Real-World Development of E. coli Persister Strains

Certain patients with gram-negative bacterial bloodstream infections (GNB-BSIs) are well-known to experience recurrent bacteremia after receiving antimicrobial therapy — but is this phenomenon due to microbial factors? Researchers have analyzed isolates from patients with relapsed GNB-BSIs in which the initial and subsequent strains were nearly identical genetically.

Paired bacteremic isolates of E. coli, Klebsiella species, Serratia marcescens, and Pseudomonas aeruginosa were identified for a detailed analysis of the E. coli strains. Time-kill studies found that 4 of the 11 recurrent isolates had a higher number of bacterial colony-forming units persisting through 24 hours of exposure to meropenem. The recurrent strain with the greatest num…