Infant Antibiotic Resistance and Implications for Therapeutic Decision-making

Escalating resistance to antibiotics among disease-causing community bacteria increasingly threatens our ability to treat patients' infections. At the level of the physician-patient encounter, incentives at the patient level often take priority to society; this is often the case with antibiotic prescribing. Each patient level antibiotic treatment decision is based on how we value potential outcomes, including short-term benefits and risks and longer-term risks, including those related to future bacterial resistance to antibiotics. Unfortunately, antibiotics are often prescribed for illnesses unlikely to have a bacterial etiology; even a very small likelihood of benefit seems to outweigh an increased risk of future antibiotic resistance. While short-term effects of antibiotics on colonization with resistant bacteria have been demonstrated, the overall implications of each treatment for future individual, family and societal-level resistance remain difficult to quantify, and are often steeply discounted or ignored during decision-making. Knowledge regarding the longer-term effects of personal and household antibiotic use could better quantify these future resistance-related risks, and help guide antibiotic decision-making for physicians and patients.

Infants are born with sterile nasopharyngeal and gastrointestinal tracts and yet, during the 1st year of life, become important reservoirs of resistant organisms; this creates an opportunity to study colonization and resistance starting from a microbiological tabula rasa. In this proposal, we will use an observational cohort to following newborns' antibiotic exposure and longitudinal colonization with specific bacterial pathogens and related antibiotic resistance in the 1st year of life. Our hypothesis is that during the 1st year of life, infants with personal and household antibiotic exposure will have greater colonization with resistan organisms than infants without antibiotic exposure. This project will help us understand the development of bacteria that are resistant to antibiotics within the community, and help to inform judicious decision-making regarding antibiotic prescribing.