Caroline Michelle

Increased Gut Redox and Depletion of Anaerobic and Methanogenic Prokaryotes in Severe Acute Malnutrition

Severe acute malnutrition (SAM) is associated with inadequate diet, low levels of plasma antioxidants and gut microbiota alterations. The link between gut redox and microbial alterations, however, remains unexplored. By sequencing the gut microbiomes of 79 children of varying nutritional status from three centers in Senegal and Niger, we found a dramatic depletion of obligate anaerobes in malnutrition. This was confirmed in an individual patient data meta-analysis including 107 cases and 77 controls from 5 different African and Asian countries. Specifically, several species of the Bacteroidaceae, Eubacteriaceae, Lachnospiraceae and Ruminococceae families were consistently depleted while Enterococcus faecalis, Escherichia coli and Staphylococcus aureus were consistently enriched. Further analyses on our samples revealed increased fecal redox potential, decreased total bacterial number and dramatic Methanobrevibacter smithii depletion. Indeed, M. smithii was detected in more than half of the controls but in none of the cases. No causality was demonstrated but, based on our results, we propose a unifying theory linking microbiota specificity, lacking anaerobes and archaea, to low antioxidant nutrients, and lower food conversion.

A Metagenomic Investigation of the Duodenal Microbiota Reveals Links with Obesity.

Background Few studies have tested the small intestine microbiota in humans, where most nutrient digestion and absorption occur. Here, our objective was to examine the duodenal microbiota between obese and normal volunteers using metagenomic techniques. Methodology/Principal Findings We tested duodenal samples from five obese and five normal volunteers using 16S rDNA V6 pyrosequencing and Illumina MiSeq deep sequencing. The predominant phyla of the duodenal microbiota were Firmicutes and Actinobacteria, whereas Bacteroidetes were absent. Obese individuals had a significant increase in anaerobic genera (p < 0.001) and a higher abundance of genes encoding Acyl-CoA dehydrogenase (p = 0.0018) compared to the control group. Obese individuals also had a reduced abundance of genes encoding sucrose phosphorylase (p = 0.015) and 1,4-alpha-glucan branching enzyme (p = 0.05). Normal weight people had significantly increased FabK (p = 0.027), and the glycerophospholipid metabolism pathway revealed the presence of phospholipase A1 only in the control group (p = 0.05). Conclusions/Significance The duodenal microbiota of obese individuals exhibit alterations in the fatty acid and sucrose breakdown pathways, probably induced by diet imbalance.

Non-contiguous finished genome sequence and description of Megasphaera massiliensis sp. nov.

Megasphaera massiliensis strain NP3T sp. nov. is the type strain of Megasphaera massiliensis sp. nov., a new species within the genus Megasphaera. This strain, whose genome is described here, was isolated from the fecal flora of an HIV-infected patient. M. massiliensis is a Gram-negative, obligate anaerobic coccobacillus. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 2,661,757 bp long genome (1 chromosome but no plasmid) contains 2,577 protein-coding and 61 RNA genes, including 5 rRNA genes.

Gut microbiota associated with HIV infection is significantly enriched in bacteria tolerant to oxygen

Objectives Gut microbiota modifications occurring during HIV infection have recently been associated with inflammation and microbial translocation. However, discrepancies between studies justified a comprehensive analysis performed on a large sample size. Design and methods In a case–control study, next-generation sequencing of the 16S rRNA gene was applied to the faecal microbiota of 31 HIV-infected patients, of whom 18 were treated with antiretroviral treatment (ART), compared with 27 healthy controls. 21 sera samples from HIV-infected patients and 7 sera samples from control participants were used to test the presence of 25 markers of inflammation and/or immune activation. Results Diversity was significantly reduced in HIV individuals when compared with controls and was not restored in the ART group. The relative abundance of several members of Ruminococcaceae such as Faecalibacterium prausnitzii was critically less abundant in the HIV-infected group and inversely correlated with inflammation/immune activation markers. Members of Enterobacteriaceae and Enterococcaceae were found to be enriched and positively correlated with these markers. There were significantly more aerotolerant species enriched in HIV samples (42/52 species, 80.8%) when compared with the control group (14/87 species, 16.1%; χ2 test, p<10−5, conditional maximum-likelihood estimate (CMLE) OR=21.9). Conclusions Imbalance between aerobic and anaerobic flora observed in HIV faecal microbiota could be a consequence of the gut impairment classically observed in HIV infection via the production of oxygen. Overgrowth of proinflammatory aerobic species during HIV infection raises the question of antioxidant supplementation, such as vitamin C, E or N-acetylcysteine.

Host-Associated Metagenomics: A Guide to Generating Infectious RNA Viromes.

