Tandem amplification of a 28-kilobase region from the Yersinia enterocolitica chromosome containing the blaA gene.

ABSTRACT: Most Yersinia enterocolitica strains are resistant to beta-lactam antibiotics due to the production of one or two chromosomally encoded beta-lactamases. Strain Y56 is a Y. enterocolitica O:3 serotype natural isolate that is resistant to moderate amounts of penicillins and that produces a single class A beta-lactamase. To select mutants with increased levels of resistance to beta-lactam antibiotics, strain Y56 was grown on plates containing increasing amounts of ampicillin, and variants resistant to up to 500 micro g of ampicillin per ml were obtained. Chromosomal DNA from hyperresistant isolates was analyzed by Southern hybridization with a blaA-specific probe to detect gene rearrangements. The use of pulsed-field gel electrophoresis revealed that the increase in the resistance level corre

SUBMITTER: Seoane A 

PROVIDER: S-EPMC151765 | biostudies-literature | 2003 Feb

REPOSITORIES: biostudies-literature