Department of Medical Microbiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Department of Microbiology Reference Laboratories, National Molecular Microbiology Reference Laboratory, Ankara, Turkey.
Ann Clin Microbiol Antimicrob. 2019 Jul 2;18(1):19. doi: 10.1186/s12941-019-0319-8.
Multidrug-resistant (MDR) Acinetobacter baumannii infections are considered as emerging nosocomial infections particularly in patients hospitalized in intensive care units (ICUs). Therefore, reliable detection of MDR strains is crucial for management of treatment but also for epidemiological data collections. The purpose of this study was to compare antimicrobial resistance and the clonal distribution of MDR clinical and environmental A. baumannii isolates obtained from the ICUs of 10 different hospitals from five geographical regions of Turkey in the context of the demographic and clinical characteristics of the patients.
A multicenter-prospective study was conducted in 10 medical centers of Turkey over a 6 month period. A total of 164 clinical and 12 environmental MDR A. baumannii isolates were included in the study. Antimicrobial susceptibility testing was performed for amikacin (AN), ampicillin-sulbactam (SAM), ceftazidime (CAZ), ciprofloxacin (CIP), imipenem (IMP) and colistin (COL) by microdilution method and by antibiotic gradient test for tigecycline (TIG). Pulsed-field gel electrophoresis (PFGE) was performed to determine the clonal relationship between the isolates. The detection of the resistance genes, bla, bla, bla bla bla bla, bla, bla and bla was carried out using the PCR method.
The mortality rate of the 164 patients was 58.5%. The risk factors for mortality included diabetes mellitus, liv1er failure, the use of chemotherapy and previous use of quinolones. Antimicrobial resistance rates for AN, SAM, CAZ, CIP, IMP, COL and TIG were 91.8%, 99.4%, 99.4%, 100%, 99.4%, 1.2% and 1.7% respectively. Colistin showed the highest susceptibility rate. Four isolates did not grow on the culture and were excluded from the analyses. Of 172 isolates, 166 (96.5%) carried bla, 5 (2.9%) bla and one isolate (0.6%) was positive for both genes. The frequency of bla was found to be 2.9%. None of the isolates had bla, bla, bla and bla genes. PFGE analysis showed 88 pulsotypes. Fifteen isolates were clonally unrelated. One hundred fifty-seven (91.2%) of the isolates were involved in 14 different clusters.
Colistin is still the most effective antibiotic for A. baumannii infections. The gene bla has become the most prevalent carbapenemase in Turkey. The distribution of invasive A. baumannii isolates from different regions of Turkey is not diverse so, infection control measures at medical centers should be revised to decrease the MDR A. baumannii infections across the country. The results of this study are expected to provide an important baseline to assess the future prophylactic and therapeutic options.
多重耐药（MDR）鲍曼不动杆菌感染被认为是新兴的医院感染，特别是在重症监护病房（ICU）住院的患者中。因此，可靠地检测 MDR 菌株对于治疗管理以及流行病学数据收集至关重要。本研究的目的是比较来自土耳其五个地理区域的 10 家不同医院 ICU 的临床和环境 MDR 鲍曼不动杆菌分离株的抗生素耐药性和克隆分布情况，并结合患者的人口统计学和临床特征进行分析。
在土耳其的 10 家医疗中心进行了一项为期 6 个月的多中心前瞻性研究。共纳入 164 株临床和 12 株环境 MDR 鲍曼不动杆菌分离株。采用微量稀释法和抗生素梯度试验检测阿米卡星（AN）、氨苄西林-舒巴坦（SAM）、头孢他啶（CAZ）、环丙沙星（CIP）、亚胺培南（IMP）和多黏菌素（COL）的药敏性，替加环素（TIG）采用微量稀释法进行检测。采用脉冲场凝胶电泳（PFGE）分析确定分离株之间的克隆关系。采用 PCR 法检测 bla、bla、bla、bla、bla、bla、bla 和 bla 耐药基因。
164 例患者的死亡率为 58.5%。死亡的危险因素包括糖尿病、肝功能衰竭、化疗和喹诺酮类药物的使用。AN、SAM、CAZ、CIP、IMP、COL 和 TIG 的抗生素耐药率分别为 91.8%、99.4%、99.4%、100%、99.4%、1.2%和 1.7%。多黏菌素的敏感性最高。有 4 株分离物在培养物中未生长，因此被排除在分析之外。在 172 株分离物中，166 株（96.5%）携带 bla，5 株（2.9%）携带 bla，1 株（0.6%）同时携带这两种基因。bla 的检出率为 2.9%。未检测到 bla、bla、bla 和 bla 基因。PFGE 分析显示 88 种脉冲场凝胶电泳型。15 株分离株无克隆相关性。157 株（91.2%）分离株涉及 14 种不同的聚类。
多黏菌素仍然是治疗鲍曼不动杆菌感染最有效的抗生素。bla 基因已成为土耳其最常见的碳青霉烯酶。来自土耳其不同地区的侵袭性鲍曼不动杆菌分离株的分布并不多样，因此，应修订医疗机构的感染控制措施，以减少全国范围内的 MDR 鲍曼不动杆菌感染。本研究的结果有望为评估未来的预防性和治疗性选择提供重要的基线数据。
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