Evaluation of Antibiotic Resistance to Colistin in Nosocomial Infections with Multidrug-Resistant Acinetobacter

Background and Objective:Acinetobacter infection is one of the most common nosocomial infections that its antibiotic resistance has increased in recent years.This study aimed to evaluate drug resistance to colistin in nosocomial infections with multidrug-resistant (MDR) Acinetobacterbaumannii. Materials and Methods:This cross-sectional study was performed on 45 blood or body fluid culture samples collected from hospitalized patients at Sina Hospital, Hamadan, Iran, within 2018-2019.The Minimum Inhibitory Concentration (MIC) was determined using E-test trips and disk diffusion method to evaluate the resistance of Acinetobacterbaumannii to the antibiotic colistin according to the guidelines of the Clinical and Laboratory Standards Institute.The collected data were analyzed in SPSS software (version 16). Results:In this study, out of 45 patients, 24 (53.3%) and 21 (46.7%) of the subjects were male and female, respectively.The mean age of patients was estimated at 68.0±15.9 years. The antibiotic-resistance of samples was determined using the disk diffusion method. Accordingly, all samples were 100% resistant to ceftriaxone, ceftazidime, ciprofloxacin, cefepime, imipenem, meropenem, ampicillin sulbactam.Out of 45 culture samples examined with MIC, 39 (86.7%) and 6 (13.3%) of samples were sensitive and resistant to colistin, respectively.Based on the results of the disk diffusion method, 21 (46.7%), 19 (42.2%), and 5 (11.1%) of samples were sensitive, intermediate, and resistant to colistin. Conclusion:Based on the findings, colistin was effective against multidrug-resistant Acinetobacterbaumannii and is suggested to be used in cases of Acinetobacter MDR as an effective treatment in combination with other antibiotics.