Detection Of Multidrug-resistant Tuberculosis Research Articles

Multicenter evaluation of TB-SPRINT 59-Plex Beamedex\xae: accuracy and cost analysis

BackgroundMolecular tests can allow the rapid detection of tuberculosis (TB) and multidrug-resistant TB (MDR-TB). TB-SPRINT 59-Plex Beamedex® is a microbead-based assay developed for the simultaneous spoligotyping and detection of MDR-TB. The accuracy and cost evaluation of new assays and technologies are of great importance for their routine use in clinics and in research laboratories. The aim of this study was to evaluate the performance of TB-SPRINT at three laboratory research centers in Brazil and calculate its mean cost (MC) and activity-based costing (ABC).MethodsTB-SPRINT data were compared with the phenotypic and genotypic profiles obtained using Bactec™ MGIT™ 960 system and Genotype® MTBDRplus, respectively.ResultsCompared with MGIT, the accuracies of TB-SPRINT for the detection of rifampicin and isoniazid resistance ranged from 81 to 92% and 91.3 to 93.9%, respectively. Compared with MTBDRplus, the accuracies of TB-SPRINT for rifampicin and isoniazid were 99 and 94.2%, respectively. Moreover, the MC and ABC of TB-SPRINT were USD 127.78 and USD 109.94, respectively.ConclusionTB-SPRINT showed good results for isoniazid and rifampicin resistance detection, but still needs improvement to achieve In Vitro Diagnostics standards.

Drug resistance and epidemiology characteristics of multidrug-resistant tuberculosis patients in 17 provinces of China.

As China is one of high MDR-TB burden countries, it is important to determine the drug resistant pattern and clinical characteristics of multidrug resistant tuberculosis (MDR-TB). We conducted a comprehensive and nationwide study on MDR-TB in 17 provinces for the period from June 2009 to June 2015, and a total of 1154 cases of MDR-TB were finally investigated. The study sought to assess the clinical features and contrast drug susceptibility profiles of MDR-TB patients in China. Cavitary disease, young age, and long duration of TB disease among MDR-TB patients were important predictors. A high resistance proportion of first-line drugs was observed in Beijing, Shanghai and Tianjin. Resistant proportions of second-line anti-TB drugs in western region for amikacin, aminosalicylic acid, and levofloxacin were higher than eastern and central regions. High levels of drug resistance were seen in earlier cases (before 2011) and outpatients. We found high levels of resistance to 1st- and 2nd-line drugs in all settings, with considerable variabilities in terms of different Directly Observed Treatment Short Course (DOTS) programme, level of economic development(eastern, central and western regions) and patient source (inpatients and outpatients). Timely drug susceptibility testing (DST) and effective management are necessary to ensure an early detection of MDR-TB and its proper treatment.

Rapid Diagnosis Of Multidrug-Resistant Tuberculosis Impacts Expenditures Prior To Appropriate Treatment: A Performance And Diagnostic Cost Analysis.

BackgroundIn this study, we aimed to describe the impact of the Genotype® MTBDRplus line probe assay (LPA) for multidrug-resistant tuberculosis (MDR-TB) on total costs in a high-burden setting in China. The second objective was to evaluate the performance of HAIN on smear-positive sputum and clinical isolates.MethodsAll definitive TB inpatients at the Shandong Provincial Chest Hospital between May 2012 and May 2017 were included in the study. Two sputum specimens were collected from each patient to conduct smear microscopy, conventional drug susceptibility testing (DST), and the HAIN test. Laboratory and cost data were collected from the electronic medical record system.ResultsA total of 1670 definitive TB patients were included in this study. Of these patients, 1307 (78.3%) had smear-positive/culture-positive tuberculosis, and the remaining 363 (21.7%) had smear-negative/culture-positive tuberculosis. The sensitivity and specificity of the HAIN test for RIF resistance was 94.8% (95% confidence interval [CI]: 91.9–97.6%) and 98.8% (95% CI: 98.3–99.4%), respectively. For INH resistance, the sensitivity and specificity was 89.5% (95% CI: 85.7–93.2%) and 95.6% (95% CI: 94.5–96.7%), respectively. The mean time for detection of MDR-TB in smear-negative cases was determined to be 32 days by the HAIN test, which was significantly shorter than that by conventional DST (56 days). Similarly, the mean time for detection of MDR-TB by the HAIN test was significantly shorter than that by conventional DST in smear-positive cases (3 versus 53 days). In addition, by utilizing the HAIN test, the total health care cost decreased by 71.0% for smear-positive cases and 25.9% for smear-negative cases.ConclusionIn conclusion, our data demonstrate that the HAIN test is an accurate rapid test for detecting both RIF and INH resistance in TB patients. The use of the HAIN test can decrease health care costs and reduce the detection time for MDR-TB patients in China, despite the increased costs for laboratory testing.

