Wash up! The dirty science of bacteria...from CNN.com

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Sunday, February 15, 2004 Posted: 4:08 PM EST (2108 GMT)

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SEATTLE, Washington (AP) -- That soap scum that forms on the shower

curtain? It's really a biofilm loaded with more than a billion

bacteria per cubic inch.

The moving belt on an escalator? When you put your hand there, you're

dipping into a puddle of bacteria left by all those who went before.

How about the potting soil for your petunias? It's the happy home of

a pathogen called Microbial Avian Complex, a potentially troublesome

bug.

Then there's the sponge you use to rinse dishes at the sink. Yep,

loaded with thriving bacteria.

If this makes you want to go relax in a hot tub, think again. The air

wafting from the hot water is probably loaded with microbes, some of

them able to give you a hacking cough.

It's a microbial world, says Norman P. Pace, a researcher at the

University of Colorado at Boulder. Virtually everything you touch is

coated with microbes. You couldn't escape them if you wanted to

because your skin is covered with about 100 million bacteria, says

Pace.

Yet, science knows very little about environmental microbes, how they

live, reproduce and thrive in the natural world. Most of what is

known comes from germs cultured and studied in the lab.

" We live in a microbial world and I find it appalling that this is

ignored by science, " Pace said Saturday at the national meeting of

the American Association for the Advancement of Science.

He discovered the colonies of soap scum bacteria when, out of

curiosity, he took a sample from his own shower curtain and examined

it under a microscope.

" I was amazed, " he said. Later studies of shower curtains from other

homes found the same thing.

" When you step into a shower, you are enmeshed in a bio-aerosol, " he

said.

Most of the soap scum bacteria is harmless to the healthy. But for

people with compromised immune systems, such as patients with AIDS or

on chemotherapy or with open wounds, some of the germs can be deadly.

Pace recommends that shower curtains be cleaned weekly.

When he rides an escalator, Pace said he puts down only his knuckles

because of the potential broth of bacteria that may be present.

The kitchen sink sponge, he said, " is a spectacular source of

bacteria. "

In his own home, he regularly wrings out the sponge and lets it dry,

breaking up the wet, warm bacteria paradise.

Pace explored the microbial world of hot tubs after he was asked to

investigate why some on the staff at a therapeutic swimming pool were

developing " lifeguard lung, " a nagging cough that plagues pool

workers.

He found that the air above a heated, indoor pool or above a hot tub

is enriched with microbes by about 60 percent. Persistent exposure to

the air caused the " lifeguard lung " in sensitive people. The same

thing can happen around a hot tub.

" These findings are a bit scary. The bottom line is people should be

aware of the risk of swimming in indoor pools or sitting in indoor

hot tubs, " Pace said.

One hot tub and pool solution, he said, is to increase ventilation so

the cloud of microbes is swept away. " Lifeguard lung " generally

clears when the exposure is stopped.

But, Pace said, " I wouldn't get into a public hot tub, or even a

private one for that matter. "

Despite the scary image of bacteria everywhere, Pace said it's not

reasonable to go into a " mode. " The late eccentric

billionaire isolated himself and sterilized most things out of fear

of germs.

Among microbes there are good guys and bad guys. Many bacteria are

beneficial, helping to keep the harmful ones in check. Antibiotics

can kill both the useful germs and the bad ones. That gives an

advantage to bacteria that are resistant to antibiotics, some of

which can be harmful.

Instead, Pace practices prudence.

People should wash their hands frequently, clean off soap scum often,

dry out the kitchen sponge and avoid excessive exposure to indoor

pools and hot tubs, he said.

Pace said there also needs to be more research about the life and

times of microbes in the natural world so science can determine where

there is a risk to human health and then develop solutions.