Plasmid-mediated and inducible cephalosporinase DHA-2 from Klebsiella pneumoniae

A Klebsiella pneumoniae strain resistant to cefoxitin and oxyimino-cephalos porins was cultured from a child hospitalized in Paris, France, in 1992. Th is isolate harboured a beta -lactamase gene located on an approximately 200 kb non-self-transferable plasmid. The beta -lactamase identified, DHA-2, s hared 99% amino acid identity with the AmpC enzyme of Morganella morganii. DHA-2 was a point-mutant derivative of DHA-I identified previously in a Sal monella enteritidis isolate. DHA-2 expression was inducible due to an ampR regulatory gene. This is the first report of an inducible and plasmid-locat ed cephalosporinase from K. pneumoniae.