ABSTRACT
Several studies have shown associations between groups of intestinal bacterial or specific ratios between bacterial groups and various disease traits. Meanwhile, little is known about interactions and associations between eukaryotic and prokaryotic microorganisms in the human gut. In this work, we set out to investigate potential associations between common single-celled parasites such as Blastocystis spp. and Dientamoeba fragilis and intestinal bacteria. Stool DNA from patients with intestinal symptoms were selected based on being Blastocystis spp.-positive (B+)/negative (B-) and D. fragilis-positive (D+)/negative (D-), and split into four groups of 21 samples (B+ D+, B+ D-, B- D+, and B- D-). Quantitative PCR targeting the six bacterial taxa Bacteroides, Prevotella, the butyrate-producing clostridial clusters IV and XIVa, the mucin-degrading Akkermansia muciniphila, and the indigenous group of Bifidobacterium was subsequently performed, and the relative abundance of these bacteria across the four groups was compared. The relative abundance of Bacteroides in B- D- samples was significantly higher compared with B+ D- and B+ D+ samples (P < 0.05 and P < 0.01, respectively), and this association was even more significant when comparing all parasite-positive samples with parasite-negative samples (P < 0.001). Additionally, our data revealed that a low abundance of Prevotella and a higher abundance of Clostridial cluster XIVa was associated with parasite-negative samples (P < 0.05 and P < 0.01, respectively). Our data support the theory that Blastocystis alone or combined with D. fragilis is associated with gut microbiota characterized by low relative abundances of Bacteroides and Clostridial cluster XIVa and high levels of Prevotella.
Subject(s)
Bacteria/classification , Bacteria/genetics , Blastocystis Infections/microbiology , Dientamoebiasis/microbiology , Gastrointestinal Microbiome , Real-Time Polymerase Chain Reaction , Adolescent , Adult , Aged , Aged, 80 and over , Animals , Bacterial Load , Blastocystis/isolation & purification , Blastocystis Infections/parasitology , Child , Dientamoeba/isolation & purification , Dientamoebiasis/parasitology , Feces/microbiology , Feces/parasitology , Female , Humans , Male , Middle Aged , Young AdultABSTRACT
Dientamoeba fragilis is a pathogenic trichomonad parasite that causes gastrointestinal disease in humans. We report seven cases of travelers' diarrhea caused by D fragilis in patients who had traveled to overseas destinations within Asia or the Pacific which occurred over an 8-month period. Patients presented with diarrhea lasting from 5 days to over 4 weeks. Dientamoeba fragilis should be considered as a cause of diarrhea in returning travelers.
Subject(s)
Diarrhea/diagnosis , Diarrhea/prevention & control , Dientamoeba , Dientamoebiasis/diagnosis , Dientamoebiasis/prevention & control , Travel , Adult , Aged , Animals , Australia , Diagnosis, Differential , Diarrhea/microbiology , Dientamoebiasis/microbiology , Female , Humans , Male , Middle AgedABSTRACT
OBJECTIVES: To describe the clinical and microbiological features of Dientamoeba fragilis and Giardia lamblia infected patients, and to analyze the genetic variation of D. fragilis strains. METHODS: For a period of two years, all stool samples collected from patients suspected of having a parasitic gastrointestinal infection were examined according to our specific triple feces test (TFT) protocol. A retrospective case-control study was performed on D. fragilis and G. lamblia infected patients. Furthermore, PCR and genotyping by restriction fragment length polymorphism (RFLP) were performed upon the former. RESULTS: D. fragilis (6.3%) and G. lamblia (7.1%) were the most common pathogenic protozoa isolated out of 448 patients studied. Symptoms most frequently encountered with D. fragilis and G. lamblia infection were abdominal pain (69.2% and 72.4%, respectively) and diarrhea (61.5% and 79.3%, respectively). However, patients with D. fragilis infections suffered significantly less frequently from nausea and/or vomiting, anorexia and weight loss. After treatment, all D. fragilis and G. lamblia infected patients presenting a negative TFT follow-up also reported a complete resolution of their symptoms. Only genotype 1 could be detected in D. fragilis infected patients. CONCLUSIONS: D. fragilis and G. lamblia were the most frequently encountered parasites in our study population. Improved diagnostic tests are essential tools to study the prevalence and pathogenesis of D. fragilis.
