Chennai, October 30, 2011: It is well-known that honey bees can detect scents of flowers and visit those with scents associated with nectar or pollen. A recent study1 by researchers at Christchurch's New Zealand Institute for Plant and Food Research Limited, shows that the bees can detect even traces of sweet-smelling volatiles produced by the tuberculosis (TB) bacterium, Mycobacterium tuberculosis. Reporting this finding, Kloe Palmer in the 3 News, New Zealand dated October 27, 2011 says the Christchurch scientists might soon add honey bees as tuberculosis diagnosing aids, that help in the battle against tuberculosis.
It is estimated that about 2 billion people unknowingly have M. tuberculosis in their lungs, while 200 million of them fall ill with TB at some stage during their life. TB kills almost 2 million people every year.
In 2008 scientists of the Department of Pathology, Christchurch School of Medicine and Health Sciences, University of Otago identified2 volatile metabolites from the laboratory cultures of TB bacterium, M. tuberculosis, and of M. bovis, as methyl p-anisate, methyl phenylacetate, methyl nicotinate and o-phenylanisole. These compounds could be detected even before the visual appearance of bacterium-colonies and thus are potentially useful as highly sensitive biomarkers and can form the basis of a non-invasive diagnostic test for TB.
In the latest study, the researchers trained honey bees to recognize particular smells and associate each smell with a food reward. When the bees detect the smell, they extend their proboscis (the Proboscis Extension Reflex) in expectation of food. Later they trained the bees to respond to three of the chemicals given off by the M. tuberculosis cultures - methyl p-anisate, methyl phenylacetate and methyl nicotinate. The researchers found that the bees were responding to even traces of each chemical. It is not yet certain whether these volatiles are actually present in the breath of TB patients. "But if they are, and we can detect them," says Palmer in the news report, "then breath analysis could lead to a cheap, rapid and non-invasive test for TB."
- Suckling, D.M. and Sagar, R.L. 2011. Honeybees Apis mellifera can detect the scent of Mycobacterium tuberculosis. Tuberculosis 91 (4): 327-328. doi:10.1016/j.tube.2011.04.008 (Abstract)
- Syhre, M. and Chambers, S.T. 2008. The scent of Mycobacterium tuberculosis. Tuberculosis (Edinb) 88 (4): 317-323. doi:10.1016/j.tube.2008.01.002 (Abstract)