ant(3″)-Ⅰ是最为常见的氨基糖苷类抗菌素耐药基因。

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

Abstract: 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 (AmAn). MethodsThe 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′)-Ⅰ b, aac(6′)-Ⅱ , ant(2′′)-Ⅰ and 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. ResultsGram 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 AmAn (73.17%). The predominant drug resistance gene to AmAn was ant(3′′)-Ⅰ(65.85%), and aac(3′)-Ⅰ gene 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 AmAn was more serious, and ant(3′′)-Ⅰ gene identified from PA isolates was the most commonresistance gene identified to AmAn