The swimming pool and feces connection

Olympic Swimming Pool Fast Lane Category:Outdo...

Olympic Swimming Pool Fast Lane Category:Outdoor_swimming_pools (Photo credit: Wikipedia)

A study conducted by Georgia state health officials, along with the Centers for Disease Control and Prevention, has noted the presence of a number of microbial markers of feces contamination in a number of Atlanta area public swimming pools. Public health officials used polymerase chain reaction-based detection methods to look for potential indicators of contamination in the filters used to clean public pools during the 2012 swimming season. The filters are used to remove physical contaminants, including microorganisms from the water, and as such will typically have a higher level of contamination  in comparison to the rest of the water. Because contaminants accumulate in the filters, they must be regularly backwashed by reversing the water flow periodically, in order to maintain their effectiveness. Waste materials discharged from the backwash should be collected and removed as waste, and should not reenter the pool water system.

Filter samples were collected during the summer, and pool chlorine was immediately inactivated by adding sodium thiosulfate. Standard sets of patron data (indoor vs outdoor pool, public vs private, mixed ages vs primarily adult swimmers, specific signage at the pool) were also collected with the water samples. DNA from any microorganisms present in the water was purified, and used as a template for quantitative PCR using primers for specific microorganisms. Escherichia coli and Pseudomonas aeruginosa were detected in approximately 60% of the water samples. P. aeruginosa contamination was presumed to have occurred from the presence of environmental influx (either dirt or pool fill water; the organism is ubiquitously distributed), however E. coli contamination was used as an indicator of potential fecal contamination of the pool. Two other markers (Giardia intestinalis and Cryptosporidium sp.) of fecal contamination were only detected in a very small number of samples, and norovirus, adenovirus, and a pathogenic isolate of E. coli (E. coli O157:H7) were not detected in any samples. The proportion of samples positive for E. coli varied significantly between membership/club pools and public pools, but this figure did not vary significantly for P. aeruginosa between the two types of pools.

As is the norm with these types of studies, the CDC presents some “best practices” recommendations for individuals wanting to avoid recreational water illnesses (RWI). The risk for RWI rises dramatically if swimmers introduce feces via diarrhea; it is estimated that one swimmer can release up to 108 Cryptosporidium oocysts into the water, a number sufficient to cause disease if a mouthful of water is ingested. The CDC recommends that feces and urine be kept out of pool water, and offers these concrete steps to do so:

  • Don’t swim when you have diarrhea.
  • Shower with soap before you start swimming.
  • Take a rinse shower before you get back into the water.
  • Take bathroom breaks every 60 minutes.
  • Wash your hands after using the toilet or changing diapers.

About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on May 20, 2013, in gross, Its aeruginosa not aeruginoeso and tagged , , , . Bookmark the permalink. 4 Comments.

  1. This whole post is flaring up my high school swim team PTSD. Oh the horror.

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