HAVE YOU EVER WONDERED...

if urine is really sterile?

The idea that urine is sterile came about in the 1950s when epidemiologist Edward Kass designed a strip to change colour if it detected more than 100,000 bacterial clusters per millilitre of urine. Any number under 100,000 would be considered “negative”. Over time, this negative finding became mistakenly equated with zero bacteria.

Researchers at Loyola University, Chicago, took a closer look at urine specimens from women with and without urinary tract infections. After analysing the samples, they discovered that even healthy urine contains bacteria. It could lead to a new way to detect infection and, eventually, treat an overactive bladder.

Medical textbooks have long taught that if there is bacteria present in urine, then an infection also is present.

However, the Loyola researchers used an ultra-sensitive DNA-based method to uncover low levels of bacteria in normal urine from patients without urinary tract infections. The bacteria wouldn’t have been detected otherwise.