BACKGROUND 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. METHODS 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, blaOXA-23, blaOXA-24, blaOXA-51, blaOXA-58, blaIMP, blaNDM, blaKPC, blaOXA-48 and blaPER-1 was carried out using the PCR method. RESULTS 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 blaOXA-23, 5 (2.9%) blaOXA-58 and one isolate (0.6%) was positive for both genes. The frequency of blaPER-1 was found to be 2.9%. None of the isolates had blaIMP, blaKPC, blaNDM and blaOXA-48 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. CONCLUSIONS Colistin is still the most effective antibiotic for A. baumannii infections. The gene blaOXA-23 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.

中文翻译：

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在具有临床和环境特征的重症监护病房中，对多重耐药的鲍曼不动杆菌感染的抗菌素耐药性和分子流行病学评估进行前瞻性多中心研究。

背景技术多重耐药性（鲍氏不动杆菌）鲍曼不动杆菌感染被认为是新发的医院内感染，特别是在重症监护病房（ICU）住院的患者中。因此，对MDR菌株的可靠检测对于治疗管理以及流行病学数据收集至关重要。本研究的目的是根据患者的人口统计和临床特征，比较从土耳其五个地理区域的10家不同医院的ICU获得的MDR临床和环境A.鲍曼不动杆菌的抗药性和克隆分布。方法在六个月的时间里，对土耳其的10个医疗中心进行了多中心前瞻性研究。该研究共包括164种临床和12种环境MDR鲍曼不动杆菌。通过微稀释法和替加环素（TIG）的抗生素梯度试验对阿米卡星（AN），氨苄青霉素-舒巴坦（SAM），头孢他啶（CAZ），环丙沙星（CIP），亚胺培南（IMP）和粘菌素（COL）进行了药敏试验。进行脉冲场凝胶电泳（PFGE）以确定分离株之间的克隆关系。使用PCR方法检测抗性基因blaOXA-23，blaOXA-24，blaOXA-51，blaOXA-58，blaIMP，blaNDM，blaKPC，blaOXA-48和blaPER-1。结果164例患者的死亡率为58.5％。死亡的危险因素包括糖尿病，轻度衰竭，使用化学疗法和以前使用喹诺酮。AN，SAM，CAZ，CIP，IMP，COL和TIG的耐药率分别为91.8％，99.4％，99.4％，100％，99.4％，1.2％和1.7％。Colistin的敏感性最高。四个分离株未在培养物中生长，因此从分析中排除。在172个分离株中，有166个（96.5％）携带blaOXA-23，5个（2.9％）携带blaOXA-58，其中一个分离株（0.6％）两种基因均为阳性。发现blaPER-1的频率为2.9％。分离株均没有blaIMP，blaKPC，blaNDM和blaOXA-48基因。PFGE分析显示88种脉冲型。十五个分离株在克隆上无关。157个（91.2％）分离株涉及14个不同的簇。结论Colistin仍然是鲍曼不动杆菌感染的最有效抗生素。blaOXA-23基因已成为土耳其最流行的碳青霉烯酶。来自土耳其不同地区的入侵性鲍曼不动杆菌的分布情况并不多样，应修订医疗中心的感染控制措施，以减少全国范围内的耐多药鲍曼不动杆菌感染。预期这项研究的结果将为评估未来的预防和治疗选择提供重要的基线。