Grant: Banting Postdoctoral Fellowship Program

Bacteria living in the digestive tract (known as gut microbiota) play a crucial role in immune system development. Disruption of infant gut microbiota has the potential to cause allergic disease later in childhood. We and others have found that antibiotic use, formula feeding and caesarean delivery can significantly alter the infant gut microbiota. These exposures are also important risk factors for allergy and asthma in children. The impact of antibiotic-mediated microbiota disturbance is poorly understood because infants receiving antibiotics are often excluded from studies, and the impact of other environmental factors (e.g. siblings, pets, daycare attendance) has not been widely studied. My goal is to systematically investigate the impact of antibiotic use and environmental exposures on infant gut microbiota, and subsequent development of allergic disease. I will employ the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort study as a research platform. Environmental exposures and type of feeding will be obtained by parent questionnaire, and antibiotic use will be determined from provincial prescription records. Microbiota profiles will be generated via genetic analysis of fecal samples, and allergic disease will be evaluated by skin prick test for common allergies, diagnosis of allergic eczema, and parent-reported wheeze. Specialized statistical methods will be used to examine microbiota changes according to exposures, and to test their impact on subsequent development of allergic disease. The incidence of allergic disease has increased dramatically in recent years, representing a significant global health and economic burden. New evidence suggests that modifiable environmental exposures may be responsible, through their impact on the gut microbiota. My proposed research aims to provide evidence for this "microbiota hypothesis", with the potential to impact clinical practice guidelines and prevention strategies.