This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology Pa 1 (Gram Positive Cocci, Gram Negative Cocci), Subject name: Microbiology
Most common staphylococcal phage strain causing hospital infection 
Select and explain. 
A. 80/81, B. 79/80, C. 3A/3C, D. 69/70
A: 80/81
Answer: A: 80/81 
Explanation: Option 1 Phage typing - Method used for detecting single strains of bacteria. Trace the source of outbreaks of infections. Identify different strains of bacteria within a single species. National reference center for phage typing - MAMC New Delhi. Phage type 80/81 (epidemic strains) Cause hospital infections throughout the world Possess PVL (Panton-Valentine leucocidin) Penicillin-resistant. Option 2, 3, 4 No associated with hospital infections.