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 showedpandrug 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.