Bacterial infections and nutrition - a primer

Bacteria are the predominant organisms in the human microbiome. They can be beneficial to the host, or they can cause focal and invasive diseases and clinical infections. The chapter explores the broad diversity of bacteria and ways in which they interact with the host. It considers the influence of host nutritional status and specific nutrients on colonization, invasion, severity, and mortality of bacterial infections. Overnutrition and metabolic diseases also affect risks of bacterial diseases, but are not a focus of this chapter. The effects of undernutrition on responses to vaccines against bacterial pathogens and the effects of antimicrobials on growth are addressed. Most examples are taken from malnutrition in children as, globally, they bear the greatest burden both of undernutrition and serious morbidity from bacterial infections and of disruptions in the commensal bacterial populations in the gastrointestinal tract that affect normal child growth and development. Where clinical trials are discussed, the main focus is on whether the trials demonstrate differences in bacterial disease incidence or mortality in response to nutrient interventions.