Which among the following is the most common cause of acute infective endocarditis?

Appeared in: JIPMER Pondicherry NO - 2022

Explanation

Staphylococcus aureus is a highly virulent bacterium capable of infecting normal, healthy heart valves.
It causes acute infective endocarditis, which is characterized by a rapid, destructive clinical course with high fever and significant morbidity.
S. aureus is the leading cause of IE in developed countries, particularly in cases related to intravenous drug use and healthcare-associated infections.

Option B: Streptococcus viridans is the most common cause of subacute bacterial endocarditis, not acute.
Option C: Streptococcus intermedius, part of the viridans group, can cause endocarditis but is not the most common agent for the acute form.
Option D: Candida albicans is a fungal, not bacterial, cause of endocarditis and is relatively uncommon compared to S. aureus.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Acute Infective Endocarditis as background academic context rather than a clinical decision trigger.
Identifying the causative organism is critical for selecting the correct antibiotic therapy. S. aureus infections often require more aggressive treatment than S. viridans infections.
A key nursing assessment is to identify risk factors. A history of intravenous drug use strongly suggests S. aureus as the cause, often affecting the right-sided heart valves (tricuspid).
Patient education on completing the full course of intravenous antibiotics is crucial for eradicating the infection and preventing relapse, which is a significant patient-safety issue.

How to Approach the Question

First, identify the key terms in the question stem: 'acute infective endocarditis' and 'most common cause'.
Recognize that infective endocarditis is broadly divided into 'acute' and 'subacute' forms, each with a different primary pathogen.
Recall the distinction: 'Acute' implies a highly virulent organism causing rapid disease, while 'Subacute' implies a low-virulence organism causing a slow, indolent disease.
Associate Staphylococcus aureus with acute endocarditis due to its high virulence.
Associate Streptococcus viridans with subacute endocarditis, often linked to dental procedures and pre-existing valve damage.
Evaluate the options based on this core knowledge to select the correct answer.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 548-550

E6 Microbiology OneStop Sastry p. 59-61

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