The investigators performed two case-control studies in Niger and Senegal analysing fecal microbiota to characterize the specificity of the gut microbiota alteration associated with severe acute malnutrition (SAM).

Fecal samples of cases (severe acute malnutrition (SAM) ascertained according to the WHO definition) and controls (asymptomatic healthy children ascertained by clinical and anthropometric criteria) were analysed by v3v4 16S rRNA sequencing, redox and pH measurement and using specific polymerase chain reaction targeting Methanobrevibacter smithii and Bacteroides thetaiotaomicron. Based on the literature and oxydative stress reported in SAM, the investigators tested if the proportion of aerotolerant prokaryotes is increased among gut prokaryotes enriched in SAM in comparison to prokaryotes enriched in controls. The investigators further linked this to fecal redox potential and assessed the total number of bacteria in feces by flux cytometry.

Inclusion criteria:

• Children aged 0-59 months of varying nutritional status from Niamey (Niger) and Dakar (Senegal).

Exclusion Criteria:

• Absence of parent or patient consent, antibiotic administration <2 months before stool collection and insufficient fecal amount. Exclusion criteria for controls included any form of malnutrition, presence of fever, acute respiratory infection (cough), acute or chronic diarrhea in the previous 4 weeks. Symptoms and complications of malnutrition (cough, fever, diarrhoea, vomiting) nor other form of malnutrition (moderate to severe stunting and underweight) were not a reason of exclusion for cases since they are considered as direct consequence and part of severe acute malnutrition.

Children from Niamey and Dakar, Senegal