By Margarita Nahapetyan
Swimming in sub-tropical waters such as those in the Mediterranean, Florida and California, are likely to expose people to a small but significant risk from the infection from Staphylococcus organisms, including Methicillin-resistant Staphylococcus aureus (MRSA), according to a new study by U.S. researchers.
The scientists have known for a while that staph bacteria could spread in water. This new research, in its turn, shows that MRSA is also present at the beach - in the sea water and potentially in the sand.
To pin this down, Dr. Lisa Plano of the University of Miami's Miller School of Medicine, and her colleagues focused on 1,303 adults who swam for 15 minutes at a particular beach in South Florida. All the participants were divided into two groups. The first group which included half of the adults just sat on the beach, while another one took a dip in the water and brought back samples of water in sterilized jugs for later lab analysis.
Analysis of the water found that more than 37 per cent of those who swam in the Atlantic Ocean on South Florida's coasts were diagnosed with dangerous staph bacteria, and 3 per cent came in contact with an even more-dangerous, antibiotic-resistant form of the MRSA bug. Plano, who presented the results at the American Association for the Advancement of Science meeting in Chicago yesterday, said that they pointed to bathing as a possible risk factor for picking up MRSA.
"The majority of the isolated MRSA were those likely to be of the more aggressive variety," she said. "This exposure might lead to colonization or infection by water-borne bacteria, which are shed from every person who enters the water."
She added that there was no reason to avoid swimming in the sea, but recommended that people take precautions to reduce the risk of spreading, or picking up the bugs, by taking shower before and after going for a swim in order to keep from depositing their own germs into the water. "I don't think you should fear going to the beach. If you don't go into the water with a gaping wound, you should be fine." Plano said.
So-called staph or Staphylococcus aureus, the bacteria that responds to antibiotics, is actually not a big problem for the general public. Nearly one third of people have it living in their noses or on the skin all the time, and no one gets sick from the bug. But for small children, sick people, the elderly and others with impaired or lowered immune systems, staph bug may lead to an infection that can even be fatal. The symptoms include a red bump or a spot that is swollen, painful and warm when touched, and full of pus.
Researchers say that many major medical complications associated with skin reported by emergency room patients can be attributed to MRSA, with thousands of people affected and about nineteen thousand death outcomes every year. Significant raise of new strains of potentially more aggressive MRSA have been seen in the last ten to twelve years in large numbers of healthy people, including some rumored infections among NFL and NBA players. Staph and MRSA strains have also been found in schools, daycare settings, gyms, and homes for the elderly.
"Staph is a really complicated bug," Plano said and explained that Staphylococcus aureus has an excess of forty different virulence factors that it potentially has and uses them to determine different types of infections, and not all staph will have all of them. Basically, according to the scientist, most staph will have some of the infections, and what the researchers looked at and compared to, are the ones to be associated with skin-infecting bugs.
Municipal chlorinated pools and most private pools are safe from S. aureus if chlorine levels are appropriate, Plano said and also warned that there is some evidence that staph could be spread in beach sand. In one study experiment, few quarts of sea water free from bug were poured over fourteen previously staph-free toddlers in diapers who had stayed in beach sand for 10 minutes. The water that flowed off the kids was collected and later analyzed. It was found that some of it had S. aureus in it.
"We think that people are the instruments for bringing their organisms into the water and leaving it behind," Dr. Plano said. "I do not know if that is the only source. The bacteria may still be in the sand left over from other people, but we have not studied that. These are things we plan to do in the future."
The research was funded by the National Science Foundation, the Florida Department of Health and Environmental Protection, the Centers for Disease Control and Prevention, and the Environmental Protection Agency.