Effect of Antibiotics on Urinary Microbiome: Randomized Trial

Urinary tract infections (UTI) are the most common type of human bacterial disease, prompting more than 10 million physician office visits annually at a healthcare cost of over $1 billion dollars. Treatment of UTI is typically empiric or culture-driven antibiotics which are associated with ever increasing bacterial resistance. Over the last decade, The Human Microbiome Project has established that even 'culture-negative' urine represents a diverse ecosystem of bacteria. Despite broad use of antibiotics to cure disease for the past 90 years, the broader impact of antibiotics on typical flora are not well understood. Antibiotics are also commonly used as prophylaxis for surgical procedures in the urinary tract altering patient outcomes in unforeseen ways. Despite widespread utilization of antibiotics, the longitudinal impact on the dynamic intravesical environment remains completely unknown.

Dysbiosis in the microbiome has been suggested as a causative agent in a wide range of disease: arthritis, metabolic disorders, neurologic disease, inflammatory bowel conditions, and cancer. Yet there remains a fundamental knowledge gap regarding the short and long-term effect of antibiotics on microbiota communities. Specifically within the urinary tract, variance in baseline commensal organisms have been associated with interstitial cystitis, overactive bladder, frequent symptomatic urinary tract infection and potentially cancer development. The study of microbiota reveal pathways and mechanisms that play important roles in immunological response and health but studies typically are limited to the gut.

To address this knowledge gap, the investigators plan a placebo controlled randomized trial to test the longitudinal impact of 10 days of trimethoprim-sulfamethoxazole on the urinary microbiome in healthy adults. Data collection for individual participants will persist for a period of 6 months. The investigators hypothesize antibiotic administration contributes to a rise in bacterial resistance and directly leads to urine microbiome dysbiosis. The investigators further hypothesize the urinary microbiome does not return to baseline, with loss of certain bacteria permanent during the study period. While the investigators' study is groundbreaking and novel, the feasibility of the investigators' experimental plan has been previously demonstrated in the study of the salivary and gut microbiome. Ultimately the investigators anticipate even a single course of antibiotic treatment may increase the risk of bacterial resistance and lead to long-lasting shifts in the urinary microbiome. If confirmed, this knowledge will directly influence clinical decision making in antibiotic selection, duration, and utility.