Health & Wellness

US researchers say that shower heads can be particular “breeding grounds for bacteria and when water is passed through them, they blast out the bugs”. This can in some cases lead on to severe respiratory infections particularly to susceptible persons, who may have compromised immune systems or may be suffering from chronic respiratory conditions.

Research was carried out by Dr Leah M Feazel and a team from the University of Colorado, led by Professor Norman Pace. It was published in the Proceedings of the National Academy of Sciences in the US and was peer-reviewed. Funding for the research was provided by the “National Institute of Occupational Safety and Health” & the “Alfred P Sloan Foundation”.

A particular culprit was identified as Mycobacterium avium which is commonly found in the environment. The small scale study which examined “microbial composition of biofilms inside showerheads” in samples from 45 shower heads from nine cities in the US, basically verified the presence of the potentially infection causing bacteria.

The microbes reproduce rapidly in the dank, dark, environments found in the recesses of shower heads’. They clump together in “biofilms” which are slime like residues. Levels of bacteria in samples, were more than 100 times higher than in ordinary tapwater.

This gives particular concern because water from the shower is “aerosolised” – vaporised into tiny drops. There is thus a potential to inhale a “a faceful of aerosolised bacteria” from the shower-head, especially at initial start-up when any microbial residue is forced out. Therefore microbes can be inhaled deep into the respiratory tract and lungs.

Exposure to these pathogen can potentially lead to fairly low-level infections which can persist in healthy people. They can also lead to more severe conditions with symptoms similar to tuberculosis, in the aged and those with impaired immunity.

The leader of the research study, Prof. Norman Pace, who is a molecular biologist at the university, is quoted as saying: “How many people do you know with a shallow cough? Probably a lot. I would bet that in a lot of cases Mycobacterium avium is responsible. I think it’s a serious public health concern.”

In the cases of those at “greatest risk” such as HIV victims, those on steroidal medication, cystic fibrosis sufferers and those with chronic pulmonary/repiratory conditions, he continued: “For these people I think there’s a serious risk and I would recommend avoiding showers,”

It must be emphasised however, that the study did not directly examine the increase in risk of getting infected, by having a shower. This may well be grounds for further research in the future. Therefore ordinarily healthy people, with effective immune systems, should not have undue concerns about having showers – at least for now, until there is more concrete evidence of a causal relationship. It is in the interim, strongly advisable to flush out the shower-head before subsequent showering, to ameliorate this risk.

Professor Pace also suggests that plastic shower heads seem to “load up” with higher levels of microbe-laden biofilms. It may therefore be advisable to replace these by metal shower heads where possible.

Showers have also been implicated as a transmission medium for some other infectious diseases, including Legionnaires’ disease – a type of pneumonia, and chest infections by the “Pseudomonas aeruginosa” bacterium.

For more details please also visit the following links:

NHS.uk Article

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BBC News

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Times OnLine

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CNN Article