Journal of University of Duhok, Vol. 24, No.1 (Pure and Eng. Sciences), Pp 19-25, 2021 Marwan.qader@uod.ac 91 MOLECULAR STUDY OF Acinetobacter baumannii USING 16S RRNA AND BLA OXA-51 GENE ISOLATED FROM HOSPITALS IN DUHOK- KURDISTAN REGION, IRAQ MARWAN KHALIL QADER Dept. Biology, College of Science, University of Duhok, Kurdistan Region-Iraq (Received: September 16, 2020; Accepted for Publication: February 28, 2021) ABSTRACT Background and objective: Acinetobacter baumannii is pathogenic and multiresistant bacteria that cause nosocomial infection. The aim of this study are diagnosis A. baumannii by using specific bla OXA-51 and 16SrRNA. Methods: out of 150 Acinetobacter species samples were collected from patients in Azadi teaching hospital, Duhok Emergency hospital; and burn Duhok cosmetic and burn hospital from May 2020 to August 2020. The samples were phenotypically diagnosed by bacteriological strategy. Out of 100 samples were selected and by molecular level confirmed as Acinetobacter spp. Results: isolates were revealed as small, pale, and late-lactose fermenter colonies on MacConkey agar appeared as a creamy, opaque, andnon-hemolytic colony on blood agar All suspected isolates, as A. baumannii, were growing at 44ºC. By using the genus-specific bla OXA-51 primer that produced 353 bp amplification band and 75 samples were diagnosed by PCR as A. baumannii by 16S rRNA as a specific primer and showed 150 bp amplicon. 10 samples out of the 75 resembling A. baumannii were identified as a multidrug resistant isolates by method of diffusion. Disc, A. baumannii isolates displayed a high resistance rate of 85% to azithromycin and 80% to imipenem. Moreover, amikacin, meropenem, and gentamycin, Trimethoprim-Sulfamethoxazole, and ciprofloxacin, norfloxacin showed a low level of efficacy against A. baumannii isolates with the resistant rate of 88%, 90%, 90%, and 93% respectively. KEYWORD: Acinetobacter baumannii, bla OXA-51, multi-drug resistant, 16S rRNA, PCR 1. INTRODUCTION cinetobacter is currently classified under the family Moraxellaceae, which includes the genera Moraxella, Psychrobacter, and other related organisms (Almasaudi., 2018). Acinetobacter baumannii (A. baumannii) is considered as an opportunistic pathogen causing nosocomial infections in hospitalized patients, particularly in Intensive care units (ICU), as well as community-acquired infections (Jessie et al., 2020). These infections include pneumonia, bloodstream infection, skin and soft tissue infections, wound infection, meningitis, urinary tract infection and endocarditis (Liu et al., 2017). Acinetobacter infections have been historically associated with military and injured soldiers in combat due to direct environmental contamination of wounds (Diancourt et al., 2010). During the past decade, the incidence of nosocomial outbreaks by A. baumannii has been described mostly in burn, surgical and intensive care units (Jafari and Karbasizade, 2014). Most surveillance studies report high mortality rates among patients with A. baumannii bacteremia and may be associated with considerable morbidity and mortality reach up to 70% (Wong et al., 2017). The management and prevention of A. baumannii spreading health care settings require identifying potential reservoirs of this organism, the modes of transmission and investigating A. baumannii clones which cause the outbreaks from epidemiologically unrelated strains. A comparison of isolates at the subspecies level is required by the application of molecular typing methods (Sadeghi et al., 2016). The use of molecular tools, especially the Polymerase Chain Reaction (PCR), has a great impact on simplifying and specificity for identification, characterization, and taxonomy of infectious agents (Shahi et al., 2018). 2- MATERIALS AND METHODS Out of 150 samples were collected from burns and sputum inpatients in Azadi teaching hospital, Duhok Emergency hospital; and burn Duhok cosmetic and burn hospital between May-August 2020 both genders bunches. The A