What is an appropriate antibiotic for the empiric treatment of a man with a history of MRSA skin infections?

For the empiric treatment of a man with a history of MRSA (Methicillin-Resistant Staphylococcus Aureus) skin infections, the most appropriate choice is cotrimoxazole. This antibiotic is a combination of trimethoprim and sulfamethoxazole, which is effective against a variety of bacterial infections, including those caused by MRSA.

Cotrimoxazole is particularly useful in treating skin and soft tissue infections associated with MRSA due to its ability to penetrate bacterial cells and inhibit folate synthesis, which is crucial for bacterial growth. Its effectiveness against MRSA is well-documented, making it an appropriate choice when there is a suspicion of MRSA involvement.

Other antibiotics listed, such as ciprofloxacin and cephalexin, may not be effective against MRSA. Ciprofloxacin is a fluoroquinolone primarily effective against gram-negative bacteria and does not have reliable activity against MRSA. Cephalexin, a first-generation cephalosporin, is generally ineffective against MRSA as it is designed to target methicillin-sensitive Staphylococcus species.

Pyrimethamine is an antiprotozoal medication and is not indicated for bacterial infections. This further solidifies cotrimoxazole as the