MRSA Isolates from United States Hospitals Carry dfrG and dfrK Resistance Genes and Succumb to Propargyl-Linked Antifolates.

Antibiotic resistance is a rapidly evolving health concern that requires a sustained effort to understand mechanisms of resistance and to develop new agents that overcome those mechanisms. The dihydrofolate reductase (DHFR) inhibitor, trimethoprim (TMP), remains one of the most important orally administered antibiotics. However, resistance through chromosomal mutations and mobile, plasmid-encoded insensitive DHFRs threatens the continued use of this agent.