Showing posts with label RNTCP. Show all posts
Showing posts with label RNTCP. Show all posts

Are WHO approved nucleic acid amplification tests causing large-scale "false identification" of rifampicin-resistant tuberculosis?

By Dr Deepu
The nucleic acid amplification tests (NAATs): Line probe assay and GeneXpert (Xpert) have evolved as the primary tool for identification of rifampicin (RIF)-resistant (RR) tuberculosis (TB) worldwide, primarily because of the ease and speed. They rechecked RR isolates identified by NAATs from presumptive RR TB cases belonging to South India by the Revised National TB Control Program, India using multiple RIF concentrations on Bactec MGIT system and compared the mutation patterns with the resistance levels.
Researchers state that they used standard protocol for Bactec MGIT system as given by the manufacturer modified for the multiple RIF concentrations. All the retests were done in a certified BSL3 laboratory.
Astonishingly they found that there is a mismatch of up to 20% (RIF breakpoint 0.5 mg/L); the NAATs probably overidentifying RR TB. Half of the cases with mismatch showed a sub-breakpoint rise in resistance level (0.125 mg/L to 0.5 mg/L RIF).
They finally concluded by stating probable reasons for the mismatch are "sub-breakpoint low-level resistance mutants," hetero-resistant bacterial populations, and other inherent test limitations along with the low RR TB prevalence in South India (<5%) among "presumptive multidrug-resistants." They also quoted, could be due to the incomplete selection pressure by an inadequate RIF exposure caused by various factors including a low-RIF dosage being used widely and poor Directly observed treatment.
They concluded"To prevent the false diagnosis of RR TB in a massive scale when using NAATs, we may need to enforce a carefully targeted testing approach and a phenotypic susceptibility testing with multiple RIF concentrations for confirmatory purposes".
Find the full text article here

RNTCP comes out with daily regimen for drug sensitive TB

By Dr Deepu
RNTCP India has come out with a new recommendation to use daily ATT in treatment of drug sensitive tuberculosis.
The Revised National Tuberculosis Control Programme (RNTCP) was launched in India in 1997 
based on World Health Organization endorsed Directly Observed Treatment Short-Course (DOTS) 
strategy, employing the thrice weekly treatment regimen.
The Standards for TB Care in India, 2014, which were jointly laid down by Ministry of Health &  Family Welfare, Government of India and World Health Organization, in consultation with experts, based on available evidences and WHO Treatment of TB Guidelines (2010), state that ‘all patients should be given daily regimen. The initial phase should consist of two months of 
Isoniazid (H), Rifampicin (R), Pyrazinamide (Z), and Ethambutol (E). The continuation phase should consist of three drugs, Isoniazid (H), Rifampicin (R) and Ethambutol (E) given for at least 
four months’. The National Technical Working Group (NTWG) on TB/HIV (2013) has recommended use of daily 
regimen using Fixed Dose Combination (FDC) first line TB treatment for PLHIV patients. 
Considering the above, the National Expert Committee to examine type of drug regimen for drug sensitive TB has recommended RNTCP to move towards introducing daily regimen for drug sensitive Tuberculosis in India.
The link to download the guidelines is given below. Please visit the link to download.

Download here

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