Alterations in Gut Microbiota Profiles of Mice Infected with Echinococcus granulosus sensu lato Microbiota Profiles of Mice Infected with E. granulosus s.l

Identification and comparison of intestinal microbial diversity in patients at different stages of hepatic cystic echinococcosis

There is a significant focus on the role of the host microbiome in different outcomes of human parasitic diseases, including cystic echinococcosis (CE). This study was conducted to identify the intestinal microbiome of patients with CE at different stages of hydatid cyst compared to healthy individuals. Stool samples from CE patients as well as healthy individuals were collected. The samples were divided into three groups representing various stages of hepatic hydatid cyst: active (CE1 and CE2), transitional (CE3), and inactive (CE4 and CE5). One family member from each group was selected to serve as a control. The gut microbiome of patients with different stages of hydatid cysts was investigated using metagenomic next-generation amplicon sequencing of the V3-V4 region of the 16S rRNA gene. In this study, we identified 4862 Operational Taxonomic Units from three stages of hydatid cysts in CE patients and healthy individuals with a combined frequency of 2,955,291. The most abundant genera observed in all the subjects were Blautia, Agathobacter, Faecalibacterium, Bacteroides, Bifidobacterium, and Prevotella. The highest microbial frequency was related to inactive forms of CE, and the lowest frequency was observed in the group with active forms. However, the lowest OTU diversity was found in patients with inactive cysts compared with those with active and transitional cyst stages. The genus Agatobacter had the highest OTU frequency. Pseudomonas, Gemella, and Ligilactobacillus showed significant differences among the patients with different stages of hydatid cysts. Additionally, Anaerostipes and Candidatus showed significantly different reads in CE patients compared to healthy individuals. Our findings indicate that several bacterial genera can play a role in the fate of hydatid cysts in patients at different stages of the disease.

Rodent Gut Bacteria Coexisting with an Insect Gut Virus in Tapeworm Parasitic Cysts: Metagenomic Evidence of Microbial Selection in Extra-Intestinal Clinical Niches

In medicine, parasitic cysts (e.g., brain cysticerci) are believed to be sterile, and are primarily treated with antiparasitic medications, not antibiotics, which could prevent abscess formation and localized inflammation. This study quantified the microbial composition of parasitic cysts in a wild rodent, using multi-kingdom metagenomics to comprehensively assess if parasitic cysts are sterile, and further understand gut microbial translocation and adaptation in wildlife confined environments, outside the gut. Analysis was conducted on DNA from two hepatic parasitic cysts from a feline tapeworm, Hydatigera (Taenia) taeniaeformis, affecting a wild vole mouse (Microtus pennsylvanicus), and from feces, liver and peritoneal fluid of this and two other concurrent individual wild voles trapped during pest control in one of our university research vegetable gardens. Bacterial metagenomics revealed the presence of gut commensal/opportunistic species, Parabacteroides distasonis, Bacteroides (Bacteroidota); Klebsiella variicola, E. coli (Enterobacteriaceae); Enterococcus faecium and Lactobacillus acidophilus (Bacillota) inhabiting the cysts, and peritoneal fluid. Remarkably, viral metagenomics revealed various murine viral species, and unexpectedly, a virus from the insect armyworm moth (Pseudaletia/Mythimna unipuncta), known as Mythimna unipuncta granulovirus A (MyunGV-A), in both cysts, and in one fecal and one peritoneal sample from the other non-cyst voles, indicating the survival and adaption potential of the insect virus in voles. Metagenomics also revealed a significantly lower probability of fungal detection in cysts compared to that in peritoneal fluid/feces (p < 0.05), with single taxon detection in each cyst (Malassezia and Pseudophaeomoniella oleicola). The peritoneal fluid had the highest probability for fungi. In conclusion, metagenomics revealed that bacteria/viruses/fungi coexist within parasitic cysts supporting the potential therapeutic benefits of antibiotics in cystic diseases, and in inflammatory microniches of chronic diseases, such as Crohn's disease gut wall cavitating micropathologies, from which we recently isolated similar synergistic pathogenic Bacteroidota and Enterobacteriaceae, and Bacillota.

