What are the health risks posed by our shower heads?
Most people shower several times a week to improve their personal hygiene. For many people it will be surprising that the impurities in the shower heads can also transmit dangerous bacteria to the users, which can then lead to various illnesses.
University of Colorado scientists recently found that people are sometimes exposed to life-threatening bacteria in their showers. The experts published the results of their study in the English-language journal “mBio”.
Doctors examined the bacteria in our shower heads
For their study, the researchers examined the bacteria in our shower heads. Most of the microbes are harmless, but there are dangerous exceptions, explains study author Noah Fierer from the University of Colorado. The experts were particularly interested in the microbes of the genus Mycobacterium. This group of bacteria can cause leprosy and tuberculosis, for example. In addition, the bacteria studied also included almost 200 other species that are common in our environment. These bacteria are found in soil, dust and tap water. Together they are referred to as non-tuberculous mycobacteria (NTM). Such bacteria grow in colonies in a slimy, moldlike way. This leads to NTM lurking in the dirtiest areas of your bathroom, such as the edges of the sink and shower head.
DNA from 656 biofilm samples from showers was tested
It is important to understand the pathways of mycobacterial exposure, especially in the household, says study author Matt Gebert of the University of Colorado. For this purpose, the scientists examined the DNA of 656 biofilm samples from household showers as well as basic water chemistry data for each source. As they suspected, there was no lack of NTM in their analysis, although large differences were found depending on the region where the samples were collected and the water sources used.
The genus Mycobacterium was most frequently identified
The analyses showed that the genus Mycobacterium was consistently the most abundant genus of bacteria found in showerheads in residential buildings. Mycobacteria were more common in US households than in European households. The experts suspect that this is due to differences in the chemicals used to purify the water. Chlorine is more commonly used in the US, but NTMs tend to become resistant to this type of disinfectant.
Metal showerheads were more contaminated
Strangely enough, more NTM were found in metal showerheads, while a more diverse microbiome was found in plastic showerheads. The researchers explain that this may be due to chemicals in the plastic that keep the mycobacteria in check. The team discovered that in the regions of the USA where NTM lung disease was most common, the microbiomes in showerheads also contained more NTM. For the time being, however, the team’s results only show a correlation and no causal connection. Further investigations are now required to deal with this topic.