There are microbes in your urine – and now we know why

23rd July 2020 – Paz García

You have microbes in your urine and that’s completely normal, according to the latest TwinsUK research.

Contrary to popular belief, urine is not sterile but rather home to a variety of microbes – and not just when you have a urinary tract infection (UTI).

The study of the microbiome in the urine, known as the “urobiome”, is relatively new. We know from previous research that certain microbes are responsible for infections, including UTIs. In the first large-scale study of its kind, TwinsUK researchers wanted to understand what microbes are typically present in the urobiomes of healthy adults and why.

The researchers analysed urine samples from 1,600 healthy female TwinsUK participants who were on average 66 years old.

The team found that microbes in urine varied greatly from person to person, with only 2.2% of bacteria present found in at least 5% of samples, and diversity increasing with age.

The community of microbes in the urine was also distinct from microbes found in stool samples, showing that the urinary tract has its own, unique microbiome.

The team found that age, menopausal status, previous UTIs and genetics were the top factors defining the urobiome. Diet and use of antibiotics however had a smaller effect on the diversity of microbes present.

In addition, the researchers found a strong connection between a person’s genetics and key bacteria linked to urinary tract infections.

First author Dr Adewale Adebayo explained:

“This is the first large-scale study to look at the microbes present in the urinary tracts of healthy adult females. Further research will need to focus on the differences between males and females and how this may affect susceptibility to infections.”

Senior author Dr Claire Steves said:

“Thank you to our twin participants for donating a urine sample – it may not be a glamorous task, but it has allowed us to get the first real sense of what a healthy urobiome looks like and what factors affect it. This is invaluable for future studies of the urobiome.”

Adebayo, A.S. et al. The urinary tract microbiome in older women exhibits host genetic and environmental influences. Cell Host & Microbe, 2020.

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