Carbapenem-hydrolyzing Oxacillinase Genes in Clinical Isolates of Acinetobacter baumannii
Mona Embarek Mohamed *
Department of Microbiology and Immunology, Faculty of Medicine, Assiut University, Egypt.
Alaa Thabet Hassan
Department of Chest diseases, Faculty of Medicine, Assiut University, Egypt.
Soheir Mostafa Kasem Ahmed
Department of Internal Medicine, Faculty of Medicine, Assiut University, Egypt.
*Author to whom correspondence should be addressed.
Abstract
Aims: We aimed in this study to detect the prevalence of carbapenem-hydrolyzing oxacillinase genes among Acinetobacter baumannii clinical isolates recovered from Assiut University Hospitals, Egypt.
Methods: The antimicrobial susceptibilities of 23 non-repetitive Acinetobacter baumannii clinical isolates collected from patients with multiple types of infections were determined. Amplification of blaOXA-23, blaOXA-51, and blaOXA-58 genes was performed by PCR.
Results: Acinetobacter baumannii isolates showed high resistance to carbapenems and other antibiotics. Eleven (48%) isolates were extensively drug resistant and 12 (52%) isolates showed pandrug resistance. Among 23 Acinetobacter baumannii strains; oxacillinase genes were detected in 19 (83%) strains, none of the examined genes were found in 4 (17%) strains. Twelve (52%), 9 (39%), and 4 (17%) isolates harbored blaOXA-51, blaOXA-23, and blaOXA-58 genes, respectively, either in single form (12 isolates; 52%) or combined (7 isolates; 30%). blaOXA-producers associated with longer hospital stay and poor outcome. A. baumannii isolates expressed blaOXA-23 and blaOXA-58 genes, had higher MIC for carbapenems than blaOXA-51 gene.
Conclusion: We concluded that, the presence of oxacillinase genes, especially blaOXA-23 and blaOXA-58, may convey resistance to carbapenems in Acinetobacter baumannii isolates and are associated with high comorbidities and poor outcome in patients.
Keywords: Acinetobacter baumannii, oxacillinases, blaOXA-23, blaOXA-51, blaOXA-58