Detection on the Resistance and Genotype of β-Lactamases in Acinetobacter Baumannii Isolated from Burn Units

Objective:To investigate the antimicrobial resistance and the genotype of the plasmid-mediated β-Lactamases -encoding genes of acinetobacter baumannii isolated from burn units in the 98th hospital of PLA.Methodes:Microdilute tests were performed to detect the susceptibility of 24 kinds of antimicrobial agents against 141 strains of acinetobacter baumannii.TEM,SHV,CTX-M-1,CTX-M-2,CTX-M-9,OXA,PER and VEB genotypes of β-Lactamases were analyzed by PCR and verificated by DNA sequencing in 11 of 141 isolates tested. Results:There was no strain resistant to cefoperazone/ sulbactam. The resistant rates to imipeneme, meropeneme , polymyxin E and piperacillin/ tazobactam were 3.5%,3.8%,5.4% and 41.1% respectively. The resistant rates to cefepime,ceftriaxone, ceftazidime, aztreonam, cefotaxime and cefoperazone were between 55.2% and 73.2%. The resistant rates to other antimicrobial agents were more than 50%.TEM type β-Lactamases genes were positive in all of the 11 isolates tested, 6 of which were TEM-1. SHV type β-Lactamases genes were positive in 2 of 11 isolates tested, they were SHV-12. Conclusions:The multiple-drug-resistance of acinetobacter baumannii isolated from burn units in the 98th hospital of PLA is a serious issue and at least 2 kinds of β-Lactamases genes exsisted including TEM-1 and SHV-12. To deal with the infection which strains cause, such antimicrobial as carbapenems,cefoperazone/sulbactam, polymyxin E and others which are sensitive to such strains can be used on the basis of the sensitive test of antimicrobial.