Subway commuters pick up bacteria and pathogens from EVERYONE who has traveled on the same system as them on their evening journey, researchers find

In recent years, numerous studies have confirmed what every commuter in a busy urban area already knows – the subways are rife with bacteria.

The issue even gives rise to distinct microbiomes between the different lines, with certain types of bacteria linked to particular areas of the city.

But, according to a new study in Hong Kong, these differences only linger for so long.

As the day wears on, researchers found the individual groups eventually blend together to create one uniform set of bacteria that represents the ‘fingerprint of the whole city.’

In the morning, each line has unique microbial features reflecting the regions it passes, but with more and more people using the subway during the day, the microbial communities of all the lines become more similar, dominated by human skin commensal bacteria,’ says Gianni Panagiotou, a systems biologist at the Hans Knoell Institute in Germany and the University of Hong Kong.

‘The Metro is constantly cleaning every surface that we touch, but the train compartments have little personal space – passengers are squashed there, and we are talking about one of the busiest and densest cities in the world.’

For the study, the researchers sent volunteers out to different subway lines across Hong Kong’s 100-mile-long Metro system.

The volunteers rode the subways for half an hour during both morning and evening rush hours, and swabbed their palms for bacteria samples after each trip.

And, they found all sorts of bacteria had transferred.