Project Lead(s): Francis Nano
Issue
Despite recent strides in controlling tuberculosis (TB) worldwide, infections with Mycobacterium tuberculosis remain the largest cause of morbidity and mortality from a bacterial pathogen (8 million new cases of TB and 2 million deaths per year).
Researchers working in microbiological diagnostic and research laboratories are likely to be exposed to infection risk with pathogens.
The incidence of TB among laboratory personnel working with M. tuberculosis is known to be three to nine times higher than the infection risk for those working on other diseases.
Solution
The project goal was to develop strains of M. tuberculosis that are unable to grow at 37°C or higher temperatures, to create safe variants of the bacteria that can be used in diagnostic laboratories.
This was done by applying Arctic essential gene technology to the problem of multiple-drug resistance in M. tuberculosis.
In approaching the problem, the project team first chose to work with Mycobacterium smegmatis. This bacterium is often used as a research surrogate for M. tuberculosis, since it is relatively safe for humans and it grows much faster than M. tuberculosis.
Outcome
The first success from the project was the creation of a non-reverting, temperature-sensitive M. smegmatis, providing strong evidence that pathogenic or vaccine strains of Mycobacterium can be altered so that they are temperature-sensitive.
This may have direct applications in making the anti-tuberculosis vaccine strain, BCG, safer in areas of the world with high HIV infection rates.
The second achievement was the cloning of essential genes from M. tuberculosis into strains of E. coli that conditionally express the cognate-essential genes that were introduced. This showed that the M. tuberculosis genes can functionally substitute for the E. coli genes.
Establishing this system will allow the use of directed evolution to change M. tuberculosis genes into temperature-sensitive forms that can be used to engineer M. tuberculosis strains to temperature-sensitivity.
The project was not completed due to time constraints, but preliminary findings were disseminated in publications.
It is estimated that about $1 million in funding will be needed over a period of 3–4 years to bring this technology to the point where private sector firms can commercialize it.