Validation of an indigenous assay for rapid molecular detection of rifampicin resistance in presumptive multidrug-resistant pulmonary tuberculosis patients.

BACKGROUND & OBJECTIVES: There is a need for an affordable, easy, high-sensitivity test usable at the peripheral health facility for diagnosis of drug-resistant (DR) tuberculosis (TB) to interrupt disease transmission. Nucleic acid amplification tests (NAATs) for early detection of DR-TB are ideal to bring testing near to the patient. TruenatTM MTB (Mycobacterium tuberculosis) and TruenatTM MTB-RIF (rifampicin) is an indigenous chip-based real-time polymerase chain reaction (PCR) based test for detection of multidrug-resistant (MDR) TB. The test involves extraction of DNA using automated, battery operated Trueprep instrument and real-time PCR performed on the Truelab analyzer. We report here multicentric validation of Truenat MTB-RIF for detection of DR-TB in suspected DR-TB patients. METHODS: Consecutive patients aged 18-65 yr, with symptoms suggestive of TB and with a history of previous treatment, reporting to the National TB Elimination Programme (NTEP) clinics under four national institutes, namely AIIMS (All India Institute of Medical Sciences, New Delhi), NITRD (National Institute of Tuberculosis and Respiratory Diseases, New Delhi), NIRT (National Institute for Research in Tuberculosis, Chennai) and ICMR-National JALMA Institute for Leprosy and other Mycobacterial Diseases, Agra, were included in the study. Two sputum samples (one spot and one morning) were collected from each patient, after obtaining informed written consent. The samples were subjected to smear, GeneXpert and MGIT 960 culture (and drug susceptibility testing to RIF) (surrogate for MDR-TB) to serve as reference tests. The samples were coded to ensure blinding and subjected to Truenat MTB-RIF. Truenat MTB-RIF Version 1.5 was used for testing 1084 samples for RIF resistance, while Version 2.0 was used to test another 1201 samples. RESULTS: Truenat MTB-RIF Version 1.5 in comparison with comprehensive laboratory reference standards yielded sensitivity and specificity of 76.2 and 94.7 per cent, respectively for the detection of RIF resistance in 1084 samples, collected across four sites. Based on the analysis of discordant samples, Version 2.0 of Truenat was developed by the manufacturer and this was further tested on additional 1201 samples, yielding a sensitivity of 87.5 per cent and specificity of 99.5 per cent. INTERPRETATION & CONCLUSIONS: Multicentric trial of TruenatTM MTB-RIF demonstrated a great potential of this point of care NAAT for detection of MDR-TB. The test would be useful in limited resource settings and inaccessible areas without need for any additional infrastructure.

Gridlock from diagnosis to treatment of multidrug-resistant tuberculosis in Tanzania: low accessibility of molecular diagnostic services and lack of healthcare worker empowerment in 28 districts of 5 high burden TB regions with mixed methods evaluation.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) outcomes are adversely impacted by delay in diagnosis and treatment. METHODS: Mixed qualitative and quantitative approaches were utilized to identify healthcare system related barriers to implementation of molecular diagnostics for MDR-TB. Randomly sampled districts from the 5 highest TB burden regions were enrolled during the 4th quarter of 2016. District TB & Leprosy Coordinators (DTLCs), and District AIDS Coordinators (DACs) were interviewed, along with staff from all laboratories within the selected districts where molecular diagnostics tests for MDR-TB were performed. Furthermore, the 2015 registers were audited for all drug-susceptible but retreatment TB cases and TB collaborative practices in HIV clinics, as these patients were in principal targeted for drug susceptibility testing by rapid molecular diagnostics. RESULTS: Twenty-eight TB districts from the 5 regions had 399 patients reviewed for retreatment with a drug-susceptible regimen. Only 160 (40%) had specimens collected for drug-susceptibility testing, and of those specimens only 120 (75%) had results communicated back to the clinic. MDR-TB was diagnosed in 16 (13.3%) of the 120 specimens but only 12 total patients were ultimately referred for treatment. Furthermore, among the HIV/AIDS clinics served in 2015, the median number of clients with TB diagnosis was 92 cases [IQR 32-157] yet only 2 people living with HIV were diagnosed with MDR-TB throughout the surveyed districts. Furthermore, the districts generated 53 front-line healthcare workers for interviews. DTLCs with intermediate or no knowledge on the clinical application of XpertMTB/RIF were 3 (11%), and 10 (39%), and DACs with intermediate or no knowledge were 0 (0%) and 2 (8%) respectively (p = 0.02). Additionally, 11 (100%) of the laboratories surveyed had only the 4-module XpertMTB/RIF equipment. The median time that XpertMTB/RIF was not functional in the 12 months prior to the investigation was 2 months (IQR 1-4). CONCLUSIONS: Underutilization of molecular diagnostics in high-risk groups was a function of a lack of front-line healthcare workforce empowerment and training, and a lack of equipment access, which likely contributed to the observed delay in MDR-TB diagnosis in Tanzania.