Evaluation of risk factors associated with drug-resistant tuberculosis in Yemen: data from centres with high drug resistance

BackgroundThe World Health Organization (WHO) has reported that Yemen has a high burden of drug resistance and a worrying shortage of implemented diagnostic methods and drug treatment regimens. Therefore, in this study, we evaluated the risk factors associated with multidrug-resistant tuberculosis (MDR-TB) and explored the poor TB management in Yemen.MethodsBetween January 2014 and December 2016, we enrolled 135 patients with MDR-TB from drug resistance programmes at four major TB centres in Yemen for this prospective study. After exclusion of 20 patients, treatment outcomes were reported for 115 patients who attended a series of follow-ups.ResultsA total of 115 patients with MDR-TB were analysed from the four main TB centres in Yemen. Most patients (35.2%) were from the Aden TB centre. A success rate of 77.4% was reported for TB treatment. Of the 115 patients, 69.6% were resistant to two drugs, 18.3% were resistant to three drugs, and 12.2% were resistant to four drugs. During the intensive phase of treatment, 19 patients (16.5%) reported one or more adverse events. A multivariate logistic regression analysis revealed that a baseline body weight of ≤40 kg [p = 0.016; adjusted odds ratio (AOR) = 25.09], comorbidity (p = 0.049; AOR = 4.73), baseline lung cavities (p = 0.004; AOR = 15.32), and positive culture at the end of the intensive phase (p = 0.009; AOR = 8.83) were associated with the unsuccessful treatment outcomes in drug-resistant TB patients.ConclusionsThe success rate achieved after treatment was below the levels established by the WHO End TB Strategy (90%) and the United Nations Sustainable Development Goals (80%). Identification of risk factors associated with MDR-TB in Yemen is essential because it allows health workers to identify high-risk patients, especially in the absence of a second-line treatment or a laboratory diagnostic method. The Yemen National Tuberculosis Control Program should formulate new strategies for early detection of MDR-TB and invest in new programmes for MDR-TB management.

Comparison of Quantamatrix Multiplexed Assay Platform and GenoType MTBDR Assay Using Smear-Positive Sputum Specimens From Patients With Multidrug- Resistant/Extensively Drug-Resistant Tuberculosis in South Korea

Rapid detection of drug-resistant tuberculosis (DR-TB) is crucial for timely treatment and management. The GenoType MTBDRplus and MTBDRsl (MTBDR) assays have been endorsed by the World Health Organization (WHO) for the detection of DR-TB. However, MTBDR assays cannot simultaneously detect multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). Furthermore, interpretation of the MTBDR assay requires trained people, and the assay has low sample throughput, processing only up to 12 samples in parallel. We have developed the Quantamatrix Multiplexed Assay Platform (QMAP) to detect MDR-/XDR-TB simultaneously. The interpretation of QMAP results is automated, and the platform can process up to 96 samples in parallel. To compare the performance of QMAP with MTBDR assays, we performed QMAP and the MTBDR assay on 76 smear-positive, Mycobacterium tuberculosis culture-positive sputum specimens. Compared with phenotypic drug susceptibility testing (DST) results, the sensitivity and specificity of QMAP were 100 and 98% for rifampin resistance, 80 and 100% for isoniazid resistance, 44.4 and 100% for ethambutol resistance, 100 and 100% for fluoroquinolone resistance, and 100 and 100% for second-line injectable drug resistance, respectively. The sensitivity and specificity of MTBDR assays were 100 and 98% for rifampin resistance, 80 and 100% for isoniazid resistance, 44.4 and 98.1% for ethambutol resistance, 100 and 100% for fluoroquinolone resistance, and 100 and 100% for second-line injectable drug resistance, respectively. The sensitivity and specificity of QMAP were 85.0 and 100%, respectively, for the detection of MDR-TB and 100 and 100%, respectively, for XDR-TB. The sensitivity and specificity of MTBDR assays was consistent with those of QMAP. Our study showed that the QMAP assay has sensitivity and specificity equivalent to that of MTBDR assays in smear-positive sputum specimens. In combination with phenotypic DST, QMAP might be useful as a supplementary DST assay for rapid detection of MDR-/XDR-TB.

