Utility of the Rapid Antigen Detection Test E. histolytica Quik Chek for the Diagnosis of Entamoeba histolytica Infection in Nonendemic Situations.

Yasuaki Yanagawa,Toshikazu Miyagawa,Taiichiro Kobayashi,Hiroyuki Gatanaga,Shinichi Oka,Ayaka Nagata,Mami Shibuya,Michiko Koga,Kasumi Hayasaka,Tomoyuki Endo,Risa Otsuka,Kazumi Sakai,Rika Fukushima,Yoshimi Kikuchi,Hirotomo Nakata,Hiroyuki Shingyochi,Kenji Yagita,Rieko Shimogawara,Tomohiko Koibuchi,Etsuko Tsuchihashi ,Kôji Watanabe

doi:10.1128/jcm.01991-20

Abstract

Entamoeba histolytica infection is an increasingly common sexually transmitted infection in Japan. Currently, stool ova and parasite examination (O&P) is the only approved diagnostic method. Here, we assessed the utility of the commercially available rapid antigen detection test (Quik Chek) for E. histolytica A multicenter cross-sectional study was conducted. Stool samples that had been submitted for O&P were included. The samples were subjected to both Quik Chek and PCR, and the Quik Chek results were assessed in comparison with PCR as the reference standard. E. histolytica infection was confirmed in 5.8% (38/657) of the samples and comprised 20 diarrheal and 18 nondiarrheal cases. The overall sensitivity and specificity of Quik Chek were 44.7% (95% confidence interval, 30.1 to 60.3) and 99.8% (99.1 to 100), respectively. The sensitivity of Quik Chek was higher for diarrheal cases (60.0%) than for nondiarrheal cases (27.8%). Furthermore, the combined use of Quik Chek with O&P increased the sensitivity (78.9%), especially for diarrheal cases (up to 90%). The E. histolytica burden assessed by quantitative PCR was similar between Quik Chek-positive and -negative samples. The Quik Chek assay sensitivity was lower for cyst-containing stools than for trophozoite-containing stools, although it was shown that cultured E. histolytica clinical strains from Quik Chek-negative cyst-containing stools exhibited antigenicity in vitro The present study confirmed the high specificity of Quik Chek for E. histolytica infection. Combined use with O&P increased the sensitivity of detection, facilitating the use of Quik Chek in point-of-care settings in nonendemic situations.

Highlights

Yasuaki Yanagawa and Rieko Shimogawara contributed to the manuscript
Nonpathogenic Entamoeba spp. were not reported in the E. histolyticanegative samples, recently discovered E. bangladeshi was not assessed in the present study (Fig. 1). These results suggest that E. histolytica infection is the most common enteric parasite in Japan, which emphasizes the need for well-constructed diagnostic systems for E. histolytica infection
In the present study, we evaluated the utility of a commercial rapid antigen detection test based on immunochromatography (E. histolytica Quik Chek) in clinical settings in Japan

Summary

Introduction

Yasuaki Yanagawa and Rieko Shimogawara contributed to the manuscript. R. O&P is a low-cost and rapid diagnostic tool for enteric parasite infection; in most developed countries, it is not recommended for the diagnosis of E. histolytica [10, 11] This is because (i) O&P cannot distinguish nonpathogenic Entamoeba spp., such as E. dispar and E. moshkovskii, from potentially pathogenic E. histolytica, and (ii) the sensitivity and specificity of O&P are highly dependent on local health care settings, such as the skill of the technician and the timing of the examination, as O&P should be carried out by a well-trained laboratory technician immediately (within 1 h) after sampling. We assessed the utility of Quik Chek through a multicenter cross-sectional study in Japan, and we sought to determine the best use of this technique to improve the diagnosis of amebiasis in clinical settings

Methods

Results

Conclusion