CLONING AND SEQUENCING OF THE GENE ENCODING THE AMPC BETA-LACTAMASE OF MORGANELLA-MORGANII

The chromosomal beta-lactamase gene of a clinical isolate of Morganell a morganii was cloned in Escherichia coli and sequenced. The beta-lact amase had a pI of 7.4 and conferred a typical AmpC susceptibility patt ern. The insert obtained was found to encode a protein of 379 amino ac ids. Its deduced amino acid sequence revealed it to be a class C beta- lactamase: 39-56% identity with chromosomal AmpC beta-lactamases of Se rratia marcescens, Yersinia enterocolitica, Citrobacter freundii, Ente robacter cloacae and Escherichia coli; and 37-56% identity with plasmi d-mediated beta-lactamases (MOX-1, CMY-1, FOX-1, ACT-1, LAT-1, BIL-1 a nd CMY-2). The ampC gene was linked to a gene only part of which (450 bp) was cloned homologous to the regulatory ampR genes of chromosomal class C beta-lactamases.