Characterisation of black‐pigmented anaerobes isolated from diseased and healthy periodontal sites

摘要

Prevotella intermediahas recently been re‐defined and a new species,Prevotella nigrescenshas been proposed. However, there is little data available on the incidence of these new species in periodontal health or disease. Black‐pigmented anaerobes isolated from diseased and healthy subgingival sites were identified by serotyping, SDS‐PAGE and physiological tests. In adult periodontitis subjects, 64 of active sites, 35.7 of inactive sites and 38.5 of healthy sites yielded black‐pigmented anaerobes. Of these,Porphyromonas gingivaliswas found in 11 of active and 5 of healthy sites in diseased patients,Prevotella intermediain 15.5 of active and 20.5 of healthy sites,Prevotella nigrescensin 37.7 of active and 11.5 of healthy sites andPrevotella denticolain 3 of active and 1 of healthy sites. In healthy subjects, 50 of sites yielded black‐pigmented anaerobes.P. gingivaliswas not found in healthy subjects butP. intermediawas found in 18 andP. nigrescensin 31 of sites. SDS‐PAGE proved to be a useful method for routinely differentiatingP. intermediaandP. nigrescensand two sub‐types of the latter species were detected on the basis of band pattern. Only oneP. nigrescenssub‐type was found in any given individual and one type, typified by ATCC 25261, was more commonly found in deep pockets. However, overall bothP. nigrescensandP. intermediaas species were just as frequently found at healthy sites as diseased sites. Thus, these species, in contrast toP. gingivalis, appear to be common commensals but they may act as opportun