title: Amoxicillin-clavulanate therapy increases childhood nasal colonization by methicillin-susceptible Staphylococcus aureus strains producing high levels of penicillinase.
abstract: We examined factors associated with penicillinase production by nasal carriage Staphylococcus aureus strains in 648 children aged 3 to 6 years attending 20 randomly sampled playschools. The children were prospectively monitored for drug use and medical events for 6 months and were then screened for S. aureus carriage. Isolates were tested for their susceptibility to penicillin G and methicillin, and penicillinase production by methicillin-susceptible, penicillin-resistant strains was quantified. S. aureus was isolated from 166 children (25.6%). Exposure to amoxicillin-clavulanate during the previous 3 months was associated with higher penicillinase production by penicillin-resistant, methicillin-susceptible strains (odds ratio, 3.6; P = 0.03). These results suggest that use of the amoxicillin-clavulanate combination could induce a herd selection process of S. aureus strains producing higher levels of penicillinase.
authors.affiliation: Institut Pasteur, Paris 15, France. guillemo@pasteur.fr
authors.forename: Didier
authors.initials: D
authors.lastname: Guillemot
authors.forename: Stephane
authors.initials: S
authors.lastname: Bonacorsi
authors.forename: John S
authors.initials: JS
authors.lastname: Blanchard
authors.forename: Philippe
authors.initials: P
authors.lastname: Weber
authors.forename: Sylvie
authors.initials: S
authors.lastname: Simon
authors.forename: Bruno
authors.initials: B
authors.lastname: Guesnon
authors.forename: Edouard
authors.initials: E
authors.lastname: Bingen
authors.forename: Claude
authors.initials: C
authors.lastname: Carbon
mesh_terms: D019980:Amoxicillin-Potassium Clavulanate Combination / Q000009:adverse effects* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004359:Drug Therapy, Combination / Q000009:adverse effects* / Q000627:therapeutic use; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D008712:Methicillin / Q000494:pharmacology*; D016106:Methicillin Resistance; D009296:Nasal Cavity / Q000382:microbiology*; D010403:Penicillin Resistance; D010405:Penicillinase / Q000032:analysis / Q000096:biosynthesis*; D010406:Penicillins / Q000494:pharmacology*; D012307:Risk Factors; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000201:enzymology*; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D010406:Penicillins; D047090:beta-Lactams; D019980:Amoxicillin-Potassium Clavulanate Combination; D010405:Penicillinase; D008712:Methicillin