Biofilm Succession — MFDS Part 1 MCQ

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ModerateMicrobiologyBiofilm SuccessionMFDS Part 1

In the classical sequential model of dental plaque biofilm development, which event characteristically occurs immediately after stable attachment and growth of pioneer species on the acquired enamel pellicle?

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Correct answer: D — Co-aggregation and recruitment of secondary colonisers

Explanation lettering: E = shown as A · D = shown as B · B = shown as C · A = shown as D · C = shown as E

In the classical sequential model, pioneer organisms—particularly oral streptococci and Actinomyces species—first attach to receptors in the acquired enamel pellicle and proliferate. Secondary colonisers then bind to these established bacteria through specific cell-to-cell adhesion, termed co-aggregation. Fusobacterium nucleatum can act as a bridging organism, promoting increasing diversity and structural complexity. Pellicle formation (C) occurs before bacterial colonisation. Predominance of late obligate anaerobes (B) develops later as the biofilm environment changes. Calculus formation (D) is mineralisation of established plaque and is not an obligatory developmental stage. Detachment and dispersal (E) occur after maturation rather than immediately after pioneer colonisation.

Reference: Wijesinghe GK et al. Inverted amino acids reduce the adhesion and biofilm biomass of early oral colonizers. Dental and Medical Problems. 2024;61(3):385–390. https://pubmed.ncbi.nlm.nih.gov/38809132/