Characterisation of drug resistance-associated mutations among clinical multidrug-resistant Mycobacterium tuberculosis isolates from Hebei Province, China.

Multidrug-resistant tuberculosis (MDR-TB) is a major public-health problem in China. However, there is little information on the molecular characterisation of clinical MDR-TB isolates in Hebei Province. In this study, 123 MDR-TB isolates were identified in sputum cultures using traditional drug susceptibility testing. The isolates were analysed for mutations in seven genes associated with resistance to antituberculous four drugs: katG and inhA promoter for isoniazid (INH); rpoB for rifampicin (RIF); gyrA and gyrB for ofloxacin (OFLX); and rrs and eis promoter for kanamycin (KAN). All strains were genotyped by spoligotyping and 15-loci MIRU-VNTR analysis. A total of 39 distinct mutations were found at the seven loci in 114/123 (92.7%) MDR-TB isolates. Frequencies of INH, RIF, OFLX and KAN resistance-associated mutations were 82.1% (101/123), 83.7% (103/123), 92.1% (35/38) and 76.2% (16/21), respectively. The most prevalent mutations involved in resistance were: Ser315Thr in katG (70/123; 56.9%) and C(-15)T in inhA (15/123; 12.2%) for INH; Ser531Leu in rpoB (72/123; 58.5%) for RIF; Asp94Gly in gyrA (10/38; 26.3%) for OFLX; and A1401G in rrs (12/21; 57.1%) for KAN. Four novel gyrB mutants (Leu442Leu, Ser447Phe, Asn499Thr and Ala504Val) were identified. Mutations in katG, rpoB (or both) and the inhA promoter showed a sensitivity of 75.6% and specificity of 97.0% for detection of MDR-TB. DNA sequencing of the seven loci was 57.1% sensitive and 91.0% specific for prediction of XDR-TB isolates. These results may be of value in rapid molecular detection of MDR- and XDR-TB isolates in clinical samples in Hebei Province.

Lab-on-a-Film disposable for genotyping multidrug-resistant Mycobacterium tuberculosis from sputum extracts.

We describe a Lab-on-a-Film disposable that detects multidrug-resistant tuberculosis (MDR-TB) from sputum extracts. The Lab-on-a-Film disposable consists of 203 gel elements that include DNA sequences (probes) for 37 mutations, deletions, or insertion elements across 5 genes (including an internal control). These gel elements are printed on a flexible film, which costs approximately 500 times less than microarray glass. The film with printed gel elements is then laminated to additional rollable materials (films) to form a microfluidic flow cell. We combined multiplex amplification and hybridization steps in a single microfluidic chamber, without buffer exchanges or other manipulations up to and throughout hybridization. This flow cell also incorporates post hybridization wash steps while retaining an entirely closed-amplicon system, thus minimizing the potential for sample or amplicon cross-contamination. We report analytical sensitivity of 32 cfu mL-1 across all MDR-TB markers and detection of MDR-TB positive clinical specimens using an automated TruTip workstation for extraction and the Lab-on-a-Film disposable for amplification and detection of the extracts.

Detection of drug-resistant mycobacterium tuberculosis using Geno Type MTBDRplus assay in smear-positive cases

