Streptococcal Infections MCQ Quiz | Infectious Diseases – Bacterial

Welcome to the Streptococcal Infections MCQ Quiz, designed specifically for MBBS students. This quiz will test your understanding of the diverse spectrum of diseases caused by Streptococcus species, a clinically significant group of gram-positive bacteria. You will be challenged on topics ranging from the fundamental microbiology and virulence factors of organisms like S. pyogenes and S. pneumoniae, to the clinical presentation, diagnosis, and management of suppurative infections such as pharyngitis and cellulitis. The quiz also covers the critical non-suppurative sequelae, including Acute Rheumatic Fever and Post-Streptococcal Glomerulonephritis. This assessment consists of 25 multiple-choice questions to help you consolidate your knowledge. After submitting your answers, you can review your score and download a PDF of all questions with their correct answers for future revision.

1. The Lancefield classification system for streptococci is primarily based on which of the following cellular components?

2. Which virulence factor of Streptococcus pyogenes is primarily responsible for its anti-phagocytic properties and is a key determinant of serotype?

3. A 7-year-old child presents with a high fever, sore throat, a fine “sandpaper” rash on the trunk, and a “strawberry tongue.” These clinical findings are most characteristic of which condition?

4. Which of the following is a non-suppurative, post-infectious sequela that typically follows a Streptococcus pyogenes pharyngeal infection but rarely a skin infection?

5. The modified Jones criteria are a set of clinical and laboratory findings used for the diagnosis of:

6. Superficial skin infections characterized by thick, adherent, “honey-crusted” lesions, commonly seen in children, are typical of:

7. The enzyme Streptokinase, produced by some streptococci, contributes to pathogenesis by:

8. A rising Anti-Streptolysin O (ASO) titer is most indicative of a recent infection with which of the following organisms?

9. What is the universally recommended first-line drug for treating Group A Streptococcal pharyngitis in non-allergic patients?

10. Which streptococcal species is a major cause of neonatal meningitis, pneumonia, and sepsis, often acquired during childbirth?

11. A 10-year-old boy develops acute onset of periorbital edema, hypertension, and cola-colored urine about 3 weeks after being treated for impetigo. This clinical picture is most consistent with:

12. The primary virulence factor of Streptococcus pneumoniae, which is targeted by both conjugate and polysaccharide vaccines, is its:

13. Which group of streptococci is a prominent member of the normal oral flora and is most commonly implicated in the pathogenesis of subacute bacterial endocarditis, especially after dental procedures?

14. Erysipelas is a specific type of superficial cellulitis characterized by raised, fiery-red lesions with sharply demarcated borders. It is almost exclusively caused by:

15. The mechanism of streptococcal toxic shock syndrome involves pyrogenic exotoxins (e.g., SpeA, SpeC) that function as:

16. In a clinical microbiology lab, a beta-hemolytic streptococcus is isolated. Which simple test can provide presumptive identification of Streptococcus pyogenes (Group A)?

17. Which of the following is considered a MINOR criterion, not a major one, in the Jones criteria for diagnosing Acute Rheumatic Fever?

18. Bacteremia with Streptococcus gallolyticus (formerly S. bovis), a Group D streptococcus, is strongly associated with which underlying malignancy?

19. On a blood agar plate, Streptococcus pneumoniae typically exhibits what type of hemolysis?

20. The Quellung reaction is a laboratory test that uses specific antisera to cause microscopic swelling of which structure, allowing for serotyping of S. pneumoniae?

21. A patient with a known mitral valve prolapse develops subacute bacterial endocarditis a few weeks after a dental cleaning. The most likely causative organism is:

22. Continuous, long-term antibiotic prophylaxis (secondary prevention) is most crucial for patients with a history of which condition to prevent recurrences?

23. Necrotizing fasciitis, a life-threatening “flesh-eating” disease, is a rapidly progressing infection primarily involving the:

24. The CAMP test, which shows an arrowhead-shaped zone of enhanced hemolysis, is used for the presumptive identification of:

25. The underlying immunologic mechanism responsible for Post-Streptococcal Glomerulonephritis (PSGN) is best described as: