Bacterial discovery may help CF patients

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Bacterial discovery may help CF patients

 

Bacterial discovery may help CF patients

 

By STEPHEN SHELDON

 

SYDNEY, Australia, Feb. 21 (UPI) -- A team of Australian and Danish

microbiologists have discovered a way to prevent or disrupt the formation of

bacterial colonies, which they believe may bring a string of benefits from

preventing lung infections in cystic fibrosis sufferers to cleaner contact

lenses.

 

The discovery, by scientists at the University of Queensland's Institute

for Molecular Bioscience and the Technical University of Denmark, was released

Friday and is published in the journal Science.

 

Researchers found a DNA-destroying enzyme, called DNaseI, may break up or

disrupt the formation of stubborn biofilms of the bacteria Pseudomonas

aeruginosa.

 

Biofilms are communities of bacteria enmeshed in a matrix of long,

chain-like molecules, which includes DNA. When biofilms form in the human body,

as they frequently do in the lungs of people with cystic fibrosis, they are

particularly resistant to antibiotics and the body's own immuneresponse.

 

Cystic fibrosis is a genetic disease characterized by the build up of

thick sticky mucus in the lungs and pancreas, leading to breathing difficulties

and nutritional problems.

 

Co-author of the paper, Professor John Mattick, said infection by this

bacteria resulted in inflammation and tissue damage in the lungs of cystic

fibrosis patients.

 

" During lung infection, Pseudomonas aeruginosa creates a biofilm, a soup

rich in proteins, complex sugars and DNA. This biofilm plays a vital role in

establishing bacterial colonies that are also resistant to antibiotics and the

host's immune response, " Mattick said.

 

Scientists have known for a while the biofilm of this pathogen has a high

DNA content but they thought the DNA in the matrix was not an important part of

the biofilm structure. The new research found the majority of the matrix

material in the biofilm consists of DNA, and that it seems to be released by the

living bacteria.

 

The researchers found treating the biofilm with the DNaseI enzyme, which

breaks down DNA into its component molecules, destroys the biofilm and restricts

the establishment of infectious colonies. It appears DNaseI treatment may also

be beneficial as an early prophylactic measure to prevent the establishment of

bacterial infection in the lungs of people with cystic fibrosis.

 

However, while DNaseI dissolved the biofilm during its early stages of

growth, it became less effective over the next 84 hours. The authors propose the

matrix in mature biofilms may be strengthened by other substances or that mature

biofilms may produce sufficient counter-enzymes to locally inactivate the

DNaseI.

 

Mattick's co-author, Dr. Cynthia Whitchurch, told United Press

International her research began several years when she started wondering

whether DNA might have a structural role. " It was a fortunate observation, " she

said.

 

She said while more research is needed, she is hopeful the discovery will

be useful in other settings where biofilm form, such as inside catheter tubes

and on the surface of contact lenses.

 

Professor Staffan Kjelleberg, a microbiologist who specializes in biofilms

at the University of New South Wales, was surprised when he heard of the

discovery.

 

" The discovery that DNA is the major component of the matrix, and the use

of DNaseI to dissolve it is a breakthrough, " he Kjelleberg told UPI. " My

question is, is it also relevant to other biofilms or only those pertaining to

Pseudomonas. You see, there are many types of biofilm, and they are formed

everywhere there's an aqueous environment. So the possibilities here are

endless. "

 

 

 

 

 

 

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Copyright 2002 by United Press International

 

 

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