TB strain identification via 'genetic barcode'

Date: Sep-05-2014A study published in Nature Communications describes how a team led by the

London School of Hygiene and Tropical Medicine in the UK has devised a genetic barcode to help

doctors and researchers easily identify different types of tuberculosis.

Lead author Dr. Taane Clark, Reader in the School's Genetic Epidemiology and Statistical

Genomics, says:

"There is increasing interest in new technologies that can assist those treating tuberculosis

patients. This new barcode can be easily implemented and used to determine the strain-type that

is a surrogate for virulence."

Although TB usually involves the lungs, it can affect any part of the body.

"New technology is making it easier to track mutations but genomes are very complicated and

we hope this simple barcode will help people with their research," explains co-author and tuberculosis (TB) expert Dr. Ruth McNerney, a Senior Lecturer in Pathogen Biology and

Diagnostics at the School.

TB is a worldwide, deadly respiratory disease caused by various strains of

Mycobacterium tuberculosis. Although it usually involves the lungs, it can affect any

part of the body. It takes about 6 months to treat the disease with antibiotics.

According to the World Health Organization (WHO), TB is second only to HIV/AIDS as the greatest

killer worldwide due to a single pathogen. The disease causes illness in over 8 million people

every year and kills over 1 million. Most of the deaths occur in low- and middle-income

countries.

In healthy people infected with TB, the immune system keeps it at bay. People who are not

aware they are infected can carry the pathogen around the world.

Over the last 70,000 years, TB bacteria have been evolving alongside humans, diversifying

into families of strains that affect different people in different ways, and spreading from

person to person through the air.

62 of 90,000 mutations sufficient for TB barcode

To pinpoint the origins and map how TB moves around the globe, Dr. Clark and colleagues

examined over 90,000 genetic mutations across a global collection of 1,600 M.

tuberculosis genomes.

Of the 90,000 or so mutations, around 7,000 of them are strain-specific, but the team

discovered you only need 62 of them to code the entire known global family of circulating TB

bacteria strains.

The authors say the barcode is the first to cover all main lineages, and "classifies a

greater number of sublineages than current alternatives."

Dr. Clark says they are making their findings "available to the doctors and scientists

working with tuberculosis so that they can more easily know what strains they are dealing

with."

In July 2014, Medical News Today reported how WHO plan to eradicate TB in 33 countries.

Written by Catharine Paddock PhD

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Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.