Antibiotic Options Against Enterobacterales That Produce Wild-Type AmpC β-Lactamases

Certain bacteria produce wild-type AmpC β-lactamases at low levels, making these organisms susceptible to third-generation cephalosporins (3GCs) and piperacillin with or without tazobactam. However, among other bacterial species — particularly Enterobacter cloacae, Klebsiella aerogenes, and Citrobacter freundii — such therapy can induce AmpC derepression, leading to increased β-lactamase production and clinical treatment failure. The Infectious Diseases Society of America recommends avoiding the use of 3GCs and piperacillin for these organisms, but not for other AmpC-producing pathogens (such as Serratia marcescens, M. morganii, and Providencia species) that have not been associated with AmpC derepression.

French researchers conducted a retr…