Effect of co-aggregation on the pathogenicity of oral bacteria Ochiai, K. and Kurita-Ochiai, T. and Kamino, Y. and Ikeda, T.,, 39, 183-190 (1993), doi = https://doi.org/10.1099/00222615-39-3-183, publicationName = Microbiology Society, issn = 0022-2615, abstract= Summary The pathogenicity of oral bacteria was studied by measuring the development of subcutaneous abscesses in mice after infection with Actinomyces viscosus and Streptococcus mitis either singly or as co-aggregated pairs. Heat-treated cells were also tested. The pathogenicity of the co-aggregates was examined in various viable and heat-treated combinations of the two bacterial species. More abscesses were formed by A. viscosus than S. mitis at all the bacterial concentrations tested. Also, abscess formation by co-aggregates of the two strains produced a higher percentage of abscess formation than those caused by infection with pure suspensions of A. viscosus or S. mitis. Co-aggregated cells were more resistant to phagocytosis and killing by neutrophils in vitro and in vivo. Furthermore, A. viscosus in co-aggregates were resistant to killing after engulfment by neutrophils. These results suggest that oral bacteria that are able to co-aggregate may resist phagocytosis, and this ability may be linked with pathogenicity., language=, type=