en ميکروب شناسي Microbiology Research Article Research Article <div style="text-align: justify;"><span style="font-size:12px;"><span style="font-family:Times New Roman;"><b>Background:</b> <i>Acinetobacter baumannii</i> (<i>A. baumannii</i>) has emerged as the predominant etiological agent responsible for bloodstream infections among hospitalized patients. The objective of this study was to evaluate antibiotic resistance in <i>A. baumannii</i> isolates identified from blood cultures.<br> <b>Methods:</b> A retrospective cohort evaluation was conducted on 117 <i>A. baumannii</i> isolates obtained from blood cultures collected between 2018 and 2019 at the Microbiology Laboratory of Tokat Gaziosmanpaşa University Hospital (T&uuml;rkiye). The blood culture samples were incubated using the BACT-ALERT 3D system (bioM&eacute;rieux, Durham, NC, USA). Microorganism identification and antibiotic susceptibility testing were performed using the VITEK 2 (bioM&eacute;rieux, France) automated system.<br> <b>Results:</b> Of the 117 samples, 59.8% were obtained from males and 40.2% from females. A total of 90.6% of blood culture samples were collected from the intensive care unit, and 88.9% of isolates were identified as multidrug-resistant (MDR). The highest resistance was observed against meropenem (99.1%), while the lowest resistance was noted for colistin (17.1%) and tigecycline (27.3%). Resistance to amikacin was 74.4%, while resistance levels to gentamicin, tobramycin, cefoxitin, and cefotaxime were within the range of 80&ndash;90%. Resistance to imipenem, amoxicillin/clavulanic acid, ampicillin/sulbactam, ceftazidime, cefepime, ciprofloxacin, levofloxacin, meropenem, and ertapenem exceeded 90%.<br> <b>Conclusion</b>: The increasing number of MDR <i>A. baumannii</i> isolates poses a significant threat to all hospitalized patients. However, colistin and tigecycline remain preferable options for the treatment of MDR <i>A. baumannii</i> infections. Considering the increasing prevalence of MDR <i>A. baumannii</i> isolates, periodic analysis of epidemiological data in healthcare centers is important for managing resistance to colistin and tigecycline.</span></span><br> &nbsp;</div> Acinetobacter baumannii, Blood culture, Colistin, Multiple drug resistance, Tigecycline 8 10 http://mlj.goums.ac.ir/browse.php?a_code=A-10-1524-1&slc_lang=en&sid=1 Zaid Faris Hasan zaidfaris25@gmail.com 100319475328460028901 100319475328460028901 No Instutite of Graduate Studies, Tokat Gaziosmanpaşa University, Tokat, Turkey Umut Safiye Şay Coşkun umut.saycoskun@gop.edu.tr 100319475328460028902 100319475328460028902 Yes Department of Medical Microbiology, Faculty of Medicine, Tokat Gaziosmanpaşa University, Tokat, Turkey