Wednesday, September 9, 2009

Will Swimming Pools Kill MRSA?

These are common questions I get fairly often.

Can I transmit MRSA to someone else in a swimming pool?

Can I get MRSA from a swimming pool?

Amazingly, I just heard from someone who has MRSA and apparently their doctor advised them to go into a swimming pool as the doctor said the pool will kill the MRSA on their body.

Is this good advice? Or not? Well, first of all, I'm not a doctor but I can share with you my research on this matter as well as my experience as a Microbiologist.

According to a recent study, swimming pools will kill MRSA and Staph bacteria in the water IF they are properly maintained. Now, let me break this down into some very important points.

First of all, it's generally advised to avoid using pools, spas, or whirlpools if you have open wounds. Most swimming pools have adopted policy's that do not allow people to enter the water with open wounds. You may have seen this policy at your local pool. This policy is used because there is a chance of transmitting bacteria to other people in improperly disinfected water. Therefore, if you have an active infection, I think it's wise to stay out of the water. You don't want to chance giving your infection to someone else and you don't want your open wound to become infected with more bacteria.

Secondly, yes, chlorine will kill MRSA and Staph at proper swimming pool or spa concentrations, but not all pools and spas are maintained at the proper levels of chlorine. There are many factors that come into play with maintaining proper levels of chlorine. And, there have been many instances, particularly with sporting teams where MRSA has been isolated from improperly maintained spas. And these improperly maintained spas have been implicated in transmitting MRSA from player to player (Kazakova et al. 2005). See below for CDC's guidelines on how to determine if your pool or spa is being properly maintained.

Thirdly, as a Microbiologist I know that swimming pools will not kill all of the bacteria on your skin. Swimming pools and spas have disinfectants like chlorine in them to disinfect the water. These levels are not high enough to kill all the bacteria on your body, nor should they be. It would be quite chemically-toxic to enter. Sure, some bacteria will probably die from your skin, but not all of them. And, as I've said before, it's important to remember that many of the bacteria living on your skin are there to protect you from "bad" bacteria. And, bacteria have many defenses including the formation of biofilms. Biofilms are like houses over the bacteria that help protect them from disinfectants and other threats.

In summary, swimming pools or spas will not cleanse your body of MRSA, Staph or any other bacterial skin infection. Chlorine in the pool is meant to reduce or eliminate free-floating bacteria and parasites that come off of people into the water, making the pool a safer environment for all. When pools and spas are maintained appropriately, they will kill MRSA and Staph bacteria in the water fairly quickly making it fairly unlikely for anyone to get MRSA from a pool (see article Tolba, O., et al. below). However, improperly maintained pools or spas have had MRSA isolated from them and they are suspect in transmitting MRSA from person to person.

Here's a neat little chart from the CDC with chlorine disinfection times for some common pool germs:

The CDC has posted some great information about swimming pool and spa "health" and how you can better determine how well swimming pools and spas are maintained. You can learn more from the CDC about healthy swimming here:

Be well,

Michelle Moore
Microbiologist, Staph Researcher and Natural Health Advocate
Natural MRSA Treatment Options


Tolba, O., et al., Survival of epidemic strains of healthcare (HA-MRSA) and community-associated (CA-MRSA) meticillin-resistant Staphylococcus aureus (MRSA) in river-, sea- and swimming pool water Int. J. Hyg. Environ. Health (2007), doi:10.1016/j.ijheh.2007.06.003

Centers for Disease Control, Healthy Swimming:

Kazakova, S.V., Hageman, J.C., Matava, M., Srinivasan, A., Phelan, L., Garfinkel, B., Boo, T., McAllister, S., Anderson, J., Jensen, B., Dodson, D., Lonsway, D., McDougal, L.K., Arduino, M., Fraser, V.J., Killgore, G., Tenover, F.C., Cody, S., Jernigan, D.B., 2005. A clone of Methicillin resistant Staphylococcus aureus among professional football players. N. Engl. J. Med. 352, 468–475