A reactive antibacterial compound is represented by formula (I) or (II): wherein R1 represents OCN-L-NHCOOR′, OCN-L-NHCONHR′, OCN-L-NHCOSR′, OCN-L-COOR′, or OCN-L-COONHR′. G1 represents OCN-M-NHCOOG′, OCN-M-NHCONHG′, OCN-M-NHCOSG′, OCN-M-COOG′, or OCN-M-COONHG′. L, M, R′ and G′ independently for each occurrence represent divalent alkyl and cycloalkyl having from 1 to 18 carbon atoms, optionally substituted by up to 18 heteroatoms. R4 and G4 independently for each occurrence represent a divalent alkyl and cycloalkyl having from 1 to 18 carbon atoms, optionally substituted by up to 18 heteroatoms. G2 and G3 independently for each occurrence represent —H, —F, —Cl, —Br, —I, —OCH3, —OCH2CH3, —OPr, —CN, —SCN, —NO, —NO2, a monovalent unsubstituted or substituted alkyl, cycloalkyl, or aryl having from 1 to 7 carbon atoms. Z and X independently for each occurrence represent —COO, —SO3, or —OPO2OR5. R5 represents a monovalent unsubstituted or substituted alkyl, cycloalkyl, or aryl having from 1 to 6 carbon atoms.