Our car may seem like a fairly harmless environment, but a study carried out by researchers at the School of Health and Life Sciences at Aston University (England) and commissioned by Scrap Car Comparison has concluded that our vehicle can be dirtier than an average toilet.
To conduct the study, the researchers took samples from two toilets used for 24 hours and studied five vehicles between 2 and 17 years old. Samples were swabbed inside five used cars using a sterile cotton swab hydrated with phosphate-buffered saline.
Each swab was spread on nutrient agar (usual culture medium for all types of bacteria) and violet red bile glucose agar (VRBG). Nutrient Agar supports all bacterial growth, while VRBG only supports growth of Enterobacteriaceae, which is found in human and animal feces.
The results were tremendously striking, and elucidated not only which are the dirtiest parts of our cars, but also what bacteria we could find in them.
What you can find in your car, according to the study:
E. coli ( Escherichia coli) , a bacteria of the gut.
Most gut strains are harmless; the transmission of pathogenic strains is normally faecal-oral transmission, for example, if you drop some food on the driver’s seat – which is very dirty – and eat it. This could cause food poisoning in some cases.
Pseudomonas (Pseudomonas aeruginosa)
This organism is found in many places in the environment: soil, water, skin, but it is a bacterial species of growing concern because some strains cannot be easily treated with antibiotics.
Bacillus (Bacillus subtilis)
It can be found in the gastrointestinal tract of humans and ruminant animals. It does not normally come from the environment and, fortunately, it does not pose a threat to humans.
Estafilococo. Epi (Staphylococcus epidermidis)
We are talking about skin microbes that we can find on our hands . They can cause infections in immunosuppressed people.
Staphylococcus aureus ( Staphylococcus aureus )
It is found in the upper respiratory tract (mainly in the nose) and, rarely, on the skin. Associated with coughing and sneezing.
Rhodotorula (Rhodotorula mucilaginosa)
An environmental yeast (soil, water, milk…) that can rarely cause infections in immunosuppressed people.
What were the dirtiest areas of the analyzed vehicles?
In general, the trunk of the car had the most bacteria, followed by the driver’s seat, the gear lever and the back seat. As a curiosity, the flyers had the lowest amounts of bacteria of all the areas the researchers tested. Probably because, since the COVID-19 pandemic started, we’ve become much more careful with hand sanitizer,
- Trunk : 1,425 bacteria identified
- Driver’s seat – 649 bacteria identified
- Gear lever – 407 bacteria identified
- Back seat – 323 bacteria identified
- Dashboard – 317 bacteria identified
- Flyer : 146 bacteria identified.
This study is a reminder that just because a surface appears clean does not mean it is clean . Mobile phones are also no better than cars: they have also been found to be dirtier than toilets. Even an earlier study carried out by the University of New York (USA) concluded that the surface of a single bill can harbor up to 3,000 types of bacteria.
Reference: Study commissioned by the ScrapCarComparison company to Jonathan Cox, Senior Lecturer in Microbiology at Aston University, and his research team.
