Detection of 22 beta-lactamase genes and enzyme activities in multi-drug resistant Acinetobacter baumannii / 中华临床感染病杂志

ABSTRACT

Objective To investigate the distribution of 22 beta-lactamase genes and enzyme activities in multi-drug resistant Acinetobacter baumannii (MDRAB). Methods Sixty-two MDRAB strains were isolated from the First Affiliated Hospital, College of Medicine, Zhejiang University. Twenty-two beta-lactamase genes were analyzed by PCR and verified by DNA sequencing. Enzyme activities of extended spectrum beta-lactamases (ESBLs) , cephalosporinase ( AmpC) and metallo-beta-lactamases ( MBL) were detected by the modified three-dimensional method using enzyme extraction. Results In 62 MDRABs, 51 (82.3% ) , 50 (80.6% ) and 36 (58.1% ) isolates were found to carry blaTEM, blaOXA-23 cluster, and blaADC, respectively. The rest 19 genes were not detected in this study. DNA sequencing and genomic comparison showed that 5 isolates carrying blaTEM had the same genotype as blaTEM-l , 6 isolates carrying blaOXA-23 cluster had the same genotype as blaOXA-23 carbapenemases (accession; CAB69042. 1) , and 2 isolates carrying blaADC had the same genotype as blaADC-like (accession EU081908). Thirty-two isolates (51.6% ) produced ESBLs and AmpC, 19 isolates (30.6% ) produced ESBLs only, and 1 isolate (1.6%) produced AmpC only; and no isolate produced MBL. Conclusion MDRAB carrying blaOXA-23 carbapenemase and blaADC AmpC in this study are of high drug resistance.