Faecal matter, skin bacteria and yeast have been found on the seats and handrails of public transport in Dublin.
Random samples that were taken last week found that the Luas had the highest number of microbes and bacteria, compared to the Dart and Dublin Bus.
The three service providers say their fleets are cleaned on a daily basis with deeper cleans undertaken every four to six weeks.
People are being reminded to wash their hands after using public transport.