Clinical isolates of Acinetobacter baumannii from bloodstream infections: PFGE characterization and virulence-associated factors / 中华检验医学杂志

ABSTRACT

Objective The epidemiology of Acinetobacter baumannii isolates from bloodstream infections,their antibiotic resistance profiles and virulence-associated factors were studied.Methods A total of 90 isolates from 17 hospitals were collected from the patients with bloodstream infections during July 2013 and July 2014.Vitek-2 Compact system was used for identification of the strains and antibiotic susceptibility testing.The epidemiology was studied by pulsed-field gelectrophoresis(PFGE).Drug-resistant genes and associated virulence genes were amplified by PCR.Results According to antimicrobial susceptibility testing,75 isolates are multi-drug resistant Acinetobacter baumannii.PFGE results showed that 75 multi-drug resistant Acinetobacter baumannii isolates belonged to eight clone types(A to H),with the A (n=51)and B (n=14)clone being the dominant PFGE clone types.Different clone isolates spread in different hospitals.Most of the hospitals were given priority to with clone A.Clone A only maintaining high sensitive rate to cefoperazone/sulbactam、amikacin and tigecycline.Virulence gene abaI,cusE,ompA,bap,bfms detection rates are 93.3% (84/90),92.2% (83/90),100.0% (90/90),84.4% (76/90),92.2% (83/90),respectively.There were 7 mucoid isolates,which are all multi-drug resistant Acinetobacter baumannii,all belong to clone B and all associated virulence genes can be detected.Conclusions The dominant clone type of multi-drug resistant Acinetobacter baumannii from bloodstream infections is clone A.The abaI-,bap-and bfms-positive strains are associated with a higher incidence of antibiotic resistance in most types of antimicrobials.The acquisition of mucous type may indicate the emergence of virulent strains,which should be paid attention to during clinical treatment.