Effect of adhered bacteria on the binding of Acanthamoeba to hydrogel lenses

Arch Ophthalmol. 1996 May;114(5):576-80. doi: 10.1001/archopht.1996.01100130568013.


Objectives: To determine the effect of Pseudomonas aeruginosa and Staphylococcus epidermidis on the binding of Acanthamoeba species to hydrogel lenses.

Methods: Cells of amebae and bacteria were incubated with different types of hydrogel lenses. Densities of amebae that were bound to the lenses after rinsing were determined from direct counts with a cell detachment procedure and from scintillation counts of cells, which were radiolabeled with tritiated leucine.

Results: With both methods, amebae showed significantly increased binding to hydrogel lenses with attached P aeruginosa. The numbers of amebae that were retained on lenses with attached S epidermidis were not significantly different from those that were retained on lenses without bacteria. The binding of amebae to unworn hydrogel lenses, in contrast to the irreversible adherence of P aeruginosa, was tenuous.

Conclusions: The binding of Acanthamoeba species to unworn hydrogel lenses was tenuous and appeared to be related to water content, surface tensions, and ionic charge. The presence of adhered P aeruginosa on the hydrogel lenses facilitated the binding of Acanthamoeba species. The cocontamination of lens systems with bacteria (eg, P aeruginosa) may be a prime factor in the development of amebic keratitis.

MeSH terms

  • Acanthamoeba / isolation & purification
  • Acanthamoeba / metabolism*
  • Animals
  • Bacterial Adhesion / physiology*
  • Cell Adhesion
  • Colony Count, Microbial
  • Contact Lenses*
  • Humans
  • Hydrogel, Polyethylene Glycol Dimethacrylate
  • Polyethylene Glycols*
  • Pseudomonas aeruginosa / isolation & purification
  • Pseudomonas aeruginosa / physiology*
  • Staphylococcus epidermidis / isolation & purification
  • Staphylococcus epidermidis / physiology*


  • Hydrogel, Polyethylene Glycol Dimethacrylate
  • Polyethylene Glycols