Contrasting microbiota profiles observed in children carrying either Blastocystis spp. or the commensal amoebas Entamoeba coli or Endolimax nana.

Recent studies have shown how intestinal parasites can modulate gut microbiota. This observation is not surprising since the human intestinal lumen, like any other niche, is a battlefield of microbial competition, and Eukaryotes can affect bacterial populations. Intestinal pathogenic protist has been associated with reshaping the microbial community structure; however, the interactions between the colonic bacterial communities and parasites like Blastocystis spp., Entamoeba coli, and Endolimax nana have been poorly studied. In this work, we studied the distal intestinal bacterial microbiota of 49 children attending 7 public daycare centers in Medellin, Colombia, and compared the bacterial microbiota structure in the presence or absence of the protists Blastocystis spp., E. coli, and E. nana. Parasite colonization was associated with an increase in bacterial richness. Moreover, Blastocystis spp. presented a positive relationship with Prevotella, since this bacterium was selectively enriched in children carrying it. Remarkably, the E. coli colonized children showed a microbial profile that was closer to uninfected controls, although some bacterial taxa displayed to be enriched. This is the case for Akkermansia, which showed to be favored in E. coli colonized individuals, while notably reduced in the Blastocystis spp. parasitized group.

Horizontal transmission of Endolimax piscium, causative agent of systemic amoebiasis in Senegalese sole Solea senegalensis.

Systemic amoebiasis of Senegalese sole Solea senegalensis is caused by Endolimax piscium Constenla, Padrós & Palenzuela, 2014 a cryptic parasitic member of the Archamoebae whose epidemiology is yet unknown. To test whether the parasite can be transmitted horizontally, an experimental trial by cohabitation between non-infected and infected fish was designed. Transmission of the parasite from naturally infected to healthy fish was confirmed in the experiment, with the water as the most likely route of infection. Under the conditions of the study, the infection process was remarkably slow, as parasites could be detected by in situ hybridization within the intestinal mucosa of recipient fish only after 17 wk of cohabitation, and none of the new hosts displayed clinical signs of disease. Long prepatent period and the need for additional triggering factors for the development of the clinical condition are suggested. The intestinal mucosa is proposed as the tissue where the amoeba can survive as endocommensal, but also as an invasion route from which the parasite would disperse to other organs.

A Cross-Sectional Study on Intestinal Parasitic Infections in Children in Suburban Public Primary Schools, Saraburi, the Central Region of Thailand.

Intestinal parasitic infection rate among school-aged children in Thailand has been decreasing. However, certain intestinal parasites remain problematic in some regions. This cross-sectional study was conducted between February and September 2016 in three suburban government primary schools (KK, BR, and HK), Saraburi, Thailand. Stool was collected from 263 asymptomatic subjects (4-15 years old), using simple direct smear, formalin-ether concentration, Boeck and Drbohlav's Locke-Egg-Serum (LES) medium culture, and agar plate culture. A self-administered questionnaire was used to collect data about lifestyle and socioeconomic status. The overall rate of intestinal parasites was 22.1% (15.6% single infection and 6.5% multiple infections). The helminths involving the digestive system found were Strongyloides stercoralis (1.5%) and Opisthorchis viverrini (0.4%). For protozoan infection, the major cause was Blastocystis hominis (17.5%). The other protozoa included Endolimax nana (4.6%), Entamoeba coli (3.4%), Entamoeba histolytica/Entamoeba dispar (1.1%), and Giardia intestinalis (0.8%). The sensitivity for the detection of B. hominis increased with the LES culture technique. The infection rate of each organism was not significantly different among the three schools except for B. hominis which showed the highest prevalence in the HK school (P = 0.001). This was correlated with the questionnaire results in which the HK school showed the highest risk of drinking contaminated water (P = 0.004). The present study emphasized the persistent problems of protozoan infections among suburban school-aged children. Lifestyle was still an important factor for intestinal parasitic infections among suburban school-aged Thai children in this study. Health education as well as routine surveillance was necessary to control the infections.

Variación estacional de las infecciones por protozoos intestinales en pacientes ambulatorios del sector norte de Santiago, Chile: 1995-1996 / Seasonal variation of intestinal protozoa infections in outpatients of the north section of Santiago, Chile: 1995-1996

Formalin preserved fecal samples from 6,058 and 5,863 outpatients were examined for intestinal parasites during 1995 and 1996 respectively. Prevalence rates of infections by intestinal protozoa in both years were similar. By age group (0-9, 10-19 and >20 years old). Blastocystis hominis was observed in 18.6-19.3, 37.0-31.1 and 25.3-25.4 percent in 1995-1996 respectively. Prevalence of giardia intestinalis infections decreased from 16.6-17.4 per cent in the 0-9 year-old children group to 4.1-4.5 percent in patients over 20 years. Overall percentages of infection by entamoeba histolytica varied between 4.2 and 10.9.Rates of infections by G. intestinalis, E. histolytica, and entamoeba coli observed during rainy-cold months (april-september) of the year versus dry-warmy period (october-march) were the same. On the contrary, more cases of B. hominis infection 25.8 percent versus 18.2 percent (this difference being statistically significant, p >0.001) were observed during rainy-cold months of the year

Blastocystis hominis e o exame parasitológico das fezes / Blastocystis hominis and the routine stool examination

Blastocystis hominis, um parasito intestinal do homem, foi anteriormente descrito como levedura. Ziertd e colaboradores estudaram e reclassificaram este organismo como um protozoário. O B. hominis no exame parasitológico das fezes deverá ser quantificado (raros, poucos, moderados, muitos). No mínimo três exames das fezes, para a pesquisa de ovos e parasitas (incluindo esfregaços permanentes corados), deveräo ser realizados, para assegurar a ausência de outros protozoários, antes de atribuir os sintomas ao B. hominis. A presença de outros agentes microbianos deverá também ser considerada

Contribution to the problem of the so-called nonpathogenic amoebae in the intestine of man.

Among 10,418 patients of a Prague hospital, a plain infection with intestinal parasitic protozoans was identified in 1,319 persons (12.7%). Of these, 3.5% were infested with Giardia intestinalis, 0.3% with Entamoeba histolytica forma minuta, 5.7% with Endolimax nana. We evaluated the frequency of findings of protozoans in various clinical diagnoses. A statistically significant increase in frequency was recorded for E. nana in diagnoses of eosinophilia, giardiasis, amoebiasis and helminthiasis. A slight increase above the average was found for Entamoeba coli in diagnoses of giardiasis and helminthiasis. Most cases of infection with Entamoeba histolytica were associated with a stay abroad. No increase in the frequency of these protozoans was recorded for patients with diarrhea. An analysis of the results indicated that a nonpathogenic amoeba might participate in the origin of intestinal disorders in man.