Human_infections_with_the_whipworm__Trichuris_trichiura__are_not_associated_with_alterations_in_the_faecal_microbiota_

Materials and Methods: We carried out the study in two rural communities in Esmeraldas Province, Ecuador. School-age children were screened for the presence of STH infections and allocated to one of 3 groups: uninfected, T. trichiura only, and mixed infections with T. trichiura and Ascaris lumbricoides. A sample of uninfected children and those with T. trichiura infections only were treated with albendazole (800 mg/day for 3 days) and ivermectin (single dose of 200 ug/kg), and stool samples were collected 3 weeks post-treatment. Bacterial DNA was extracted using the FastDNA Spin kit for soil, and bacterial community profiles were studied by 454 pyrosequencing of 16S rRNA genes. This generated 999,796 sequences, which were processed and analysed using mothur. Results: Microbiota analyses were done using stool samples from 97 children aged 8-14 years of whom 30 were not infected, 17 were infected with T. trichiura alone, and 50 had mixed infections with both T. trichiura and A. lumbricoides. Post-treatment samples were analyzed for 14 of the 17 children initially infected with T. trichiura alone and 21 of 30 uninfected children. Treatment resulted in 100% cure of STH infections. Comparisons of the microbiota at different taxonomic levels showed no statistically significant differences in composition between uninfected children and those with T. trichiura infections. A surprising finding was a decreased proportional abundance of a few bacterial genera from the clostridia class of Firmicutes, in tandem with a reduced overall bacterial diversity, among children with mixed infections compared to either uninfected children or those with T. trichiura infections only, indicating a specific effect of A. lumbricoides infection on intestinal microbiota. Anthelmintic treatment of children with T. trichiura did not appear to alter composition of faecal microbiota. Discussion: This is the first molecular study to analyse the effect of whipworm infection on the human intestinal microbiota. Our data indicate that T. trichiura infections alone have no effect on the faecal microbiota of children living in endemic communities, but that A. lumbricoides colonisation might be associated with a disturbed microbiota. Our results also catalogue the microbiota that is present in rural Ecuadorians, and indicate that there are differences between this cohort and individuals from more urban, industrialised societies.