Many people say that human urine is devoid of bacteria, but the new study questions that idea.

Dr. Linda Brubaker, dean of Loyola University Chicago Stritch School of Medicine and her team analyzed urine samples from 90 women. It found bacteria both in the urine of healthy women as well as the urine of women with overactive bladder. However, the germs were different between the two groups, the WebMD reported.

About 15 percent of women have overactive bladder, which triggers a sudden need to urinate. Forty percent to 50 percent of these women do not respond to medication. Brubaker's team believes differences in bladder bacteria may be why some women respond to drug therapy while others don't.

The study was presented Sunday in Boston at the annual meeting of the American Society for Microbiology. Findings presented at medical meetings are typically considered preliminary until published in a peer-reviewed journal.

The next steps for the Loyola team will be to determine which bladder bacteria are helpful and which are harmful, how these bacteria interact with each other and their host, and how this new knowledge can help patients.