Australian and Danish researchers may have found a way to prevent the build-up of bacteria on surfaces - from contact lenses to the lungs of people with cystic fibrosis.
Dr Cynthia B. Whitchurch from the University of Queensland's Institute for Molecular Bioscience and colleagues report in today's issue of Science they have found a way to dissolve the 'glue' that holds together the bacteria Pseudomonas aeruginosa.
"We've found we can stop bacterial biofilm from forming," said Dr Whitchurch.
Biofilms, formed by bacterias such as Pseudomonas, are a slimy matrix which includes proteins, sugars and DNA, all produced outside the bacterial cell.
These structures enable bacteria to survive on all kinds of surfaces and protect them from antibiotics and immune system attack. They are believed to prevent the successful treatment of Pseudomonas aeruginosa in the lungs of cystic fibrosis (CF) patients.
The researchers found that the DNA in the matrix was the key to its structure.
"This is the structural glue of the biofilm," said Dr Whitchurch who is currently on sabbatical at the University of California, San Francisco.
The researchers then found that an enzyme called DNAse 1 - which breaks down DNA - can be used to break down biofilms and prevent their build-up in the first place.
According to Dr Whitchurch this could have broad applications in the future, not least in the treatment of patients with CF.
People with CF have very thick sputum because of DNA released by immune damage. This is currently treated with DNAse 1 in aerosol form to help break down the sputum. However this treatment was often too late to prevent the build up of biofilms.
"If it was used earlier, DNAse 1 has the potential of preventing biofilms from forming in the first place," said Dr Whitchurch.
"It could also be used to keep catheters and contact lenses free of biofilm."
Exploring the biology of biofilms and their importance is a fairly new area of research. It was only in 2000 that the bacteria infecting the lungs of CF patients were found to exist in a biofilm.
The DNA in biofilm had been ignored because it was thought to be dead bacteria. Dr Whitchurch initially thought that sugars were the glue in the PS biofilm.
But when this line of research met a dead end, she re-discovered old reports that showed DNA was deliberately produced by the bacteria in their 'slime'. This was when she realised the DNA might be the structural key to the biofilm.
According to Dr Simon Bowler, Director of Respiratory Medicine at Mater Public Hospital in Brisbane, increases in life expectancy of people with CF are due to improved standards of care. Babies diagnosed with CF now have a life expectancy of 50 years.
He considers understanding the biology of biofilms to be a very promising area of research and described the idea of using DNAse 1 as a preventative as "exciting" and worth further investigation.
But he pointed out the treatment was quite expensive - around $900 per month.
Anna Salleh - ABC Science Online
Posted by AliG (Member # 9734) on :
This is very interesting, James.
I noticed it was from 2/22/02. I wonder if they've been doing anything with this information since then.
Posted by aklnwlf (Member # 5960) on :
Thanks James! I like to read anything that pertains to biofilm and it's destruction.
Posted by AliG (Member # 9734) on :
Dinty J. Musk, David A. Banko and Paul J. Hergenrother Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, Illinois 61801
Received 19 February 2005; revised 29 April 2005; accepted 6 May 2005. Published: July 22, 2005. Available online 22 July 2005.
Summary
Bacterial biofilms are thought to aid in the survivability of a variety of intractable infections in humans.
Specifically, biofilm production in Pseudomonas aeruginosa has been shown to play a significant role in chronic infection of cystic fibrosis (CF) patients.
Unfortunately, no clinically effective inhibitors of biofilm formation are available.
A rapid screen of 4509 compounds for nonantibiotic biofilm inhibitors in Pseudomonas aeruginosa PA14 was executed in 384-well plates.
Among those compounds, ferric ammonium citrate inhibited biofilm formation in a dose-dependent manner; other iron salts functioned similarly. In addition to biofilm inhibition in static culture, pregrown biofilms could be disrupted and cleared by switching to iron-rich media in flow-chamber experiments.
Furthermore, P. aeruginosa strains taken from the sputum of 20 CF patients showed a similar response to elevated iron levels.
Previous expression-profiling analyses demonstrated that high levels of iron repress the expression of genes whose products are essential for scavenging iron and that expression of these genes is critical for virulence.
Our results, combined with existing transcriptional-profiling data, now indicate that elevated iron concentrations repress the expression of certain genes essential for biofilm production in P. aeruginosa.
PMID: 16039526 [PubMed - indexed for MEDLINE]
Posted by AliG (Member # 9734) on :
Department of Oral Health Sciences, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA. [email protected]
Living-tissue biofilms remained unrecognized until very recently, mainly as a result of traditional microbial sampling techniques or histologic processing, which disrupt the spatial organization of the tissue microorganisms.
Thus, the biofilm nature of certain mucosal infections was frequently unintentionally missed or disregarded.
To a large extent, the study of human tissue biofilms is still in its infancy.
However, with the advent of newer methodologies, such as fluorescent in situ hybridization and endoscopic confocal laser scanning microscopy, which combine the identification of microbes with in situ, direct visualization of their relationships with each other and with their substratum, mucosal tissue biofilms are becoming easier to study and, thus, their role in human infections is becoming more apparent.
This review summarizes the challenges in the study of tissue biofilms, proposes two inflammation-centered - albeit opposite - pathogenetic models of mucosal tissue biofilm infections and suggests directions for future research and novel therapeutic approaches.
PMID: 18380602 [PubMed - indexed for MEDLINE
Posted by AliG (Member # 9734) on :
If you do a search on here about biofilms, I believe there was a groundbreaking discovery in Princeton, not too long ago, with regard to biofims.
I believe that bacteria signal each other through sound and if their signals can be disrupted the become non-pathogenic.
I could be wrong on that, it might not have had to do with biofilms, maybe just bacteria.
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