Which is the causative organism of Typhoid?

MP NHM CHO-2024 (Shift-1)

Applied Microbiology & Infection control

Easy

Appeared in: MP NHM CHO-2024 (Shift-1)

Explanation

Typhoid fever, also known as enteric fever, is a systemic illness caused specifically by the bacterium Salmonella enterica serotype Typhi.
This bacterium is transmitted through the fecal-oral route, typically by ingesting contaminated food or water.
After ingestion, S. Typhi invades the intestinal mucosa, enters the bloodstream, and disseminates to various organs, causing the characteristic symptoms of sustained fever, abdominal pain, and malaise.

Option A: Staphylococcus aureus is a gram-positive bacterium that causes a wide range of infections, including skin infections, food poisoning, and toxic shock syndrome, but it does not cause typhoid fever.
Option C: Pseudomonas aeruginosa is an opportunistic gram-negative bacterium known for causing hospital-acquired infections, particularly in immunocompromised individuals. It is not the cause of typhoid fever.
Option D: Yersinia pestis is the bacterium responsible for causing plague, a severe infectious disease transmitted by fleas from rodents. It is distinct from typhoid fever.

Visual 1: Micrograph - A Gram stain of Salmonella typhi, showing gram-negative (pink) bacilli. This helps visualize the pathogen's morphology.
Visual 2: Flowchart - The pathophysiology of typhoid fever, illustrating the path from ingestion to systemic dissemination (ingestion -> intestinal invasion -> lymphatic system -> bloodstream -> reticuloendothelial system). This clarifies how the infection becomes systemic.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Causative agent of Typhoid Fever as background academic context rather than a clinical decision trigger.
A nurse's primary role in managing typhoid includes administering prescribed antibiotics (like fluoroquinolones or third-generation cephalosporins), ensuring adequate hydration and nutrition, and monitoring for life-threatening complications such as intestinal hemorrhage or perforation.
Patient education on hygiene is critical for prevention. This includes teaching proper handwashing techniques, safe food and water practices (boiling water, avoiding raw vegetables and fruits), and the importance of vaccination for travelers to endemic areas.
What if? If a patient presents with fever and abdominal pain but also has profuse, watery diarrhea ('rice-water stools'), the nurse should suspect cholera (Vibrio cholerae) instead of typhoid, necessitating different isolation and fluid management protocols.

How to Approach the Question

This is a factual recall question that tests your knowledge of microbiology.
First, identify the key term in the question stem: 'Typhoid'.
Next, systematically review each option, recalling the primary disease associated with each bacterium.
Match the disease (Typhoid) with its known causative agent (Salmonella typhi).
Eliminate the other options by recalling the diseases they cause (Staphylococcus -> skin infections, Pseudomonas -> nosocomial infections, Yersinia pestis -> plague).

Concept Tested & Keywords

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