Swimming pools

Question

Does swimming in a normally chlorinated swimming pool bring extra risk of getting infected with bacteria?

Answer

Your question is quite appropriate since prevention of infection is better than treating it. Patients with cystic fibrosis (CF) nearly always suffer from chronic infection of the airways, usually with bacteria as Staphyloccus aureus, Hemophilus influenzae and Pseudomonas aeruginosa. The latter bacteria is ubiquitous in the environment and especially likes water. Therefore the question whether a pool brings the risk of infection is often asked.

Patients with CF are especially vulnerable for infection with pseudomonas. This infection should be actively sort for and treated if present because chronic infection of the airway with pseudomonas leads to accelerated deterioration of lung function. In case of a new or recent infection adequate treatment can eradicate the bacteria out of the lungs for some time. Where and how patients with CF occur this infection with pseudomonas is unclear. We know with a great deal of certainty that cross-infection between patients happens, even though this is rather the exception than the rule. Consensus guidelines prescribe that contact between patients with and without pseudomonas should be avoided in CF centers by having separate hospital rooms and separate days for outpatient clinic. The same separation between patients has to be taken care of during other meetings. The great importance of correct hand hygiene is also obvious.

Other sources of infection are less clear. Pseudomonas is really everywhere in the environment. The bacteria thrives best in humid, warm places such as stagnant water. Of course, exposure to environmental bacteria cannot be avoided completely. There is no hard evidence that avoiding activities such as swimming or showering will decrease the amount of infection with Pseudomonas. In most European countries there are strict hygienic rules for public swimming pools and the water is regularly examined for the presence of bacteria. With correct treatment of the water and good hygienic measures, high bacterial counts of Pseudomonas in the water are very unlikely. For tropical pools it is much harder to guarantee the quality of the water: due to the warmth and the humidity the bacteria will grow faster. For this reason many CF centers will advise against the use of tropical pools even without there being a lot of proof that this really increases the risk of contamination by Pseudomonas.

Since prevention is not always based on hard evidence there may be subtle differences in the advice given from center to center also based on local hygienic standards. A reasonable equilibrium should be found between some prudence but still the possibility to participate in social activities. Our advice is that swimming in a public pool and a private pool that is well maintained does not hold a significant risk to get infected with Pseudomonas. But of course you should discuss it with your local doctor as well.

Kind regards
Dr. F. Vermeulen

04.01.2010