BACKGROUND The small-colony variants (SCVs) of Staphylococcus aureus were 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 of S. aureus which enables them to hide inside host's cells and induces a less severe immune response than to wild-type S. aureus. However, contrary to other medical devices, dental prosthesis as a surface potentially colonized by SCVs of S. aureus has not been examined thus far. We reported the first case of SCVs - S. aureus infection in denture wearer. CASE PRESENTATION A 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 as Candida 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 as S. aureus based on PCR amplification of species specific nuc and coa genes. Methicillin-resistance was verified by mecA gene detection. The isolates turned out to be susceptible to methicillin (MSSA) and resistant to gentamicin. The isolate was identified as menadione-auxotrophic variant. CONCLUSIONS This case demonstrated that oral cavity in denture wearers may be a reservoir of small-colony variants of S. aureus, besides C. 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.

中文翻译：

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与金黄色葡萄球菌的小菌落变体有关的假牙口腔炎：一例报告。

背景技术从持续和反复感染中分离出金黄色葡萄球菌的小菌落变体（SCV），特别是在放置与人体组织直接接触的医疗器械之后。SCV的出现是金黄色葡萄球菌的生存策略，它使它们能够隐藏在宿主细胞内，并诱导出比野生型金黄色葡萄球菌更轻的免疫反应。但是，与其他医疗设备相反，到目前为止，尚未检查假牙作为可能被金黄色葡萄球菌SCV定殖的表面。我们报告了第一例SCV-假牙佩戴者中的金黄色葡萄球菌感染。病例介绍一名62岁的妇女，带有完全可移动的丙烯酸义齿，其上颚出现广泛的升高的红斑病变，与义齿口腔炎相适应。该患者有动脉高血压病史，晚上吸烟和戴假牙。在Sabouraud琼脂上培养被鉴定为白色念珠菌的真菌菌落。在哥伦比亚琼脂上培养了三支拭子（来自硬pa黏膜，假牙表面和角性唇炎的病灶），以发现精确，透明，无色素和非溶血菌落。这些小菌落原来是革兰氏阳性球菌，过氧化氢酶，Pastorex Staph Plus，聚集因子阳性和氧化酶阴性。根据物种特异性nuc和coa基因的PCR扩增，可疑表型SCV形式最终确定为金黄色葡萄球菌。通过mecA基因检测验证了耐甲氧西林的能力。分离物证明对甲氧西林（MSSA）敏感并对庆大霉素具有抗性。该分离物被鉴定为甲萘醌营养缺陷型变体。结论该病例表明假牙佩戴者的口腔可能是除白色念珠菌外的金黄色葡萄球菌小菌落变种的宿主。这些细菌的流行及其在口腔疾病发病机理中的作用尚不清楚。由于其检测和鉴定存在问题，因此可能低估了口腔SCV的真实患病率。