Decreased Susceptibility to Polymyxin B during Treatment for Carbapenem-Resistant Klebsiella pneumoniae Infection

In the United States, the major mechanism of carbapenem resistance among Enterobacteriaceae is the production of Klebsiella pneumoniae carbapenemase (KPC) (2). Polymyxins and tigecycline are the antimicrobials most often used for treatment of infections caused by carbapenem-resistant Enterobacteriaceae (4, 11). Polymyxin B, discovered more than 60 years ago, has been reintroduced as a valuable therapeutic agent with efficacy against...