ECJ EUROPEAN Cleaning Journal

Passengers on the Hong Kong subway are being exposed to a cocktail of germs brought in by commuters from all over the city and beyond, according to a new study.

And cross-border trains could lead to antibiotic-resistant germs coming in from mainland China, it has emerged.

Volunteers with clean hands were sent out to travel on eight MTR lines and told to touch different handrails in trains for 30 minutes. Samples of aquatic and sewage bacteria were picked up from a line running alongside a brackish river channel, while another line passing through the city's mountainous areas spawned an abundance of bacteria species from habitats 3,000ft above sea level.

These distinct patterns of microorganisms were particularly noted during the morning commute but as the day wore on, the differences between the types of germs began to blur as commuters continued to spread bacteria across the city.

Led by the University of Hong Kong, the study suggested that cross-border antibiotic resistance transmission could become an issue since greater numbers of bacteria with antibiotic-resistant genes were found where the rail line connected to the mainland Chinese city of Shenzhen.

These bacteria showed particular resistance to tetracycline, a commonly-used drug used in swine feed in mainland China. And fears were expressed that the bacteria could mutate into multidrug-resistant organisms. However, no severe pathogens have been detected in samples so far.

Hong Kong was devastated by a rapidly spreading Sars outbreak in 2003 which left 299 people dead and more than 1,700 infected. About five million passengers use the MTR railway system's 11 lines daily.