Background Multidrug-resistance tuberculosis (MDR-TB) has become an annoying health problem with supreme concern in the developing countries. Several methods of detection of MDR-TB have developed over recent years. Objective To investigate the diagnostic accuracy of GenoType MTBDRplus assay in detection of rifampicin (RIF)- and isoniazid (INH)-resistant isolates from sputum specimens of patients with active TB. Patients and methods This is a cross-sectional study. Sputum samples from 50 cases with active TB were collected, and the drug sensitivity test was evaluated by two methods: the standard conventional culture method and the GenoType MTBDRplus assay as a newly developed genotypic (molecular) method. Results The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of GenoType MTBDRplus assay in detection of RIF resistance were 100, 97.5, 90, 100, and 98%, respectively versus 100, 94.4, 87.5, 100, and 96%, respectively, for detection of INH resistance. The prevalence of MDR-TB by genotypic method was 12 versus 8% by conventional culture. On the contrary, drug resistance to either RIF or INH was detected in 28% of cases by the molecular method versus 30% of cases by using conventional culture. Conclusion The diagnostic yield of GenoType MTBDRplus assay for detection of RIF and INH resistance was satisfactory enough to support its alternative use for rapid identification of MDR-TB isolates, facilitating early and proper anti-TB drug regimen.

Rapid drug susceptibility testing and treatment outcomes for multidrug-resistant tuberculosis in Peru.

The detection of multidrug-resistant tuberculosis (MDR-TB) using rapid drug susceptibility testing (DST) has increased steadily in recent years in Peru, from 9216 tests in 2010 to 27 021 tests in 2015. Research examining the impact of rapid DST on treatment outcomes is required. To evaluate the association between rapid DST use (nitrate reductase assay, microscopic observation drug susceptibility assay [MODS] and GenoType® MTBDRplus) and treatment outcomes and mortality in MDR-TB patients in Peru. Retrospective cohort study of patients diagnosed with pulmonary MDR-TB between 2010 and 2013 (with treatment outcomes up to December 2015) using the electronic registry of the Peruvian National TB Programme. A total of 2671 MDR-TB patients were included; the median age was 27 years, 2.8% were co-infected with the human immunodeficiency virus. Use of rapid DST was associated with a 40% increase in the adjusted odds of treatment success (aOR 1.40, 95%CI 1.19-1.64) and a 54% reduction in mortality (aOR 0.46, 95%CI 0.33-0.64). Higher treatment success rates were driven by MODS and GenoType® MTBDRplus testing (aORs for unsuccessful outcomes respectively 0.68 and 0.66). The use of rapid DST (MODS and MTBDRplus) to diagnose MDR-TB was associated with a reduction in the odds of death and a substantial increase in the odds of treatment success.

Evaluation of the GenoType MTBDRplus and MTBDRsl for the detection of drug-resistant Mycobacterium tuberculosis on isolates from Beijing, China.

BackgroundThe incidence of tuberculosis (TB), especially multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB), continues to increase alarmingly worldwide. Molecular line probe assays (LPAs) are endorsed by the World Health Organization for the fast detection of MDR-TB and XDR-TB. The aim of this study was to evaluate the performance of LPAs in China.MethodsWe analyzed MDR-TB and XDR-TB in 96 isolates from Beijing by using culture-based drug susceptibility testing (DST) and LPAs to compare the detection rate of the two methods.ResultsCompared to phenotypic DST, the GenoType® MTBDRplus and MTBDRsl, respectively, showed a sensitivity of 98.7% and a specificity of 88.9% for detection of rifampicin resistance, 82.1% and 94.4% for isoniazid, 89.7% and 94.4% for levofloxacin, 60.0% and 98.7% for amikacin/capreomycin, and 57.5% and 98.2% for ethambutol. The sensitivity and specificity of LPAs, respectively, were 80.8% and 100% for MDR-TB and 50.0% and 97.6% for XDR-TB. Mutations in codon S531L of the rpoB gene and S315T1 of the KatG gene were dominated in MDR-TB strains. The most frequently observed mutations were in codon A90V of the gyrA gene, A1401G of the rrs gene, and M306V of the embB gene, according to the MTBDRsl results.ConclusionOur study showed that, in combination with phenotypic DST, application of the LPAs might be an efficient and reliable supplementary DST assay for rapid susceptibility screening of MDR-TB and XDR-TB. Using LPAs in countries with high MDR/XDR burden allows for appropriate and timely treatment, which will reduce transmission rates and morbidity, and improve treatment outcomes in patients.

