Children with severe malnutrition who are admitted sick to hospitals have a high mortality, usually because of infection. All children with severe malnutrition admitted to hospitals are treated with antibiotics. However, policymakers are not sure that the current antibiotics are the most effective. It is possible that the antibiotics that are currently used as second-line should be used first. Finding this out will need a large trial comparing different antibiotics. To prepare for such a trial the investigators first want to make sure that the doses given are correct for malnourished children. The investigators also want to check whether malnourished children more commonly carry resistant bacteria in their feces than well-nourished children. The study is important because the types of antibiotics and the doses needed to fight infection may be different in malnourished children because of the changes in their body due to malnutrition and the types of bacteria present.