Abstract
SUMMARY: Plasmid pBP11 contains a sequence homologous to Tn21-like element Tn2410 encoding dihydropteroate synthetase and β-lactamase OXA-2. The nucleotide sequence of a 1.5 kb segment of this region has been determined including the bla gene. It reveals strong sequence homology with the OXA-2 operon of plasmid R46. The implications of an additional 319 bp segment in pBP11 for the different evolution of R46/pKM101 and pBP11 are discussed.