In-vitro and in-vivo studies of trimethoprim-sulphamethoxazole against multiple resistant Staphylococcus aureus.

Methicillin and gentamicin resistant strains of Staphylococcus aureus (MRSA) remains a cause of significant morbidity and mortality. Vancomycin is usually effective against these strains, but toxicity and expense are significant drawbacks. Resistance to the new quinolones has been demonstrated in vitro and during clinical therapeutic trials. Trimethoprim-sulphamethoxazole has proved to be effective in vitro against staphylococcal strains that are resistant to gentamicin, methicillin, and quinolones. As determined by time-kill kinetic studies, trimethoprim-sulphamethoxazole was rapidly bactericidal. Clinical evaluation of trimethoprim-sulphamethoxazole against MRSA in patients with osteomyelitis is under study. We believe that our data support the use of trimethoprim-sulphamethoxazole as a potentially economical and effective alternative for the treatment of infections caused by MRSA.