Why your toothbrush is contaminated with fecal matter, and how to avoid it

The toothbrush you keep in your washroom may be serving as a vector for fecal bacteria, according to new research.

Data presented at the annual meeting of the American Society for Microbiology showed that toothbrushes stored in communal washrooms can become contaminated with fecal bacteria.

"The main concern is not with the presence of your own fecal matter on your toothbrush, but rather when a toothbrush is contaminated with fecal matter from someone else, which contains bacteria, viruses or parasites that are not part of your normal flora," Quinnipiac University graduate student Laurn Aber said in a statement.

Microorganisms that can be potentially introduced into your system include enteric bacteria normally found in the gut as well as pseudomonads, a group of bacteria commonly found in soil, water, plants and animals. They too are considered to be part of the normal flora of the human intestine, and can also be found on the skin.

The data is based on an analysis of toothbrushes that came from participants who use communal bathrooms. Each of the bathrooms had an average of 9.4 occupants.

According to the data:

Fecal bacteria were observed on 54.85 per cent of the toothbrushes;

There was an 80 per cent chance that the fecal bacteria seen on the toothbrushes came from another person using the same bathroom;

There was no difference in the level of effectiveness for different decontamination methods including rinsing with cold water, hot water or mouthwash.

Aber also said that using a toothbrush cover doesn't actually protect against bacteria, but rather creates a moist, fertile environment for bacteria to grow.

She said people who share bathrooms with others should use better hygiene practices to store their toothbrushes, including those recommended by the American Dental Association.

The recommended best practices include:

Do not share toothbrushes with others;

Rinse toothbrushes with tap water after brushing to remove remaining toothpaste and debris;

Do not use toothbrush covers or store brushes in closed containers;

Replace your toothbrush every three to four months or sooner if the bristles become frayed.