Abstract: Cephem and penem compounds having a styrylmethylene moiety at the 3-position in the cephem or penem ring to which a positively charged leaving group is bonded and wherein the leaving group contains a vicinal diol or is bonded to a unsubstituted or substituted catechol. The leaving group can be a positively charge nitrogen leaving group. Cephems include cephalosporins, cephamycins, carbacephems, and oxacephems. Penems include penems, carbapenems and oxapenems. Preferred cephems are cephalosporins. Preferred penems are carbapenems. Compounds exhibit antibiotic activity against Gram-negative bacteria and/or Gram-positive bacteria. Compounds exhibit antibiotic activity against bacteria which exhibit multi-drug resistance. Compounds of the invention exhibit antibiotic activity against bacterial strains which produce extended spectrum beta-lactamases (ESBL), which produce AmpC beta-lactamases or which produce a carbapenemase.