Add TMP/SMX  to cover MRSA if:

• rapid onset
• necrotizing process on CXR
• post-influenza
• injection drug use (IDU)
• colonization/recent infection with MRSA
• Gram positive cocci in clusters on Gram stain.

Oral quinolones have excellent absorption and bioavailability. With equal/equivalent doses, the serum concentration attained with the oral formulation is comparable to that of the IV formulation. Therefore, unless the patient is strictly NPO, use oral formulation. (See IV to PO Switch Recommendations).

Avoid macrolides and quinolones if used within previous 3 months.