JMM Editor's Choice: a new skin test for latent tuberculosis
Posted on September 5, 2019 by Microbiology Society
The Journal of Medical Microbiology (JMM) is a journal published by the Microbiology Society, focused on providing a comprehensive coverage of medical, dental and veterinary microbiology and infectious diseases, including bacteriology, virology, mycology and parasitology. This month, Associate Professor Rikke Louise Meyer has selected an outstanding paper from the July issue to highlight as Editor's Choice. The paper, titled 'Application of transdermal patches with new skin test reagents for detection of latent tuberculosis' discusses a new diagnostic tool to identify patients with dormant tuberculosis.
Tuberculosis is a major global health problem and inaccurate diagnostic tests for latent tuberculosis infection is a challenge for managing the spread of this disease. In this important study, Kasempimolporn et al. sought to develop a novel diagnostic skin test based on specific tuberculosis antigens. Current commercial tests are based on the tuberculin purified protein derivative (PPD). PPD-based tests can produce false-negative results because PPD antigens are not specific for pathogenic strains, and false-positive results are common in vaccinated individuals. The antigens used in the current study were specific to Mycobacterium tuberculosis, and skin tests performed on guinea pigs sensitized with Mycobacterium tuberculosis were positive, while vaccinated individuals tested negative. The study therefore presents an important step forward for easy and accurate diagnostic tests for latent tuberculosis infection.
Current intradermal tuberculin skin tests (TST) for latent tuberculosis infection have poor specificity. Developing a better skin test antigen, as well as a simple skin patch test, may improve and facilitate the diagnostic performance. The defined antigens that were unique to Mycobacterium tuberculosis were used as diagnostic skin test reagents in comparison to a standard tuberculin and the performance of skin patches was evaluated in guinea pigs. Compared with the TST, transdermal application of defined purified antigens might be a promising method for laternt tuberculosis infection screening. Further studies of its application in humans would be necessary.