The Investigation of Clonal Relationship Among Multiple Drug Resistant Acinetobacter baumannii Isolates with Pulsed-Field Gel Electrophoresis

Background: With this study, the detection of the resistance rates of A.baumannii strains isolated from the patients in the intensive care units to the antibiotics and the demonstration of the clonal relationship of the isolates with multi-drug resistant of the factor of nosocomial infection were aimed by using the method of pulsed-field gel electrophoresis (PFGE). Materials and Methods: At the Medical Faculty Hospital of Yüzüncü Yıl University, 69 patients followed between January 2010-October 2011 at the Intensive Care Unit of Anesthesiology and Reanimation (ICUAR), Intensive Care Unit of Chest Diseases and Pediatric Intensive Care Unit and July-November 2012 at ICUAR and the same number of isolates formed with A.baumanii, Ventilator Associated Pneumonia (VAP) and diagnosis of Primary Bloodstream Infection (PBI) were enrolled to the study. Results: Of the 69 patients included in the study, 35 were men (50.7%) and 34 (49.3%) were women. The ages of the patients ranged from 1 to 86 years (mean age 54). 63 (91%) of the patients were diagnosed with VAP and 6 (9%) of them with PBI. At least two invasive interference had been performed to the all patients during the staying at the ICU. Urinary catheterization (100%), mechanical ventilation (94.2%) and peripheral venous catheterization (91.3%) were the most frequently performed invasive interferences. Antibiotic susceptibilities to imipenem, colistin and tigecycline were studied with the E-test and to the other antibiotics with the disk diffusion. Colistin was the most effective antibiotic for all of the strains (98.6%). Then, tigecycline (97.1%) and levofloxacin (69.6%) were in the second place. All of the strains were resistant to ceftriaxone, piperacillin/tazobactam, meropenem and imipenem. With the PFGE analysis of A.baumannii isolates performed to the genomic DNA cut with ApaI, it was found that 62 of the 69 A.baumannii strains (89.9%) were within the cluster. These strains were located within 16 clusters. 7 of the strains (10.1%) showed the profiles of specific PFGE and 23 pulsotip were detected among the strains. Conclusion: Being high of clustering rate of multidrug-resistant A. baumannii isolates and isolating the isolates in similar genotypes from the patients in different units is the indicator of these bacteria to be endemic situation in the ICUs of our hospital. If precautions are not taken, A. baumannii has been able to remain in the hospitals for many years and can be easily transmitted among the patients. Especially for the prevention of cross-contamination, the necessity and importance of infection control programs have once again emphasized.