Denture stomatitis associated with small-colony variants of Staphylococcus aureus: a case report

Abstract

AbstractBackgroundThe small-colony variants (SCVs) ofStaphylococcus aureuswere isolated from persistent and recurrent infections, especially after placement of medical devices having direct contact with human tissues. The emergence of SCVs is a survival strategy ofS. aureuswhich enables them to hide inside host’s cells and induces a less severe immune response than to wild-typeS. aureus. However, contrary to other medical devices, dental prosthesis as a surface potentially colonized by SCVs ofS. aureushas not been examined thus far. We reported the first case of SCVs -S. aureusinfection in denture wearer.Case presentationA 62-year-old woman with a complete removable acrylic denture presented extensive elevated erythematous lesions on the palate, compatible with denture stomatitis. The patient had a history of arterial hypertension, cigarette smoking and wearing denture at night. The fungal colonies, identified asCandida albicans, were cultured on Sabouraud agar. From three swabs (from hard palate mucosa, denture surface and angular cheilitis lesions) were cultured of pinpoint, clear, non-pigmented, and non-haemolytic colonies on Columbia agar. The small colonies turned out to be Gram-positive cocci, catalase-, Pastorex Staph Plus -, and clumping factor-positive, and oxidase-negative. Suspected phenotypically SCVs forms were definitively identified asS. aureusbased on PCR amplification of species specificnucandcoagenes. Methicillin-resistance was verified bymecAgene detection. The isolates turned out to be susceptible to methicillin (MSSA) and resistant to gentamicin. The isolate was identified as menadione-auxotrophic variant.ConclusionsThis case demonstrated that oral cavity in denture wearers may be a reservoir of small-colony variants ofS. aureus,besidesC. albicans. The prevalence of these bacteria and their role in the pathogenesis of oral diseases are not understood. Due to problems with their detection and identification, the true prevalence of oral SCVs may be underestimated.