MDR – TB Emerging Methods in Diagnosis Dr.T.V.Rao MD
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MDR – TB Emerging Methods in Diagnosis Dr.T.V.Rao MD A post graduate student’s question? – What are the newer/emerging methods in Diagnosis of MDR – TB? The question Answered with emerging technologies in mind by Dr.T.V.Rao MD The Professionals and public should understand the definitions before they define the patients to be suffering with MDR TB, when the patients failed to respond to the DOTS regime or taken the empirical therapeutic regimes without much improvement What is multidrug-resistant tuberculosis (MDR TB)? Multidrug-resistant TB (MDR TB) is caused by an organism that is resistant to at least isoniazid and rifampin, the two most potent TB drugs. These drugs are used to treat all persons with TB disease. An estimated 480 000 people developed MDR-TB in 2014 and 190 000 people died as a result of it How does drug resistance happen Resistance to anti-TB drugs can occur when these drugs are misused or mismanaged. Examples include when patients do not complete their full course of treatment; when health-care providers prescribe the wrong treatment, the wrong dose, or length of time for taking the drugs; when the supply of drugs is not always available; or when the drugs are of poor quality. What are the symptoms of TB disease? The general symptoms of TB disease include feelings of sickness or weakness, weight loss, fever, and night sweats. The symptoms of TB disease of the lungs may also include coughing, chest pain, and coughing up blood. Symptoms of TB disease in other parts of the body depend on the area affected. However many in the Government and private sectors are just not limiting to RNTCP program recommendation going to Gene Xpert methods to diagnose the DNA is of Mycobacterium and to determine whether it is Rifampicin resistant or not, WHO and Many National TB control programs are on the way for detection of Rifampicin resistance by Gene expert EMERGING MOLECULAR METHODS TO DETECT MDR- TB CHANGING POLICY RECOMMENDATIONS FROM WHO - WHO recommends the use of the SL-LPA for patients with confirmed rifampicin-resistant TB or MDR-TB as the initial test to detect resistance to fluoroquinolones and the second-line injectable drugs, instead of phenotypic culture-based drug- susceptibility testing (DST). WHO RECOMMENDS A NEW TEST - In May 2016, WHO issued new recommendations on the use of a rapid diagnostic test – a line probe assay to detect resistance to second-line anti-TB drugs (SL- LPA). WHO recommends this rapid diagnostic test for identifying those MDR- or rifampicin-resistant TB patients who can be placed on the shorter MDR-TB regimen? The results of this test will also be critical in placing patients on targeted conventional MDR-TB regimens with improved outcomes.
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MDR – TB Emerging Methods in Diagnosis Dr.T.V.Rao MD
Transcript of MDR – TB Emerging Methods in Diagnosis Dr.T.V.Rao MD
MDR – TB Emerging Methods in Diagnosis
Dr.T.V.Rao MD
A post graduate student’s question? – What are the newer/emerging methods in Diagnosis of
MDR – TB?
The question Answered with emerging technologies in mind by Dr.T.V.Rao MD
The Professionals and public should understand the definitions before they define the patients to be
suffering with MDR TB, when the patients failed to respond to the DOTS regime or taken the
empirical therapeutic regimes without much improvement
What is multidrug-resistant tuberculosis (MDR TB)?
Multidrug-resistant TB (MDR TB) is caused by an organism that is resistant to at least isoniazid and
rifampin, the two most potent TB drugs. These drugs are used to treat all persons with TB disease.
An estimated 480 000 people developed MDR-TB in 2014 and 190 000 people died as a result of it
How does drug resistance happen
Resistance to anti-TB drugs can occur when these drugs are misused or mismanaged. Examples
include when patients do not complete their full course of treatment; when health-care providers
prescribe the wrong treatment, the wrong dose, or length of time for taking the drugs; when the
supply of drugs is not always available; or when the drugs are of poor quality.
What are the symptoms of TB disease?
The general symptoms of TB disease include feelings of sickness or weakness, weight loss, fever, and
night sweats. The symptoms of TB disease of the lungs may also include coughing, chest pain, and
coughing up blood. Symptoms of TB disease in other parts of the body depend on the area affected.
However many in the Government and private sectors are just not limiting to RNTCP program
recommendation going to Gene Xpert methods to diagnose the DNA is of Mycobacterium and to
determine whether it is Rifampicin resistant or not, WHO and Many National TB control programs
are on the way for detection of Rifampicin resistance by Gene expert
EMERGING MOLECULAR METHODS TO DETECT MDR- TB
CHANGING POLICY RECOMMENDATIONS FROM WHO - WHO recommends the use of the SL-LPA for
patients with confirmed rifampicin-resistant TB or MDR-TB as the initial test to detect resistance to
fluoroquinolones and the second-line injectable drugs, instead of phenotypic culture-based drug-
susceptibility testing (DST).
WHO RECOMMENDS A NEW TEST - In May 2016, WHO issued new recommendations on the use
of a rapid diagnostic test – a line probe assay to detect resistance to second-line anti-TB drugs (SL-
LPA).
WHO recommends this rapid diagnostic test for identifying those MDR- or rifampicin-resistant TB
patients who can be placed on the shorter MDR-TB regimen? The results of this test will also be
critical in placing patients on targeted conventional MDR-TB regimens with improved outcomes.
The SL-LPA produces results in just 24-48 hours, a vast improvement over the 3 months or longer
currently required. It allows quick triage of confirmed rifampicin-resistant or MDR-TB patients into
either the shorter MDR-TB regimen or the conventional longer regimen. WHY IT IS IMPORTANT -
Excluding second-line drug resistance a critical prerequisite for identifying patients who can be
placed on the shorter MDR-TB regimen.
These recommendations apply to the use of SL-LPA for the direct testing of sputum specimens as
well as indirect testing on culture isolates from rifampicin-resistant or MDR-TB patients, including
adults and children (irrespective of the smear status).
LABORATORY NEEDS INFRASTRUCTURE AND BIOSAFETY - Adequate and appropriate
laboratory infrastructure and equipment must be available, including the necessary biosafety
precautions and prevention of contamination: specimen processing for culture and manipulation of
cultures require TB containment laboratories with appropriate biological safety cabinets. Laboratory
facilities for LPA require at least three separate rooms - one each for DNA extraction,
preamplification procedures, and amplification and post-amplification procedures. Restricted access
to molecular facilities, unidirectional work flow, and stringent cleaning protocols must be
established to avoid contamination.
WHAT ARE ADVANTAGES OF THE NEWER METHODS WHAT TO DO AND NOT TO DO - Detection of any second-line resistance by the SL-LPA means that MDR-TB patients should not be
enrolled on the shorter regimen (RNTCP) as this could jeopardise their treatment outcome and fuel
the development of XDR-TB. Patients detected with XDR-TB by the SL-LPA should also not be
enrolled on the shorter regimen but require carefully designed individual regimens to optimise their
chances of success
INTERESTED TO EATABLISH A LABORATORY CAN FOLLOW - FIND has negotiated a preferential
price of Euro 7.50 (approximately USD10) for the MTBDRsl strips in 138 countries
(http://www.finddx.org/pricing/);
It is time to think to establish Molecular laboratories at all our Medical colleges, or else the
creditability of our reporting at stake,
Adopted from MOLECULAR LINE-PROBE ASSAY FOR THE DETECTION OF RESISTANCE TO SECOND-
LINE ANTI-TB DRUGS (SL-LPA) TUBERCULOSIS DIAGNOSTICS by WHO
Dr.T.V.Rao MD Professor of Microbiology Freelance writer
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Mob 8281669524 (India)
