APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -Clostridia is a gram-positive spore-forming rod consisting of C. tetani, C. botulinum, C. perfringens, and C. difficile. C. difficile is often secondary to antibiotic use (clindamycin/ampicillin), PPI use, and recent hospitalization.

Detailed explanation-2: -The clostridia are classically anaerobic rods, but some species can become aerotolerant on subculture; a few species (C carnis, C histolyticum, and C tertium) can grow under aerobic conditions. Most species are Gram-positive, but a few are Gram-negative.

Detailed explanation-3: -There are five medically important genera of gram-positive rods: Bacillus, Clostridium, Corynebacterium, Listeria, and Gardnerella. Bacillus and Clostridium form spores, whereas Corynebacterium, Listeria, and Gardnerella do not.

Detailed explanation-4: -Clostridia are Gram-positive, anaerobic, endospore-forming bacteria, incapable of dissimilatory sulfate reduction. Comprising approximately 180 species, the genus Clostridium is one of the largest bacterial genera.

Detailed explanation-5: -Endospore formation is usually triggered by lack of nutrients, and usually occurs in Gram-positive bacteria. In endospore formation, the bacterium divides within its cell wall. One side then engulfs the other. Endospores enable bacteria to lie dormant for extended periods, even centuries.