| novel cefotaximase (ctx-m-16) with increased catalytic efficiency due to substitution asp-240-->gly. | three clinical strains (escherichia coli rio-6, e. coli rio-7, and enterobacter cloacae rio-9) collected in 1996 and 1999 from hospitals in rio de janeiro (brazil) were resistant to broad-spectrum cephalosporins and gave a positive double-disk synergy test. two bla(ctx-m) genes encoding beta-lactamases of pl 7.9 and 8.2 were implicated in this resistance: the bla(ctx-m-9) gene observed in e. coli rio-7 and e. cloacae rio-9 and a novel ctx-m-encoding gene, designated bla(ctx-m-16), observed in e. ... | 2001 | 11451684 |