摘要：Members of the genus Simonsiella are aerobic Gram-negative segmented multicellular filamentous bacteria found in the oral cavity. There is a wide variation in the reported prevalence of Simonsiella in the oral cavity of man (0.5 per cent to 32 per cent). The aim of the investigation was to determine the prevalence of Simonsiella at different sites in the healthy oral mucosa of 100 dental patients and to compare this with isolates from lesions of 50 patients with oral erosive lichen planus. Oral swabs were inoculated at the chairside onto a complex serum enriched agar. Utilising the unique morphological characteristics, identification was made by direct microscopic examination of culture plates. The morphology and ultrastructure were further investigated by scanning and transmission electron microscopy. Simonsiella was isolated from 22 per cent of patients at one or more sites, with the dorsum of the tongue being the most frequently colonised area. The 50 patients with erosive lichen planus yielded only two positive cultures from the site of the lesion and in one of these Simonsiella was also isolated from the healthy site. In the remaining 48 patients, two were positive at non-lesion sites only. No strong association between Simonsiella and lesions of erosive lichen planus could be demonstrated in this study.Keywords: Simonsiella; oral flora; erosive lichen planus; morphology; ultrastructure
