Objective    To investigate the molecular epidemiology and drug resistance mechanism of carbapenem-resistant

Acinetobacter baumannii

(CRAB).     Methods    Antimicrobial susceptibility was tested on 51 strains of

Acinetobacter baumannii

isolated in our hospital from January to December 2008 by Kirby-Bauer method. The results were assessed according to the standards recommended by CLSI (2008). The homology of 51 isolates of CRAB was determined by randomly amplifie

d polymorphism DNA (RAPD). The genotype of TEM

SHV

CTX-M

IMP-1

IMP-2

VIM

VIM-2

OXA-23

OXA-24 and class Ⅰ

Ⅱ integrase (Int-1 and Int-2) was detected by polymerase chain reaction (PCR).     Results    These 51 strains

Acinetobacter baumannii

were all multi-drug resistant

and were resistant to most antibiotics except amikacin. Among them

50 strains were the same clone. Positive rate of these strains to TEM

SHV

CTX-M

IMP-1

VIM-2

OXA-23 and Int1 was 98.0%

23.5%

19.6%

25.5%

19.6%

72.5%

and 86.3%

respectively. But no genotype of IMP-2

VIM

OXA-24 and Int-2 was detected.     Conclusion    The stain of CRAB with TEM

OXA-23

IMP-1

VIM-2 and Int-2 genotypes breaks out in our hospital. Its production of OXA-23 carbapenemase and metallo-β-lactamase might be the main mechanisms of carbapenem resistance .