Browsing by Author "Rajneesh Tripathi"

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Detection of clinically important non tuberculous mycobacteria (NTM) from pulmonary samples through one-step multiplex PCR assay
(BioMed Central, 2020) Kamal Singh; Richa Kumari; Rajneesh Tripathi; Smita Gupta; Shampa Anupurba
Background: The burden of non-tuberculous mycobacterial (NTM) disease is increasing worldwide but still its diagnosis is delayed and it is mistaken as multidrug-resistant tuberculosis (MDR-TB).The present study was performed to develop a multiplex PCR assay for detection and identification of clinically most common NTM to the species level from pulmonary samples. Results: Out of 50 isolates, 26 were identified as Mycobacterium kansasii (MK), 20 were identified as Mycobacterium abscessus (MA) and 4 were identified as Mycobacterium avium complex (MAC) through multiplex PCR and further confirmed by sequencing. Conclusion: Our study showed that multiplex PCR assay is a simple, convenient, and reliable technique for detection and differential identification of major NTM species. © 2020 The Author(s).
Detection of mutations in the rpoB gene of rifampicin-resistant Mycobacterium tuberculosis strains inhibiting wild type probe hybridization in the MTBDR plus assay by DNA sequencing directly from clinical specimens
(BioMed Central Ltd, 2020) Pallavi Sinha; G.N. Srivastava; Rajneesh Tripathi; Mukti Nath Mishra; Shampa Anupurba
Background: The potential of genetic testing for rapid and accurate diagnosis of drug-resistant Mycobacterium tuberculosis strains is vital for efficient treatment and reduction in dissemination. MTBDR plus assays rapidly detect mutations related to drug resistance and wild type sequences allied with susceptibility. Although these methods are promising, the examination of molecular level performance is essential for improved assay result interpretation and continued diagnostic development. Therefore this study aimed to determine novel mutations that were inhibiting wild type probe hybridization in the Line probe assay by DNA sequencing. Using data collected from Line Probe assay (GenoType MTBDRplus assay) the contribution of absent wild type probe hybridization to the detection of rifampicin resistance was assessed via comparison to a reference standard method i.e. DNA sequencing. Results: Sequence analysis of the rpoB gene of 47 MTB resistant strains from clinical specimens showed that 37 had a single mutation, 9 had double mutations and one had triple mutations in the ropB gene. Conclusions: The absence of wild type probe hybridization without mutation probe hybridization was mainly the result of the failure of mutation probe hybridization and the result of the novel or rare mutations. Additional probes are necessary to be included in the Line probe assay to improve the detection of rifampicin-resistant Mycobacterium tuberculosis strains. © 2020 The Author(s).
Differentiation of Mycobacterium tuberculosis complex from non-tubercular mycobacteria by nested multiplex PCR targeting IS6110, MTP40 and 32kD alpha antigen encoding gene fragments
(BioMed Central Ltd., 2016) Pallavi Sinha; Anamika Gupta; Pradyot Prakash; Shampa Anupurba; Rajneesh Tripathi; G.N. Srivastava
Background: Control of the global burden of tuberculosis is obstructed due to lack of simple, rapid and cost effective diagnostic techniques that can be used in resource poor-settings. To facilitate the early diagnosis of TB directly from clinical specimens, we have standardized and validated the use of nested multiplex PCR, targeting gene fragments IS6110, MTP40 and 32kD α-antigen encoding genes specific for Mycobacterium tuberculosis complex and non-tubercular mycobacteria (NTM), in comparison to smear microscopy, solid culture and single step multiplex PCR. The results were evaluated in comparison to a composite reference standard (CRS) comprising of microbiological results (smear and culture), clinical, radiological and cytopathological findings, clinical treatment and response to anti-tubercular therapy. Methods: The nested multiplex PCR (nMPCR) assay was evaluated to test its utility in 600 (535 pulmonary and 65 extra-pulmonary specimens) clinically suspected TB cases. All specimens were processed for smear, culture, single step multiplex PCR and nested multiplex PCR testing. Results: Out of 535 screened pulmonary and 65 extra-pulmonary specimens, 329 (61.5 %) and 19 (29.2 %) cases were culture positive for M. tuberculosis. Based on CRS, 450 patients had "clinical TB" (definitive-TB, probable-TB and possible-TB). Remaining 150 were confirmed "non-TB" cases. For culture, the sensitivity was low, 79.3 % for pulmonary and 54.3 % for extra-pulmonary cases. The sensitivity and specificity results for nMPCR test were evaluated taken composite reference standard as a gold standard. The sensitivity of the nMPCR assay was 97.1 % for pulmonary and 91.4 % for extra-pulmonary TB cases with specificity of 100 % and 93.3 % respectively. Conclusion: Nested multiplex PCR using three gene primers is a rapid, reliable and highly sensitive and specific diagnostic technique for the detection and differentiation of M. tuberculosis complex from NTM genome and will be useful in diagnosing paucibacillary samples. Nested multiplex PCR assay was found to be better than single step multiplex PCR for assessing the diagnosis of TB. © 2016 Sinha et al.
