January 21, 2006

Bugs in the dirt

Interesting study of soil bacteria and drug resistance. From Nature:
Superbugs abound in soil
Survey of bacteria reveals an array of antibiotic-resistance.

Bacteria that live in soil have been found to harbour an astonishing armoury of natural weapons to fight off antibiotics. The discovery could help researchers anticipate the next wave of drug-resistant 'superbugs'.

Researchers have long known that soil-dwelling bacteria make natural antibiotics, and that they have inbuilt ways to survive their own and other bugs' toxins; in some cases, the genes that help them dodge antibiotics have transferred into infectious bugs that plague humans.

Microbiologists have identified a few of the ways that soil microbes neutralize antibiotics. But Gerard Wright and his team at McMaster University in Ontario, Canada, have shown that soil microbes carry a hidden trove of such arms.

The team collected handfuls of dirt from towns and forests across Canada, and grew the bacteria contained within them. They isolated 480 different strains of the common soil bacteria Streptomyces, which are known to synthesize a large number of antibiotics, and so are expected to have natural defenses against them. They then threw 21 different antibiotics (some natural, some synthetic), at the bugs to see if they could survive.

The strains were impervious to seven or eight antibiotics on average, the researchers report in Science, and two hardy ones were resistant to 15 drugs.

Many of the bacterial strains were immune to antibiotics that they have probably never been exposed to before. And the crafty creatures used some previously unknown ways to detoxify some drugs, such as adding a sugar molecule on to the drug telithromycin, which prevents it from crippling a cell.
Interesting! A blessing and a bane. Blessing in that we will gain insights on how bacteria adapt and gain resistance but a bane because this resistance can jump to something that seriously bothers us (thinking something like S. aureus which is a serious problem in hospitals). Posted by DaveH at January 21, 2006 8:07 PM