Chlorhexidine for the Treatment of Fusarium Keratitis: A Case Series and Mini Review

Abstract

Fungal keratitis is difficult to treat, especially Fusarium keratitis. In vitro studies show that chlorhexidine could be an interesting option as monotherapy. We describe a case series of four patients (four eyes) with Fusarium keratitis at Radboud University Medical Center (Nijmegen, the Netherlands). The patients were treated with chlorhexidine 0.02% eye drops. The in vitro activity of eight antifungals and chlorhexidine was determined according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. We also reviewed the literature on the use of chlorhexidine in the treatment of fungal keratitis. Topical chlorhexidine was well tolerated, and all patients showed complete resolution of the keratitis upon treatment with chlorhexidine. A PubMed search of the available literature was conducted (last search 8 March 2020) and yielded two randomized clinical trials (natamycin versus chlorhexidine) and one case report addressing the treatment of fungal keratitis with chlorhexidine. Chlorhexidine was found to be safe with regard to toxicity and to be superior to natamycin in the clinical trials. Chlorhexidine showed in vitro fungicidal activity against Fusarium and clinical effectiveness in our cases, supporting further clinical evaluation. Advantages of chlorhexidine are its topical application, its general availability, its low costs, its broad-spectrum activity, and its fungicidal mechanism of action at low concentrations.

Fusarium Keratitis—Review of Current Treatment Possibilities

“…The fungicidal activity of other tested substances was lower than activity of CHX. As proof of the clinical significance of the above mentioned results, Oliveira dos Santos et al published a case series of four patients with culture proven Fusarium keratitis, with small infiltrates that were successfully treated with 0.02% CHX alone [ 102 ]. The study showed good susceptibility of the isolated Fusarium strains to CHX as well as the high CHX fungicidal effect.…”

Fungal keratitis caused by Pseudallescheria boydii: clinical and mycological characteristics

“…The chlorhexidine MICs of all isolates of P. boydi tested were 0.008 μg/ml. Four patients with Fusarium keratitis were successfully treated with chlorhexidine 0.02% eye drops by Oliveira dos Santos et al [24]. The efficacy of chlorhexidine for treating fungal keratitis has been confirmed by studies [24,25].…”

“…Four patients with Fusarium keratitis were successfully treated with chlorhexidine 0.02% eye drops by Oliveira dos Santos et al [24]. The efficacy of chlorhexidine for treating fungal keratitis has been confirmed by studies [24,25]. There is a need for further research on the use of chlorhexidine in Pseudallescheria keratitis.…”

Chlorhexidine gluconate 0.2% as a treatment for recalcitrant fungal keratitis in Uganda: a pilot study

“…A more recent case series from the Netherlands also reported MICs isolates from four patients with FK (all Fusarium spp ) as ranging from 2 to 32 mg/L. 31 The Mycotic Treatment Trial I (MUTT I) also reported the MICs of natamycin for the 256 patients who had fungal culture results. 32 The reported natamycin MIC ranged from 2 to 32 mg/L for Fusarium spp and from 8 to 64 mg/L for Aspergillus flavus .…”