Strengthening the Tuberculosis Specimen Referral Network in Uganda: The Role of Public-Private Partnerships.

BACKGROUND: Diagnosis of multidrug-resistant tuberculosis and prompt initiation of effective treatment rely on access to rapid and reliable drug-susceptibility testing. Efficient specimen transport systems and appropriate training on specimen referral contribute to optimal and timely access to tuberculosis diagnostic services. METHODS: With support and technical assistance from a public-private partnership (PPP) between Becton Dickinson and the US President's Emergency Plan for AIDS Relief, the Uganda National TB Reference Laboratory (NTRL) and National TB and Leprosy Program redesigned the tuberculosis specimen transport network and trained healthcare workers with the goal of improving multidrug-resistant tuberculosis detection. RESULTS: Between 2008 and 2011, the PPP mapped 93% of health facilities and trained 724 healthcare and postal staff members covering 72% of districts. Strengthening the tuberculosis specimen referral system increased referrals from presumptive multidrug-resistant tuberculosis cases by >10-fold, with 94% of specimens reaching the NTRL within the established target transport time. CONCLUSIONS: This study demonstrates the potential of PPP collaborations with ministries of health to positively influence patient care by strengthening laboratory systems through increased access to drug-susceptibility testing in Uganda. Ongoing efforts to integrate specimen transport networks will maximize resources and improve patient management.

Tuberculosis retreatment 'others' in comparison with classical retreatment cases; a retrospective cohort review.

BACKGROUND: Many of the countries in sub-Saharan Africa are still largely dependent on microscopy as the mainstay for diagnosis of tuberculosis (TB) including patients with previous history of TB treatment. The available guidance in management of TB retreatment cases is focused on bacteriologically confirmed TB retreatment cases leaving out those classified as retreatment 'others'. Retreatment 'others' refer to all TB cases who were previously treated but with unknown outcome of that previous treatment or who have returned to treatment with bacteriologically negative pulmonary or extra-pulmonary TB. This study was conducted in 11 regional referral hospitals (RRHs) serving high burden TB districts in Uganda to determine the profile and treatment success of TB retreatment 'others' in comparison with the classical retreatment cases. METHODS: A retrospective cohort review of routinely collected National TB and Leprosy Program (NTLP) facility data from 1 January to 31 December 2010. This study uses the term classical retreatment cases to refer to a combined group of bacteriologically confirmed relapse, return after failure and return after loss to follow-up cases as a distinct group from retreatment 'others'. Distribution of categorical characteristics were compared using Chi-squared test for difference between proportions. The log likelihood ratio test was used to assess the independent contribution of type of retreatment, human immunodeficiency virus (HIV) status, age group and sex to the models. RESULTS: Of the 6244 TB cases registered at the study sites, 733 (11.7%) were retreatment cases. Retreatment 'others' constituted 45.5% of retreatment cases. Co-infection with HIV was higher among retreatment 'others' (70.9%) than classical retreatment cases (53.5%). Treatment was successful in 410 (56.2%) retreatment cases. Retreatment 'others' were associated with reduced odds of success (AOR = 0.44, 95% CI 0.22,0.88) compared to classical cases. Lost to follow up was the commonest adverse outcome (38% of adverse outcomes) in all retreatment cases. Type of retreatment case, HIV status, and age were independently associated with treatment success. CONCLUSION: TB retreatment 'others' constitute a significant proportion of retreatment cases, with higher HIV prevalence and worse treatment success. There is need to review the diagnosis and management of retreatment 'others'.

Cutaneous tuberculosis due to multidrug-resistant tubercle bacilli and difficulties in clinical diagnosis.

This report describes 6 HIV-negative patients including 5 children with scrofuloderma and an adult with lupus vulgaris, out of a total of 303 cases of cutaneous tuberculosis seen during a 4½-year period, who showed a positive tuberculin test and granulomatous histopathology, but failed to respond to first-line antitubercular therapy. They were suspected to have multidrug-resistant infection as no other cause could be ascertained. Tissue aspirate or biopsy was sent for histopathology and culture. Mycobacterium tuberculosis was isolated from the aspirate in three patients and sputum in one with associated pulmonary tuberculosis. Drug susceptibility tests showed that all isolates were resistant to rifampicin and isoniazid, and one each additionally to streptomycin and ethambutol, respectively. In two, culture was unsuccessful. All were administered second-line antitubercular drugs. Clinical improvement was appreciable within 2 months as weight gain, and regression of ulcers, swellings and plaques. Two completed the recommended 24 months of therapy. Multidrug-resistant cutaneous tuberculosis should be suspected in patients with no response to first-line drugs, with clinical deterioration, and where other causes of treatment failure are not forthcoming. Owing to poor isolation rates on culture and low sensitivity of molecular tests, in such cases, a trial of second-line anti-tubercular drugs may be justified for a reasonable period of 2 months. Where facilities permit, culture and drug sensitivity tests should be done before starting treatment. Culture positivity is better from aspirated material.

