Drug Resistant Acinetobacter Baumannii: Pattern of Infection and In Vitro Tigecycline Activity

Abstract

Objective: The purpose of this study is; firstly, to find out the prevalence of drug resistant Acinetobacter baumannii, secondly, to find the most common site of infection by Acinetobacter baumannii, and thirdly, to assess the in vitro effectiveness of tigecycline against drug resistant Acinetobacter baumannii, in our hospital setting. Study Design: Retrospective/Observational study. Setting: Charsada Teaching Hospital affiliated with Jinnah Medical College Peshawar. Period: One year from January 2016 to December 2016. Methodology: All the reports occurring during this study period with positive diagnosis for Acinetobacter were retrieved from the archives, irrespective of patient’s age and gender. Only one isolate of Acinetobacter per patient was considered in the study. The organisms were identified and species determined manually. Susceptibility for antimicrobial agents was determined according to criteria of CLSI 2016. MIC for tigecycline in the isolates was determined by E-test. Results: On analyzing all the Acinetobacter isolates (n=391) during one year time, it was found that the large majority of these isolates were of Acinetobacter baumannii (96.2%), while only few were of Acinetobacter lwoffii (3.8%). Multidrug resistant Acinetobacter baumannii represented about one third (31%) of all the Acinetobacter baumannii isolates. Most of the isolates of Acinetobacter baumannii were from skin and soft tissue wounds (44.4%), followed by isolates from respiratory secretions (42.7%), urine (6.8%), blood (5.2%) and CSF (0.9%) (Table II). The isolates of Acinetobacter baumannii showed maximum sensitivity to Tigecycline (88.9%), followed by Colistin (81.2%) and Polymyxin (79.5%) (Table III). Conclusions: Drug resistant Acinetobacter baumannii is present in 31% of isolates, it is most commonly isolated from infected wounds and respiratory tract secretions in debilitated patients, and also Tigecycline is an excellent treatment choice for infections caused by drug resistant Acinetobacter baumannii.