Aliakbarzade Katayun, Farajnia Safar, Karimi Nik Ashraf, Zarei Farzaneh, Tanomand Asghar
Department of Microbiology, Science and Research Branch, Islamic Azad University of Kerman, IR Iran.
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, IR Iran.
Jundishapur J Microbiol. 2014 Oct;7(10):e11924. doi: 10.5812/jjm.11924. Epub 2014 Oct 1.
Acinetobacter baumannii is one of the major causes of nosocomial infections and is resistant to most available antibiotics. Aminoglycosides remain as drugs of choice for treatment of Acinetobacter infections yet resistance to aminoglycosides has increased in the recent years.
The present study investigated the prevalence of genes encoding aminoglycoside-modifying enzymes in A. baumannii strains isolated from patients of Tabriz city, northwest of Iran.
A total of 103 Acinetobacter isolates were collected from Imam Reza Hospital of Tabriz University of medical sciences. Antimicrobial susceptibility patterns of the isolates to different antimicrobial agents including cephalosporins, gentamicin, amikacin, tobramycin, colistin and polymyxin, were evaluated by the disc diffusion method. The frequency of aminoglycoside modifying enzymes encoding genes aacC1, aphA6, aadA1 and aadB was analyzed by the PCR method.
Antimicrobial susceptibility analysis showed that the highest resistance was towards beta-lactam antibiotics including cephalosporins whereas the highest sensitivity was observed towards colistin (77%) and polymyxin (84%). The resistance rate to aminoglycosides was 81%, 86% and 63% for amikacin, gentamicin and tobramycin, respectively. The PCR results showed that among the 103 A. baumannii isolates, 56 (65.11 %) were positive for aacC1, 52 (60.46 %) for aphA6, 24 (27.9 %) for aadA1 and 16 (18.6 %) for aadB resistant genes.
The results of this study indicated that the genes encoding aminoglycoside-modifying enzymes are prevalent in A. baumannii isolates in the study region, which highlighted the necessity of considering preventive measures to control dissemination of these resistance genes.
鲍曼不动杆菌是医院感染的主要病因之一，对大多数现有抗生素具有耐药性。氨基糖苷类药物仍是治疗鲍曼不动杆菌感染的首选药物，但近年来对氨基糖苷类药物的耐药性有所增加。
本研究调查了从伊朗西北部大不里士市患者中分离出的鲍曼不动杆菌菌株中编码氨基糖苷类修饰酶基因的流行情况。
从大不里士医科大学伊玛目礼萨医院收集了103株不动杆菌分离株。采用纸片扩散法评估分离株对不同抗菌药物（包括头孢菌素、庆大霉素、阿米卡星、妥布霉素、黏菌素和多黏菌素）的药敏模式。采用PCR法分析编码氨基糖苷类修饰酶基因aacC1、aphA6、aadA1和aadB的频率。
药敏分析表明，对包括头孢菌素在内的β-内酰胺类抗生素耐药性最高，而对黏菌素（77%）和多黏菌素（84%）敏感性最高。阿米卡星、庆大霉素和妥布霉素对氨基糖苷类药物的耐药率分别为81%、86%和63%。PCR结果显示，在103株鲍曼不动杆菌分离株中，56株（65.11%）aacC1基因阳性，52株（60.46%）aphA6基因阳性，24株（27.9%）aadA1基因阳性，16株（18.6%）aadB耐药基因阳性。
本研究结果表明，编码氨基糖苷类修饰酶的基因在研究区域的鲍曼不动杆菌分离株中普遍存在，这突出了考虑采取预防措施以控制这些耐药基因传播的必要性。
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