EFFECT OF RED-BLOOD-CELLS ON THE GROWTH OF PORPHYROMONAS-ENDODONTALISAND MICROBIAL COMMUNITY-DEVELOPMENT

Establishment of a microbial community in the root canal system depend s on numerous factors, of which nutrient availability may be one of th e most important. We hypothesized that the presence of red blood cells or hemoglobin in this environment could cause shifts in microbial com position of communities, resulting in organisms such as Porphyromonas endodontalis becoming more dominant. An in vitro model system using mi xed, batch cultures was performed with the bacteria P. endodontalis, F usobacterium nucleatum, Peptostreptococcus micros and Campylobacter re ctus. Bacteria were cultured in media with or without the addition of washed red blood cells, hemoglobin, or serum. Cyclic growth studies re vealed that P. endodontalis lost from the community of organisms after three cycles. However, inclusion of red blood cells resulted in estab lishment of this organism. Moreover, red blood cells added to pure cul tures of P. endodontalis substantially enhanced growth and protected t he organisms from oxygen. Sire conclude that the presence of red blood cells could result in shifts of microbial communities of organisms wi thin the root canal system.