Disinfecting was all the rage during the COVID-19 pandemic—and rightfully so. And while no one is cleaning off their mail or groceries with wipes while wearing gloves anymore, that doesn't mean we shouldn't still be cautious where necessary.
A new study from researchers at Florida Atlantic University highlights one necessary area that is super common but overlooked—wristbands on wearables. From Fitbits to Apple Watches and everything in between, millions of people wear something on their wrist every day. Unlike traditional watches, smartwatches are rarely taken off, instead worn 24/7 for health data purposes. Thus, without explicit and proper cleaning, these wristbands can become a hotbed for harmful bacteria growth. In fact, scientists recently found that nearly all—95%—of the bands they studied were contaminated with bacteria including Staphylococcus aureus, Pseudomonas, and E.coli.
For their study, published in Advances in Infectious Diseases, researchers worked with 20 volunteers who consistently wore wristbands. The wristbands were made of different materials—including plastic, rubber, cloth, leather and metal—so researchers could see if there was a correlation between material and prevalence of bacteria.
While nearly all wristbands were contaminated, the metal ones—especially gold and silver—had little to no bacteria. For example, a gold wristband had the lowest level of bacteria, which the team attributed to the material’s natural anti-bacterial properties. Conversely, S. epidermidis showed enhanced bio-adhesion on stainless steel compared with a skin model substrate, although S. aureus demonstrated the opposite effect. Meanwhile, the highest total counts were found on rubber and plastic wristbands.
“Plastic and rubber wristbands may provide a more appropriate environment for bacterial growth as porous and static surfaces tend to attract and be colonized by bacteria,” said senior author Nwadiuto Esiobu, professor of biological sciences at Florida Atlantic University.
Overall, the researchers identified Staphylococcus (cause of staph infections), Pseudomonas (cause of pneumonia) and intestinal organisms of the genera Escherichia, specifically E. coli. According to the study results, Staphylococcus was prevalent on 85 percent of the wristbands, while Pseudomonas was found on 30 percent. E. coli bacteria was also recorded on 60 percent of the wristbands.
In terms of occupation, the largest counts of fecal bacteria (such as E. coli) and total bacteria were observed from a veterinarian’s wristband, while the largest count of Pseudomonas bacteria was recorded from the wristband of a gym-goer. That wristband also displayed signs of S. aureus. A second gym-goer, had the highest staphylococcal counts.
“Even at relatively low numbers these pathogens are of public health significance,” said Esiobu. “Importantly, the ability of many of these bacteria to significantly affect the health of immunocompromised hosts indicates a special need for healthcare workers and others in hospital environments to regularly sanitize these surfaces.”
The study also evaluated the three different disinfection methods used. The results showed that Lysol Disinfectant Spray and 70 percent ethanol were highly effective—regardless of wristband material—with a 99.99 percent kill rate within 30 seconds. However, apple cider vinegar was not as potent and required a full 2-minute exposure to reduce bacterial counts. While the disinfectants proved at least somewhat effective on all materials, antibacterial efficacy was significantly increased at two minutes compared with 30 seconds, meaning the longer exposure the better changes of pathogen-killing.
In the future, the researchers say other potential forms of bacterial transmission, such as earbuds and cell phones, should be similarly studied.