Diagnostic Yield of Xpert MTB/RIF Assay Determined by Clinical Presentation in Childhood Intra-Thoracic Tuberculosis

Background: Diagnosis of Intra-thoracic Tuberculosis (ITTB) in children is challenging. Contribution of Xpert MTB/RIF assay to diagnosis of suspected ITTB and multi-drug resistant TB (MDR-TB) was evaluated. Methods: Children with suspected ITTB (395) were subjected to gastric aspirates and induced-sputum twice.Samples were tested by Ziehl-Neelsen stain, Xpert MTB/RIF-assay and MGIT-960 culture. Subjects were grouped as Confirmed, Probable and No-TB and classified as progressive primary disease (PPD, lung parenchymal lesion/pleural effusion/ pneumothorax) and primary pulmonary complex (PPC, hilar lymphadenopathy) on Chest X-ray. Findings: Of children with confirmed TB 51(12.9%), probable TB 306(77.4%) and No-TB 38(9.6%),11(2.7%) were smear positive, 98(24.8%) Xpert MTB/RIF positive and 51(12.9%) culture positive. Xpert MTB/RIF detected 42/51 culture confirmed cases (sensitivity 82% and NPV 97%) and rifampicin resistance in additional 5 cases. Culture detected more children presenting as PPD (p<0.001).Lung parenchymal involvement was seen in 37/42(88%) Confirmed TB, and 51/56(91%) Probable TB children detected by XpertMTB/RIF. Interpretation: Xpert MTB/RIF improved diagnosis by two-fold, and increased detection of MDR-TB. Both liquid culture and Xpert MTB/RIF proved to be more useful in children with PPD. Laboratory diagnosis of PPC is difficult due to pauci bacillary/localised disease. Microbiological tests cannot be blamed alone for poor yield in pediatric TB. Funding: ICMR Grant no. (Grant: 5/8/5/9/2012/ECD-I);AIIMS Intramural Grant. Declaration of Interests: Authors declare no conflicts. Ethical Approval: Study was approved by the Ethics Committee (IEC-IEC/NP-19412012 & RP-ll/2012), All India Institute of Medical Sciences, New Delhi. Consent was taken from the parents/guardians of all the study subjects.

Molecular diagnosis of multidrug-resistant tuberculosis in sputum samples by melting curve analysis

To analyze melting curves for the diagnosis of multidrug-resistant tuberculosis from sputum samples. Sputum samples (n = 250) were collected from patients with clinical suspicion of pulmonary tuberculosis as a result of bacilloscopy and cultured in solid medium Lowenstein Jensen. According to the reference method, 124 samples sensitive to rifampicin and isoniazid, 24 resistant to rifampicin, 33 resistant to isoniazid, and 69 multidrug-resistant were used. It was evaluated by real-time PCR and then by melting curves, the rpoB gene was used as a biomarker of rifampicin resistance, and the katG gene and inhA promoter region were used as biomarkers of isoniazid resistance. The H37Rv strain was considered a drug-sensitive control. The results of the reference method and the results of the melting curve analysis were compared to evaluate the parameters of sensitivity, specificity, positive predictive value and negative predictive value. Rifampicin resistance showed a sensitivity of 90.3%, specificity of 90.4%, positive predictive value of 84.8% and negative predictive value of 94.0%. Isoniazid resistance showed a sensitivity of 90.2%, specificity of 93.9%, positive predictive value of 91.1% and negative predictive value of 93.3%. The detection of multidrug-resistant tuberculosis showed values of 89.9%, 90.6%, 78.5% and 95.9% for sensitivity, specificity, positive predictive value and negative predictive value, respectively. The melting curve analysis showed to be safe and reliable to be used in the rapid diagnosis of multidrug-resistant tuberculosis in sputum samples.

Impact of scaling up Xpert® MTB/RIF testing for the detection of rifampicin-resistant TB cases in Karachi, Pakistan.

