Back

Polymyxin heteroresistance in Klebsiella oxytoca

Ayerakwa, E. A.; Douglas, E. J. A.; Larrouy-Maumus, G.; Edwards, A. M.; Isawumi, A.

2025-08-01 microbiology
10.1101/2025.08.01.668101 bioRxiv
Show abstract

Antibiotic heteroresistance presents a growing public health concern since the phenotype is associated with treatment failure and is hard to detect using conventional diagnostic testing. In this study, we characterized polymyxin B heteroresistance in a collection of clinical and environmental isolates of Klebsiella oxytoca, an opportunistic pathogen associated with hospital-acquired infections. All six of the isolates tested exhibited heteroresistance, indicated by a 16-fold difference between the highest non-inhibitory concentration (2 {micro}g/mL) and the minimum inhibitory concentration (32-64 {micro}g/mL) observed in population analysis profile (PAP) assays. Heteroresistance was found to be due to the presence of a stable sub-population of resistant bacteria and was unaffected by growth phase or the presence of host antimicrobial factors present in human serum. MALDI-TOF analysis revealed L-Ara4N modifications of the lipid A of resistant sub-populations. This pilot study identifies polymyxin heteroresistance in K. oxytoca may complicate treatment of infections caused by this organism.

Matching journals

The top 5 journals account for 50% of the predicted probability mass.

50% of probability mass above

"Similar papers" are the closest papers from that journal in the model's embedding space. They show what the match is built on, but the ranking comes mostly from a classifier over the whole training set, not from these examples alone.