RETRACTED ARTICLE: Increased Gut Redox and Depletion of Anaerobic and Methanogenic Prokaryotes in Severe Acute Malnutrition

Abstract

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.

Rubeoparvulum massiliense gen. nov., sp. nov., a new bacterial genus isolated from the human gut of a Senegalese infant with severe acute malnutrition

“…Its composition matures rapidly for the first year and reaches adult form by 3 years [2], [3]. A disruption of its equilibrium has been proven to be implicated in a growing number of pathologies such as inflammatory bowel disease, irritable bowel syndrome, obesity [3], [4] and severe acute malnutrition [5], [6], [7].…”

Community metabolic modeling approaches to understanding the gut microbiome: Bridging biochemistry and ecology

“…In the mature gut, different species continue to position themselves along this radial oxygen gradient in the same manner, with bacteria capable of consuming oxygen concentrated near the oxygen-rich gut mucosa[21]. Importantly, research in mice shows that altering the host’s oxygen levels can modify the composition of the gut microbiota[21]; in humans, it has been proposed that diet may affect oxygenation levels in the gut by modulating the availability of antioxidants[22]. …”

Draft Genome Sequence of Blautia faecis Strain Marseille-P328, Isolated from the Human Ascending Colon

“…Species of this genus are Gram positive, coccoid or oval-shaped, and strictly anaerobic bacteria normally found in human stool samples. Blautia species are part of the human healthy mature anaerobic gut microbiota (2, 3). Three new Blautia species ( B. faecis , B. stercoris , and B. glucerasea ) were then discovered, and another Ruminococcus species ( R. obeum ) was moved to this genus, bringing the total number of Blautia species to 11 (4–7).…”