Empiric therapy of severe infections in adults

The third-generation cephalosporins are useful for empiric therapy of most of the severe infections in adults as a result of their broad spectrum of antimicrobial activity (particularly against clinically important gram-negative bacteria), good tissue penetration, and lack of serious adverse effects. This review examines their use in respiratory tract infections, bacterial meningitis, skin-structure infections, and urinary tract infections in adult patients. Penicillin G remains the optimal therapy for severe community-acquired pneumonia, since Streptococcus pneumoniae still accounts for the majority of cases. However, for empiric treatment of nosocomial pneumonia, therapy must ensure coverage both of aerobic gram-negative bacilli and Staphylococcus aureus. The choice of empiric antibiotic therapy in the treatment of urinary tract infections depends on the pattern of resistance in the patient's environment. At present, the treatment of bacterial meningitis in otherwise healthy adults does not constitute a major problem provided that penicillin resistance among pneumococci and meningococci (responsible for at least 80 percent of cases) does not become a clinical problem. However, in meningitis in which gram-negative bacilli are suspected and where specific problems include antibiotic resistance among these organisms and the inadequate penetration of many antibiotics into the cerebrospinal fluid, third-generation cephalosporins are the drugs of choice, and they have markedly improved the clinical outcome. Most skin-structure infections are due to S. aureus and are best treated by an anti-staphylococcal penicillin or an older cephalosporin. Nevertheless, the third-generation cephalosporins have proved to be highly effective agents for infections of skin and soft-tissue infections associated with both gram-positive and gram-negative pathogens in patients at risk from these organisms or in the elderly.