title: Trends in the activity of macrolide and beta-lactam antibiotics and resistance development. Alexander Project Group.
abstract: The Alexander Project is an ongoing international multicenter study monitoring trends in the antimicrobial susceptibilities of community-acquired lower respiratory tract (LRT) pathogens. In 1995, 4011 isolates were collected. The incidence of beta-lactamase-positive Haemophilus influenzae was 28.4% in the United States and 15.4% in Europe, and the incidence of beta-lactamase-positive Moraxella catarrhalis has risen to > 90% in Europe and the United States. The incidence of penicillin-resistant Streptococcus pneumoniae is higher in Europe (24.9%) than the Unites States (12.3%). For the majority of centers, there is a marked association between penicillin and macrolide resistance in S. pneumoniae with erythromycin, azithromycin and clarithromycin exhibiting MIC90s of > or = 32 mg/l against penicillin-resistant strains. For Toulouse and Genoa, at least, the high levels of macrolide resistance may be attributable to high macrolide usage. Ceftriaxone and amoxycillin/clavulanate are the most potent agents for empirical therapy, with MIC90s of < or = 2 mg/l against all three principal pathogens. The majority of oral agents studied are active against > 90% H. influenzae and M. catarrhalis and > 80% S. pneumoniae on breakpoint criteria. However, on the basis of the time above MIC criteria for the beta-lactam and macrolide agents tested, only amoxycillin/clavulanate and the parenteral agent ceftriaxone can be recommended for empirical therapy of LRT infections caused by these pathogens.
authors.affiliation: Institute of Microbiology, University of Genoa Medical School, Italy.
authors.forename: G C
authors.initials: GC
authors.lastname: Schito
authors.forename: S
authors.initials: S
authors.lastname: Mannelli
authors.forename: A
authors.initials: A
authors.lastname: Pesce
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D006193:Haemophilus influenzae / Q000187:drug effects*; D006801:Humans; D007391:International Cooperation; D018942:Macrolides; D008826:Microbial Sensitivity Tests; D001936:Moraxella catarrhalis / Q000187:drug effects*; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D018440:beta-Lactam Resistance; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides; D047090:beta-Lactams