Antimicrobial resistance of Staphylococcus aureus isolated from impetigo patients between 1994 and 2000

Background The incidence of strains of Staphylococcus aureus resistant to the antimicrobial agents used in treating impetigo has been increasing. Aim To determine the antimicrobial susceptibility of S. aureus in impetigo. Methods We measured the antimicrobial susceptibility of Staphylococcus aureus isolated from impetigo patients between 1994 and 2000. Results The MIC50 of gentamicin was always higher than that of other antimicrobial agents until 1999. In isolates obtained since 1996, the MIC90 of gentamicin was over 12.5 mug/mL, which is markedly higher than that found for other skin infections (folliculitis, furuncles, paronychia, phlegmone, secondary infection of eczema, dermatitis, ulcer and decubitus). There were no strains of S. aureus resistant to vancomycin and fusidic acid. After 2000, we could find only one strain resistant to minocycline and ofloxacin. Conclusion Clindamycin has shown excellent activity against most S. aureus isolates between 1994 and 2000. The incidence of methicillin-resistant S. aureus was always below 20%.