Researchers have dubbed hand hygiene facilities in Hong Kong's public washrooms "reservoirs of drug-resistant bacteria", after finding 52 bacterial species, some harmful to humans, in them.
Scholars warned on Tuesday of "recontamination risks" for those using public toilets, as they revealed 87 per cent of the Staphylococcus species in tested samples were resistant to at least one first-line antibiotic such as penicillin, while a fifth of them exhibited co-resistance to at least three antibiotics.
"Washroom users avail themselves of the handwashing and hand-drying facilities provided under the impression that these amenities are hygienic," said Dr Lorna Suen Kwai-ping, associate professor of Polytechnic University's nursing school, who led the study.
"However, such facilities may be potential sites for the transmission of pathogenic bacteria. Attention should be paid to the potential risks of recontamination of hands from contaminated washroom facilities and surfaces."Warm air hand dryers came third in total bacterial counts. PHOTO: South China Morning Post
The research project, conducted between April and August 2017 by a group of PolyU academics, collected and examined 220 samples from 55 public washrooms, 28 female and 27 male, across the city.
Eleven were in wet markets, parks and piers, 36 in sports grounds, public libraries and shopping centres, and eight in high-end establishments such as five-star hotels or luxury malls.
Internal door handles had the most bacteria, with 148 bacterial cells per square centimetre, followed by jet air dryers with 142 cells.
Warm air hand dryers came third in total bacterial counts, with 138 cells per square centimetre, followed by paper towels, which had 112, and paper towel dispensers with 90.
The researchers found 87 per cent of the Staphylococcus species tested were resistant to at least one first-line antibiotic such as penicillin, cefoxitin, erythromycin, co-trimoxazole, clindamycin or gentamicin.
Among the samples, 23 per cent showed co-resistance to at least three antibiotics, with the most common combination being penicillin, erythromycin and clindamycin.
While most of the bacteria identified were considered part of the normal human flora and did not commonly cause disease in healthy individuals, the experts said E coli, Proteus mirabilis and Staphylococcus saprophyticus found in the samples were common urinary tract pathogens, while Staphylococcus aureus was the most frequent cause of community-associated skin and soft tissue infections.
"These bacteria can be a cause of community-acquired infections. People infected with bacteria that are resistant to multiple antibiotics are unlikely to receive effective first-line treatment, resulting in an unfavourable clinical outcome," said Dr Gilman Siu Kit-hang, associate professor at PolyU's health, technology and informatics department.
Gender also played a role in the bacterial count discovered.
All three Staphylococcus aureus strains isolated were recovered from internal door handles of men's washrooms, for example.
"It is possible these strains were transferred from the hands of male washroom users due to a failure to wash hands or inadequate handwashing technique," Suen said, adding that the women's washrooms researched had better overall cleanliness.
The research team suggested some solutions to the health hazard.
Future washroom designs should consider adopting a no-door design, automatic controlled or hands-free paper towel dispensers or hands-free bathroom taps with motion sensor, while existing hand hygiene facilities should be cleaned frequently.
"Good hand hygiene practices, which include handwashing with soap and water, and thorough hand drying should be done after going to the toilet for individual protection," Suen said.
This article was first published in South China Morning Post.