Evaluation of Antibiotic Susceptibility, Carbapenemase and Metallobetalactamase-producing Strains of Acinetobacter baumannii Isolated from Hospitalized Patients in Zahedan During 2019 - 2022

Background: Microbial resistance caused by Acinetobacter baumannii, which leads to various infectious diseases, is projected to result in ten million deaths by 2050. This is mainly due to the production of beta-lactamase enzymes, a significant concern for the World Health Organization. Objectives: This study utilized phenotypic analysis to examine isolates producing metallo-beta-lactamase and carbapenemase and to determine the pattern of antibiotic resistance in Acinetobacter baumannii. Methods: Following the isolation and identification of 372 Acinetobacter baumannii strains from clinical isolates using a variety of biochemical tests, the antibiotic resistance pattern was examined using the disc diffusion method. The production of beta-lactamase and carbapenemase was determined using the combined disc diffusion phenotypic test (CDDT) and the Modified Hodge Test (MHT), respectively. Results: Based on this study, minocycline (7.4%) exhibited the lowest resistance rate, while carbapenems (imipenem and meropenem) showed the highest resistance. All antibiotic groups demonstrated over 80% resistance, suggesting extensive drug resistance in all samples. Furthermore, 325 (94.6%) strains of Acinetobacter baumannii produced metallo-beta-lactamase, 215 (57.7%) strains strongly produced carbapenemase, and 135 (36.1%) strains weakly produced carbapenemase. Conclusions: Due to minimal resistance to colistin, minocycline, and ampicillin-sulbactam, it is advisable to use these drugs either individually or in combination for treatment.