A hospital epidemic caused by a multiple antibiotic resistant Klebsiella pneumoniae: implication of a conjugative R plasmid.

: A R-plasmid of about 65 X 10(6) Md was found in several Klebsiella pneumoniae strains, responsible for an outbreak at the Lancisi Cardiological Hospital in Ancona. This plasmid was self-transferable and carried a "core" of resistance markers to ampicillin, carbenicillin and streptomycin; to this "core" the resistance markers to chloramphenicol, tetracycline, kanamycin and gentamicin can individually link, without appreciable changes in the molecular weight. We think that these Klebsiella pneumoniae strains are a potential reservoir of plasmid-mediated antibiotic resistance.