Researchers studying the microbiology of water systems at 45 sites in seven different states across the U.S. found unusually high levels of bacteria in showerheads—almost 100 times more than any other place in the home. Although bacteria levels were high in all showerheads, some sample sites in the New York City and Denver areas had large amounts of Mycobacterium avium, a relative of the bacteria that causes tuberculosis and leprosy.

“If you’re getting a face full of water when you first turn your shower on, that means you are probably getting a particularly high load of Mycobacterium avium,” says study author Norman Pace, professor of biology at the University of Colorado.

Mycobacteria are found in soil, water, and decaying matter. Certain Mycobacteria, such as Mycobactrium avium, can cause digestive, lymphatic, and pulmonary infections. In the shower, these bacteria are delivered as aerosols. Particles are small enough to get into the lungs, and when inhaled or swallowed, can lead to a host of pulmonary problems.

The study, part of a bigger study that began as a class project, used DNA barcode testing to extract rRNA (bacterial DNA) from different parts of the shower and showerhead. Researchers sampled water flowing from the showerhead and obtained swab samples from the inside of the showerhead. Finally, samples were collected from water flowing out of the pipe after the showerhead was removed.

Homes with well water systems did not have Mycobacteria in their showerheads, a factor authors believe may be due to Mycobacteria’s chlorine resistance. Although they suggest that bathing may be safer, researchers assure that it’s not dangerous to shower.

“We did see some organisms that might be of concern if you have immune issues (such as) cystic fibrosis, AIDS, recent organ transplant, substance abuse, or are pregnant or otherwise immune compromised,” the authors wrote.

Click for more information on pulmonary disease.

Although there were no deaths reported from the recent string of wildfires in Southern California, the danger from such fires goes beyond the fire lines. Residents in regions surrounding the fires were exposed to air containing high levels of soot and particulates that can have serious health repercussions for people with asthma and other respiratory problems. The poor air quality may even adversely affect normally healthy individuals, according to the American Lung Association.

For sensitive people, poor air quality can be a life-threatening emergency. A study released this week reports on the devastating impact of another set of wildfires that occurred in Southern California in October 2003. During a 90 day period surrounding those fires, Southern California hospitals saw a 34% increase in asthma admissions, a 67% increase in acute bronchitis admissions, a 48% increase in chronic obstructive pulmonary disease (COPD) admissions, and a 45% increase in pneumonia admissions. While young children and the elderly were most affected, teens with asthma also accounted for some of the increase in hospital visits.

Whether you have respiratory problems or not, the American Lung Association of California recommends that you stay indoors as much as possible during periods when you can smell smoke in the air or you notice irritation in your eyes or throat. If you have to be outside, limit your activity level and try not to exert yourself. Wearing a mask such as those available at hardware stores may help but it will not filter out the smallest particles.

People with asthma or other respiratory problems who live in the areas surrounding a fire should also use air purifiers or air conditioners set to recirculate if possible, to prevent exposure to toxic outside air. If outdoor trips in smoky areas are necessary, you can breathe through a damp cloth to help filter out particles in the air.

Those with asthma should consult their asthma management plan or talk with their doctor about how to optimize their asthma medications during the time of the fire and about what to do in case of an asthma attack. If your asthma symptoms are not under control normally you are more likely to have problems when you are exposure to irritants such as smoke from fires. If you are not sure whether your asthma is under control or not, see the Healia Health Guide on Uncontrolled Asthma. If you find that your symptoms are not relieved by your usual medications, or if you develop a persistent cough or painful breathing, seek medical attention right away. Remember that symptoms may appear as much as two days after exposure to smoke and may last for many days after the fires have ended.

For more information about asthma, see the Healia Health Guide for Asthma. If your asthma symptoms seem to be holding you back from living a normal life, check out the Healia Health Guide on Uncontrolled Asthma, or take the Asthma Quiz and find out if your asthma really is under control.

_{Photo: Erik Charlton, Flickr, Creative Commons}