title: Clarithromycin treatment selects for persistent macrolide-resistant bacteria in throat commensal flora.
abstract: The aim of the study was to determine the effect of clarithromycin treatment on resistance development in the commensal throat flora. Alpha-haemolytic streptococci and Neisseria spp. were isolated from patients receiving clarithromycin for eradication of Helicobacter pylori. The treatment resulted in an immediate increase in the number of macrolide-resistant streptococci, which remained for one year after treatment, but declined to background level three years later. The most prevalent resistance gene was mef(A). Neisseria spp. were less affected by the treatment: the number of resistant isolates increased in only in one case during treatment. In conclusion, a one-week standard therapy with clarithromycin selects for an increased prevalence of macrolide-resistant streptococci that persisted for more than one year.
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University and Swedish Institute for Infectious Disease Control, Solna, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Jönsson
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Qvarnström
authors.forename: Lars
authors.initials: L
authors.lastname: Engstrand
authors.forename: Göte
authors.initials: G
authors.lastname: Swedberg
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use*; D017291:Clarithromycin / Q000008:administration & dosage / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial / Q000187:drug effects* / Q000235:genetics; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects; D006801:Humans; D018942:Macrolides / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D008826:Microbial Sensitivity Tests; D009343:Neisseria / Q000187:drug effects / Q000254:growth & development; D010614:Pharynx / Q000187:drug effects / Q000382:microbiology*; D013291:Streptococcus / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides; D017291:Clarithromycin