Related Experiment Video

Updated: Mar 29, 2026

Antimicrobial Synergy Testing by the Inkjet Printer-assisted Automated Checkerboard Array and the Manual Time-kill Method
12:03

Antimicrobial Synergy Testing by the Inkjet Printer-assisted Automated Checkerboard Array and the Manual Time-kill Method

Published on: April 18, 2019

28.0K

Polymyxin heteroresistance in Klebsiella oxytoca

Eunice A Ayerakwa1,2, Edward J A Douglas3,4, Gerald Larrouy-Maumus3,5

  • 1Department of Biochemistry, West African Centre for Cell Biology of Infectious Pathogens, Cell and Molecular Biology, University of Ghana, Accra, Ghana.

Journal of Medical Microbiology
|March 27, 2026
PubMed

Insights

Antibiotic heteroresistance in Klebsiella oxytoca is a significant public health concern. This study reveals polymyxin B heteroresistance in K. oxytoca, complicating treatment of infections.

Area of Science:

  • Microbiology
  • Antimicrobial Resistance
  • Clinical Diagnostics

Background:

  • Antibiotic heteroresistance is a growing public health threat, linked to treatment failures and diagnostic challenges.
  • Klebsiella oxytoca, an opportunistic pathogen, is frequently implicated in hospital-acquired infections.
  • Characterization of heteroresistance in K. oxytoca is lacking.

Purpose of the Study:

  • To characterize polymyxin B heteroresistance in clinical and environmental isolates of K. oxytoca.
  • To investigate the underlying mechanisms of this heteroresistance.

Main Methods:

  • Population analysis profile (PAP) assays were employed to assess heteroresistance.
  • Lipid A modifications were analyzed using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry.

Main Results:

  • All six K. oxytoca isolates exhibited polymyxin B heteroresistance, with a 8-16 fold increase in MIC for resistant subpopulations.
  • Heteroresistance was attributed to a stable resistant subpopulation, independent of growth phase or human serum factors.
  • MALDI-TOF analysis identified 4-amino-l-arabinose modifications in the lipid A of resistant subpopulations.

Conclusions:

  • Polymyxin B heteroresistance is present in K. oxytoca.
  • This heteroresistance may pose challenges for treating K. oxytoca infections.
  • Further research is warranted to understand and manage this phenomenon.
Keywords:
KlebsiellaOxytocaheteroresistancepolymyxinresistanceserum

More Related Videos

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes08:58

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

Published on: March 3, 2023

8.4K
Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance09:00

Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance

Published on: May 2, 2018

12.5K

Related Concept Videos

Development of Antibiotic Resistance01:30

Development of Antibiotic Resistance

Antibiotic resistance is a major public health concern that arises when bacteria evolve mechanisms to withstand the effects of antibiotic treatments. This resistance can be intrinsic, acquired through genetic mutations, or transferred between bacteria via horizontal gene transfer. The development of antibiotic resistance poses significant challenges in treating bacterial infections and necessitates ongoing research to develop new therapeutic strategies.Intrinsic resistance occurs when bacterial...
1.9K
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and...
95
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within...
29
Antibiotic Selection00:57

Antibiotic Selection

Overview
62.1K
Inhibitors of Gram-positive Cell Wall Synthesis01:23

Inhibitors of Gram-positive Cell Wall Synthesis

Bacterial cell walls are typically rigid structures composed mainly of peptidoglycan, a mesh-like polymer that provides mechanical strength and maintains cell shape. The synthesis of peptidoglycan is a crucial process in bacterial growth and serves as a primary target for many antibiotics.Mechanism of Action of Beta-Lactam AntibioticsBeta-lactam antibiotics, such as penicillin, inhibit peptidoglycan synthesis in actively growing cells. These antibiotics share a characteristic four-membered...
39
Inhibitors of Bacterial Protein Synthesis01:25

Inhibitors of Bacterial Protein Synthesis

Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...
31