Swimming in the ocean can be an extremely fun and refreshing experience. However, a new study suggests that ocean swimming alters the microbes on our skin in a way that makes us more vulnerable to infections. The research was presented at the ASM Microbe 2019 conference at the annual meeting of the American Society of Microbiology.
“Our data demonstrate for the first time that ocean water exposure can alter the diversity and composition of the human skin microbiome,” University of California, Irvine PhD student Marisa Chattman Nielsen said in a statement accompanying the results of the study. “While swimming normal resident bacteria were washed off while ocean bacteria were deposited onto the skin.”
All the participants in the ocean swimming experiment showed ocean bacteria symptoms after air drying at six and 24 hours after swimming in the ocean. Researchers detected even more ocean bacteria on some participants, while other participants acquired more persistent bacteria which lasted for a longer time.
This study comes after previous studies found evidence of ocean swimming being connected to infections in some way. The infections were likely triggered by poor water quality in the oceans at many beaches, which are result of wastewater and storm water runoff. It showed how humans are vulnerable to infections.
The most recent study examined how poor-quality ocean water changes us and how changes in the microbiome can affect a host that is prone to infection. According to the research, ocean swimming in poor-quality water can cause gastrointestinal and respiratory diseases and ear and skin infections.
The researchers picked nine volunteers on a beach who weren’t using sunscreen and swam in the ocean infrequently. The volunteers also did not take a bath in the 12 hours before the experiment and were not on antibiotics for the previous six months. The researchers tested them before they entered the water and after drying following a 10-minute swim and then between six and 24 hours after swimming.
“One very interesting finding was that Vibrio species–only identified to the genus level–were detected on every participant after swimming in the ocean, and air drying,” Nielsen said.
The Vibrio genus includes the bacterium that causes cholera. At six hours post swim, they were still present on most of the volunteers, but by 24 hours, they were present only on one individual.
“Recent studies have shown that human skin microbiome plays an important role in immune system function, localized and systemic diseases, and infection,” Nielsen said. “A healthy microbiome protects the host from colonization and infection by opportunistic and pathogenic microbes.”