Rodent Gut Bacteria Coexisting with an Insect Gut Virus in Parasitic Cysts: Metagenomic Evidence of Microbial Translocation and Co-adaptation in Spatially-Confined Niches

In medicine, parasitic cysts or cysticerci (fluid-filled cysts, larval stage of tapeworms) are believed to be sterile (no bacteria), and therein, the treatment of cysticerci infestations of deep extra-intestinal tissues (e.g., brain) relies almost exclusively on the use of antiparasitic medications, and rarely antibiotics. To date, however, it is unclear why common post-treatment complications include abscessation. This study quantified the microbial composition of parasitic cyst contents in a higher-order rodent host, using multi-kingdom shotgun metagenomics, to improve our understanding of gut microbial translocation and adaptation strategies in wild environments. Analysis was conducted on DNA from two hepatic parasitic cysts (Hydatigera (Taeenia) taeniaeformis) in an adult vole mouse (Microtus arvalis), and from feces, liver, and peritoneal fluid of three other vole family members living in a vegetable garden in Ohio, USA. Bacterial metagenomics revealed the presence of gut commensal/opportunistic species, including Parabacteroides distasonis, Klebsiella variicola, Enterococcus faecium, and Lactobacillus acidophilus, inhabiting the cysts. Parabacteroides distasonis and other species were also present outside the cyst in the peritoneal fluid. Remarkably, viral metagenomics revealed various murine viral species, but unexpectedly, it detected an insect-origin virus from the army moth (Pseudaletia/Mythimna unipuncta) known as Mythimna unipuncta granulovirus A (MyunGV-A) in both cysts, and in one fecal and one peritoneal sample from two different voles, indicating survival of the insect virus and adaption in voles. Metagenomics also revealed a significantly lower probability of fungal detection in the cysts compared to other samples (peritoneal fluid, p<0.05; and feces p<0.05), with single taxon detection in each cyst for Malassezia and Pseudophaeomoniella oleicola. The samples with a higher probability of fungi were the peritoneal fluid. In conclusion, commensal/pathobiont bacterial species can inhabit parasitic tapeworm cysts, which needs to be considered during therapeutic decisions of cysticerci or other chronic disease scenarios where immune privileged and spatially restricted ecosystems with limited nutrients and minimal presence of immune cells could facilitate microbial adaptation, such as within gut wall cavitating micropathologies in Crohn's disease.

Changes in intestinal flora of mice induced by rEg.P29 epitope peptide vaccines

OBJECTIVE

Cystic echinococcosis (CE), a zoonotic parasitic disease caused by Echinococcus granulosus, remains a public health and socioeconomic issue worldwide, making its prevention and treatment of vital importance. The aim of this study was to investigate changes in the intestinal microbiota of mice immunized with three peptide vaccines based on the recombinant antigen of E. granulosus, P29 (rEg.P29), with the hope of providing more valuable information for the development of vaccines against CE.

METHODS

Three peptide vaccines, rEg.P29T , rEg.P29B , and rEg.P29T + B , were prepared based on rEg.P29, and a subcutaneous immunization model was established. The intestinal floras of mice in the different immunization groups were analyzed by 16 S rRNA gene sequencing.

RESULTS

The intestinal microbiota analysis at both immunization time points revealed that Firmicutes, Bacteroidota, and Verrucomicrobiota were the predominant flora at the phylum level, while at the genus level, Akkermansia, unclassified_Muribaculaceae, Lachnospiraceae_NK4A136_group, and uncultured_rumen bacterium were the dominant genera. Some probiotics in the intestines of mice were significantly increased after immunization with the peptide vaccines, such as Lactobacillus_taiwanensis, Lactobacillus_reuteri, Lachnospiraceae_NK4A136_group, Bacteroides_acidifaciens, and so forth. Meanwhile, some harmful or conditionally pathogenic bacteria were decreased, such as Turicibacter sanguinis, Desulfovibrio_fairfieldensis, Clostridium_sp, and so forth, most of which are associated with inflammatory or infectious diseases. Kyoto Encyclopaedia of Genes and Genomes enrichment analysis revealed that the differential flora were enriched in multiple metabolic pathways, primarily biological systems, human diseases, metabolism, cellular processes, and environmental information processing.

CONCLUSION

In this study, we comprehensively analyzed and compared changes in the intestinal microbiota of mice immunized with three peptide vaccines as well as their related metabolic pathways, providing a theoretical background for the development of novel vaccines against E. granulosus.