Differences in the Biodiversity of the Fecal Microbiota of Infants With Rotaviral Diarrhea and Healthy Infants

Analysis of the intestinal microbial community altered during rotavirus infection in suckling mice

Background

Rotavirus (RV) is a principal cause of diarrhea. However, there is a limited understanding regarding alteration of the gut microbial community structure and abundance during RV infection. This study was to characterize any potential associations between RV infection and the intestinal microbiota.

Methods

Suckling mice were divided into normal group (NC) and infected group (RV) randomly. All of the suckling mice were euthanized four days post-RV infection. The virus titer was counted as fluorescent focus assay, and viral load was quantified by QPCR. Five sucking mice were randomly selected from each RV group and NC group for sample collection and pathological analysis. Mixed intestinal contents of the colon and rectum were collected from all of the suckling mice. To investigate the detailed relationship between RV infection and intestinal microbiota, the composition and distribution of intestinal microbiota from suckling mice were first analyzed using 16S rRNA sequencing technology.

Results

The results of the pathological characteristics showed that vacuolar degeneration, vasodilation, hyperemia, and destruction of the intestinal epithelium were apparent in the RV group. Representative genera from Lactobacillus and Fusobacterium were enriched in the NC group, while the Enterococcus and Escherichia/Shigella genera were enriched in the RV group. Helicobacter, Alloprevotrlla, Brevundimonas, Paenibacillus, and Parabacteroides were completely undetectable in the RV group. The predicted intestinal flora metabolic function results showed that “carbohydrate metabolism” and “lipid metabolism” pathways were significantly enriched within the NC group. A significant difference has been observed in the gut microbiota composition between the two groups.

Conclusions

Our results demonstrated a significant difference in the gut microbiota composition in RV-infected suckling mice as compared to the RV un-infected suckling mice group. This work may provide meaningful information regarding the bacterial genera changed during RV infection. Moreover, the changes in these bacteria may be related with the replication and pathogenesis of RV infection.

Intestinal microbiota profiles in infants with acute gastroenteritis caused by rotavirus and norovirus infection: a prospective cohort study

OBJECTIVE

To compare the intestinal microbiota profiles in infants following rotavirus (RV) and human norovirus (HNoV) infection.

METHODS

Faecal specimens from 18 infants {mean age 11.8 months [standard deviation (SD) 3.0] months} with acute gastroenteritis caused by RV (G9P8) and 24 infants [mean age 8.8 (SD 6.4) months] with acute gastroenteritis caused by HNoV (GII) infection were collected prospectively. The faecal microbiome was assessed by 16S rRNA amplicon pyrosequencing. Alpha diversity, beta diversity, deferentially abundant taxa and microbial functions were assessed by bioinformatic analysis.

RESULTS

The Chao1 index for the HNoV group was significantly higher compared with the control group (P=0.0003), and was lower for the RV group compared with the HNoV group (P=0.0078). No significant difference in beta diversity was observed between the RV and HNoV groups. The RV group showed greater abundance of Actinobacteria at phylum level and Bifidobacterium spp., Streptococcus spp., Enterococcus spp. and Lactobacillus spp. at genus level. The HNoV group showed richness in Fusobacteria and Cyanobacteria at phylum level, and Enterococcus spp. and Streptococcus spp. at genus level. Bacillus was the characteristic genus in infected infants. In comparison with the control group, the viral group (P≤0.01), the RV group (P=0.002) and the HNoV group (P≤0.01) showed significant differences in potentially pathogenic bacteria.

CONCLUSIONS

Changes in microbiotic structure were observed in infants following RV and HNoV infection. The Chao 1 index of alpha diversity increased significantly in the HNoV group. Bacillus was the characteristic genus in infected infants. An increase in pathogenic bacteria, particularly Streptococcus spp. and Enterococcus spp., was detected in infected infants.

Development and diversity of lactic acid producing bacteria and bifidobacteria in healthy full term Indian infants from Himachal Pradesh

Background/Aims

The initial microbial colonization is a crucial step for the healthy development of an infant. Previous studies from India reported the dominance of target microbial species among Indian infants without any analysis on the diversity of target groups. This is the first study from India with an objective to investigate the establishment and diversity of lactic acid producing bacteria (LAB) and bifidobacteria in vaginally delivered, full term, breastfed infants for the first 4 months after birth.

Methods

Present study used polymerase chain reaction-denaturating gradient gel electrophoresis (PCR-DGGE) based sequence analysis of LAB and bifidobacteria in healthy infants. The results were used to compare the development and early colonization by LAB and bifidobacteria using diversity indices during the initial months of development of gut microbiota in infants.

Results

During the first 4 months, the Shannon diversity index (H) of LAB increased from 1.16 to 1.318 and for bifidobacteria the H increased from 0.975 to 1.293 (P<0.05). Higher Sorenson's pair wise similarity coefficient was observed for LAB and bifidobacteria during 2nd and the 3rd month. The species of the genera Enterococcus, Streptococcus, and Lactobacillus were dominant among the LAB group whereas Bifidobacterium breve was dominant species among Bifidobacterium group.

Conclusions

Our results indicate that in breast fed infants, the microbial diversity of LAB and bifidobacteria increased during the period of study.

Impact of nutrition and rotavirus infection on the infant gut microbiota in a humanized pig model

BACKGROUND

Human rotavirus (HRV) is a major cause of viral gastroenteritis in infants; particularly in developing countries where malnutrition is prevalent. Malnutrition perturbs the infant gut microbiota leading to sub-optimal functioning of the immune system and further predisposing infants to enteric infections. Therefore, we hypothesized that malnutrition exacerbates rotavirus disease severity in infants.

METHODS

In the present study, we used a neonatal germ free (GF) piglets transplanted with a two-month-old human infant's fecal microbiota (HIFM) on protein deficient and sufficient diets. We report the effects of malnourishment on the HRV infection and the HIFM pig microbiota in feces, intestinal and systemic tissues, using MiSeq 16S gene sequencing (V4-V5 region).

RESULTS

Microbiota analysis indicated that the HIFM transplantation resulted in a microbial composition in pigs similar to that of the original infant feces. This model was then used to understand the interconnections between microbiota diversity, diet, and HRV infection. Post HRV infection, HIFM pigs on the deficient diet had lower body weights, developed more severe diarrhea and increased virus shedding compared to HIFM pigs on sufficient diet. However, HRV induced diarrhea and shedding was more pronounced in non-colonized GF pigs compared to HIFM pigs on either sufficient or deficient diet, suggesting that the microbiota alone moderated HRV infection. HRV infected pigs on sufficient diet showed increased microbiota diversity in intestinal tissues; whereas, greater diversity was observed in systemic tissues of HRV infected pigs fed with deficient diet.

CONCLUSIONS

These results suggest that proper nourishment improves the microbiota quality in the intestines, alleviates HRV disease and lower probability of systemic translocation of potential opportunistic pathogens/pathobionts. In conclusion, our findings further support the role for microbiota and proper nutrition in limiting enteric diseases.