Study on the homology of imipenem-resistant Acinetobacter baumannii and the genotype of carbapenemase
- VernacularTitle:亚胺培南耐药鲍曼不动杆菌同源性及碳青霉烯酶研究
- Author:
Xiao-Xing DU
;
Xing-Guo ZHANG
;
Hua ZHOU
;
Yun-Song YU
;
Ya-Gang CHEN
;
Lan-Juan LI
;
- Publication Type:Journal Article
- Keywords:
Acinetobacter baumannii;
Carbapenemase;
Pulsed-field gel electrophoresis
- From:
Chinese Journal of Infection and Chemotherapy
2006;0(04):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To characterize the antibiotic resistance,homology and carbapenemase genotypes of imipenem resistant Acinetobac1ter baumannii isolated from our hospital,and analyze the clonal relatedness of the test strains.Methods Ninety five strains of imipenem resistant A.baumannii were isolated from August 2003 to December 2004 in the First Affiliated Hospital, College of Medicine,Zhejiang University.The MICs of 16 antimicrobial agents against these strains were determined by agar dilution and E-test method.The homology of these isolates was analyzed by pulse-field gel electrophoresis(PFGE).The coding gene of carbapenemases was amplified.PCR products were purified,cloned and sequenced.Plasmid DNA was extracted and purified.Conjugation and Southern blot were performed to locate the position of oxa 23 gene.Results The resistance rates to ampicillin-sulbactam and cefoperazone sulhactam were 67.9% and 30.2%.Polymyxin E had the lowest resistance rate of 17%. The resistance rate to other antimicrobial agents was higher than 90%.The 95 strains,isolated from 10 clinical units,were classified into 6 clones.Clones A and B were predominant clones.All strains produced carbapenemases which were confirmed as OXA 23 by PCR and sequencing analysis.No plasmid was extracted and conjugation was not successful.Southern bolt showed that oxa-23 gene was located on Apal-digested chromosomal segments about 220 kb and 200 kb in Clones A and B,re spectively.Conclusions OXA 23-producing A.baumannii has become one of the most important multi-resistant pathogens in our hospital.Clones A and B have widely spread in our hospital.Oxa-23 gene is located on chromosomal DNA.
