title: Predominance of resistant oral streptococci in saliva and the effect of a single course of josamycin or erythromycin.
abstract: We have investigated the influence of the macrolides erythromycin and josamycin on the selection of resistant oral streptococci by sampling saliva of volunteers before and after oral administration of 1.5 g of either agent followed by a further 0.5 g of the same drug after 6 h, as in routine prophylaxis for oral or dental procedures. The small proportion of resistant organisms present before antibiotic administration increased substantially 48 h after the macrolides were given. After antibiotic administration mean counts of oral streptococci resistant to 1, 4 and 64 mg/l erythromycin were 23%, 17% and 6%, respectively, of the total numbers of streptococci isolated; after josamycin, the values were 13%, 6% and 4% respectively. The proportion of resistant streptococci then declined gradually but remained above pre-antibiotic levels three months later. Streptococci isolated on media containing 64 mg/l of macrolides were mainly Streptococcus sanguis and S. mitis with one isolate of S. salivarius; the majority were resistant to 256 mg/l erythromycin, josamycin, all other macrolides tested and clindamycin. Amoxycillin and pristinamycin were the only compounds tested that were inhibitory to these organisms at therapeutically attainable concentrations.
authors: Department of Medical Microbiology, London Hospital Medical College, UK.
authors: J P
authors: JP
authors: Maskell
authors: A M
authors: AM
authors: Sefton
authors: H
authors: H
authors: Cannell
authors: C
authors: C
authors: Kerawala
authors: A
authors: A
authors: Seymour
authors: Z M
authors: ZM
authors: Sun
authors: J D
authors: JD
authors: Williams
mesh_terms: D000293:Adolescent; D000328:Adult; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000494:pharmacology*; D006801:Humans; D015570:Josamycin / Q000494:pharmacology*; D012463:Saliva / Q000382:microbiology*; D013291:Streptococcus / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D004917:Erythromycin; D015570:Josamycin