Public Release:  Study debunks common myth that urine is sterile

Bacterial differences found in urine of healthy women and women with overactive bladder

Loyola University Health System

Bacteria live in the bladders of healthy women, discrediting the common belief that normal urine is sterile. This finding was presented today by researchers from Loyola University Chicago at the 114th General Meeting of the American Society for Microbiology in Boston.

"Doctors have been trained to believe that urine is germ-free," said Linda Brubaker, MD, MS, co-investigator and dean, Loyola University Chicago Stritch School of Medicine (SSOM). "These findings challenge this notion, so this research opens the door to exciting new possibilities for patient treatment."

This study also revealed that bladder bacteria in healthy women differ from the bladder bacteria in women affected by overactive bladder (OAB), which causes a sudden need to urinate.

"The presence of certain bacteria in women with overactive bladder may contribute to OAB symptoms," said Evann Hilt, lead investigator and second-year master's student, Loyola University Chicago. "Further research is needed to determine if these bacterial differences are clinically relevant for the millions of women with OAB and the doctors who treat them."

Approximately 15 percent of women suffer from OAB and yet an estimated 40 - 50 percent do not respond to conventional treatments. One possible explanation for the lack of response to medication may be the bacteria present in these women.

"If we can determine that certain bacteria cause OAB symptoms, we may be able to better identify those at risk for this condition and more effectively treat them," said Alan Wolfe, PhD, co-investigator and professor of Microbiology and Immunology, SSOM.

This study evaluated urine specimens of 90 women with and without OAB symptoms. Urine samples were collected through a catheter and analyzed using an expanded quantitative urine culture (EQUC) technique. This EQUC technique was able to find bacteria that are not identified by the standard urine culture techniques typically used to diagnose urinary tract syndromes.

"While traditional urine cultures have been the gold standard to identify urine disorders in the past, they do not detect most bacteria and have limited utility as a result," said Paul Schreckenberger, PhD, director, clinical microbiology laboratory, Loyola University Health System. "They are not as comprehensive as the EQUC protocol used in this study."

Loyola researchers now plan to determine which bacteria in the bladder are helpful and which are harmful. They also will look at how these bacteria interact with each other and with their host, and how we can use this information to help patients. This research is in line with a larger international effort that is underway to identify the core bacterial composition of a healthy human body. The goal is to correlate changes in the composition of bacterial communities in and on the body with certain diseases.

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