Anecdotes suggest that some bacteria have lost their resistance to older antibiotics

Recent reports have lent support to the potential use of previous generation antibacterial drugs to treat infections caused by new resistant bacteria. The Morbidity and Mortality Weekly Report recently described two isolates from the United States of vancomycin resistant Staphylococcus aureus with a minimum inhibitory concentration≥32 μg/ml, both of which were found to be sensitive in vitro to co-trimoxazole as well as to other older antimicrobials. 1 2 Co-trimoxazole was successfully used to treat one of these patients.1 Unpublished data from our institution and elsewhere3 show that in the last 15 years isolates of methicillin resistant S aureus (MRSA) have progressively, and by now almost universally, become susceptible to co-trimoxazole. Preliminary data indicate that this drug can be used as an alternative to vancomycin to treat infections due to …