Investigation of the presence of metallo-beta-lactamase enzyme in two different phenotypic methods in carbapenem resistant Acineobacter baumannii strains isolated from clinical specimens

Aim: Acinobacter baumannii strains are nosocomial infections that can develop resistance to many antibiotic strains. One of the mechanisms of resistance of the carbapenem group to anobiotics in A.baumannii strains is the production of meallo-beta-lactamase enzyme. Metallo-beta-lactamase enzymes (VIM, IMP, etc.) are enzymes that inhibit all beta- lactamases outside of aztreonam and require zinc ions. The aim of this study is to investigate the presence of metallo-beta-lactamase in carbapenem resistant A. baumannii strains by two different phenotypic methods. Material and Method: The study included 82 A. baumannii strains isolated in various clinical specimens resistant to carbapenem. Bacteria identification was performed using conventional manners and an automated system from BD Phoenix (Becton Dickinson, USA). Antibiotic susceptibility tests were determined by disc diffusion method in accordance with the EUCAST recommendation. MBL presence was investigated by the combined disc method and the modified Hodge test. Results: MBL enzyme was detected by combined disc method in 3 of carbobehim resistant 82 A.baumannii strains (3.7%), whereas unde MBL production was detected in 27 of 70 A. baumannii strains tested (Modifiye Hodge test) Conclusion: In our hospital, MBL enzyme positivity was detected at low rate by combination disc method in carbapenem resistant A. baumannii strains, but it was detected high with the modified Hodge test. No correlation was found between the two methods. In conclusion, it would be appropriate to identify the presence of MBL enzyme by molecular methods which are the reference methods and to determine which of the two phenotypic methods is more appropriate