At What Cost Echinocandin Resistance?

(See the article by Ben-Ami et al, on pages 626–35.) The treatment and prevention of infec-tious diseases caused by antimicrobial-resistant pathogens is one of the great challenges confronting modern medi-cine. Meeting this challenge will require better understanding of the various fac-tors that determine the emergence and spread of resistance. Major determinants of the rate and trajectory of the evolu-tion of resistance include the size of the microbial population exposed to a given agent, mutation rates, and the effect of resistance mechanisms on microbial fitness [1, 2]. Fitness, defined in the