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

Dai Miyazaki,Yuichi Ohashi,Hiroshi Eguchi,Masamaru Inaba,Tomomi Kuwahara,Shin-Ichi Sasaki,Yumiko Shimizu,Motozumi Itoi,Kiichi Ueda,Yoshitsugu Inoue,Haruyuki Nakayama-Imaohji,Satoshi Mizutani,Hitoshi Miyamoto,Kazushige Sado

doi:10.1038/s41598-020-69554-2

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.

Highlights

Acanthamoeba can cause visually destructive Acanthamoeba keratitis (AK) in contact lens (CL) users
We tested for Acanthamoeba, bacterial, and fungal contaminations by real-time PCR and culturing the contents of the contact lenses (CL) cases (Fig. 1b)
Hygiene of CL cases is an important factor in preventing CL case-related infectious keratitis including bacterial and Acanthamoeba keratitis

Summary

Introduction

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. Using real-time PCR, Acanthamoeba DNA was detected in 19.1% of CL cases, their presence was not directly associated with poor CL case care. The presence of Acanthamoeba DNA was associated with significant levels of many different bacterial species. 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. It has been reported that Acanthamoeba contamination of the rivers supplying water to the population was the cause of increased AK occurrences[6]. Most CL users do not develop AK even though they are exposed to Acanthamoeba on daily basis from the environment

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