The antibiotic susceptibilities of Acinetobacter baumannii strains isolated from various culture samples of intensive care patients

Abstract

Aim: In this study, we aim to evaluate the antibiotic susceptibilities by using E-test and disc diffusion methods in 80 Acinetobacter baumannii (A. baumannii) strains against to different antibiotics groups that were isolated from various clinical samples of patients hospitalized in intensive care units at three different centers. Material and methods: We included 80 strains of A. baumannii that were isolated from one clinical samples of 80 hospitalized patients in Intensive Care Units of Ankara, Antalya and Van provinces in between 2010 and 2012. Of those 80 strains, 34 were obtained from endotracheal aspirate, 16 from wound , 14 from urine, 10 from blood, 2 from catheters, 2 from sputum and 2 from cerebrospinal fluid. The antibiotic susceptibilities for colistin (CO), tigecycline (TG), doripenem (DOR), piperacillintazobactam (TZP), cefoperazone-sulbactam (CES) were determined by E-test method whereas disc-diffusion method was used for imipenem (IMP), meropenem (MEM), ticarcillin-clavunate (TIM), ciprofloxacine (CIP), cefepime (FEB), ampicillin-sulbactam (SAM), tobramycine (TOB), netilmycine (NET),and amikacin (AK) according to the Clinical and Laboratory Standards Institute (CLSI) recommendations. Results: All A. baumannii strains isolated from the patients in intensive care units were found to be multidrug resistant . Varying propotion of antibiotic resistance were determined in multidrug resistant A.baumannii strains. There was no resistance to colistin whereas the resistance rate for tigecyline was 6%. The resistance rates were found to be %87 DOR, %92 for TZP, and %89 for CES by E-test . The resistance rates were found to be %94 for IMP, %90 for MEM, %95 for TIM, %100 for CIP, %97 for FEB, %91 for SAM %91, %79 for NET, %82 for AK and %90 for TOB by Kirby-Bauer disk diffusion method.The minimum inhibitory concentration (MIC) 50 and MIC90 values of isolated strains to CO, TG, DOR, CPS and TZP were ; 0.125,0.75; 0.75,24; 24, 128; 32,128 ; 128,256, respectively. Conclusion: Considering to the MIC50 and MIC90 values, colistin and tigecyline were determined to most effective antibiotics for MDR A.baumannii strains isolated from various culture samples of intensive care unit patients. The high antibiotic resistance rates for carbapenems, TZP and CES were remarkable As a result, to prevent MDR A. baumannii infections in intensive care units infection control measures to be implemented carefully, monitoring of rational antibiotic therapy and antibiotic resistance rates are required.