Which of the following pathogens causes gas gangrene?

JSSH Staff Nurse - 2019

Applied Microbiology & Infection control

Easy

Appeared in: JSSH Staff Nurse - 2019

Explanation

Clostridium perfringens is a Gram-positive, anaerobic bacterium that is the most common cause of gas gangrene (clostridial myonecrosis).
This pathogen thrives in deep, contaminated wounds with poor blood supply, which creates the necessary anaerobic environment for its growth.
It produces powerful exotoxins, most notably alpha-toxin (a lecithinase), which destroys muscle tissue, red blood cells, and platelets, leading to necrosis and gas production.
The gas produced by bacterial fermentation within the tissue leads to the characteristic clinical sign of crepitus (a crackling sensation under the skin).

Option A: Mycoplasma species are primarily associated with respiratory infections, most notably atypical pneumonia, often referred to as 'walking pneumonia'. They are not involved in causing myonecrosis or gangrene.
Option C: Enteroviruses are a group of viruses, not bacteria. They are responsible for a wide range of illnesses, including hand-foot-and-mouth disease, viral meningitis, and the common cold, but not bacterial infections like gangrene.
Option D: Vibrio cholerae is the bacterium that causes cholera, a severe intestinal infection. Its toxin acts on the intestinal lining, causing massive fluid loss and characteristic 'rice-water' diarrhea. It does not cause tissue necrosis or gas gangrene.

Clinical Relevance

Nursing practice connection: Knowing Etiology of Gas Gangrene helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Gas gangrene is a life-threatening surgical emergency. Nurses must be able to rapidly identify its signs—severe pain out of proportion to the injury, crepitus, skin discoloration, and foul-smelling discharge—to ensure immediate medical and surgical intervention.
Nursing care involves preparing the patient for emergency surgery (debridement), administering high-dose IV antibiotics as prescribed, managing pain, and implementing strict infection control measures.
What if? If the patient presented with a superficial, well-oxygenated wound, the risk of gas gangrene would be minimal. The aerobic environment would inhibit the growth of the obligate anaerobe C. perfringens, making an infection like cellulitis from aerobic bacteria (e.g., Staphylococcus aureus) more likely.

How to Approach the Question

First, identify the key terms in the question: 'pathogen' and 'gas gangrene'. This is a direct recall question asking for the specific causative agent of a known disease.
Analyze the term 'gas gangrene'. The name itself provides clues: 'gangrene' implies tissue death (necrosis), and 'gas' suggests a gas-producing organism.
Systematically evaluate each option based on your knowledge of microbiology:
Mycoplasma: Associate this with atypical pneumonia.
Clostridium perfringens: Recall this as a classic anaerobic bacterium known for causing severe wound infections and gas production.
Enterovirus: Recognize this as a virus, which cannot cause bacterial gangrene.

Concept Tested & Keywords

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E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 387-389

E6 Microbiology Essentials Sastry 4e Part 1 p. 84-86

E6 Microbiology Essentials Sastry 4e Part 2 p. 81-83