title: Macrolide resistance of Streptococcus pneumoniae isolated during long-term macrolide therapy: difference between erythromycin and clarithromycin.
abstract: Longterm macrolide therapy (LTMT) has been employed as an effective therapy both for diffuse panbronchiolitis in Japan and for cystic fibrosis in European countries. However, effects on antibiotic susceptibility profiles of microorganisms, associated with such long-term administration of antibiotics, are of concern. We retrospectively identified 57 pneumococcal isolates, recovered from the same number of patients receiving either LTMT with 400 mg of clarithromycin daily (CAM group; n = 31) or 600 mg of erythromycin daily (EM group; n = 26) by reviewing the patients' records at Nara Medical University. On analysis, we found that all isolates recovered from the CAM group and 25 of the 26 recovered from the EM group were resistant to EM, showing either an MLSB: or an M phenotype. Interestingly, isolates exhibiting the M phenotype were much less frequent in the CAM group (2 of 31; 6.5%) than in the EM group (15 of 26; 57.7%). No increase in the rate of penicillin resistance was observed in either group. The macrolide resistance profiles of microorganisms may be influenced differently according to differences in the kind of macrolide antibiotics used.
authors.affiliation: Second Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan. kassan@naramed-u.ac.jp
authors.forename: Kei
authors.initials: K
authors.lastname: Kasahara
authors.forename: Eiji
authors.initials: E
authors.lastname: Kita
authors.forename: Koichi
authors.initials: K
authors.lastname: Maeda
authors.forename: Kenji
authors.initials: K
authors.lastname: Uno
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Konishi
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Yoshimoto
authors.forename: Koichi
authors.initials: K
authors.lastname: Murakawa
authors.forename: Keiichi
authors.initials: K
authors.lastname: Mikasa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kimura
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017291:Clarithromycin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008826:Microbial Sensitivity Tests; D012189:Retrospective Studies; D013296:Streptococcus pneumoniae / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D004917:Erythromycin; D017291:Clarithromycin