Customer stories: New, quicker method to diagnose tuberculosis

Each year, approximately nine million individuals are infected by bacteria causing tuberculosis. The disease causes the death of some 2 million human beings due to poor health care and lack of diagnostic services. Fast detection of the infection is a key issue, enabling immediate treatment. In collaboration with the University of New Delhi, Dag Ilver and his coworkers at Acreo are designing a quicker, less expensive diagnostic method that can be used under field conditions.

The conventional and most secure method in use to make a diagnosis of tuberculosis is to cultivate bacteria from sputum samples, followed by identification in a laboratory. This is a time-consuming process that can take more than a month, while the patient runs the risk of becoming more ill. If the patient is not isolated, he or she can infect others. The most common alternative to cultivation is staining and microscopy of the sputum sample. This method is faster than cultivation but less specific, and requires a well-equipped laboratory with trained persons for performing the diagnostics.

Diagnostic service for rural areas

Dag Ilver and his colleagues are developing a biosensor system capable of efficient diagnostic service mainly targeted for the rural areas in developing countries. Using the instrument, it will be possible for a non-specialist to perform the diagnostic assay. The method is based on antibodies labeled with fluorescent nanoparticles that bind to the surface of bacteria causing tuberculosis. The fluorescent antibodies track down and attach to the tuberculosis bacteria in a sputum sample, making the bacteria “glow in the dark”. With the help of ultraviolet light, the nanoparticles, now acting as markers for the tuberculosis bacteria, can be detected. The team has developed a low-cost, minimalistic flow cytometer technique to count the number of bacteria in the sample; after being illuminated by laser, any fluorescent bacteria in the sample is filmed when it passes an optical flow cell and the results are automatically analysed in a computer program.

Portable, low cost and easy to use

The big advantage of this technique is the combination of portable size, low cost and ease of use, enabling the equipment to be used under field conditions. This is of high importance, especially in areas missing disseminated health care.

“The research project has demonstrated the system’s ability to conduct analyses in a lab environment. But we still need to get it into a smaller unit that can be taken to a clinic. So far, it hasn’t been tested in field conditions,” says Dag Ilver.

In India, his partner Vijay Chaudhary at the biochemical department, University of New Delhi, develops antibodies that are essential for the analyses. The goal is to conduct a field test and get the results in only 15 minutes, and then start the treatment the same day.

“The next natural step in the project is to make the system more robust and conduct field tests in India to collect statistical data”, says Dag Ilver.

Project partners

Acreo Swedish ICT, University of New Delhi

Contact

BESbswyBESbswyBESbswyBESbswyDag Ilver: dag.ilver [at] acreo.se