For purulent cellulitis with MRSA concern, what is the first line treatment?

The first-line treatment for purulent cellulitis with concerns for Methicillin-resistant Staphylococcus aureus (MRSA) is trimethoprim-sulfamethoxazole (TMP-SMX), commonly known as Bactrim. This oral antibiotic is effective against MRSA and is recommended due to its favorable oral bioavailability and efficacy in treating skin and soft tissue infections caused by this resistant strain of bacteria.

In cases of purulent cellulitis, the presence of pus often indicates a potential infection with MRSA, making it crucial to select an antibiotic that targets this organism specifically. TMP-SMX works by inhibiting bacterial folate synthesis, which is essential for the growth and replication of bacteria, thereby effectively treating the infection.

Other options, while they may be effective against non-resistant strains of Staphylococcus or Streptococcus, do not provide adequate coverage against MRSA. For example, cephalexin is a first-generation cephalosporin, which is less effective against MRSA, and penicillin is generally ineffective against strains of Staphylococcus that are resistant to methicillin. Doxycycline can be effective against MRSA as well, but TMP-SMX is typically preferred in many clinical guidelines as a first-line therapy for this specific