546 Therapeutic beta-lactam dosages and broad-spectrum antibiotics are associated with short-term reductions in microbial richness and beta-diversity

People with cystic fibrosis (PwCF) have recurrent pulmonary exacerbations associated with morbidity and mortality. Antibiotics are a mainstay of therapy, yet the beta-lactam doses administered are less than half the time. Our hypothesis was that sub-therapeutic and broad-spectrum antibiotic exposure leads to decreasing microbial diversity over time.