Levofloxacin based non-rifampicin anti-tuberculous therapy: An effective alternative in renal transplant recipients in resource limited setting.

INTRODUCTION: Rifampicin is one of the most effective components of anti-tuberculous therapy (ATT). Since rifampicin is a hepatic enzyme (CYP3A4) inducer, in a post-renal transplant recipient, the dose of calcineurin inhibitors needs to be up-regulated and frequently monitored. In resource-limited (low- and lower-middle-income countries) setting this is not always feasible. Therefore, we evaluated a non-rifampicin-based ATT using levofloxacin in kidney transplant recipients. METHODS: We retrospectively studied the medical records of renal transplant recipients diagnosed with tuberculosis in our institute between 2014 and 2017. After a brief discussion with patients regarding the nature and course of ATT, those who opted for a non-rifampicin based therapy due to financial constraints were included in the study and followed for a minimum of 6 months period after the completion of ATT. RESULTS: Out of the 550 renal transplant recipients, 67 (12.2%) developed tuberculosis after a median period of 24 (1-228) months following transplantation, of them, 64 patients opted for non-rifampicin-based ATT. The mean age was 37.6 years. Only 25% were given anti-thymocyte globulin based induction, while the majority (56; 87.5%) of them were on tacrolimus-based triple-drug maintenance therapy. Extrapulmonary tuberculosis was noted in 33% of cases, while 12 (18.7%) had disseminated disease. The median duration of treatment was 12 months and the cure rate of 93.7% (n = 60) was achieved at the end of therapy. CONCLUSION: Levofloxacin based ATT appears to be a safe and effective alternative of rifampicin in kidney transplant recipients who cannot afford heightened tacrolimus dosage.

Long-term efficacy of BCG vaccination in goat herds with a high prevalence of tuberculosis.

Vaccination of goats against tuberculosis (TB) has been promoted as an ancillary tool for controlling the disease in infected livestock herds. A three-year trial to assess the efficacy of BCG vaccine was carried out in five goat herds. At the beginning of the trial (month 0), all animals were tested for TB using thee different diagnostic tests. Animals negative to all tests were vaccinated with BCG and all replacement goat kids were also systematically vaccinated throughout the trial. All animals were tested by Interferon-gamma release assay (IGRA) using vaccine compatible reagents at months 6, 12, 24, and 36. The risk factors for TB infection were also evaluated. At the end of the study, four out of five farms showed variable reductions of the initial prevalence (93.5%, 28.5%, 23.2%, and 14.3% respectively), and an overall incidence reduction of 50% was observed in BCG vaccinated goats, although adult vaccinated goats showed higher incidences than vaccinated goat kids. The unvaccinated positive animals remaining in herds and adult BCG vaccinated goats significantly enhanced the risk of infection in vaccinated animals. A systematic vaccination of goats with BCG, together with the removal of positive unvaccinated animals, may contribute to reducing the TB prevalence in goat herds.

Assessment of Immune Protective T Cell Repertoire in Humans Immunized with Novel Tuberculosis Vaccines.

Tuberculosis (TB) is one of the major global health concerns. There has been a lack of an effective vaccine strategy. The Bacillus Calmette-Guerin (BCG), the only licensed vaccine against TB, is not effective against adult pulmonary TB, the highly contagious form of TB. In the past two decades or so, many novel TB vaccines have been developed, and some of them were evaluated in clinical trials. However, the lack of validated immune correlates to assess the clinical relevance of novel TB vaccines before their entry into costly efficacy trials is a huge challenge to the field of TB vaccine development. Here we describe a general protocol for the procedure of a systematic immunological approach that can be utilized to better assess the clinical relevance of TB vaccine-activated T cells in early phases of clinical studies.

BCG vaccine: WHO position paper, February 2018 - Recommendations.

This article presented the World Health Organization's (WHO) recommendations on the use of on Bacille Calmette-Guérin (BCG) vaccine excerpted from the BCG vaccines: WHO position paper - February 2018 published in the Weekly Epidemiological Record [1]. This position paper replaces the 2004 WHO position paper on Bacille Calmette-Guérin (BCG) vaccine [2] and the 2007 WHO revised BCG vaccination guidelines for infants at risk for human immunodeficiency virus (HIV) infection [3]. It incorporates recent developments in the tuberculosis (TB) field, provides revised guidance on the immunization of children infected with HIV, and re-emphasizes the importance of the birth dose. This position paper also includes recommendations for the prevention of leprosy. Footnotes to this paper provide a number of core references including references to grading tables that assess the quality of the scientific evidence, and to the evidence-to-recommendation tables. In accordance with its mandate to provide guidance to Member States on health policy matters, WHO issues a series of regularly updated position papers on vaccines and combinations of vaccines against diseases that have an international public health impact. These papers are concerned primarily with the use of vaccines in large-scale immunization programmes; they summarize essential background information on diseases and vaccines, and conclude with WHO's current position on the use of vaccines in the global context. Recommendations on the use of cholera vaccines were discussed by the Strategic Advisory Group of Experts (SAGE) in October 2017; evidence presented at these meetings can be accessed at: http://www.who.int/immunization/sage/meetings/2017/october/presentations_background_docs/en/.

