Evaluation of Antibiotic Resistance Patterns and Frequency of Carbapenemase-Producing Acinetobacter baumannii Isolates by the Carbacineto NP Test

ABSTRACT Background and Objectives: Acinetobacter baumannii is an opportunistic pathogen associated with nosocomial infections. Treatment of infections caused by this bacterium has become challenging due to increasing rate of resistance to a wide range of antibiotics such as carbapenems. One of the main mechanisms of resistance to carbapenems is the production of carbapenemase. The objective of this study was to evaluate antibiotic resistance patterns and frequency of carbapenemase-producing A. baumannii strains using the CarbAcineto NP Test. Methods: In this descriptive cross-sectional study, 130 A. baumannii isolates were collected from clinical specimens of teaching hospitals in Zahedan in 2016. After determining the antibiotic resistance patterns, all A. baumannii isolates were examined using the phenotypic method of CarbAcineto NP test to evaluate production of carbapenemase enzymes. Results: Based on the antibiogram results, more than 90% of the isolates were resistant to the antibiotics tested in this study. However, the lowest rate of resistance was observed against colistin, minocycline, tigecycline and doxycycline, respectively. Based on the results of the CarbAcineto NP test, 96% of carbapenem-resistant strains were positive for the production of carbapenemases. Conclusion: Due to the high resistance of A. baumannii to carbapenems, they are not currently suitable for the treatment of infections caused by this bacterium. However, since most carbapenem-resistant strains are susceptible to colistin, minocycline, tigecycline, and doxycycline, these antibiotics or their combination are recommended for the treatment of the infections caused by the resistant strains. Rapid identification of carbapenemase-producing bacteria using efficient methods such as CarbAcineto NP test is essential to prevent their spread, particularly in hospitals. KEYWORDS: Acinetobacter baumannii, Carbapenemase, CarbAcinetoNP Test