Many people reared in Hawai'i believe that swimming in the ocean is a good way to cleanse and heal skin infections.

University of Hawai'i microbiologist Roger Fujioka said there's some wisdom behind the old wives' tale, since land-based bacteria don't do well in a saltwater environment. But as scientists learn more about Vibrio vulnificus and other marine bacteria, Fujioka and other experts are advising caution in entering sea water with open wounds — especially if you're suffering from ill health.

The same goes for freshwater streams and ponds.

Keeping cuts and scrapes clean and dry remains the best prescription for preventing skin infections that can worsen and invade the bloodstream, causing life-threatening complications. And with the speed at which these infections can spread, physicians are now urging people to seek medical care at the first sign of fever, nausea and increased swelling, pain and redness.

"In Hawai'i, if you have any flu symptoms and have been in fresh water, immediately you think it's leptospirosis and you should go to the doctor. And now, if you go in the marine water and get an infection, you do the same thing," Fujioka said.

The best defense is a good cleansing with antibacterial soap and water to remove dirt and damaged tissue, physicians said. Alcohol-based skin-cleansing gels are an effective alternative, unless dirt is present.

If injured during an outdoor outing, Dr. Scott Hoskinson at Maui Memorial Medical Center said, do not delay treatment, if possible.

"The sooner you can clean it the better," he said. "Bacteria divide every 20 minutes, so you can see how quickly they move, and if you wait 12 hours until you get home. ... "

Other common home remedies include soaking infected cuts in hot water, but Hoskinson said the treatment is not effective, although hot compresses are sometimes used to liquify and drain boils. Hydrogen peroxide's foaming action can help clean a wound, he said, but it's a weak germ-killer and no substitute for soap and water. It hurts like heck, too, Hoskinson noted.

The experts had differing opinions on whether it was a good idea to immediately slather on antibiotic ointments such as Neosporin or bacitracin, but did agree that it's best to keep wounds dry. Hoskinson said ointments can cause allergic reactions that can be mistaken for infection.

A visit to the doctor's office may be necessary to completely remove sand, coral and other foreign material from cuts. Bandages are useful for protecting cuts and scrapes on hands and feet, but wounds should be allowed to dry out at night by taking the bandage off.

UH infectious disease specialist Dr. Alan Tice had advice for keeping Staphylococcus and streptococcal bacteria at bay: "Wash your hands, take good care of yourself and don't pick your nose."

And don't forget about tetanus, a bacterial disease commonly known as "lock jaw." Adults should get tetanus booster shots every 10 years.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.