Hand washing is important -- but is your sink clean?

The Flinders University environmental health study found handbasin biofilms contained a diverse range of pathogens including microbes typically found in water, and other pathogens not found in water.

"The study also found that residential handbasins have a more diverse bacterial community present on handbasin biofilms compared with hospitals.

"There was also a higher number of Legionella bacteria present in the residential samples compared with those taken from hospitals."

Legionnaires' disease is caused by the Legionella bacteria, found in natural bodies of water, spas, warm water systems, potting mix and air-conditioning. A system that used water for cooling was linked to a large outbreak in Melbourne recently which affected almost 90 people and caused two deaths.

Biofilms, a slimy substance found on drains and around the faucet of handbasins, contain a community of microbes including disease-causing pathogens that can pose a threat to human health.

These pathogens are likely transferred to the biofilm from patients or staff during handwashing, from incoming water supply or biological waste, according to the study in Science of the Total Environment.

The new study compared biofilms in hospital and residential handbasins to assess infection risk levels and possible routes of contamination.

Lead researcher Claire Hayward says: "The difference in the diversity of the microbial communities could be due to more regular cleaning, usage and the design of basins in hospitals through the implementation of healthcare infection control practices.

"This poses a risk to patients receiving healthcare in the home which has been emerging as an alternative to extensive inpatient hospital stays to reduce the burden on the healthcare system.

"Patients receiving healthcare in the home need to be informed of infection control practices such as cleaning handbasin outlets and drains using effective disinfectants," she says.

"Biofilms formed in the faucet and drains of handbasins can potentially harbour pathogenic microbes and increase the rise of antimicrobial resistance," says PhD candidate Ms Hayward.

"In both settings we found a high abundance of pathogenic and corrosive germs, including some not typically carried in water.

"These complex and diverse microbial communities also differed depending on building type and indicate hospitals also need more control guidelines to manage these under-recognised areas of potential infection."

The Australian Guidelines for the Prevention and Control of Infection in Healthcare recommends cleaning handwashing basins up to twice a day with detergent along with other high touch surfaces such as light switches, doorknobs and bedrails with the same frequency.

Researchers recommend further research into cleaning protocols and hand basin design to reduce risks.