Antimicrobial agents targeting bacterial cell walls and cell membranes

Antimicrobial agents that target the bacterial cell wall or cell membrane have been used effectively for the past 70 years. Among the agents that inhibit bacterial cell wall synthesis, the beta-lactam antibiotics have emerged into broad-spectrum agents that inhibit most pathogenic bacteria, but are now being threatened by the rapid spread of drug-inactivating beta-lactamases. Glycopeptides still retain high activity against staphylococci, but resistance among the enterococci has become a major problem. Recently, fosfomycin has been used in the treatment of multidrug-resistant Gram-negative bacteria. Daptomycin, which targets both membrane function and peptidoglycan synthesis, is especially effective in treating staphylococcal infections. The polymyxin antibiotics that target cell membranes are being used more frequently to treat multidrug-resistant Gram-negative infections. The ionophore antibiotics, used in veterinary medicine, target membranes in many microbial and animal species. Although increasing resistance is a continuing concern, these classes of bactericidal agents can provide highly effective antibiotics.