 Cefotiam inhibits final cross-linking stage of peptidoglycan production, thus inhibiting bacterial cell wall synthesis.It has similar or less activity against Gram-positive staphylococci and streptococci, but is resistant to some beta-lactamases produced by Gram-negative bacteria.It is more active against many of the Enterobacteriaceae including "Enterobacter, E. coli, Klebsiella, Salmonella" and indole-positive "Proteus" species.