Brazilian study finds Staph, E. coli, and other bacteria that contribute to hospital-acquired infections in reusable water bottles used by members of multiple fitness centers

In the latest example of Microbiologists swabbing and culturing samples taken from common, everyday items, a research team in Brazil has found germs associated with hospital-acquired infections (HAIs) infections on reusable water bottles carried by individuals working out in local fitness clubs. 

Dark Daily recently reported on a University of Pennsylvania Perelman School of Medicine study which showed that healthcare providers unknowingly spread deadly bacteria—including Staphylococcus aureus (Staph)—with their clothing and even stethoscopes throughout healthcare networks nationwide. Microbiologists and other clinical laboratory professionals battle HAIs that result from such contaminations every day.

The Brazilian study, which was published in the Journal of Exercise Physiology Online, the official research journal of the American Society of Exercise Physiologists (ASEP), has concluded that infrequent washing of reusable water bottles creates a reservoir of deadly germs that also include Staph and E. coli.

Their results may cause gym members to consider the impact the bottles they tote can have on their health.

Worse than Licking a Dog Toy

The researchers analyzed the presence of different bacterial strains in the water bottles of 30 fitness club members at two different fitness center locations, as well as 30 new unused bottles. They also conducted antimicrobial susceptibility tests for the isolated strains.

The scientists found contamination in 90% of the used plastic bottles, while none of the new bottles showed signs of bacterial contamination. Twenty-five (83%) of the used bottles contained Staph (26.66%) and E. coli (16.66%). In addition, four of the reused bottles tested positive for the presence Pseudomonas, an antibiotic-resistant bacterium that also causes HAIs.

“We tested in a real-world scenario, by surprise, asking for those who were arriving at the gym at those particular days, stated Gilmar Weber Senna, PhD, Professor at the Federal University of Rio de Janeiro, in a Runner’s World article. “We did this to avoid an intentional over-cleaning.”

Similar results were found in testing performed by the website That study revealed an average athlete’s water bottle contained 313,499 viable bacteria cells (313,400 colony-forming units per square centimeter).

“To put it bluntly, drinking from the average refillable bottle can be many times worse than licking your dog’s toy,” Treadmill Reviews noted.

Philip M. Tierno, Jr., Professor of Microbiology and Pathology at New York University and NYU Langone Medical Center, is not surprised by the findings of the Brazilian study, which found that 83% of fitness club members’ reusable water bottles were contaminated with bacteria. He suggests frequent handwashing before refilling reusable water bottles will help prevent spreading the bacteria. Clinical pathologists will agree that diligent cleaning of hands, clothes, and medical instruments can prevent the spread of deadly diseases. (Photo copyright: NYU Langone Health.)

CDC Downplays Presence of Staph and E. coli

Despite the ick-factor of the water-bottle testing results, Runner’s World also notes that the Centers for Disease Control and Prevention (CDC) determined that Staph bacteria can be found in the noses of 30% of the population, while E. coli is present in healthy gastro intestinal tracts, with only certain strains causing illness.

The Brazilian study’s authors also noted that most of the bacteria isolated in their research belong to the Enterobacteria group, which lives in the intestines and are pathogenic. Thus, the researchers surmised that “manipulation with contaminated hands may contribute to the colonization of the [reusable water bottles].

“We conclude the best way to avoid bacterial proliferation in the [reusable water bottles] is to make sure they are correctly and frequently cleaned, such as daily washing with neutral soup in association with proper hand hygiene to prevent contamination,” Senna and co-authors wrote.

Philip M. Tierno, Jr, PhD, Professor of Microbiology and Pathology at New York University (NYU) and the NYU Langone Medical Center supports the study’s conclusions. He suggests water bottles likely become contaminated through handling by their owners, an issue proper hand hygiene can help remedy. He recommends properly washing hands before filling a gym water bottle.

“Wash 20 seconds,” Tierno told Runner’s World. “Get soap on the top and bottom of hands and in between digits and under the nail bed. Run your hands like a claw in the center of the opposite palm to get suds into the nail bed, and sing the song ‘Happy Birthday’ twice to wash hands adequately.”

Reusable water bottles also should be cleaned thoroughly, preferably in a dishwasher.

Until the general public begins routinely following such advice, microbiologists and clinical pathologists will remain the tip of the spear in infection control programs and education. But that should not stop clinical laboratory managers from implementing constant monitoring and cleaning protocols to stop the spread of infectious bacteria in their labs.

—Andrea Downing Peck

Related Information:

Just How Filthy Is Your Reusable Water Bottle?

Microbial Contamination in Shaker Bottles among Members of Fitness Centers

A Look Under the Cap: Water Bottle Germs Revealed

Stanford University Study Traces Hospital-Acquired Bloodstream Infections to Patients’ Own Digestive Tract

CMS Missed 96 Hospitals with Suspected HAI Reporting Due to Limited Use of Analytics, OIG Report Reveals

Collaboration between Pathologists, Medical Laboratories, and Hospital Staff Substantially Reduced Hospital-Acquired Infections, AHRQ Reports

Leapfrog Group Report Shows Hospitals Failing to Eliminate Hospital-Acquired Infections; Medical Laboratories Can Help Providers’ Antimicrobial Stewardship Programs