The use of beta-lactam antibiotics in infections--an overview.

Any new antibiotic must be compared with older agents with respect to therapeutic efficacy, protection against infection, toxicity, cost and pharmacokinetic properties. For a new drug to be considered an "advance", it should achieve some definite advantage in one or more of these areas. By expanding their microbiologic activity and by killing many organisms at extremely low concentration, a number of new beta-lactam antibiotics have become useful agents in the therapy of difficult infections, particularly those occurring in patients with generalized immunodeficiencies or those occurring in body sites of localized immunodeficiency. Of additional clinical relevance has been the ability of some of these new drugs to replace the necessity of combination antibiotic therapy, reducing the chances for adverse reactions. To use the new beta-lactam antibiotics properly, one must now know much more than whether an organism is merely resistant or sensitive to the drug. One must know how sensitive and how resistant the bacterium is to the drug and for how long do serum and tissue levels remain above inhibitory or bactericidal concentrations of the drug for the suspected or proven pathogen. Of course, we cannot forget the cost of the drug and its potential for adverse reactions. In brief to prevent or to treat infections, the clinicians must be familiar with the microbiology, pharmacology, toxicology and cost of antibiotics.