Pakistan ranks fourth among the countries with a high burden of multidrug-resistant tuberculosis (MDR-TB), with only 19.2% of the 15 000 estimated incident cases being notified. Increasing treatment coverage for MDR-TB is a key priority for Pakistan's National Tuberculosis Programme. The World Health Organization recommends the use of the Xpert® MTB/RIF assay as the first-line diagnostic test for individuals with presumed TB. To describe a multifaceted case-finding intervention targeting public and private sector health care facilities that used the Xpert assay as a frontline diagnostic test for individuals with presumptive TB, in Karachi, Pakistan, and its impact on case notifications of MDR-TB. Cross-sectional study. A total of 51 168 individuals were tested using Xpert, of whom respectively 7581 and 1534 people were diagnosed with TB in the public sector (reverse public-private mix) and private sector (social business model) arms; 574 (6.3% of all TB cases) were identified as having rifampicin (RMP) resistance. A total of 517 (90.1%) people with RMP-resistant TB (RR-TB) identified through the project were initiated on second-line treatment. The intervention resulted in 194 additional cases of RR-TB, an increase of 43% over the baseline. This project, one of the largest Xpert testing programmes conducted at city level, resulted in significantly increased detection and treatment of MDR-TB.

Performance of Biochip system in detecting drug resistant and multidrug-resistant tuberculosis using sputum collected from multiple clinical settings in Zhejiang, China

The objective of the present study was to conduct a multicentre, prospective evaluation of the diagnostic performance of the Biochip system for the detection of drug-resistant tuberculosis using smear-positive sputum specimens. This prospective study evaluated the diagnostic performance of this new platform for drug resistant and multidrug-resistant tuberculosis (MDR-TB) using 1491 smear-positive sputum specimens collected from multiple clinical settings. Using conventional culture-based culturing and drug-susceptibility testing as reference standards, the biochip system had a sensitivity of 86.08% and a specificity of 97.7% for rifampicin (RIF) detection, in detecting isoniazid (INH) resistance, it had a sensitivity of 79.36% and a specificity of 98.71%. With respect to MDR-TB detection, the sensitivity was 78.01% and the specificity was 98.86%. The performance only varies among different sites for RIF resistance, and there are no other statistically difference in diagnostic performance for other variables considered. The Biochip system shows favourable sensitivity and specificity for RIF and INH resistance, along with MDR-TB detection, directly using clinical smear-positive sputum samples. It is an alternative to conventional drug-susceptibility testing (DST) for detecting drug resistance or MDR-TB and is a method worth expanding to clinical settings in China.

Evaluation of Microscopic observation drug susceptibility (MODS) assay as a rapid, sensitive and inexpensive test for detection of tuberculosis and multidrug resistant tuberculosis

BackgroundMicroscopic observation drug susceptibility (MODS) assay has been suggested as a low cost method for rapid, accurate detection of tuberculosis (TB) and multidrug resistant tuberculosis (MDR-TB). MethodsA total of 2424 samples collected from 1063 eligible patients of suspected pulmonary or extrapulmonary TB were subjected to MODS assay. Performance of MODS was compared with culture and drug susceptibility testing (DST) by conventional solid Lowenstein–Jensen (LJ) media or liquid Mycobacteria Growth Indicator Tube (MGIT) culture. ResultsWhen compared to reference gold standard of positivity in either solid or liquid reference culture, the MODS assay had sensitivity, specificity, positive predictive value and negative predictive value of 91.3%, 98.2%, 96.0% and 95.9% respectively. MODS took a median time of 10.3 days to culture positivity as compared to 13.8 days using MGIT and 30.5 days using LJ culture. Culture and DST being concurrent in MODS, the median turnaround time for DST was the same as that for culture i.e. 10.3 days. The overall median turn around time for culture positivity and DST using manual MGIT and LJ medium was 23.6 days and 61.2 days respectively. The concordance between MODS culture and the reference susceptibility method was 97.7% for rifampicin, 95.6% for isoniazid, 98.5% for rifampicin and isoniazid. The cost of performing a single MODS assay was INR 200. ConclusionMODS is a rapid and sensitive, yet simple and inexpensive test that may be helpful to enhance diagnostic accuracy, and case detection of TB and MDR-TB in resource constrained settings.

Provider reported barriers and solutions to improve testing among tuberculosis patients 'eligible for drug susceptibility test': A qualitative study from programmatic setting in India.

