title: Irrigant divalent cation concentrations influence bacterial adhesion.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors: Department of Surgery, Michigan State University and the John D Dingell VAMC, Lansing, MI 48912, USA.
authors: Clarissa L
authors: CL
authors: Dass
authors: Mary F
authors: MF
authors: Walsh
authors: Sue
authors: S
authors: Seo
authors: Hiroe
authors: H
authors: Shiratsuchi
authors: David H
authors: DH
authors: Craig
authors: Marc D
authors: MD
authors: Basson
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects*; D002118:Calcium / Q000494:pharmacology*; D002413:Cations, Divalent / Q000494:pharmacology*; D002460:Cell Line; D002614:Chelating Agents / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004926:Escherichia coli; D008274:Magnesium / Q000494:pharmacology*; D051379:Mice; D010969:Plastics; D011550:Pseudomonas aeruginosa; D013211:Staphylococcus aureus; D013530:Surgical Wound Infection / Q000517:prevention & control*; D007507:Therapeutic Irrigation
chemical_list: D002413:Cations, Divalent; D002614:Chelating Agents; D010969:Plastics; D004533:Egtazic Acid; D004492:Edetic Acid; D008274:Magnesium; D002118:Calcium