For the first time, medical experts have challenged the established view that the tuberculosis bacteria coughed up in sputum by infected individuals multiply rapidly. Experts at the universities of Leicester and London have identified that the TB bug lays down body fat that may help it survive passing from one person to another. In the process, the bacteria increase their resistance to anti-TB drugs. Mike Barer, Professor of Clinical Microbiology at the University of Leicester, said "strenuous efforts were being made to reduce the global burden of tuberculosis, a disease which kills four people every minute'. "Our success so far has been limited for many reasons; one of these is our failure to control the spread of TB from one person to another. Very little is known about this vital part of the bacterium's life cycle,' he said. The scientists might be able to identify new therapeutic and preventative targets if they could understand more about the transmission of TB between people. The Leicester team discovered that, unlike TB bacteria growing in test tubes, many of the bugs in sputum were loaded with fat droplets. These "fat bacilli' were in an inert non-growing state, a condition in which they are more likely to survive the process of passing from one person to another. The discovery sheds light on the story of "persister bacteria' in TB