The most common causative agent of rheumatic fever is?

Appeared in: AIIMS BBSR SNO - 2019

Explanation

Rheumatic fever is an inflammatory, non-suppurative complication that follows an untreated or inadequately treated pharyngeal infection.
The causative agent is Group A β-hemolytic Streptococcus (GAS), scientifically known as Streptococcus pyogenes.
The disease mechanism is 'molecular mimicry,' an autoimmune response where antibodies against the streptococcal M protein cross-react with host tissues, particularly the heart, joints, and central nervous system.
Prompt treatment of streptococcal pharyngitis with antibiotics can prevent the initial onset of rheumatic fever.

Option B: This bacterium is not associated with rheumatic fever. It is a common inhabitant of the oral cavity.
Option C: This pathogen causes listeriosis, a serious foodborne illness, and is not linked to rheumatic fever.
Option D: This organism is a nontuberculous mycobacterium and has no association with rheumatic fever.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Rheumatic Fever as background academic context rather than a clinical decision trigger.
The primary nursing role in preventing rheumatic fever is patient education regarding the completion of antibiotic therapy for strep throat. This is a critical patient safety issue.
Nurses must recognize that rheumatic fever can lead to rheumatic heart disease (RHD), a chronic condition causing permanent damage to heart valves, which is a major cause of cardiovascular morbidity and mortality in developing nations.
What if? If the patient had a skin infection (impetigo) with S. pyogenes instead of pharyngitis, the primary risk would be for post-streptococcal glomerulonephritis, not rheumatic fever. RF is almost exclusively a sequela of pharyngeal infections.

How to Approach the Question

This is a factual recall question testing knowledge of microbiology and infectious diseases.
First, identify the key terms in the question: 'rheumatic fever' and 'causative agent'.
Recall the classic association between strep throat and its potential complication, rheumatic fever.
Connect strep throat to its causative organism, Group A Streptococcus.
Identify the scientific name for Group A Streptococcus, which is Streptococcus pyogenes, among the options.
Eliminate the other options by recalling their primary disease associations (oral infections, food poisoning, and atypical lung disease).

Concept Tested & Keywords

QhX7zQ-ZRfy6_jU4hOJTvt

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 368-370

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 pp. 1715-1717, 1710-1712

Practise the full AIIMS BBSR SNO - 2019

Attempt every question from this paper in a timed mock, then review the full solution for each one.