Role of Fusobacterium nucleatum and coaggregation in anaerobe survival in planktonic and biofilm oral microbial communities during aeration.
Coaggregation is a well-characterized phenomenon by which specific pairs of oral bacteria interact physically. The aim of this study was to examine the patterns of coaggregation between obligately anaerobic and oxygen-tolerant species that coexist in a model oral microbial community. Obligate anaerobes other than Fusobacterium nucleatum coaggregated only poorly with oxygen-tolerant species. In contrast, F. nucleatum was able to coaggregate not only with both oxygen-tolerant and other obligately anaerobic species but also with otherwise-noncoaggregating obligate anaerobe-oxygen-tolerant species pairs. The effects of the presence or absence of F. nucleatum on anaerobe survival in both the biofilm and planktonic phases of a complex community of oral bacteria grown in an aerated (gas phase, 200 ml of 5% CO2 in air x min-1) chemostat system were then investigated. In the presence of F. nucleatum, anaerobes persisted in high numbers (>10(7) x ml-1 in the planktonic phase and >10(7) x cm-2 in 4-day biofilms). In an equivalent culture in the absence of F. nucleatum, the numbers of black-pigmented anaerobes (Porphyromonas gingivalis and Prevotella nigrescens) were significantly reduced (P </= 0.001) in both the planktonic phase and in 4-day biofilms, while the numbers of facultatively anaerobic bacteria increased in these communities. Coaggregation-mediated interactions between F. nucleatum and other species facilitated the survival of obligate anaerobes in aerated environments.
Bradshaw
D J
DJ
Centre for Applied Microbiology & Research, Salisbury SP4 0JG, United Kingdom. david.bradshaw@camr.org.uk
Marsh
P D
PD
Watson
G K
GK
Allison
C
C
D000190:Actinomyces / Q000254:growth & development; D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000254:growth & development*; D001422:Bacterial Adhesion; D001431:Bacteriological Techniques; D001438:Bacteroidaceae / Q000254:growth & development; D018441:Biofilms; D016967:Fusobacterium nucleatum / Q000254:growth & development*; D009055:Mouth / Q000382:microbiology*; D013291:Streptococcus / Q000254:growth & development