Direct detection of resistance to fluoroquinolones/SLIDs in sputum specimen by GenoType MTBDRsl v.2.0 assay A study from Eastern Uttar Pradesh, India
(BioMed Central Ltd, 2021) Kamal Singh; Richa Kumari; Smita Gupta; Rajneesh Tripathi; Anjali Srivastava; Vidisha Shakya; Ankush Gupta; Shampa Anupurba
Background: According to World Health Organization (WHO), drug-resistant tuberculosis (DR-TB) is a major contributor to antimicrobial resistance globally and continues to be a public health threat. Annually, about half a million people fall ill with DR-TB globally. The gradual increase in resistance to fluoroquinolones (FQs) and second-line injectable drugs (SLIDs), poses a serious threat to effective TB control and adequate patient management. Therefore, WHO suggests the use of GenoType MTBDRsl v.2.0 assay for detection of multiple mutations associated with FQs and SLIDs. Hence, the study was conducted to determine the prevalence of resistance to FQs and SLIDs by comparing direct GenoType MTBDRsl v.2.0 assay with phenotypic drug susceptibility testing (DST). Methods: The study was conducted on 1320 smear positive sputum samples from a total of 2536 RR-TB, confirmed by GeneXpert MTB/RIF. The smear positive specimens were decontaminated, and DNA extraction was performed. Furthermore, the extracted DNA was used for GenoType MTBDRsl v.2.0 assay. While 20% of the decontaminated specimens were inoculated in Mycobacterium growth indicator tube (MGIT) for drug susceptibility testing (DST). Results: Out of 1320 smear positive sputum samples, 1178 were identified as Mycobacterium tuberculosis complex (MTBC) and remaining were negative by GenoType MTBDRsl v.2.0 assay. Of the 1178 MTBC positive, 26.6% were sensitive to both FQs and SLIDs, whereas 57.3% were only FQs resistant and 15.9% were resistant to both FQs and SLIDs. Further DST of 225 isolates by liquid culture showed that 17% were sensitive to both FQs and SLIDs, 61.3% were only FQs resistant and 21.3% were resistant to both. The specificity for FQs and SLIDs was 92.31% and 100% whereas sensitivity was 100% respectively by GenoType MTBDRsl v.2.0 assay in direct sputum samples. Conclusions: Our study clearly suggests that GenoType MTBDRsl v.2.0 assay is a reliable test for the rapid detection of resistance to second-line drugs after confirmation by GeneXpert MTB/RIF assay for RR-TB. Though, high rate FQ (ofloxacin) resistance was seen in our setting, moxifloxacin could be used as treatment option owing to very low resistance. © 2021, The Author(s).
Evaluation of Xpert MTB/RIF Assay for Diagnosis of Tuberculosis in Children
(Oxford University Press, 2019) Arghya Das; Shampa Anupurba; Om P. Mishra; Tuhina Banerjee; Rajneesh Tripathi
Introduction Childhood tuberculosis (TB) is now a global priority. With the advent of Xpert MTB/RIF, more TB cases in children are being reported. This study was undertaken to evaluate the performance of Xpert in diagnosis of pulmonary and extra-pulmonary TB in children. Methods Specimens from 171 suspected TB cases in children aged <15 years were tested with Xpert, culture and smear microscopy in the Department of Microbiology, Institute of Medical Sciences, India. Results The specimens included 106 gastric aspirates, 51 cerebrospinal fluids, 8 induced sputum and 6 lymph node aspirates. Xpert detected Mycobacterium tuberculosis in 19 cases (14 pulmonary and 5 extra-pulmonary), 7 of which were rifampicin-resistant. Sensitivity, specificity, positive predictive value and negative predictive value of Xpert compared with culture were 88.89, 98.04, 84.21 and 98.68%, respectively. The sensitivity was 100% in children aged 1-5 years and 6-10 years and in gastric aspirates. Conclusion Xpert is an efficient diagnostic tool in childhood tuberculosis. © 2018 The Author(s).
Multidrug-resistant tuberculosis detection and characterization of mutations in mycobacterium tuberculosis by genotype MTBDRplus
(Medknow Publications, 2017) Rajneesh Tripathi; Shampa Anupurba
Detection of drug resistance in Mycobacterium tuberculosis by conventional phenotypic drug susceptibility testing methods requires several weeks. Therefore, molecular diagnostic tests for rapid detection of multidrug resistance tuberculosis (MDR-TB) are urgently needed. Early diagnosis helps in initiating optimal treatment which would not only enable cure of an individual patient but also will curb the transmission of drug resistance in the community. Line probe assay (LPA) has shown great promises in the diagnosis of MDR-TB. All MDR suspect patients from ten-linked districts were asked to deposit sputum samples at peripheral designated microscopy centers. The district TB officers facilitated the transport of samples collected during February 2014-December 2014 to our laboratory. The detection of rpoB gene mutations for rifampicin (RIF) and katG and inhA genes for isoniazid (INH), respectively, was performed on 663 samples by LPA. A total of 663 sputum samples from MDR suspects were received of which 321 (50.8%) were found to be MDR. Missing of WT8 along with mutation in codon S531 L was the most common pattern for RIF-resistant isolates (80.8%) and missing WT along with mutation in codon S315T1 of k atG gene was the most common pattern for INH-resistant isolates (91.3%).The MDR-TB in Eastern Uttar Pradesh, India, was found to be 50.8%. The common mutations obtained for RIF and INH in the region was mostly similar to those reported earlier. © 2017 Indian journal of pathology and microbiology.
