List the bacteria commonly referred to as the red complex.

List the bacteria commonly referred to as the red complex.

• A. Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola.
• B. Streptococcus sanguinis, Streptococcus oralis, Streptococcus mutans.
• C. Veillonella parvula, Fusobacterium nucleatum, Actinomyces naeslundii.
• D. Lactobacillus casei, Propionibacterium acnes, Streptococcus mutans.

Answer: (A)

Red complex bacteria are the group most strongly linked with destructive periodontal disease. They consist of Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. These organisms are anaerobic, Gram-negative bacteria that preferentially inhabit deep periodontal pockets and tend to co-occur in disease-associated biofilms. Their virulence factors—such as gingipains from P. gingivalis and tissue-destructive enzymes from the other members—modulate the host immune response and promote inflammation and tissue destruction. Because of their strong association with active disease and advanced pocketing, they’re grouped as the red complex. The other options include organisms that are not part of this trio, such as early colonizers or caries-associated species, which belong to different groups in periodontal ecology.

Red complex bacteria are the group most strongly linked with destructive periodontal disease. They consist of Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. These organisms are anaerobic, Gram-negative bacteria that preferentially inhabit deep periodontal pockets and tend to co-occur in disease-associated biofilms. Their virulence factors—such as gingipains from P. gingivalis and tissue-destructive enzymes from the other members—modulate the host immune response and promote inflammation and tissue destruction. Because of their strong association with active disease and advanced pocketing, they’re grouped as the red complex. The other options include organisms that are not part of this trio, such as early colonizers or caries-associated species, which belong to different groups in periodontal ecology.