Acinetobacter species and their antibiotic resistance profiles isolated from various clinical specimens between 2014 and 2018

Aim: Acinetobacter species have emerged as an important cause of nosocomial pneumonia and bloodstream infections, especiallyin immunocompromised patients with underlying pathologies. Worldwide, there has been a marked increase in resistance to mostantimicrobial agents in recent years. The aim of this study was to evaluate Acinetobacter spp., their antimicrobial resistance ratesand changes in resistance rates isolated from a tertiary hospital in a five-year period.Material and Methods: In this study, Acinetobacter strains isolated from inpatients or outpatients between January 2014 andDecember 2018 were included in the Medical Microbiology Laboratory of our hospital. BD Phoenix 100 (Becton Dickinson, USA) wasused for identification and antibiotic susceptibility of the isolates.Results: Acinetobacter baumannii and A. baumannii - A. calcoaceticus complex constituted 91% of all isolates. Acinetobacter strainswere mostly isolated from inpatients with pneumonia (37%) and soft tissue infections (22.5%). Colistin resistance was not observedbetween 2014 and 2016, but it was detected in 2017 and 2018. Colistin resistance was 2.5% and 12.6% in A. baumannii and 2.9% and13.5% in A.baumannii-calcoaceticus complex in 2017 and 2018, respectively, and this increase was statistically significant. Colistinand tigecycline were the most effective agents in all isolates. The resistance rates of tigecycline in A.baumannii and A.baumanniicalcoaceticus complex strains were 11% and 14.3%, respectively. Extensively drug-resistant isolates were 91.7% and pan drugresistant isolates were 2.3%.Conclusion: It has been observed that resistance to all used drugs including colistin in Acinetobacter species increased and the rateof pan drug-resistant isolates were also elevated. Especially the significant increase in colistin resistance observed in recent yearsraises concern. In order to prevent and cope with the development of multiple resistance, each laboratory should determine thedistribution of resistance in Acinetobacter species and in particular resistance to colistin.

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