Clinical relevance of laboratory susceptibility data

The breakpoints for macrolides proposed by various organisation differ. In vitro studies may not give a true measure of breakpoints as culture conditi ons are not necessarily analogous to the in vivo situation. The effects of pH, carbon dioxide and culture media can affect the minimum inhibitory conc entrations of macrolides; the extent of these effects varies for the differ ent agents. Microbiological efficacy should ideally be proven under clinica l conditions, but this is not always feasible. The breakpoints of macrolide s should be reviewed taking into account the site of infection. (C) 2001 El sevier Science B.V. and Intrenational Society of Chemotherapy. All rights r eserved.