Mind the handrail: Bacteria on public transport more common at night

Most people are aware that public transport such as buses and trains can be a hotspot for germs and bacteria, but new research has now determined just how much bacteria thrives on trains.

If the results are anything to go by, it’s enough to never want to touch a train or bus handrail again. The research, conducted by the University of Hong Kong and published in the Cell Reports Journal, found bacteria that commuters bring with them during the morning train commute remains on the train all day, mixing with other germs and thriving by the time people catch the same train in the evening.

Analysing Hong Kong’s subway system every morning and night for three weeks, researchers set out to determine how microbes of more than five million travellers who use the network mix throughout the day. Interestingly, each line had its own characteristic set of bacteria during the morning rush hour commute, but by evening, the unique bacteria formed one large microbiome seen across the entire subway network.

Participants in the research entered the subway system for half an hour during both the morning and evening commute and were required to simply stand in the compartment and touch the handrails. Skin samples of each participant’s hands were then taken to examine the kinds of bacteria and microbes that each person came into contact with.

“The idea for these projects is not to scare people, it’s more to realise that we are constantly exposed to diverse sets of bacteria and also accept that how we design our cities can have a significant impact on the type of bacteria that we will encounter,” lead researcher Gianni Panagiotou told Starts at 60. “Furthermore, what we observed was that higher traffic metro lines do not carry higher health risks, neither in pathogens nor antibiotic resistance genes.”

Researchers also found the subway or train line a person took determined which bacteria they would encounter during the morning commute before they all mixed with each other by the evening commute.

“I think it was fascinating to see the change of the microbiome from morning to afternoon,” Panagiotou said. “In the morning, each line has its own microbial characteristics, which to a large degree reflects the city characteristics that it’s passing through.

“For example, the Metro line that goes along the coast was mainly colonised with aquatic bacterial species. Now during the day, with more and more people using the Metro, the microbial community started becoming more similar, dominated by the human skin commensal bacteria.”

Researchers are now hopeful that the results of the study can better understand how urban development can impact the types of bacteria people encounter and to possibly shape future public health strategies and public transit designs. Because it only ran for a short period of time, Panagiotou explained it would be interesting to see changes during seasons and during flu seasons. Most of the microbes reordered in the study were harmless skin commensals and bacteria that lives on the skin. Some other pathogens were also detected.

Meanwhile, AMA President Tony Bartone previously told Starts at 60 when it comes to minimising the spread of influenza, prevention and preventative barrier techniques such as washing hands or wearing a face mask were extremely effective and should be practiced by all, especially at the height of epidemics and in very populated areas. He also said vaccinations are equally as important in stopping the spread of deadly viruses.

What do you think? Do you catch public transport? Are you ever concerned by the germs and bacteria on the bus and train?