Proteolytic clostridia: Which organisms listed are predominantly proteolytic in laboratory media and tissue, producing extensive protein breakdown?

Introduction / Context:
Clostridial species vary in metabolic profiles: some are saccharolytic (ferment carbohydrates) and others proteolytic (degrade proteins). Recognizing these tendencies helps in presumptive identification and anticipating tissue damage patterns in infections.

Given Data / Assumptions:

• C. sporogenes is a model proteolytic anaerobe used for quality control.
• C. histolyticum is proteolytic and associated with tissue destruction.
• “C. speticum” is likely a misspelling of C. septicum, which is more gas-gangrene-associated and not classically listed as predominantly proteolytic like the other two.

Concept / Approach:

Proteolysis in media such as gelatin or cooked meat manifests as liquefaction and strong odor; in vivo, it correlates with rapid soft tissue destruction. Selecting the pair known for this phenotype is appropriate.

Step-by-Step Solution:

Verification / Alternative check:

Laboratory references describe C. sporogenes as strongly proteolytic; C. histolyticum produces collagenase and other proteases, aligning with its name (“histolyticum” = tissue-dissolving).

Why Other Options Are Wrong:

Single choices omit the other well-known proteolytic species.

C. septicum is an important pathogen but not the canonical proteolytic control organism in bench media.

Common Pitfalls:

Equating gas production (saccharolysis) with proteolysis; they are distinct metabolic profiles that may coexist but are not synonymous.

Final Answer:

Both (a) and (b)