BackgroundIn a study conducted in Bhopal district (a setting with facility for molecular drug susceptibility testing (DST)) located in central India in 2014–15, we found high levels of pre-diagnosis attrition among patients with presumptive multi drug-resistant tuberculosis (MDR-TB)–meaning TB patients who were eligible for DST, were not being tested.ObjectivesIn this study, we explored the health care provider perspectives into barriers and suggested solutions for improving DST.MethodsThis was a descriptive qualitative study. One to one interviews (n = 10) and focus group discussions (n = 2) with experienced key informants involved in programmatic management of DR-TB were conducted in April 2017. Manual descriptive thematic analysis was performed.ResultsThe key barriers reported were a) lack of or delay in identification of patients eligible for DST because of using treatment register as the source for identifying patients b) lack of assured specimen transport after patient identification and c) lack of tracking. Extra pulmonary TB patients were not getting identified as eligible for DST. Solutions suggested by the health care providers were i) generation of unique identifier at identification in designated microscopy center (DMC), immediate intimation of unique identifier to district and regular monitoring by senior TB laboratory and senior treatment supervisors of patients eligible for DST that were missed; ii) documentation of unique identifier at each step of cascade; iii) use of human carriers/couriers to transport specimen from DMCs especially in rural areas; and iv) routine entry of all presumptive extra-pulmonary TB specimen, as far as possible, in DMC laboratory register.ConclusionLack of assured specimen transport and lack of accountability for tracking patient after identification and referral were the key barriers. The identification of patients eligible for DST among microbiologically confirmed TB at the time of diagnosis and among clinically confirmed TB at the time of treatment initiation is the key. Use of unique identifier at identification and its use to ensure cohort wise tracking has to be complemented with specimen transport support and prompt feedback to the DMC. The study has implications to improve detection of MDR-TB among diagnosed/notified TB patients.

Dramatic shortening of the diagnosis of multidrug-resistant tuberculosis by the detection of rifampicin resistance using a genotypic method: GeneXpert MTB/RIF assay

In spite of all the evolutions in medicine, tuberculosis (TB) continues to be a terrifying contagious disease. In addition, the rise of multidrug-resistant TB (MDR-TB) is considered as a thorny problem that has greatly hindered the efforts of TB control. The classical drug susceptibility testing (DST) is the reference technique, but it takes many weeks for the identification of TB and MDR-TB. On the other hand, GeneXpert Mycobacterium tuberculosis (MTB)/rifampicin (RIF) has dramatically shortened the identification of both MTB and RIF resistance from weeks to only 2 h leading to a great breakthrough in the modern medicine. The aim of this study is to assess the use of GeneXpert assay for accelerating the diagnosis of MDR-TB in comparison to phenotypic DST by MGIT960 as the reference method. A total of 81 confirmed TB cases by both MGIT960 culture and GeneXpert were included in the current study. All sputum samples were processed for the detection of MDR-TB by both GeneXpert MTB/RIF assay and classical first-line DST method on MGIT960. Among studied TB cases, one rifampicin (RIF) monoresistance (1.2%), two isoniazid (INH) monoresistance (2.4%), and four (4.9%) MDR-TB (resistance to both RIF and INH) were identified by phenotypic methods. A significant statistical difference was found between RIF monoresistance and MDR-TB (P value 0.05). The sensitivity, specificity, negative, and positive predictive value of GeneXpert assay for identification of rifampicin resistance compared to DST as a reference method were 100, 98.7, 100, and 83.3%, respectively. It was concluded that the results of GeneXpert MTB/RIF and the standard phenotypic DST on MGIT960 for detection of RIF resistance were nearly the same regarding the sensitivity and specificity. Moreover, GeneXpert MTB/RIF was superior to DST on MGIT960 owing to its ability to dramatically shorten the period of MDR-TB diagnosis from weeks to only 2 h with fewer biohazard risks. Resistance to RIF could be used as a good foreteller for MDR-TB as most of RIF resistance are accompanied with isoniazid resistance.

Prevalence and first-line drug sensitivity trends of Mycobacterium tuberculosis at a tertiary center in North-East India

