Researchers Find Source of Drug-Tolerant Tuberculosis

The researchers are the first to show that “Mycobacterium tuberculosis” can grow in surface-level bacteria clusters known as biofilms that are common in nature but never before shown for TB bacteria, explained the paper's senior author Graham Hatfull, chair and Eberly Family Professor of Biological Sciences in Pitt's School of Arts and Sciences. Hatfull collaborated and coauthored the paper with Professor William Jacobs Jr. of the Department of Microbiology and Immunology at the Albert Einstein College of Medicine in New York.

Hatfull, Jacobs, and their colleagues found that the biofilm bacteria are physiologically and genetically different from TB bacteria harvested in a lab-the type used in developing antibiotics. These variations result in a population of the bacteria that are “drug-tolerant and harbor persistent cells that survive high concentrations of anti-tuberculosis antibiotics,” the team reports.

People with TB typically undergo six to nine months of treatment with multiple antibiotics and most of the bacteria generally die within the first two weeks. Yet the disease can recur, presumably because of drug-tolerant bacteria that have escaped the antibiotic. The source and location of these persistent cells are unknown, but Hatfull and Jacobs' research reveals a possible biofilm origin, Jacobs said.

“The nature of persisting “M. tuberculosis” cells has been an enigma for the entire field,” Jacobs said. “Clearly “M. tuberculosis” cells in biofilms represent at least one class of persistent cells, and we are testing their biological relevance.”

It is not yet known whether the biofilm actually factors into human TB infections, Hatfull said. He added that the only similar research regarding biofilm in living creatures showed the presence of biofilm-like or biofilm-related bacteria in guinea pigs.

“While our data does not show conclusively that biofilm formation in people gives rise to a drug-tolerant population, the fact that biofilms do so in the lab makes this an interesting and testable hypothesis,” Hatfull said.

Other collaborators on the project include: Yann Guerardel and associate Xavier Trivelli of the Universite des Sciences et Technologies de Lille in France; Laurent Kremer and associate Anuradha Alahari of France's University of Montpellier; Pitt postdoctoral researcher Anil Ojha; and Jacobs' research associates Anthony Baughn, Dhinakaran Sambandan, and Tsungda Hsu.

The full paper can be read on the “Molecular Microbiology” Web site at http://www.blackwell-synergy.com/doi/full/10.1111/j.1365-2958.2008.06274.x

Source: University of Pittsburgh

Bioengineers fill holes in science of cellular self-organization
The chemical and biological aspects of cellular self-organization are well-studied; less well understood is how cell populations order themselves biomechanically – how their behavior and communication are affected by high density and physical proximity. Bioengineers and physicists at the University of California San Diego, in a paper published in the current issue of the Proceedings of the National Academy of Sciences, have begun to address these fundamental questions.
Living sensor can warn of arsenic pollution
Scientists studying arsenic pollution have discovered a living sensor that can spot contamination. They have also discovered new bacteria that can clean up arsenic spills even in previously untreatable cold areas, microbiologists heard today (Monday 8 September 2008) at the Society for General Microbiology's Autumn meeting being held this week at Trinity College, Dublin.
New research challenges notion that dinosaur soft tissues still survive
Paleontologists in 2005 hailed research that apparently showed that soft, pliable tissues had been recovered from dissolved dinosaur bones, a major finding that would substantially widen the known range of preserved biomolecules.
Biofilms use chemical weapons
Bacteria rarely come as loners; more often they grow in crowds and squat on surfaces where they form a community together. These so-called biofilms develop on any surface that bacteria can attach themselves to. The dilemma we face is that neither disinfectants and antibiotics, nor phagocytes and our immune system can destroy these biofilms. This is a particular problem in hospitals if these bacteria form a community on a catheter or implant where they could potentially cause a serious infection.
Microscopic 'clutch' puts flagellum in neutral
A tiny but powerful engine that propels the bacterium Bacillus subtilis through liquids is disengaged from the corkscrew-like flagellum by a protein clutch, Indiana University Bloomington and Harvard University scientists have learned. Their report appears in this week's Science.
Researchers identify biofilms that cause infections
Understanding the way bacterial cells "talk" to each other could lead to more effective methods for fighting the often persistent and serious infections caused by the biofilms they form, says a Texas A&M University professor of chemical engineering who not only has deciphered their language but also discovered how to quell their conversation.
Source of drug-tolerant tuberculosis possibly behind TB relapses, intensity of treatment
University of Pittsburgh-led researchers discovered that the primary bacteria behind tuberculosis can grow on surfaces and that drug-tolerant strains flourish in these bacterial communities, the research team recently reported in Molecular Microbiology. The findings suggest a possible reason why human tuberculosis (TB) requires months of intensive antibiotic treatment and indicate a potential cause of the relapses that can nonetheless occur.
Rapid escalation characterizes virus/host arms race
The interaction between a virus and its host is often portrayed as an arms race, with each new viral attack parried by the host and each new defense by the host one-upped by the virus.

Researchers Find Source of Drug-Tolerant Tuberculosis

Related stories:

News discussion: