ORAL ANAEROBES CANNOT SURVIVE OXYGEN STRESS WITHOUT INTERACTING WITH FACULTATIVE AEROBIC SPECIES AS A MICROBIAL COMMUNITY/

Anaerobic bacteria are found commonly as components of mixed culture b iofilms in many aerated habitats, including the mouth. Previous studie s showed that anaerobes could survive in planktonic and biofilm commun ities in aerated conditions when part of a community including faculta tive and/or aerobic species, and the numbers and proportions of anaero bic species increased as biofilms aged. When the obligate anaerobes we re grown in the absence of aerobic/facultative species, however, they were unable to grow in either the planktonic or biofilm culture. The m ean survival times of organisms in the aerated culture containing four anaerobic species varied from around 5 min for Fusobacterium nucleatu m and Veillonella dispar, to less than 4 min for Porphyromonas gingiva lis and Prevotella nigrescens. In addition, in this culture, the biofi lm mode of growth did not provide a haven for these bacteria in the ab sence of oxygen-consuming species.