Investigating Domestic Shower Settings as a Risk Factor for Acanthamoeba Keratitis

Abstract

Acanthamoeba keratitis (AK) is a sight-threatening infection of the cornea, which is caused by soil and the waterborne protist Acanthamoeba spp. AK most commonly occurs during contact lens (CL) wear. Risk factors for AK have been linked to non-optimal lens hygiene practices and Acanthamoeba contamination of domestic water. This study investigated the prevalence of Acanthamoeba species in domestic showers in the greater Sydney region, as well as the perception of water contamination of CL as being a risk factor for AK among previous AK patients and their family and friends. Samples from four locations of 13 participants’ shower areas were cultured and Acanthamoeba 18S rRNA was amplified by PCR, followed by sequencing. Twenty-six responses were received to the online questionnaire. Fifteen water samples (29%, 15/52) contained amoeba that were morphologically classified as Acanthamoeba spp. PCR amplification confirmed the presence of Acanthamoeba spp. in four samples (8%, 4/52). Three isolates belonged to the T4, and one isolate to the T3 genotype. On the questionnaire survey, 96% (25/26) of respondents believed that water contamination was likely to be a risk factor for Acanthamoeba keratitis and 58% rated showering with CL as ‘extremely likely’ to be a risk factor for AK. Acanthamoeba pathogenic genotypes (T3 and T4) in the domestic bathroom water suggest that clinicians should remain vigilant in educating CL wearers about avoiding domestic water contamination of CL.

Molecular Identification of Pathogenic Free-Living Amoeba from Household Biofilm Samples in Iran: A Risk Factor for Acanthamoeba Keratitis

“…Previous studies support that water exposure of contact lenses is an important risk factor for AK [40]. The fast flow of water through shower heads may have ousted Acanthamoeba, which allows the amoeba to enter the eye from the water source [40]. In a study conducted by Muchesa et al, out of 97 water and biofilm samples isolated from tap water, dry swabs, and shower water, 90% of the samples were positive for Acanthamoeba spp., Vermamoeba, and Naegleria [38].…”

“…As a result, hygiene management around sinks and showerheads should be encouraged. Previous studies support that water exposure of contact lenses is an important risk factor for AK [40]. The fast flow of water through shower heads may have ousted Acanthamoeba, which allows the amoeba to enter the eye from the water source [40].…”

A simple method for culturing Acanthamoeba from soft contact lens at a clinical laboratory of a hospital: Case report of Acanthamoeba keratitis

“…Outbreak of Acanthamoeba keratitis was related with tap water contamination. [11][12][13][14][15] In Japan, residual chlorine concentration of the tap water has been set at 0.1 mg/L, based on the Water Supply Act which was enacted in 1957. Since then, no change has been made according to the Waterworks Bureau of Okayama City Government.…”

“…Tap water has been known as the source of Acanthamoeba which develops corneal infection. Outbreak of Acanthamoeba keratitis was related with tap water contamination 11–15 . In Japan, residual chlorine concentration of the tap water has been set at 0.1 mg/L, based on the Water Supply Act which was enacted in 1957.…”

Biofilms and contact lenses: problems and solutions

“…2,3,9 Furthermore, we have shown a correlation between contamination of contact lenses by microorganisms and contamination of the domestic water supply. 24,25 Thus, we, and others, have been working on developing antimicrobial lenses.…”