Resistance of Acanthamoeba keratitis to prolonged combination therapy with cationic antiseptics and aromatic diamidines

T. K. Chan, G. J. Osterhout, K. B. Kim, J. E. Sutphin, T. P. O'Brien

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Purpose. To describe the occurrence of three cases of Acanthamoeba keratitis which were resistant to prolonged combination cationic antiseptic and aromatic diamidine therapy. Cationic antiseptics have high cysticidal activity and represent a recent advance in the treatment of Acanthamoeba keratitis. Methods. Three otherwise healthy patients with culture-proven Acanthamoeba keratitis associated with contact lens wear were treated with topical Polyhexamethylene biguanide (PHMB) 0.02% in combination with propamidine 0.1% and systemic itraconazole for prolonged periods (7, 12 and 20 months respectively). Chlorhexidine gluconate 0.02% and hexamidine were eventually substituted for PHMB and propamidine because of toxicity and/or lack of efficacy. Penetrating keratoplasty was ultimately required in all cases . Tissue from the corneal buttons were cultured on non-nutrient agar coated with E. coli. Susceptibility profiles were determined in accordance with established procedures. Results. Acanthamoeba organisms were recovered from the corneal buttons of all three cases even after prolonged multi-agent anti-amoebic therapy. In vitro cysticidal testing failed to predict the in vivo lack of efficacy. Conclusion. Clinical treatment failures of Acanthamoeba keratitis may occur despite prolonged multi-agent therapy regardless of the in vitro susceptibility data.

Original languageEnglish (US)
Pages (from-to)S312
JournalInvestigative Ophthalmology and Visual Science
Issue number3
StatePublished - Feb 15 1996
Externally publishedYes

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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