Phenotypic Characterization of Extended-Spectrum Beta-Lactamases and Metallo-Beta-Lactamase of Multi Drug Resistant Acinetobacter baumannii Causing Nosocomial Infections in Erbil City

Abstract

Background: Resistance to broad‑spectrum beta‑lactams, mediated by extended‑spectrum beta‑lactamases, and metallo‑beta‑lactamase enzymes, is an increasing problem worldwide. The main aim is to study phenotypic characterization of extended‑spectrum beta‑lactamases and metallo‑beta‑lactamase multidrug resistant Acinetobacter baumannii in Erbil City. Materials and Methods: A total of 112 Acinetobacter baumannii isolations were collected from patients of all age groups from clinical specimens sputum, blood, pus, wound swab, urine and body fluids (Pleural fluid and cerebrospinal fluid) collected from different medical wards and intensive care unit departments of hospitals in Erbil City for a period of one year from march 2018--march 2019. Isolates were tested for the presence of extended‑spectrum beta‑lactamases and metallo‑beta‑lactamase. Detection of extended‑spectrum beta‑lactamases was done by the combined disk diffusion method according to Clinical and Laboratory Standards Institute guidelines, while metallo‑beta‑lactamase was detected by meropenem and imipenem combined with ethylenediaminetetraacetic acid disk method. Results: 25% (28) Acinetobacter baumannii isolates were positive for extended‑spectrum beta‑lactamases, while 100 % (112) were metallo‑beta‑lactamase producers. Conclusion: Acinetobacter baumannii is becoming a global medical challenge due to the emergence of multi-drug resistance. Newer beta lactamase is a matter of concern as they are developing rapidly and lead to treatment failure. Carbapenems are known to be effective therapeutic agents for Acinetobacter baumannii infections and its resistance limits the use to polymyxins and colistin. Several new medicines are still in research and combination of drug therapy is being currently used in the hospitals together with ours to treat multidrug resistant Acinetobacter baumannii infections.