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Revealed: Chinks in superbug's armour

Scientists said on Sunday they had exposed key workings of a deadly superbug su·per·bug
Any of various disease-causing bacteria that develop a resistance to drugs normally used to control or eradicate them.

 that has become one of the biggest nightmares for hospitals today, opening up paths for new drugs or vaccines to roll back the peril.

Clostridium difficile Clostridium difficile A common cause of bacterial colitis; it is the causative agent in 99% of pseudomembranous colitis, and 20-30% of antibiotic-associated diarrhea  ranks alongside Methicillin-resistant Staphylococcus aureus methicillin-resistant Staphylococcus aureus Methicillin-aminoglycoside resistant Staphylococcus aureus, MRSA An organism with multiple antibiotic resistances–eg, aminoglycosides, chloramphenicol, clindamycin, erythromycin, rifampin, tetracycline,  (MRSA MRSA Methicillin-resistant Staphylococcus aureus. See MARSA. ) as a hospital threat, inflicting a rising toll each year as it spreads insidiously through health facilities.

Known as "C-diff," the bug comprises a bacterium that comes in a spore, or a hardy shell-like jacket. It naturally colonises the gut, but is not a problem for people who are healthy as it is kept in check by other intestinal bacteria.

But when antibiotics are used to treat someone who is sick, the drugs can wipe out the "good" bacteria, which leaves C. difficile to multiply uncontrolled.

As the germ reproduces, it releases toxins that cause severe diarrhoea, sometimes fatally, and colitis that can need surgical removal of the colon.

In a study published in the journal Nature, microbiologists in the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area.  reported that they had identified which of the two toxins released by C-diff does the big damage.

"For 20 years, we have been focusing on Toxin A. But it turns out the real culprit is Toxin B," said researcher Dale Gerding of Loyola University Loyola University (loi-ō`lə), at New Orleans, La.; Jesuit; coeducational. The university was established through a merger in 1911 of the College of the Immaculate Conception (opened 1849) and Loyola College and Academy (opened 1904).  in Chicago.

"This is a major finding in how C-diff causes disease in humans," he said in a press release released by the university.

"It completely flips our whole concept of what the important toxin is with the disease."

The team devised separate strains of the two toxins and tested them on hamsters.

Separately, scientists at Imperial College London History
Imperial College was founded in 1907, with the merger of the City and Guilds College, the Royal School of Mines and the Royal College of Science (all of which had been founded between 1845 and 1878) with these entities continuing to exist as "constituent colleges".
 have used X-ray crystallography X-ray crystallography, the study of crystal structures through X-ray diffraction techniques. When an X-ray beam bombards a crystalline lattice in a given orientation, the beam is scattered in a definite manner characterized by the atomic structure of the lattice.  to produce the first high-resolution images of the germ's protective jacket.

The work, published in the latest issue of the journal Molecular Microbiology, is important because it opens up a theoretical path for drugs that crack open the shield, disabling the bacterium inside.

C-diff is resistant to many types of antibiotics and can bounce back in a patient who has fallen sick with the germ. In addition, the jacket makes it easily transportable on surfaces and hands.

It causes about half a million cases of sickness, and between 15,000 and 20,000 deaths, in the United States each year, the Loyola University press release said.
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Publication:AFP Global Edition
Date:Mar 1, 2009
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