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Molecular effects of povidone-iodine on relevant microorganisms: an electron-microscopic and biochemical study
H Schreier1, G Erdos, K Reimer
1Advanced Therapies Inc., Novato, Calif., USA.
Abstract:
The aim of this study was to elucidate the effects of povidone-iodine (PVP-I) on cell ultrastructure by electron microscopy and to monitor changes in enzyme activity and nucleotide efflux. Staphylococcus aureus, Escherichia coli and Candida albicans, medically relevant gram-positive, gram-negative and yeast microorganisms, served as models. In the presence of PVP-I, rapid partitioning of the cytoplasm and pronounced coagulation of nuclear material was noted. E. coli and S. aureus showed no major structural wall damage. C. albicans exhibited a rapid, dose-dependent 'loosening' of the cell wall; cells remained intact without lysis, rupture or wall breakage. Changes in beta-galactosidase and nucleotide concentrations were measured in E. coli. A rapid and dose-dependent loss of cellular beta-galactosidase activity was found, with no increase in the supernatant; loss of cellular nucleotides corresponded with an increase in the supernatant. Electron-microscopic and biochemical observations support the conclusion that PVP-I interacts with cell walls of microorganisms causing pore formation or generating solid-liquid interfaces at the lipid membrane level which lead to loss of cytosol material, in addition to enzyme denaturation.
Insights
Povidone-iodine (PVP-I) damages microbial cell walls, causing cytoplasmic leakage and enzyme denaturation. This study observed structural changes in bacteria and yeast, revealing PVP-I
Area of Science:
- Microbiology
- Cell Biology
- Biochemistry
Background:
- Povidone-iodine (PVP-I) is a widely used antiseptic.
- Its precise mechanisms of antimicrobial action at the cellular level require further elucidation.
- Understanding PVP-I's effects is crucial for optimizing its clinical applications.
Purpose of the Study:
- To investigate the ultrastructural effects of povidone-iodine (PVP-I) on microbial cells using electron microscopy.
- To quantify changes in enzyme activity and nucleotide efflux following PVP-I exposure.
- To elucidate the molecular mechanisms underlying PVP-I's antimicrobial activity.
Main Methods:
- Transmission electron microscopy was used to examine the ultrastructure of Staphylococcus aureus, Escherichia coli, and Candida albicans after PVP-I treatment.
- Enzyme activity (beta-galactosidase) and nucleotide concentrations were measured in E. coli.
- Dose-dependent effects of PVP-I were assessed.
Main Results:
- PVP-I caused rapid cytoplasmic partitioning and nuclear material coagulation in tested microorganisms.
- Gram-positive and gram-negative bacteria showed minimal cell wall structural damage.
- Candida albicans displayed a dose-dependent loosening of the cell wall without lysis.
- A rapid, dose-dependent loss of cellular beta-galactosidase activity was observed in E. coli, without extracellular enzyme increase.
- Loss of intracellular nucleotides correlated with increased extracellular nucleotide levels.
Conclusions:
- PVP-I interacts with microbial cell walls, potentially forming pores or altering lipid membrane interfaces.
- These interactions lead to the loss of cytoplasmic material and enzyme denaturation.
- The findings provide a detailed ultrastructural and biochemical basis for PVP-I's antimicrobial efficacy.