Peptostreptococcus micros coaggregates with Fusobacterium nucleatum and non-encapsulated Porphyromonas gingivalis

Coaggregation is one of the potential colonization strategies of oral micro organisms, often involving fimbrial structures in the interactions. Tn this study, the coaggregation characteristics of the rough and smooth genotypes of the periodontal pathogen Peptostreptococcus micros were compared to inv estigate the role of the fibril-like structures of the rough genotype in co aggregation. Of the 11 oral species tested, only Fusobacterium nucleatum st rains and non-encapsulated Porphyromonas gingivalis strains coaggregated wi th P. micros. No differences in coaggregation between the smooth type (Sm), the rough type (Rg) and the smooth variant of the Rg type (Rg(Sm)) of P. m icros were observed. Heat-stable, periodate-sensitive structures on P. micr os appeared to interact with heat- and protease-sensitive structures on F. nucleatum and P. gingivalis. These data indicate that these unimodal coaggr egations are not mediated by the proteinaceous fibril-like structures of th e Rg genotype, but by carbohydrates present on both genotypes of P. micros. (C) 2000 Federation of European Microbiological Societies. Published by El sevier Science B.V. All rights reserved.