MOLECULAR CHARACTERIZATION OF ACINETOBACTER BAUMANNII ISOLATES IN HUE CENTRAL HOSPITAL AND HUE UNIVERSITY HOSPITAL

Abstract

Introduction: Acinetobacter baumannii resistant to carbapenem is the most common cause of nosocomial infection, they are recognized as one of the most difficult to control and treat resistant agents. A. baumannii is the most important member of A. calcoaceticus- A. baumannii complex (ACB complex), which are closely related genetically then biochemical test systems are not able to identify unambiguously genomic species. Objective: To identify species of Acinetobacter sp. strains of ACB complex and sequence types of A. baumannii strains. Methods: Cross- sectional study. The subjects were 90 strains of ACB complex isolated and identified by biochemical methods at Hue University Hospital (UH) and Hue Central Hospital (CH). Performing the multiplex PCRs on the target gene gyrB and sequencing rpoB gene to identify species. Determining of antibiotic resistance by Kirby-Bauer method. Multi Locus Sequence Type (MLST) method was performed for 24 strains of A. baumannii to identify sequence types. Results: Acinetobacter sp. were identified as A.bau-mannii (85.6%), A. nosocomialis (11.11%) and A. pittii (3.33%). All strains of ACB complex were sensitive to colistin and resistant to cefotaxime, amikacin. More than 90% of A.baumannii strains were resistant to carbapenem. Eleven sequence types (STs) of A.baumannii strains were identified; two of them were news (ST1463 and ST1464) and seven STs belonged to the Clonal Complex 92 (CC92), the most globally distributed clones; the ST795, ST797 and ST1463 are circulating in both of hospitals. Conclusion: Combining multiplex PCRs on the target gene gyrB and sequencing rpoB gene have shown to be adequate for Acinetobacter sp.identification. MLST identified 11 sequence types from 24 A.baumannii isolates at two hospital in Hue. Key words: ACB complex, Acinetobacter baumannii, MLST