[Characterization of plasmids in Escherichia coli strains].

BACKGROUND Strains of Escherichia coli are frequently plasmid carriers. In this species, resistance to beta-lactam antibiotics is almost always conditioned by the production of enzymes coded by plasmidic genes. The present is a study of the plasmids of 44 ampicillin-sensitive strains and 134 ampicillin-resistant (ampS and ampR). The possibility that the… CONTINUE READING