Escherichia coli bacteria, magnified 10,000 times
With hot days ahead, thoughts naturally turn to the cool blue of swimming pools. Alas, not everything floating in those crystalline waters these days turns out to be an inflatable toy. A new report from the Centers for Disease Control surveyed 161 heavily used pools in metro-Atlanta in 2012. They ranged from public pools to pools at private clubs and water parks.
The CDC researchers sampled the pools’ filters, looking at what they contained. Of the 161 tested pools, more than half – 93 or 58 percent – contained Escherichia coli, a bacterium that lives abundantly in the gut of humans and other warm-blooded animals.
For the most part, E. coli is harmless, but some strains are pathogenic and are culprits behind many contaminated food events and recalls. In this case, however, the presence of E. coli is particularly icky since the bacterium is a strong indicator that someone (plural?) didn’t quite make it out of the pool to the restroom.
Actually, the CDC puts an even ickier spin on it, as only science can: “Each person has an average of 0.14 grams of fecal material on their perianal surface that could rinse into the water,” the authors observed (metaphorically).
Public pools had the highest incidence at 70 percent, followed by water parks at 66 percent and private clubs at 49 percent.
On the plus side, the researchers didn’t find any evidence in the pool filters of O157:H7, the E. coli strain most associated with food contamination and illness.
While distinguished in its disgustingness, E. coli wasn’t the most abundant of the microbes found doing the backstroke next to swimmers. That claim fell appropriately to Pseudomonas aeruginosa, a bacterium that causes swimmer’s ear. It was found in 95 of the 161 filter samples, a 59 percent incidence.
The CDC scientists were quick to note their Atlanta survey can’t be generalized to pools everywhere, but they did say the rates of pool-related illnesses nationally have been rising. Part of the problem is pool maintenance, to be sure, but swimmers have to take some of the blame.
“Swimmers have the power and responsibility to decrease the risk for recreational water illnesses by practicing good hygiene,” they wrote, suggesting that people shower thoroughly before entering a pool, take regular restroom breaks followed by another quick shower rinse before re-entering a pool and if you’re suffering from a diarrheal ailment, best stick to lounging in the sun.
Just remember to use sunscreen.