Researchers Map Genes Of Bacteria

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Researchers Map Genes Of Bacteria

August 30, 2000

The Associated Press

Researchers have figured out the genetic blueprint of a common but

extraordinarily crafty germ that can be lethal in burn victims and people

with lung-clogging cystic fibrosis.

Armed with the information, scientists hope to develop new ways of fighting

the germ within four to five years.

The bacterium is called Pseudomonas aeruginosa and is known for its

durability and adaptability. It can be found everywhere from home plumbing

to vegetables but is harmful only to people with compromised immune systems.

But once it colonizes the lungs of cystic fibrosis patients, the wounds of

burn patients and others who are vulnerable, the bug's natural defenses make

it nearly impossible to eradicate.

" The bacteria have always been smarter than the chemist, " said Beall,

president of the Cystic Fibrosis Foundation. " The bacteria are able to

develop resistance to the common forms of antibiotics that we use. "

The foundation helped pay for the research by the University of Washington

Genome Center and PathoGenesis Corp. in Seattle. The results were published

in Thursday's issue of the journal Nature.

Already, researchers have noticed that the germ contains several " drug

pumps " that effectively wash away any antibiotics. P. aeruginosa germs have

also been found to form protective films resistant to antibiotics.

" It's a lot smarter than most bacteria, " said C. Kendall Stover, a scientist

at PathoGenesis. " You can liken it to the Pentium III of the bacterial

world. "

Scientists hope to figure out how to thwart those mechanisms. " This

information is going to certainly help us in coming up with new therapies in

dealing with drug resistance in general, " Stover said.

The genetic blueprint is by far the most complicated of the roughly 25

bacterial genomes so far mapped.

The bacterium's single circular chromosome has 6.3 million base pairs of

chemicals and at least 5,570 predicted genes. It also has the greatest

number of genes devoted to command and control systems of any sequenced

bacteria. That vast coding is what makes the bug so tenacious and versatile.

Researchers have yet to determine a function for about 35 percent of the

genome.

As a condition of the Cystic Fibrosis Foundation's funding, information on

the germ's genes has been made available around the world on the Internet to

save time and speed up the discovery of treatments.

The bug is blamed for many of the 230,000 annual cases of pneumonia in U.S.

hospital patients on ventilators. Those infected have a 40 percent greater

chance of dying. But the greatest effect is on the 70,000 cystic fibrosis

patients worldwide, including 30,000 in the United States.

Cystic fibrosis is a deadly disease caused by a defective gene. Victims have

abnormally thick and sticky mucus that clogs the airways.

Lung infections lead to the deaths of 95 percent of all victims, and P.

aeruginosa is the most prevalent and difficult infection. About half of all

cystic fibrosis patients are infected by age 5, Beall said.

Copyright 2000 The Associated Press. All rights reserved.

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