Zven SE, et al. - This study was undertaken to determine if exposure to multiple antibiotic classes in infancy was correlated with a higher risk of developing an allergic disease in early childhood. Antibiotic administration has an adverse effect on the microbiome by reducing bacterial diversity, and allergic disease has been linked to this. Exposure to multiple classes of antibiotics can result in even greater perturbations to the gut biome compared with 1 class alone.