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Friday, July 5, 2002

Bacteria thrive in
warm sea water

Here's a good question from a longtime reader: "I wish you would write about staph in the ocean. We are ocean swimmers, and my old skin frequently has raw scrapes. I coat my wounds with antibiotic salve when I swim, but is this necessary? I swim for about an hour at a time, so I sure wish I knew if the ocean is good or bad for sores."

It's bad. At least in Hawaii it's bad, because bacteria thrive in warm sea water. The most infamous of these bugs are staph and strep (which are abbreviations of their long scientific names), but there are others.

Just how many others, a group of scientists decided to find out. In 1990 they sailed 185 miles off Baja California to a group of isolated rocks called Rocos Alijos. This remnant of an ancient volcano, around the same latitude as Hawaii, is untouched by humans.

There, the scientists collected samples of 11 marine items. Besides sea water, these included rock, seaweed, snails, sponges, sea urchins and the teeth of three kinds of fish they caught. The workers stored the samples on the boat in sterilized sea water, brought them back to the laboratory and set about checking which, if any, of these specimens carried disease -- or infection-causing bacteria.

Well, we can stop blaming pollution for all our ocean ailments. Those pristine plants, animals and rocks carried germs from hell, many of which are well known to physicians: Vibrio, Pseudomonas and Klebsiella, to name just a few.

And the sea water? The researchers found practically everything except yogurt culture growing in that water. An astonishing 36 species of bacteria showed up in the samples, including staph and strep, the germs most commonly implicated in infections.

This is worth remembering when your coral or other marine cut gets infected. It's never coral growing in there, it's bacteria.

So now that we know we're swimming in Mother Nature's microbial soup, how do we keep it from infecting our open sores?

The best way is to stay out of the ocean, but that's hard for many of us. The next best thing may be my reader's remedy: Coat a sore with antibiotic ointment before going in the water.

A 1995 study published in the journal of the Academy of Emergency Medicine wasn't about sores and sea water, but it was in the ballpark. Doctors scrubbed and sutured people's cuts in the E.R., then gave them packets of antibiotic ointment to apply to the wounds as they healed. Some packets, however, contained plain petroleum jelly.

The people using the antibiotics had significantly fewer infections that the people using petroleum jelly.

Smearing antibiotic ointments on old scrapes and cuts and then swimming in the ocean is different, of course. But if you're prone to infection, there's a chance it may help.

Preventing infection in a new marine cut or scrape is another story. The best treatment is to scrub it thoroughly as soon as you get out of the water.

And I mean thoroughly. I once watched a doctor friend tend a 2-inch-long mussel cut on her foot. She spread the wound open with her fingers, scrubbed the tissue inside with a soapy washcloth for about five minutes and then taped it shut. It didn't get infected.

Those of us with less grit can go to the E.R., get the cut numbed and let someone else do the scrubbing.



Marine biologist Susan Scott writes the newspaper column, "Ocean Watch",
for the Honolulu Star-Bulletin,