Assay can ID M. tuberculosis resistance mutations

September 15, 2017

(HealthDay)—An automated molecular assay can detect Mycobacterium tuberculosis with resistance to drugs directly from sputum specimens, according to a study published in the Sept. 14 issue of the New England Journal of Medicine.

Yingda L. Xie, M.D., from the National Institutes of Health in Bethesda, Md., and colleagues compared the investigational assay against phenotypic drug-susceptibility testing and DNA sequencing among adults with symptoms of tuberculosis. The authors performed the Xpert MTB/RIF assay and sputum culture.

The researchers found that the sensitivities of the investigational assay for detecting resistance were 83.3 percent for isoniazid, 88.4 percent for ofloxacin, 87.6 percent for moxifloxacin, 71.4 percent for kanamycin, and 70.7 percent for amikacin among the 308 participants who were culture-positive for M. tuberculosis when phenotypic drug-susceptibility testing was used as the reference standard. For detection of phenotypic resistance the specificity of the assay was 93.4 percent or greater for all drugs except moxifloxacin at a critical concentration of 2.0 µg/mL. Using DNA sequencing as the reference standard, the sensitivities of the investigational assay for detecting mutations associated with resistance were 98.1, 95.8, 92.7, and 96.8 for isoniazid, fluoroquinolones, kanamycin, and amikacin; the specificity for all drugs was 99.6 percent or greater.

"This investigational assay accurately detected M. tuberculosis mutations associated with to isoniazid, fluoroquinolones, and aminoglycosides and holds promise as a rapid point-of-care test to guide therapeutic decisions for patients with tuberculosis," the authors write.

Explore further: New diagnostics tool, the Xpert Ultra assay, improves detection of mycobacterium tuberculosis

More information: Abstract/Full Text (subscription or payment may be required)

Related Stories

New diagnostics tool, the Xpert Ultra assay, improves detection of mycobacterium tuberculosis

August 29, 2017
Researchers have demonstrated a new, improved version of the Xpert MTB/RIF assay, a test for Rifampicin-resistance (RIF-R). The Xpert "Ultra" assay overcomes the shortcomings of the current Xpert assay to significantly improve ...

Improving detection of drug-resistant tuberculosis

May 2, 2012
(Medical Xpress) -- European researchers are developing new assays to detect drug resistant strains of Mycobacterium tuberculosis.

Tuberculosis drug may work better than others in its class

August 17, 2017
Treatment of tuberculosis involves a combination of several drugs, sometimes including drugs from a class known as fluoroquinolones. Using computer simulations, scientists have shown that the fluoroquinolone known as moxifloxacin ...

TB: Genetic drug resistance tests as good in gauging treatment outcome, death risk as traditional culture-based tests

August 3, 2017
Novel molecular tests are gaining popularity as a rapid way to detect genetic mutations that render tuberculosis impervious to drugs. Yet, how well these new tests fare in gauging risk of actual drug failure and patient death ...

Rapid testing for TB aims to reduce drug resistance, lower mortality rate

September 3, 2015
Researchers at University of California, San Diego School of Medicine have documented the accuracy of three new tests for more rapidly diagnosing drug-resistant forms of tuberculosis (TB), which are much harder and more expensive ...

Rapid diagnostic tests decrease waiting time for drug-resistant TB patients

September 8, 2013
Results of a new study suggest that three new diagnostic tests could each be used to successfully diagnose drug resistance in tuberculosis (TB) patients in a quarter of the time taken by the current method.

Recommended for you

Lactic acid bacteria can protect against Influenza A virus, study finds

December 13, 2017
Lactic acid bacteria, commonly used as probiotics to improve digestive health, can offer protection against different subtypes of influenza A virus, resulting in reduced weight loss after virus infection and lower amounts ...

Aging impairs innate immune response to flu

December 13, 2017
Aging impairs the immune system's response to the flu virus in multiple ways, weakening resistance in older adults, according to a Yale study. The research reveals why older people are at increased risk of illness and death ...

Lyme bacteria survive 28-day course of antibiotics months after infection

December 13, 2017
Bay Area Lyme Foundation, a leading sponsor of Lyme disease research in the US, today announced results of two papers published in the peer-reviewed journals PLOS ONE and American Journal of Pathology, that seem to support ...

Drug blocks Zika, other mosquito-borne viruses in cell cultures

December 12, 2017
If there was a Mafia crime family of the virus world, it might be flaviviruses.

Study seeks to aid diagnosis, management of catatonia

December 11, 2017
Catatonia, a syndrome of motor, emotional and behavioral abnormalities frequently characterized by muscular rigidity and a trance-like mental stupor and at times manifesting with great excitement or agitation, can occur during ...

New compound stops progressive kidney disease in its tracks

December 7, 2017
Progressive kidney diseases, whether caused by obesity, hypertension, diabetes, or rare genetic mutations, often have the same outcome: The cells responsible for filtering the blood are destroyed. Reporting today in Science, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.