en علوم آزمایشگاهی Laboratory Sciences Research Article Research Article <div style="text-align: justify;"><span style="font-size:12px;"><span style="font-family:Times New Roman;"><b>Background:</b> The widespread increase in the prevalence of antibiotic resistance in bacteria is considered one of the biggest problems in the global health and treatment system today. Therefore, this study was conducted to investigate the prevalence and antibiotic resistance pattern of bacteria isolated from blood cultures at Shahid Rahimi Hospital in Khorramabad in 2018.<br> <b>Methods:</b> This cross-sectional study investigated blood cultures of patients admitted to Shahid Rahimi Hospital from June to December 2018. The disc diffusion method was used according to CLSI instructions, and the data were analyzed using SPSS software.<br> <b>Results:</b> Out of a total of 2591 blood culture samples, 247 blood culture samples were positive. The highest frequency was related to the emergency department (62%) and ICU (23%), and the lowest frequency was related to the children&#39;s department (2.4%). Among the tested samples, 28% were Gram-negative bacilli and 72% were Gram-positive cocci. The most common Gram-negative and Gram-positive bacteria were <i>Escherichia coli</i> (38%) and <i>Staphylococcus epidermidis</i> (54.2%), respectively. Among Gram-negative bacteria, the highest level of resistance was seen in <i>Acinetobacter baumannii</i> strains, which showed resistance to all antibiotics. Among Gram-positive bacteria, the highest resistance of <i>Streptococcus</i> group D strains to the antibiotic erythromycin (92%) was reported.<br> <b>Conclusion</b>: The prevalence of antibiotic resistance in common microorganisms isolated from blood cultures in different departments is worrying, and choosing an effective drug to eliminate these bacteria by performing accurate laboratory tests is of particular importance.</span></span><br> &nbsp;</div> Blood culture, Drug Collateral Sensitivity, Bacteria 20 24 http://mlj.goums.ac.ir/browse.php?a_code=A-10-1491-1&slc_lang=en&sid=1 Shahnaz Halimi shhalimi@sina.tums.ac.ir 100319475328460031690 100319475328460031690 No Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Pegah Shakib p.shakib63@gmail.com 100319475328460031691 100319475328460031691 No Razi Herbal Medicines Research Center, School of Health and Nutrition, Lorestan University of Medical Sciences, Khorramabad, Iran Elham Mehrabnejad Elham.Mehrabnejad@yahoo.com 100319475328460031692 0009-0000-9436-6756 No Razi Herbal Medicines Research Center, Shahid Rahimi Hospital, School of Health and Nutrition Lorestan University of Medical Sciences, Khorramabad, Iran Faranak Rezaei frezaei59@gmail.com 100319475328460031693 100319475328460031693 No Department of Microbiology, School of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran Somayeh Delfani somayehdelfani@gmail.com 100319475328460031694 100319475328460031694 Yes Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran