Yasuaki Yanagawa1, Naoyoshi Nagata2,3, Kenji Yagita4, Kazuhiro Watanabe2, Hidetaka Okubo2, Yoshimi Kikuchi1, Hiroyuki Gatanaga1,5, Shinichi Oka1,5, Koji Watanabe1. 1. AIDS Clinical Center, National Center of Global Health and Medicine, Tokyo, Japan. 2. Department of Gastroenterology and Hepatology, National Center of Global Health and Medicine, Tokyo, Japan. 3. Department of Gastroenterological Endoscopy, Tokyo Medical University, Tokyo, Japan. 4. Department of Parasitology, National Institutes of Infectious Diseases, Tokyo, Japan. 5. Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan.
Abstract
BACKGROUND: Entamoeba histolytica infection is a sexually transmitted disease in some developed countries. Asymptomatic infection often occurs and can be a source of transmission; however, limited data are available regarding the pathogenesis of E. histolytica. METHODS: This is a single center cross-sectional study. Specimens were prospectively collected from patients with clinically suspected cases. "E. histolytica infection" was defined as a case in which the identification of E. histolytica was confirmed by PCR of a clinical specimen. Data from asymptomatic cases were compared with those from symptomatic invasive cases. RESULTS: Sixty-four E. histolytica-infected cases, including 13 asymptomatic cases, were identified during the study period. Microbiological diagnosis was made by endoscopic sampling in 26.6% of these cases (17/64). Endoscopy identified macroscopically visible lesions in all cases; however, the sensitivity of histopathology on biopsy samples was low (45.5%) compared with PCR (94.7%). In asymptomatic cases, infection sites were limited around the proximal colon; moreover, trophozoites were frequently identified at infection sites whereas cystic forms were commonly detected in stools. Gut microbiome analyses showed more uniform composition in asymptomatic cases than in symptomatic invasive cases, which were represented by a relatively high abundance of Ruminococcaceae, Coriobacteriaceae, and Clostridiaceae, and a low abundance of Streptococcaceae. CONCLUSION: These results indicate that the encystation and attenuation of E. histolytica are highly affected by the intestinal contents, including the gut microbiome.
BACKGROUND:Entamoeba histolytica infection is a sexually transmitted disease in some developed countries. Asymptomatic infection often occurs and can be a source of transmission; however, limited data are available regarding the pathogenesis of E. histolytica. METHODS: This is a single center cross-sectional study. Specimens were prospectively collected from patients with clinically suspected cases. "E. histolyticainfection" was defined as a case in which the identification of E. histolytica was confirmed by PCR of a clinical specimen. Data from asymptomatic cases were compared with those from symptomatic invasive cases. RESULTS: Sixty-four E. histolytica-infected cases, including 13 asymptomatic cases, were identified during the study period. Microbiological diagnosis was made by endoscopic sampling in 26.6% of these cases (17/64). Endoscopy identified macroscopically visible lesions in all cases; however, the sensitivity of histopathology on biopsy samples was low (45.5%) compared with PCR (94.7%). In asymptomatic cases, infection sites were limited around the proximal colon; moreover, trophozoites were frequently identified at infection sites whereas cystic forms were commonly detected in stools. Gut microbiome analyses showed more uniform composition in asymptomatic cases than in symptomatic invasive cases, which were represented by a relatively high abundance of Ruminococcaceae, Coriobacteriaceae, and Clostridiaceae, and a low abundance of Streptococcaceae. CONCLUSION: These results indicate that the encystation and attenuation of E. histolytica are highly affected by the intestinal contents, including the gut microbiome.