The Impact of Early-Life Antibiotic Therapy on the Microbiota and the Risk of Developing Bronchial Asthma

The use of antibiotics in infancy is now a common practice in paediatric care, and is mainly used to treat bacterial infections as well as prevent severe sequelae. However, modern research shows that early exposure to antibiotics can produce unexpected long-term outcomes, in particular in relation to the development of the microbiota and immune system. The gut and respiratory tract microbiota are essential in the first few months of life in shaping the developing immune functions, tolerance and immunoprotective effects against pathogenic attacks. The antibiotic regimens, especially repeated courses, broad-spectrum agents can disrupt these delicate microbial communities to reduce diversity and lose commensal taxa, including, but not limited to, the genera of, for example, the Bifidobacterium and the Lactobacillus. The resulting dysbiosis can impair immunologic maturation, alter the production of essential metabolites, and alter the immune balance towards atopic phenotypes, which promotes the pathogenesis of bronchial asthma. Epidemiological studies have repeatedly shown that infants exposed to antibiotics, particularly during the first year of life, have a significantly higher probability of developing asthma, as children with cumulative courses worsen the situation. It is worth noting that this association is statistically significant even after correction for possible confounders, including recurrent infections and family atopy. The explanation of the interdependence of the early exposure to antibiotics on microbial ontogeny and immune modulation is of paramount importance to the caregivers as well as clinicians. Education of rational antibiotic use, support of the restoration of endogenous intestinal microbiota through breastfeeding or probiotic administration, and the enhancement of awareness of the possible long-term impact are all capable of reducing the rate of asthma development and promoting the development of more resilient immunity in children. The review summarises the available evidence, clarifies mechanistic foundations, and outlines approaches that can be used to prevent the unintentional effects of exposure to antibiotics at a young age.