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Adherence of Bacteria to Plant Surfaces Measured in the Laboratory
Published on: June 19, 2018
Irrigant divalent cation concentrations influence bacterial adhesion
Clarissa L Dass1, Mary F Walsh, Sue Seo
1Department of Surgery, Michigan State University and the John D Dingell VAMC, Lansing, MI 48912, USA.
Background:
Surgical wounds are frequently contaminated by microbes, but rarely become infected if the bacterial burden is low, and irrigation is used to reduce contamination. Wound fluids are low in calcium and high in magnesium. We hypothesized that manipulating irrigant divalent cation concentrations might influence bacterial adhesion.
Methods:
Staphylococcus aureus, E. coli, and Pseudomonas aeruginosa were stained with fluorescent calcein AM before plating onto fibroblast monolayers, collagen I, or uncoated bacteriologic plastic. After 1 h, wells were washed with HEPES-buffered pH-balanced sterile water without or with 5 mM CaCl(2), 5 mM MgCl(2), or 1 mM EDTA+EGTA, and the remaining adherent bacteria were assayed fluorometrically.
Results:
Supplementing the irrigation with magnesium or chelators increased but calcium-supplemented irrigation reduced bacterial adhesion to collagen or fibroblasts. Nonspecific electrostatic bacterial adhesion to uncoated plastic was unaffected by calcium.
Conclusion:
Bacterial adhesion to mammalian cells and matrix proteins is influenced by divalent cations, and pathogenic bacteria may be adapted to adhere under the low calcium high magnesium conditions in wounds. Although these results await confirmation for other bacteria, and in vivo validation and safety-testing, they suggest that supplementing wound irrigation with 5 mM CaCl(2) may reduce bacterial adhesion and subsequent wound infection.
Insights
Supplementing wound irrigation with calcium chloride (CaCl2) may reduce bacterial adhesion to wounds. This finding suggests a potential strategy to prevent surgical site infections by manipulating fluid mineral content.
Area of Science:
- Microbiology
- Biochemistry
- Wound Healing Research
Background:
- Surgical wounds are susceptible to microbial contamination, but infection risk is reduced by irrigation.
- Wound fluid typically has low calcium and high magnesium concentrations.
- Bacterial adhesion to wound surfaces is a critical factor in infection development.
Purpose of the Study:
- To investigate the effect of irrigant divalent cation concentrations on bacterial adhesion.
- To determine if manipulating calcium and magnesium levels can inhibit microbial attachment to wound components.
Main Methods:
- Three common bacterial species (Staphylococcus aureus, E. coli, Pseudomonas aeruginosa) were used.
- Bacteria were applied to fibroblast monolayers, collagen I, and plastic surfaces.
- Adhesion was measured after irrigation with solutions containing calcium chloride (CaCl2), magnesium chloride (MgCl2), or chelators (EDTA+EGTA).
Main Results:
- Calcium supplementation (5 mM CaCl2) significantly reduced bacterial adhesion to fibroblasts and collagen.
- Magnesium supplementation (5 mM MgCl2) or chelators (1 mM EDTA+EGTA) increased bacterial adhesion.
- Calcium had no effect on nonspecific adhesion to uncoated plastic.
Conclusions:
- Divalent cations in wound irrigants influence bacterial adhesion to host tissues and extracellular matrix.
- Pathogenic bacteria may be adapted to adhere in the low-calcium, high-magnesium wound environment.
- Supplementing wound irrigation with 5 mM CaCl2 shows potential for reducing bacterial adhesion and preventing wound infections, pending further validation.
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