Frequency of carbapenem resistance and oxa type beta-lactamases in clinical acinetobacter baumannii isolates

This study aimed to determine the antimicrobial susceptibility of A. baumannii strains and to elucidate the presence of OXA (Oxacilinase) type beta-lactamases that have carbapenem hydrolyzing activity. A total of 121 A. baumannii strains isolated from different clinical samples were used in the study. All isolates were identified by automated systems and susceptibility tests were performed. The blaOXA genes were detected by molecular methods. As a result of susceptibility tests, most of these isolates were found to be resistant to many antimicrobial agents, except colistin and tigecycline. The resistance against carbapenems which is a common choice for the treatment of infections caused by multi drug resistant Acinetobacter species was quite high. Among OXA-type enzymes blaOXA-51 genes encoding oxacillinases were detected in all A. baumannii isolates, whereas 19% of strains were coding blaOXA-58 genes and 17.4% were carrying blaOXA-23 genes. The carbapenem resistance rates were observed relatively high in A. baumannii strains and this problem seems to grow increasingly. Also the presence of OXA type enzymes in A. baumannii emphasizes the importance of preventing the spread of these resistant organisms and the need to control the common use of carbapenems in the near future.