Drug resistance detection and mutation patterns of multidrug resistant tuberculosis strains from children in Delhi

A total of 312 sputum samples from pediatric patients presumptive of multidrug resistant tuberculosis were tested for the detection of drug resistance using the GenoTypeMTBDRplus assay. A total of 193 [61.8%] patients were smear positive and 119 [38.1%] were smear negative by Ziehl-Neelsen staining. Line probe assay [LPA] was performed for 208 samples/cultures [193 smear positive samples and 15 cultures from smear negative samples]. Valid results were obtained from 198 tests. Of these, 125/198 [63.1%] were sensitive to both rifampicin [RIF] and isoniazid [INH]. 73/198 [36.9%] were resistant to at least INH/RIF, out of which 49 [24.7%] were resistant to both INH and RIF [multidrug resistant]. Children with tuberculosis are often infected by someone close to them, so strengthening of contact tracing in the program may help in early diagnosis to identify additional cases within the household. There is a need to evaluate newer diagnostic assays which have a high sensitivity in the case of smear negative samples, additional samples other than sputum among young children not able to expectorate, and also to fill the gap between estimated and reported cases under the program

Frequency of multi-drug resistance and mutations in Mycobacterium A tuberculosis isolates from Punjab state of India

Data regarding prevalence of multi-drug resistant tuberculosis [MDR-TB] and associated common mutations is scarce from Punjab region. The study was designed to determine rate of MDR-TB among presumptive MDR-TB from Punjab and mutation patterns using GenoType MTBDRplus assay. Total of 812 consecutive sputum samples were received from January 2012 to July 2013, from 14 districts of Punjab at the National Reference Laboratory at New Delhi for diagnosis of MDR-TB as hand holding activity. Presumptive MDR-TB patients were identified on basis of criterion B defined by the programme. Smear positive and negatives patients were found to be 636/798 [79.7%] and 162/ 798 [20.3%] respectively. Total of 606 GenoType MTBDRplus tests were conducted and mutations in rpoB, kat G and inhA genes analyzed. Total of 94/606 [15.5%], 43/606 [7.1%] and 40/606 [6.6%] were found to be RIF and INH resistant, mono-RIF resistant and 40/606 [6.6%] mono-INH resistant respectively

Commonest known mutation for RIF in rpoB gene and INH in kat G gene was S531L [80/ 137; 58.4%] and S315T1 [119/134; 88.8%] respectively. Mutations in inhA were found in 21/134 ]15.7%] strains. Average turn-around time [TAT] for dispatch of result toPunjab was 4.6 days. Prevalence of RIF resistance in Punjab was found to be 22.6%. Common mutations for RIF and INH were similar to that in other regions of country. GenoType MTBDRplus was found to be useful assay for rapid detection of MDR-TB, responsible for determining better management of MDR-TB patients under the programme

First and second line drug resistance among treatment naive pulmonary tuberculosis patients in a district under Revised National Tuberculosis Control Programme [RNTCP] in New Delhi

There is limited information of level of drug resistance to first-line and second line anti-tuberculosis agents in treatment naive pulmonary tuberculosis [PTB] patients from the Indian region. Therefore, the present prospective study was conducted to determine the antimicrobial susceptibility to first-line and second line anti-TB drug resistance in such patients. Sputum samples from consecutive treatment naive PTB cases registered in Lala Ram Sarup [LRS] district, under RNTCP containing 12 Directly Observed Treatment Centre's [DOTS], were enrolled using cluster sampling technology. A total of 453 samples were received from July 2011 to June 2012. All samples were cultured on solid medium followed by drug susceptibility to first and second line anti-tubercular drugs as per RNTCP guidelines. Primary multi-drug resistance [MDR] was found to be 18/453; [4.0%]. Extensively drug resistance [XDR] was found in one strain [0.2%], which was found to be resistant to other antibiotics. Data of drug resistant tuberculosis among treatment naive TB patients are lacking in India. The presence of XDR-TB and high MDR-TB in small population studied, calls for conducting systematic multi-centric surveillance across the country