Hamadan University of Medical Sciences Avicenna Journal of Clinical Microbiology and Infection 2383-0298 7 1 2020 03 30 Efficacy of Some Antibiotics and Essential Oils Against Acinetobacter baumannii: An in Vitro Study 1 7 10.34172/ajcmi.2020.01 EN Mazen Safi https://orcid.org/0000-0002-2541-0335 Laila Al-Hallab Rasha Al-Abras Marwa Khawajkiah Heba Kherbik Ayman AL-Mariri https://orcid.org/0000-0002-9586-6573 Journal Article 10.34172/ajcmi.2020.01 2020 01 13 2020 03 20 Background and Objective: Acinetobacter baumannii is considered as a main opportunistic pathogen in hospitals and exhibit high resistance against most antibiotic groups. The aim of this study was to evaluate the efficacy of some antibiotics and essential oils against this bacterium, in vitro. Materials and Methods: Two hundred and one clinical samples were collected from the Children’s Hospital of Damascus. The polymerase chain reaction was conducted to identify the genus and type of bacteria. Finally, the minimum inhibitory concentrations of several antibiotics and essential oils, including Thymus syriacus, Origanum syriacum, Citrus aurantium, Cinnamomum verum, Syzygium aromaticum, Cupressus macrocarpa, Myristica fragrans, Biota orientalis, and Zingiber officinale, were investigated on Luria-Bertani broth agar. Results: Fifty-nine isolates of A. baumannii were identified and the results showed that the DNA fragments of 16S rRNA and the blaOXA-51 _ like gene were approximately equal to 280 bp and 350 bp, respectively. In addition, most effective antibiotics against 50% of bacteria in each isolate of A. baumannii were rifampicin, linezolid, and levofloxacin whereas most effective essential oils included Cupressus macrocarpa, Citrus aurantium, Myristica fragrans, and Biota orientalis.