Which of the following microbes is associated with causing periodontal disease?

Fusobacterium nucleatum is the correct choice because it is a key player in the development of periodontal disease. This species is part of the normal microbial flora of the oral cavity but can become pathogenic under certain conditions. It is highly associated with the progression of periodontal infections due to its ability to adhere to epithelial cells and other bacteria, forming biofilms that contribute to the dysbiosis associated with periodontal disease.

Fusobacterium nucleatum is known for its role in the formation of dental plaque, and its presence is often increased in individuals with periodontal disease. Additionally, it can stimulate an inflammatory response, leading to tissue destruction and the characteristic symptoms of periodontal disease.

In contrast, the other microorganisms listed do not have a direct association with periodontal disease. Propionibacterium acnes is primarily linked to acne and skin infections. Neisseria meningitidis is associated with meningitis and other systemic infections. Bacteroides fragilis is a significant organism in the gut microbiota and is more commonly associated with abdominal infections rather than oral health issues.