Anna Alex

Urinary tract infections (UTIs) are the most common outpatient infections in the United States, affecting ~150 million people annually. The primary causative agent of UTIs is uropathogenic Escherichia coli (UPEC), which can get introduced into the urinary tract from the perianal region. Understanding the immunological responses to UTIs has been a focus of ongoing research in the field. Previous studies have utilized specific pathogen-free (SPF) mouse models to replicate infection, but there have been some discrepancies concerning how applicable these data can be to humans. The present study utilizes a cohoused mouse model in an attempt to simulate the immune function of an adult human. Preliminary data suggest increased UPEC clearance in cohoused mice compared to SPF mice after local bladder infection, but the reason for this is unknown. Using tagged (“barcoded”) strains of UPEC, I compared the clearance of infection in the bladders of cohoused and SPF mice at various time points (1 hour, 24 hours, 7 days) to investigate whether the improved UTI clearance in cohoused mice is a result of decreased initial bacterial uptake. Both CFU/mL (a measure of bacterial load) in the bladder and the number of bands present in a gel following multiplex PCR (barcoded UTI89 tags) were measured. No significant differences were found in CFU/mL present in the bladders of mice at any time point. The band count measurement at the 24-hour time point was later omitted due to a lack of significant results in CFU/mL. There was a significantly lower number of bands present in the bladders of mice at the 1-hour time point, but not at the 7-day time point. The results suggest that if cohoused mice do indeed handle UPEC UTI infection better than SPF mice, it is likely not due to a reduced number of bacteria that initially colonize. Future research can build on this knowledge and explore other potential reasons for the improved immune function in cohoused mice, allowing for a closer correlation to human immune function.