Background Metagenomic analyses have been widely used in the last decade to describe viral communities in various environments or to identify the etiology of human, animal, and plant pathologies. Here, we present a simple and standardized protocol that allows for the purification and sequencing of RNA viromes from complex biological samples with an important reduction of host DNA and RNA contaminants, while preserving the infectivity of viral particles. Principal Findings We evaluated different viral purification steps, random reverse transcriptions and sequence-independent amplifications of a pool of representative RNA viruses. Viruses remained infectious after the purification process. We then validated the protocol by sequencing the RNA virome of human body lice engorged in vitro with artificially contaminated human blood. The full genomes of the most abundant viruses absorbed by the lice during the blood meal were successfully sequenced. Interestingly, random amplifications differed in the genome coverage of segmented RNA viruses. Moreover, the majority of reads were taxonomically identified, and only 7–15% of all reads were classified as “unknown”, depending on the random amplification method. Conclusion The protocol reported here could easily be applied to generate RNA viral metagenomes from complex biological samples of different origins. Our protocol allows further virological characterizations of the described viral communities because it preserves the infectivity of viral particles and allows for the isolation of viruses.

Genome sequence and description of Nesterenkonia massiliensis sp. nov. strain NP1(T.).

Nesterenkonia massiliensis sp. nov., strain NP1T, is the type strain of Nesterenkonia massiliensis sp. nov., a new species within the genus Nesterenkonia. This strain, whose genome is described here, was isolated from the feces of a 32-year-old French woman suffering from AIDS and living in Marseille. Nesterenkonia massiliensis is a Gram-positive aerobic coccus. Here, we describe the features of this bacterium, together with the complete genome sequencing and annotation. The 2,726,371 bp long genome (one chromosome but no plasmid) contains 2,663 protein-coding and 51 RNA genes, including 1 rRNA operon.

Noncontiguous finished genome sequence and description of Kallipyga gabonensis sp. nov.

Taxonogenomics coupled with culturomics promotes the isolation and characterization of bacteria. Kallipyga gabonensis sp. nov. strain GM4 is a strictly anaerobic, Gram-positive, and non motile coccus isolated from the stool of a Gabonese male teenager. The genome is 1,621,211 bp long with 50.01% G+C content and two scaffolds. Of the 1,536 predicted genes, 1,475 were protein-coding genes and 61 were RNA genes. A total of 931 genes were assigned a putative function, and 79 genes were identified as ORFans.

Screening for Viral Pathogens in African Simian Bushmeat Seized at A French Airport.

Summary Illegal bushmeat traffic is an important threat to biodiversity conservation of several endangered species and may contribute to the emergence and spread of infectious diseases in humans. The hunting, manipulation and consumption of wildlife‐based products, especially those of primate origin, may be a threat to human health; however, few studies have investigated the role of bushmeat trade and consumption as a potential source of human infections to date. In this study, we report the screening of viral pathogens in African simian game seized by French customs at Toulouse Blagnac Airport. Epifluorescence microscopy revealed the presence of virus‐like particles in the samples, and further metagenomic sequencing of the DNA and RNA viromes confirmed the presence of sequences related to the Siphoviridae, Myoviridae and Podoviridae bacteriophage families; some of them infecting bacterial hosts that could be potentially pathogenic for humans. To increase the sensitivity of detection, twelve pan‐generic PCRs targeting several viral zoonoses were performed, but no positive signal was detected. A large‐scale inventory of bacteria, viruses and parasites is urgently needed to globally assess the risk for human health of the trade, manipulation and consumption of wildlife‐related bushmeat.

Blautia massiliensis sp. nov., isolated from a fresh human fecal sample and emended description of the genus Blautia

The strain GD9T is the type strain of the newly proposed species Blautia massiliensis sp. nov., belonging to the family Lachnospiraceae. It was isolated from a fresh stool sample collected from a healthy human using the culturomics strategy. Cells are Gram-negative rods, oxygen intolerant, non-motile and non-spore forming. The 16S rRNA gene sequencing showed that strain GD9T was closely related to Blautia luti, with a 97.8% sequence similarity. Major fatty acids were C14:0 (19.8%) and C16:0 (53.2%). Strain GD9T exhibits a genome of 3,717,339 bp that contains 3,346 protein-coding genes and 81 RNAs genes including 63 tRNAs. The features of this organism are described here, with its complete genome sequence and annotation. Compared with other Blautia species which are Gram positive, the strain was Gram negative justifying an emended description of the genus Blautia.

Bacillus rubiinfantis sp. nov. strain mt2T, a new bacterial species isolated from human gut

Bacillus rubiinfantis sp. nov. strain mt2T is the type strain of B. rubiinfantis sp. nov., isolated from the fecal flora of a child with kwashiorkor in Niger. It is Gram-positive facultative anaerobic rod belonging to the Bacillaceae family. We describe the features of this organism alongside the complete genome sequence and annotation. The 4 311 083 bp long genome (one chromosome but no plasmid) contains 4028 protein-coding gene and 121 RNA genes including nine rRNA genes.