Mutation in MPT64 gene influencing diagnostic accuracy of SD Bioline assay (capilia)
(BioMed Central Ltd., 2019) Kamal Singh; Richa Kumari; Rajneesh Tripathi; Ankush Gupta; Shampa Anupurba
Background: Success of India's TB control program relies on rapid case detection, monitoring, care and treatment of drug resistance. Patients on multidrug resistance (MDR) treatment are monitored by follow up cultures. Discordant results (culture and smear positive while capilia negative) are usually declared negative Mycobacterium tuberculosis complex (MTBC). This study was designed to understand the possible causes of discordant results. Methods: The capilia kit was evaluated to test its utility among 4737 follow up MDR patients enrolled during a period of 1 year. A total of 889 were liquid culture positive, 3375 were negative and 473 were contaminated. Of the 889 cultures positive, 829 were found positive by ZN smear, capilia test and MTBDR plus assay. The cultures which gave a positive result on Mycobacterium Growth Indicator Tube 960 (MGIT 960) and ZN smear but were negative on capilia test with no growth on Brain Heart Infusion agar (BHI) were included in this study. The conflicting results of capilia were compared with other molecular techniques; MTBDR plus assay and DNA sequence analysis of MPT64 gene. Results: Out of 889 culture positive, 60 (6.7%) were found positive on liquid culture and ZN smear but were negative on capilia. Of these 60 cultures, 10 (16.7%) were found positive by both MTBDR plus assay and PCR. The sequencing analysis revealed that all of the capilia negative isolates had mutations within the MPT64 gene. Conclusion: Re-evaluation of culture positive but capilia negative isolates should be done before declaring them as Mycobacterium other than tuberculosis (MOTT) because such cases can act as chronic carriers of TB in the population which can lead to the rise of this lethal disease. © 2019 The Author(s).
Rapid screening of MDR-TB in cases of extra pulmonary tuberculosis using geno type MTBDRplus
(Public Library of Science, 2016) Richa Kumari; Rajneesh Tripathi; Alok Prakash Pandey; Tuhina Banerjee; Pallavi Sinha; Shampa Anupurba
Background: Drug resistance in tuberculosis is a major public health challenge in developing countries. The limited data available on drug resistance in extra pulmonary tuberculosis stimulated us to design our study on anti-tuberculosis drug resistance pattern in cases of extra pulmonary tuberculosis in a tertiary referral hospital of North India. We performed Geno Type MTBDRplus assay in comparison with conventional drug susceptibility testing by proportion method to study the mutation patterns in rpoB, katG and inhA genes. Methods: A total of 510 extra pulmonary samples were included in this study. After the smear microscopy, all the specimens were subjected for culture on Lowenstein Jensen (LJ) media. Phenotypic drug susceptibility testing (DST) was performed on LJ media for all the MTB isolates and compared with the results of Geno Type MTBDRplus assay which was performed with the DNA isolated from the culture by conventional method. Results: Of 510 specimens cultured, the total culture positivity obtained was 11.8% (60) encompassing 54 (10.6%) Mycobacterium tuberculosis and 6 (1.2%) non-tubercular mycobacteria (NTM). DST results by Geno Type MTBDRplus assay and solid culture methods were compared in 51 MTB isolates excluding the two Rif indeterminate and one invalid test. Geno Type MTBDRplus accurately identified 13 of 14 rifampicin-resistant strains, 14 of 15 isoniazid-resistant strains and 13 of 14 as multi drug resistant tuberculosis (MDR-TB) in comparison with conventional method. Sensitivity and specificity were 92.86% and 97.30% respectively for detection of RIF resistance, 93.33% and 94.44% respectively for detection of INH resistance, 92.86% and 97.30% respectively for detection of MDR-TB, while the overall concordance of Geno Type MTBDRplus assay with conventional DST was 94.11%. The turn-around time for performing Geno Type MTBDRplus assay test was 48 hours. Conclusion: The problem of MDR in extra pulmonary tuberculosis (EPTB) cannot be overlooked and due attention on patients should be given. Routine use of Geno Type MTBDRplus assay for the diagnosis of MDR-EPTB can substantially reduce the time between diagnosis and drug therapy. Culture along with Geno Type MTBDRplus assay could be a solution for rapid and accurate diagnosis of MDR-TB in low bacillary non sputum specimens. © 2016 Kumari et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.