Presence of Acanthamoeba and diversified bacterial flora in poorly maintained contact lens cases

Abstract

Acanthamoeba can cause visually destructive Acanthamoeba keratitis (AK) in contact lens (CL) users. The purpose of this study was to determine whether Acanthamoeba was present in the CL cases of CL wearers and to develop techniques to prevent the contaminations. To accomplish this, 512 CL case samples were collected from 305 healthy CL wearers. Using real-time PCR, Acanthamoeba DNA was detected in 19.1% of CL cases, however their presence was not directly associated with poor CL case care. Instead, the presence of Acanthamoeba DNA was associated with significant levels of many different bacterial species. When the CL cases underwent metagenomic analysis, the most abundant bacterial orders were Enterobacteriales followed by Burkholderiales, Pseudomonadales, and Flavobacteriales. The presence of Acanthamoeba was characterized by Propionibacterium acnes and Rothia aeria and was also associated with an increase in the α diversity. Collectively, Acanthamoeba contamination occurs when a diversified bacterial flora is present in CL cases. This can effectively be prevented by careful and thorough CL case care. Acanthamoeba is a free-living amoeba and is a representative pathogen that can cause keratitis. Acanthamoeba keratitis (AK) is a visually devastating disease and is refractory to conventional treatments. Thus, AK often requires corneal transplantation. Acanthamoeba can also cause granulomatous amoebic encephalitis (GAE). Although the incidence of GAE is rare, the mortality rate is almost 90% because of difficulties in diagnosing and treating it 1. AK is known to have strong associations with poor care of contact lenses (CL) and CL cases. When CL users engage in water activities, e.g., bathing or swimming, while wearing CL, there is a significant risk of AK 2,3. Acanthamoeba is a ubiquitous microorganism that is found in water supply systems, water sources including rivers, lakes, swimming pools, and also in soil 4,5. It has been reported that Acanthamoeba contamination of the rivers supplying water to the population was the cause of increased AK occurrences 6. For example, the river water supply in Iran was contaminated with Acanthamoeba, and almost 22% of river samples were PCR-positive for Acanthamoeba 6. In an analysis of the drinking water storage towers of Paris, approximately 20 to 25 Acanthamoebae were detected per liter 1. Thus, tap water can pose risks for AK contact together with inappropriate CL care for the general population without engagement in water activity 7,8 .

Determination of probability of causative pathogen in infectious keratitis using deep learning algorithm of slit-lamp images

“…To diagnose acanthamoeba keratitis, the clinical characteristics and either the detection of cysts in the smear by staining with Fungiflora Y, positive acanthamoeba culture, or quantification of acanthamoeba DNA using real-time PCR were required 17 , 18 . The clinical characteristics include pseudo dendrites, radial keratoneuritis, multifocal stromal infiltrates, and ring infiltrates in the advanced stages 19 .…”

Microbiota and Ocular Diseases

“…The contribution of the ocular surface microbiome to the induction of keratitis by infectious P. aeruginosa has been documented ( Kugadas et al., 2017 ). Wearing contact lenses is a possible risk factor for the development of microbial keratitis and other inflammatory eye conditions ( Eguchi et al., 2017b ; Miyazaki et al., 2020 ).…”

Determination of Probability of Causative Pathogen in Infectious Keratitis Using Deep Learning Algorithm of Slit-Lamp Images

“…To diagnose acanthamoeba keratitis, the clinical characteristics and either the detection of cysts in the smear by staining with Fungi ora Y, positive acanthamoeba culture, or quanti cation of acanthamoeba DNA using real-time PCR were required. 16,17 The clinical characteristics include pseudo dendrites, radial keratoneuritis, multifocal stromal in ltrates, and ring in ltrates in the advanced stages. 18 For the diagnosis of HSV infection, real-time PCR was used in all the cases to determine the HSV DNA levels.…”