WestIndianMedJ2017;66(1):56 From: 1 Health Policy Research Center, Institute of Health, Shiraz University of Medical Sciences, Shiraz, Iran , 2 Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran, 3 Department of Microbiology, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran, 4 Department of Biology, Ashkzar Branch, Islamic Azad University, Ashkzar, Iran and 5 Department of Health Management, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada. Correspondence: Dr H Momtaz, Department of Microbiology, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, PO Box 166, Shahrekord, Iran. Email: hamomtaz@iaushk.ac.ir; hamomtaz@yahoo. com Determination of Antimicrobial Resistance and Resistant Genes in Acinetobacter baumannii from Human Clinical Samples F Khamesipour 1, 2 , H Momtaz 3 , M Tavakol 4 , B Awodile 5 ABSTRACT Objective: The aim of this study is to determine the prevalence, antimicrobial resistance and various resistance genes in Acinetobacter baumannii (A baumannii) from human clinical specimens at the pa- yambaran and Baqiyatallah Hospitals in the city of Tehran, Iran, over a period of six months (Septem- ber 2012 to March 2013). Methods: A total of 500 samples including blood, phlegm, urine, cerebrospinal fluid (CSF) and pus were collected from patients on admission in these hospitals. A baumannii was identified by using sta- ndard microbiological procedures and conventional polymerase chain reaction (PCR) technique. Antimicrobial susceptibility test was performed according to clinical and laboratory standard institute (CLSI) guidelines using Kirby-Bauer disc diffusion technique, while different resistance genes were detected using PCR method. Results: A total of 121 A baumannii was detected out of 500 samples, representing 24.20% period preva- lence. A baumannii was detected from all the sample groups, but a higher prevalence was observed in the blood (43.87%) and phlegm (24.11%). Antibiotic resistance profile showed higher resistance of A bau- mannii to tetracycline (90.90%), trimethoprim (61.98%) and cotrimoxazole (51.23%), followed by amino- glycosides (9.91–31.40%). Relatively low resistance was observed to cephalosporins (16.52–20.66%), quinolones (6.61–9.91%) and macrolides (8.26–14.04%), while the lowest resistance was observed to carbapenems (3.3–5.78%), chloramphenicol and nitrofurantoin. Highest detection for resistant genes was observed for tetA (58.67%), aac (3)-IV (56.19%), sul1 (55.37%) and dfrA1 (48.76%). Relatively low detection was observed for aad A1, bla-genes (SHV, CTX-M, OXA-like, VIM, SIM and IMP) and lowest detection was observed for cat1 and cmlA, while no qnr gene was detected. Conclusions: Multidrug-resistant Acinetobacter infections are posing an increasing threat to the popu- lation in these communities. Carbapenems provide an effective option against infections caused by re- sistant A baumannii. Keywords: Acinetobacterbaumannii, antimicrobial resistance, human clinical samples, resistant genes DeterminacióndelaResistenciaAntimicrobianaylosGenesResistentesFrenteala Acinetobacter baumannii de Muestras Clínicas Humanas F Khamesipour 1, 2 , H Momtaz 3 , M Tavakol 4 , B Awosile 5 RESUMEN Objetivo: El objetivo de este estudio es determinar la prevalencia, resistencia antimicrobiana, y varios genes de resistencia frente a la Acinetobacter baumannii (A baumannii) de muestras clínicas humanas en el hospital de Payambaran y el de Baqiyatallah en la ciudad de Teherán, Irán, durante un período de seis meses (de septiembre de 2012 a marzo de 2013). Métodos: Se recogieron un total de 500 muestras, incluyendo muestras de sangre, flema, orina, líquido cefalorraquídeo (LCR), y pus de los pacientes al ingresar en estos hospitales. La A baumannii fue iden- tificada mediante procedimientos microbiológicos estándar y la técnica de reacción en cadena de la po- limerasa (RCP) convencional. La prueba de susceptibilidad antimicrobiana se realizó según las guías DOI:10.7727/wimj.2014.337