Which organism is a nonspore-forming, gram-positive, anaerobic bacillus?

Which organism is a nonspore-forming, gram-positive, anaerobic bacillus?

• A. Clostridium
• B. Fusobacterium
• C. Propionibacterium
• D. Veillonella

Answer: (C)

A nonspore-forming, gram-positive, anaerobic bacillus is best matched by Propionibacterium. This organism is a Gram-positive rod that does not produce endospores and grows in the absence of oxygen, fitting all three criteria described in the question. Clostridium, while gram-positive and anaerobic, forms spores and thus does not fit the nonspore-forming requirement. Fusobacterium and Veillonella are not Gram-positive rods; Fusobacterium is gram-negative and Veillonella is gram-negative, so neither matches the description.

A nonspore-forming, gram-positive, anaerobic bacillus is best matched by Propionibacterium. This organism is a Gram-positive rod that does not produce endospores and grows in the absence of oxygen, fitting all three criteria described in the question. Clostridium, while gram-positive and anaerobic, forms spores and thus does not fit the nonspore-forming requirement. Fusobacterium and Veillonella are not Gram-positive rods; Fusobacterium is gram-negative and Veillonella is gram-negative, so neither matches the description.