Setting Tuberculosis (TB) still remains one of the major health problems facing humans. India accounts for almost a quarter of TB cases worldwide. The scenario is worsening owing to multidrug resistant-tuberculosis (MDR-TB). Assessment of local prevalence rates and detection of MDR-TB are important to rationalize therapy and prevent spread of resistant strains in community. Objective The study was undertaken to understand drug sensitivity patterns of tubercle bacillus and assess resistance trends in Meghalaya. Designs Specimens were screened for acid-fast bacilli, decontaminated by N-acetyl cysteine–sodium hydroxide method, and subsequently inoculated onto Lowenstein–Jensen media. Characteristic growth was biochemically identified as TB bacillus. Drug sensitivity assessment to first-line anti-TB drugs was performed by proportion method and sensitivity patterns noted. Results Among 103 specimens received, 23 showed acid-fast bacilli. Male to female ratio was 3 : 2. Fourteen (13.6%) pure isolates of Mycobacterium spp. were obtained. Biochemically 10 isolates were confirmed as M. tuberculosis. Drug sensitivity profile revealed highest mono resistance to isoniazid and streptomycin. Two (20%) isolates were MDR. Conclusion The study gives a brief overview of the menace of TB in Meghalaya. The study results provide valuable information about presence of primary MDR-TB and provide basis for future larger field surveys.

Detection of multidrug-resistant tuberculosis from stored DNA Samples: A multicenter study.

In low-income countries, rapid detection of tuberculosis (TB) drug resistance is often restricted by the difficulties of transporting and storing sputum samples from remote health centers to the reference laboratories where molecular tests are available. The aim of this study was to evaluate the performance of four transport and storage systems for molecular detection of rifampicin (RIF) and isoniazid (INH) resistance. This was a multicenter study. Molecular detection of RIF and INH resistance was performed directly from smear-positive TB sputa spotted on a slide, FTA card, GenoCard, and ethanol using the Genotype MTBDRplus assay. The performance of the DNA extraction method from each storage support to detect drug resistance was assessed by calculating their sensitivity and specificity compared to the phenotypic method. From all sites, the overall sensitivity and specificity for RIF-resistance detection was 88% and 85%, respectively, for slides, 86% and 92%, respectively, for GenoCard, 87% and 89%, respectively, for FTA card, and 88% and 92%, respectively, for ethanol. For INH-resistance detection, the overall sensitivity and specificity was 82% and 90%, respectively, for slides, 85% and 96%, respectively, for GenoCard, 86% and 92%, respectively, for FTA card, and 86% and 94%, respectively, for ethanol. Smear slides and filter cards showed to be very useful tools to facilitate DNA extraction from sputum samples with the potential to accelerate the detection of drug resistance in remote areas.

High-risk screening and detection of multidrug-resistant tuberculosis in two prefectures of China: a drug susceptibility surveillance-based secondary data analysis

ABSTRACTBackground: In China, less than one-fifth of multidrug-resistant tuberculosis (MDR-TB) cases are detected. MDR-TB screening is conducted amongst the following five high-risk groups of TB patients: chronic cases, close contacts of MDR-TB patients, patients with treatment failure, relapsed and returned patients, and smear-positive patients at the end of the third month of initial treatment.Objective: To estimate the possibility of detecting MDR-TB cases if only the high-risk screening strategy is applied in China.Methods: A secondary analysis was applied to the surveillance-based longitudinal data of all sputum smear-positive TB patients in Prefecture E and Prefecture W of China from 2013 to 2015. The population attributable risk (PAR) was estimated using odds ratios for five risk factors/predictors and exposure proportions amongst all MDR-TB cases.Results: A total of 3513 TB patients (2807 from Prefecture E and 706 from Prefecture W) were included. Males accounted for 77.91% (2737/3513) of the patients. The average age was 52.5 ± 20.0 years old. Overall, 40.34% (71/176) of MDR-TB patients were from the five high-risk groups during the three-year study period. The detected proportion of MDR-TB cases using the high-risk screening strategy was significantly higher in Prefecture E than in Prefecture W. The PAR% for all five risk factors/predictors was 43.4% (95% CI: 24.6–61.7%), 49.9% (95% CI: 31.3–67.0%), and 30.3% (95% CI: 12.9–50.1%) in Prefecture E and 36.6% (95% CI: 10.4–64.5%), 13.3% (95% CI: −1.7–39.7%), and −82.5% (95% CI: −117.5–−11.2%) in Prefecture W in 2013, 2014, and 2015, respectively. The PAR% for the five specific risk factors/predictors ranged from 0.4% (95% CI: −0.2–4.8%) to 21.0% (95% CI: 13.1–30.0%) in these two prefectures.Conclusion: In general, a high-risk screening strategy would miss more than half of the MDR-TB patients because they do not belong to the five high-risk groups.