Breaking News:New ‘Quick DNA’ kit could speed up detection of drug-resistant Tuberculosis– What Just Happened

Researchers from the Postgraduate Institute of Medical Education and Research, Chandigarh; the National Institute of Tuberculosis and Respiratory Diseases, New Delhi; and others have developed a Quick DNA kit that significantly reduces the time required to test for multidrug-resistant tuberculosis (TB).  Their new method was found to be as accurate as standard, time-consuming laboratory tests, but significantly more practical for use in developing nations. By using a specialised filter paper called a Trans-Filter, medical workers can now transport patient samples at room temperature, even in the searing heat of the Indian summer. This eliminates the need for complex cold chain refrigeration that often fails in rural areas and could help save thousands of lives in remote communities.

At the heart of this diagnostic breakthrough is the Trans-Filter, a membrane designed to filter out TB bacteria and turn the hazardous biological samples into safe, shippable data. While standard medical testing usually requires liquid sputum to be kept in glass vials and transported to a laboratory in refrigerated trucks, the Trans-Filter allows the sample to be dried, thereby immobilising the tuberculosis bacteria on a sturdy, paper-like surface.

The researchers screened over 1,800 patients to test the new system. The process begins with a patient’s sputum sample, which is first liquefied and then passed through the Trans-Filter device. As the liquid flows through, the membrane acts like a microscopic net, capturing the TB bacteria while letting other fluids pass. The filters are then sterilised and air-dried, which locks the bacterial DNA in the filter paper. These filters are tucked into simple, lightweight zip-lock bags for travel. The researchers found that the Trans-Filter is incredibly resilient. During testing, the membranes were stored at temperatures as high as 50°C (122°F) for up to four weeks. Even in these extreme conditions, which mimic a heatwave in rural India, the bacterial DNA remained perfectly preserved.

Once this filter reaches a central laboratory, the Quick DNA kit employs a method known as heat lysis. By heating the filter in a specialised buffer solution at 80°C for five minutes, the tough outer walls of the TB bacteria are disrupted, releasing their DNA. This genetic material is then analysed using a Line Probe Assay (LPA), a method that detects specific mutations in the bacterial genome. These mutations are biological markers that indicate whether the TB strain is resistant to standard antibiotics such as rifampicin or isoniazid.

Traditionally, extracting DNA from a TB sample was a laborious seven-step process that took nearly an hour to complete. Furthermore, the standard method for transporting TB samples involves packing them on ice and transporting them to a laboratory within 48 hours to prevent spoilage. The Quick DNA kit reduces extraction to a single step that takes only five minutes, and the use of the Trans-Filter ensures that samples remain stable for weeks at room temperature. This eliminates the logistical challenges of maintaining a cold chain in regions with unreliable electricity or long travel distances, thereby making advanced testing available to patients who were previously unreachable.

The researchers, however, noted that the study focused primarily on smear-positive samples, which are those with a high bacterial concentration. Further research may be needed to determine whether the kit is sufficiently sensitive for smear-negative patients, who carry fewer bacteria and are often more difficult to diagnose. Additionally, although the test was highly accurate for most drug resistance markers, a small subset of samples involving a specific gene, inhA, showed lower sensitivity. This was largely because those specific mutations are rarer, sometimes yielding weaker signals that are more difficult for laboratory technicians to interpret.

Nevertheless, the study provides an easy test for a difficult challenge. Tuberculosis remains one of the world’s deadliest infectious diseases, and the rise of drug-resistant strains is a global health emergency. In countries such as India, the time between a patient’s first symptoms and the initiation of appropriate treatment is often far too long. By simplifying sample transport and expediting laboratory work, this new kit helps bridge that gap.