From Microbial Population Decline to Functional Shifts: Investigating the Impact of Broad-Spectrum Antibiotics on Intestinal Metabolites and Host Health

The gut microbiota, a complex and vital ecosystem, plays a fundamental role in maintaining host metabolic and immune homeostasis. However, this ecosystem is highly susceptible to disturbances from external factors, particularly broad-spectrum antibiotics. This review examines the cascading effects of these antibiotics on the structure and function of the gut microbiota and the subsequent consequences for human health. Antibiotic consumption is associated with a sharp decline in microbial diversity, the loss of beneficial commensal bacteria (such as butyrate-producing species), and the overgrowth of opportunistic pathogens—a process known as dysbiosis. This structural shift leads to profound disruptions in the gut metabolome, most notably a reduction in the production of short-chain fatty acids (SCFAs) and impaired conversion of primary to secondary bile acids. These functional alterations pave the way for a wide range of diseases. Within the gastrointestinal tract, these changes increase the risk of Clostridioides difficile infection, necrotizing enterocolitis (NEC) in premature infants, and inflammatory bowel disease (IBD). Metabolically, dysbiosis is linked to an elevated risk of obesity, type ۲ diabetes, and metabolic syndrome, partly due to altered metabolite signaling and its impact on glucose and lipid homeostasis. Furthermore, disruption of immune system development early in life can lead to an increased incidence of allergic and autoimmune diseases. Finally, this article explores therapeutic and preventive strategies such as the use of probiotics, prebiotics, and fecal microbiota transplantation (FMT) to restore microbial and metabolic balance, and outlines future research directions for developing personalized therapies and promoting more rational antibiotic prescribing.

کلیدواژه ها:

Gut microbiota ، Broad-spectrum antibiotics ، Dysbiosis ، Inflammatory bowel disease (IBD) ، Metabolic syndrome