Periapical Abscess Microbiology — MFDS Part 1 MCQ
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Correct answer: C — Polymicrobial infection dominated by obligate anaerobes, including Fusobacterium and Prevotella species
Acute apical abscesses are polymicrobial endodontic infections in which obligate anaerobic bacteria predominate. Frequently detected genera include Fusobacterium, Prevotella, Porphyromonas and Parvimonas, alongside facultative anaerobes such as oral streptococci. Therefore, A best describes the characteristic microbial community. Staphylococci may occasionally be isolated but are not the usual dominant flora and the infection is not attributable to S. aureus alone. Enteric Gram-negative bacilli and aerobic non-fermenters such as Pseudomonas are not characteristic primary pathogens in an uncomplicated endodontic abscess. Candida can occur within the oral cavity and has been associated with selected persistent endodontic infections, but acute apical abscesses are principally bacterial rather than fungal.
Reference: Siqueira JF Jr, Rôças IN. Microbiology and treatment of acute apical abscesses. Clinical Microbiology Reviews. 2013;26(2):255–273. https://pubmed.ncbi.nlm.nih.gov/23554416/