A new, rapid breath test can detect tuberculosis (TB) reports a study published online in Nature Communications. The test is specific to cases of TB that are sensitive to isoniazid, the most common antibiotic used for TB, to which resistance is uncommon.
Current methods for TB diagnosis, based on blood tests or microscopic examination of samples, are not highly reliable, and require microbiological confirmation that takes several weeks. Isoniazid, the main antibiotic used for TB treatment, is inactive when administered. Only TB bacteria possess an enzyme (KatG) that acts on the drug to yield an active antibiotic and nitrogen gas.
Graham Timmins and colleagues report the development and evaluation in laboratory animals of a breath test that detects the presence of isoniazid-sensitive TB bacteria. The test involves the administration of isoniazid that has been chemically labelled. After a period of five to ten minutes, labelled nitrogen gas is detected by mass spectrometry in the exhaled breath of the infected animals. A positive result indicates the presence of isoniazid-susceptible TB bacteria, whereas a negative result means either the absence of TB infection or presence of isoniazid-resistant TB bacteria.
Portable mass spectrometry devices are currently under development, indicating that the breath test has the potential to become a point-of-care tool in the near future. Clinical studies are required to evaluate the safety and effectiveness of the new test, which could help doctors make rapid decisions and prescribe optimal antibiotic therapies.