Molecular mechanisms of re-emerging chloramphenicol susceptibility in extended-spectrum beta-lactamase-producing Enterobacterales

Antimicrobial resistance in Enterobacterales (E) infections is becoming more challenging to treat. In Malawi, ceftriaxone replaced chloramphenicol (CHL) in 2004, leading to the emergence of extended-spectrum beta-lactamase-E. However, many susceptible isolates still carry CHL acetyltransferase genes. A study found 31% of 840 E. coli and Klebsiella isolates have discordant CHL susceptibility, suggesting CHL could be reintroduced as a reserve agent.