Gholami Mehrdad, Hashemi Ali, Hakemi-Vala Mojdeh, Goudarzi Hossein, Hallajzadeh Masoumeh
Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, IR Iran.
Department of Microbiology, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
Jundishapur J Microbiol. 2015 Oct 12;8(10):e19048. doi: 10.5812/jjm.19048. eCollection 2015 Oct.
Acinetobacter baumannii has emerged as a highly troublesome pathogen and a leading cause of mortality and morbidity among hospitalized burn patients.
The aims of this study were to determine the frequency of the AdeABC genes and the role of the efflux pump (s) in the imipenem resistance of A. baumannii strains isolated from burn patients.
This study was conducted on 60 A. baumannii isolates collected from 240 wound samples of burn patients admitted to the Burn Unit of Shahid Motahari Burn hospital, Tehran, Iran. Antibiotic susceptibility tests were performed using the Kirby-Bauer disc diffusion and broth microdilution according to the clinical and laboratory standards institute (CLSI) guidelines. The activity of the efflux pump was evaluated using the efflux pump inhibitor, the phenylalanine-arginine Β-naphthylamide (PAΒN). The AdeABC genes were detected by polymerase chain reaction (PCR) and sequencing.
In this study, 100% of the isolates were resistant to cefotaxime, ceftazidime, ceftriaxone, ciprofloxacin, cefepime, piperacillin, meropenem, co-trimoxazole, and piperacillin/tazobactam; 56 (94%) to gentamicin; 50 (81%) to amikacin; 58 (97%) to imipenem; and 45 (76%) to tetracycline. Additionally,all the isolates were susceptible to colistin. The susceptibility of the strains to imipenem was highly increased in the presence of the efflux pump inhibitor such that for 58 (96.6%) of the isolates, the PAΒN reduced the minimum inhibitory concentrations (MIC) by 4- to 64-fold. The adeA and adeB genes were detected in 60 (100%) of the isolates, and the adeC gene was present in 51 (85%).
The efflux pump may play a role in antibiotic resistance in A. baumannii isolates. The ability of A. baumannii isolates to acquire drug resistance by the efflux pump mechanism is a concern. Thus, new strategies are required in order to eliminate the efflux transport activity from resistant A. baumannii isolates causing nosocomial infections.
鲍曼不动杆菌已成为一种极具麻烦的病原体，是烧伤住院患者死亡和发病的主要原因。
本研究旨在确定AdeABC基因的频率以及外排泵在从烧伤患者分离的鲍曼不动杆菌菌株对亚胺培南耐药性中的作用。
本研究对从伊朗德黑兰沙希德·莫塔哈里烧伤医院烧伤科收治的240例烧伤患者伤口样本中分离出的60株鲍曼不动杆菌进行。根据临床和实验室标准协会（CLSI）指南，使用 Kirby-Bauer 纸片扩散法和肉汤微量稀释法进行药敏试验。使用外排泵抑制剂苯丙氨酸-精氨酸β-萘酰胺（PAβN）评估外排泵的活性。通过聚合酶链反应（PCR）和测序检测AdeABC基因。
在本研究中，100%的分离株对头孢噻肟、头孢他啶、头孢曲松、环丙沙星、头孢吡肟、哌拉西林、美罗培南、复方新诺明和哌拉西林/他唑巴坦耐药；56株（94%）对庆大霉素耐药；50株（81%）对阿米卡星耐药；58株（97%）对亚胺培南耐药；45株（76%）对四环素耐药。此外，所有分离株对黏菌素敏感。在外排泵抑制剂存在的情况下，菌株对亚胺培南的敏感性显著增加，以至于对于58株（96.6%）分离株，PAβN将最低抑菌浓度（MIC）降低了4至64倍。在60株（100%）分离株中检测到adeA和adeB基因，51株（85%）存在adeC基因。
外排泵可能在鲍曼不动杆菌分离株的抗生素耐药性中起作用。鲍曼不动杆菌分离株通过外排泵机制获得耐药性的能力令人担忧。因此，需要新的策略来消除引起医院感染的耐药鲍曼不动杆菌分离株的外排转运活性。
