This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Bacteria not affected by streptogramins is ? 
Select and explain. 
A. E. coli, B. Staphylococcuaureus, C. Legionella, D. M. pneumoniae
A: E. coli
Answer: A: E. coli 
Explanation: Ans. is 'a' i.e., E. coli Streptogramins are active against gram-positive cocci and organisms responsible for atypical pneumonia (e.g., M. pneumoniae, Legionella spp., and Chlamydia pneumoniae), but largely inactive against gram-negative organisms. They are bactericidal against streptococci and many strains of staphylococci, but bacteriostatic against E. faecium.