Ocular Microbiology and Immunology Group
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2018 OMIG Abstract

In Vitro Synergy Testing Of Commonly Used Anti-Amoebic Agents:
Antagonism Of Voriconazole

Jeremy D Keenan, MD, MPH^1,2, Maya Talbott, BS¹, Vicky Cevallos, MT^1,2, Michael C Chen²,
Stephanie A Chin², Lalitha Prajna³, Gerami D Seitzman, MD^1,2, Thomas M Lietman, MD^1,2
1F.I. Proctor Foundation, San Francisco, CA, USA; ²Department of Ophthalmology, San Francisco, CA, USA; ³Aravind Eye Care System, Madurai, India

Methods: Synergy testing for all combinations of chlorhexidine, propamidine, and voriconazole was performed with a microdilution checkerboard assayon 10 clinical acanthamoeba isolates collected at the Proctor Foundation from 2008-2012.

Results: Chlorhexidine and propamidine were cysticidal, with median minimum cysticidal concentrations (MCCs) of 12.5 (range 1.5 to 50) and 11.7 (range 0.2 to 250), respectively. Voriconazole was not cysticidal, with a median MCC of >10,000 µg/mL. The combination of chlorhexidine and propamidine did not markedly change the cysticidal activity compared to either drug alone. In contrast, voriconazole antagonized the cysticidal activity of both chlorhexidine and propamidine.

Conclusion: In an in-vitro assay, voriconazole reduced the cysticidal activity of the most commonly used anti-amoebic drugs.While the in vivo drug interactions could be different, these observations may be useful in cases of non-healing acanthamoeba keratitis being treated with combination therapies including voriconazole.

Disclosure: N

2018 Agenda and Abstracts | < Previous Next >