Tuberculosis extremadamente resistente (TB-XDR), historia y situación actual / Extremely resistant tuberculosis (XDR-TB), history and current situation

Las enfermedades ocasionadas por micobacterias constituyen sin duda un capítulo importante de la patología infecciosa en la historia de la humanidad encontrandose desde sus albores enfermedades tan antiguas como la tuberculosis y la lepra, asi como otras las producidas por otras micobacterias. La tuberculosis es una micobacteriosis causada por el Complejo Mycobacteria Tuberculosis, en la que se encuentra comprendida el Mycobacterium tuberculosis. Este evolutivamente al igual que la humanidad ha afinando sus mecanismos de sobrevivencia y resistencia a sustancias antibioticas. Como otros microorganismos, la base de la resistencia del Mycobacterium tuberculosis es la selección de bacterias mutantes con resistencia innata a las drogas antituberculosas existentes, asi en virtud a este fenómeno adaptativo-evolutivo surge una subpoblación de Mycobacteria Tuberculosis extremadamente resistentes al tratamiento antibioterápico múltiple, con un pronostico de sobrevida sobre los pacientes pobre y diferente al de las subpoblaciones catalagadas como tbc multidrogo resistente o TB-MDR. Hasta junio de 2008 la TB XDR se ha reportado en 49 países, entre ellos el Perú. Un solo caso de TB XDR y el estudio de sus contactos deben ser enfocados como una emergencia sanitaria. El desarrollo de la TB XDR revela debilitamiento de los servicios asistenciales en el primer nivel de atención. Los dos factores de riesgo más fuertemente asociados con la TB XDR son: 1) Fracaso a un régimen antituberculoso que contiene drogas de segunda línea que incluye un inyectable y una fluoroquinolona y 2) Contacto estrecho con un individuo con TB XDR documentada o que viene fracasando a un esquema con drogas de segunda línea. El enfoque que debe darse a la TB-XDR, desde un punto de vista de salud pública, es el de una emergencia sanitaria, por lo que se debe lograr los recursos financieros necesarios para controlar su diseminación, lo que pasa por diagnósticos precoces, tratamientos oportunos, ...

Diseases caused by Mycobacteria are an important area within infectious diseases in mankindÆs history, and since early times conditions such as tuberculosis (TB) and leprosy (HansenÆs disease) had already been described. This also holds true for diseases caused by other Mycobacteria. Tuberculosis is a mycobacterial disease caused by Mycobacteria tuberculosis complex, being Mycobacterium tuberculosis one of its most conspicuous components. This microorganism has perfected its mechanisms for survival, allowing it to develop resistance against antituberculous therapy. As it is the case for other microorganisms, the basis for M. tuberculosis resistance is the selection of mutant bacteria with innate resistance to currently available antituberculous drugs; so, by virtue of this adaptive and evolutive phenomenon, there is the emergence of a subpopulation of M. tuberculosis that is extremely resistant to multiple antituberculous drugs, and the survival prognosis for patients with TB disease caused by these particular microorganism is quite poor, so different to that in subpopulations with TB disease caused by multidrug-resistant (MDR-TB) M. tuberculosis. Until June 2008, XDR-TB had been reported in 49 countries, Peru amongst them. The occurrence of a single case of XDR-TB and its contacts must be approached as a sanitary emergency. The development of XDR-TB reflects a weakening of healthcare services, particularly those at the first level or primary care. The two most important risk factors associated with the occurrence of XDR-TB are: 1) failure with a second-line antituberculous drug regimen including one injectable drug and a fluoroquinolone, and 2) close contact with any individual with documented XDR-TB who is failing with a second-line antituberculous drug regimen. XDR-TB must be approached as a sanitary emergency, so adequate financial resources must be allocated for controlling its spread, which means having early diagnosis, timely therapy, integral ...

Is PGL-1 also present in Leishmania donovani promastigotes?

A soluble antigen complex (SAC) derived from the ruptured promastigotes of Leishmania donovani parasites (LD-SAC) was used for complement fixation test (CFT) in leprosy Cases of tuberculoid and borderline tuberculoid leprosy, post-kala azar dermal leishmaniasis (TT, BT, PKDL) and control sera gave negative CFT. Smear-positive cases of borderline (BB, BL) and lepromatous (LL) leprosy and drug-resisting cases of pulmonary tuberculosis gave positive CFT; smear-negative cases of LL leprosy sera also gave positive CFT. Sera of smear-negative inactive LL patients contained only PGL-1 and PDIM antigens for a long time after they become inactive. Therefore, the positive CFT in inactive LL makes us suspect whether PGL-1 is present in LD promastigotes.