Determination of Colistin and Tigecycline Resistance Profile of Acinetobacter Baumannii Strains from Different Clinical Samples in a Territory Hospital in Turkey

Abstract

Objective: Acinetobacter baumannii (A. baumannii) can develop resistance to various antimicrobial agents via different mechanisms. Hence, the aim of this study was to investigate, by using different methods, the resistance profiles of A. baumannii strains isolated from different clinical specimens; from colistin and tigecycline antibiotics, and also the distribution of this resistance according to the clinical samples. Material and Methods: For this study, 1,265 clinical samples (a samples from each patient) were obtained from various clinics, between; January 2015/December 2018. Identification was conducted by VITEK® 2 compact (bioMerieux, USA) and conventional biochemical tests. Antibiotic susceptibility tests were performed by VITEK 2, and the results of colistin and tigecycline were confirmed by E test and the broth microdilution method. Results: A. baumannii strains (1,265) were most frequently isolated from tracheal aspirate, sputum and blood samples. At the same time, strains were obtained from intensive care units (70.4%) as well as other clinics (29.6%). The rates of colistin and tigecycline-resistant strains were determined using VITEK 2, E test and the broth microdilution methods as: 3.0%, 5.7%, 9.0% and 21.7%, 24.5%, 33.0%, respectively. Conclusion: The determination of appropriate antibioticis are important for empirical treatment. Colistin and tigecycline have become prominent as an important, alternative agent in the treatment of A. baumannii-related infections. The results of this study show that colistin and tigecycline resistance rates in intensive care units have been increasing gradually over the years. Monitoring of resistance patterns of nonfermentative bacteria, isolated from intensive care units, is important for the immediate initiation of appropriate empirical treatment. In-vitro studies with A. baumannii strains should also be supported by clinical trials.