With the recent series of experiments, scientists based at the University of California, San Diego School of Medicine, collected sputum samples from 1,128 study participants. Each of the samples was examined using the three different tests. Two of the tests used advanced molecular techniques. These methods looked for genetic mutations in the bacterium’s DNA that confer resistance to antibiotics.
The third test was very different. This was a low-cost and straightforward version of a standard bacterial culture technique. Such a method is regarded as "low tech" in the world of rapid and alternative microbiological methods.
Tuberculosis is one of the most widespread bacterial diseases on the planet. It is an infection that has plagued humans for over millennia. As I’ve written elsewhere: “Tuberculosis is a widespread infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. The symptoms of infection consist of a chronic cough with blood-tinged sputum, fever, night sweats, and weight loss. Tuberculosis is closely linked to both overcrowding and malnutrition.”
With the collected data, the results were compared to a reference standard technique for detecting resistance to seven of the main anti-tuberculosis drugs. It was found that each of the three rapid assays accurately identified resistance to first- and second-line oral antibiotic treatments.
Furthermore, while the results were less accurate, each of tests was effective in detecting resistance to injectable antibiotics (amikacin and capreomycin) administered in cases of multi-drug resistance tuberculosis.
None of the tests fared well in detecting resistance to one drug, the injectable antibiotic kanamycin, which is also used to treat multi-drug resistant tuberculosis.
Despite similarities in accuracy, the rapid tests were, in fact, very "rapid." The molecular techniques gave a result in a little over one day; the culture method took 14 days, and the reference standard test took almost 25 days to deliver a result.
The research findings are described in the journal PLOS ONE. The paper is called “Performance Comparison of Three Rapid Tests for the Diagnosis of Drug-Resistant Tuberculosis.”