Impetigo is caused by which pathogen?

Appeared in: Uttarakhand CHO - 2021

Explanation

Impetigo is a superficial bacterial skin infection most commonly caused by Staphylococcus aureus.
It can also be caused by Streptococcus pyogenes (Group A Streptococcus), or a combination of both.
S. aureus is particularly responsible for the bullous form of impetigo, which is characterized by large blisters, due to the production of exfoliative toxins.
The non-bullous form, which is more common, presents with characteristic honey-colored crusts and can be caused by either S. aureus or S. pyogenes.

Option B: Klebsiella species are gram-negative bacteria that typically cause nosocomial infections like pneumonia and urinary tract infections, not superficial skin infections like impetigo.
Option C: Mycobacterium is a genus of bacteria responsible for chronic granulomatous diseases, primarily tuberculosis and leprosy.
Option D: E. coli is a gram-negative bacterium that is a major cause of urinary tract infections and various gastrointestinal diseases, but not impetigo.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Impetigo as background academic context rather than a clinical decision trigger.
Correctly identifying the likely pathogen is crucial for selecting the appropriate antibiotic therapy and preventing the spread of this highly contagious infection.
Nurses play a key role in educating patients and families about hygiene measures, such as handwashing and not sharing personal items, to control transmission in homes and schools.
Recognizing the signs of impetigo is important for early intervention to prevent complications like cellulitis or post-streptococcal glomerulonephritis (though rare).

How to Approach the Question

First, identify the key term in the question, which is 'Impetigo'.
This is a factual recall question. Access your knowledge about common skin infections and their causative agents.
Evaluate each option. Recall that Staphylococcus aureus and Streptococcus are the most common bacteria causing superficial skin infections.
Consider the other options: Klebsiella, Mycobacterium, and E. coli. Associate these with their typical infections (pneumonia/UTI, TB/leprosy, and UTI/GI infections, respectively).
Eliminate the incorrect options based on this knowledge, which leaves Staphylococcus aureus as the most plausible cause among the choices.
Confirm the answer. Staphylococcus aureus is the leading cause of impetigo.

Concept Tested & Keywords

QcZqvtpZYSJLRmuLTN7Cs7

E6 Medicine Harrison 22e Part 1 pp. 430-432, 1251-1253

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1711-1713

Practise the full Uttarakhand CHO - 2021

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