Penicillin G Sensitivity of Staphylococcus Aureus Isolated from Athletic Mouth-Guards

A number of microorganisms have been isolated from athletic mouth-guards, including numerous Staphylococcus spp. S. aureus was found in 11% of football mouth-guards (FMG), 33% of hockey mouth-guards (HMG), and 29% of medical student control mouth-guards (MSMG). OBJECTIVES: The purpose of this research was to determine the antibiotic susceptibilities of S. aureus strains isolated from different mouth-guard sources and to determine whether there are differences in susceptibilities among the groups. METHODS: The S. aureus isolates from each mouth-guard were tested for susceptibility to ciprofloxacin, clindamycin, vancomycin, oxacillin, penicillin G, azithromycin, rifampin, and sulfamethazone/trimethoprim using two different techniques (e.g., Kirby-Bauer and Etest Strips). RESULTS: No differences were noted in penicillin G susceptibilities of S. aureus isolated from HMG or MSMG (100% resistant). However, only 40% of S. aureus isolates from FMG were resistant to penicillin G. CONCLUSION: The percentage of S. aureus isolated from FMG resistant to penicillin was considerably lower than HMG, MSMG, and the literature standards (e.g., >90% of clinical isolates of S. aureus being resistant to penicillin G). These findings suggest that S. aureus isolated from FMG have been rendered susceptible to penicillin G. The alteration in sensitivity may be related to the unique exposure to the soil environment by FMG.