Assessment of BCG and inactivated Mycobacterium bovis vaccines in an experimental tuberculosis infection model in sheep.

BACKGROUND/AIMS: Animal tuberculosis (TB) is a complex animal health problem that causes disruption to trade and significant economic losses. TB involves a multi-host system where sheep, traditionally considered a rare host of this infection, have been recently included. The aims of this study were to develop an experimental TB infection model in sheep with a Mycobacterium caprae field strain isolated from a tuberculous diseased ewe, and to use this to evaluate the safety and efficacy of two vaccines against TB in sheep, the live-attenuated M. bovis BCG vaccine (Danish strain) and a heat-inactivated M. bovis (HIMB) vaccine. METHODS: Eighteen 2 month-old lambs were experimentally challenged with M. caprae by the endotracheal route (1.5 × 103 CFU). They were separated per treatment group into parenterally vaccinated with a live BCG Danish strain vaccine (n = 6), orally vaccinated with a suspension of HIMB (n = 6) and unvaccinated controls (n = 6). Clinical, immunological, pathological and bacteriological parameters of infection were measured. RESULTS: All lambs were successfully infected and developed gross TB lesions in the respiratory system. The BCG vaccine conferred considerable protection against experimental TB in lambs, as measured by a reduction of the gross lesion volumes and bacterial load. However, HIMB vaccinated animals did not show protection. CONCLUSIONS: This study proposes a reliable new experimental model for a better understanding of tuberculosis in sheep. BCG vaccination offers an effective prospect for controlling the disease. Moreover alternative doses and/or routes of administration should be considered to evaluate the efficacy of the HIMB vaccine candidate.

Multi-subunit BCG booster vaccine GamTBvac: Assessment of immunogenicity and protective efficacy in murine and guinea pig TB models.

New innovative vaccines are highly needed to combat the global threat posed by tuberculosis. Efficient components-antigens and adjuvants-are crucial for development of modern recombinant TB vaccines. This study describes a new vaccine (GamTBvac) consisting of two mycobacterial antigen fusions (Ag85A and ESAT6-CFP10)-with dextran-binding domain immobilized on dextran and mixed with an adjuvant consisting of DEAE-dextran core, and with CpG oligodeoxynucleotides (TLR9 agonists). GamTBvac and its components were assessed for immunogenicity and protective efficacy in GamTBvac-prime/boost and BCG-prime/ GamTBvac-boost in murine and guinea pig TB models. Results show that in both infectious models, GamTBvac has a strong immunogenicity and significant protective effect against Mycobacterium tuberculosis strain H37Rv under aerosol and intravenous challenges. GamTBvac showed a particularly strong protective effect as a BCG booster vaccine.

R&D in Vaccines Targeting Neglected Diseases: An Exploratory Case Study Considering Funding for Preventive Tuberculosis Vaccine Development from 2007 to 2014.

Based on an exploratory case study regarding the types of institutions funding the research and development to obtain new tuberculosis vaccines, this article intends to provoke discussion regarding the provision of new vaccines targeting neglected disease. Although our findings and discussion are mainly relevant to the case presented here, some aspects are more generally applicable, especially regarding the dynamics of development in vaccines to prevent neglected diseases. Taking into account the dynamics of innovation currently seen at work in the vaccine sector, a highly concentrated market dominated by few multinational pharmaceutical companies, we feel that global PDP models can play an important role throughout the vaccine development cycle. In addition, the authors call attention to issues surrounding the coordination of actors and resources in the research, development, manufacturing, and distribution processes of vaccine products arising from PDP involvement.

TB biomarkers, TB correlates and human challenge models: New tools for improving assessment of new TB vaccines.

The 4th Global Forum on TB Vaccines, convened in Shanghai, China, from 21 - 24 April 2015, brought together a wide and diverse community involved in tuberculosis vaccine research and development to discuss the current status of, and future directions for this critical effort. This paper summarizes the sessions on Biomarkers and Correlates, and Human Challenge Models. Summaries of all sessions from the 4th Global Forum are compiled in a special supplement of Tuberculosis. [August 2016, Vol 99, Supp S1, S1-S30].

[Risk of tuberculosis in healthcare workers: risk assessment and medical surveillance]. / Rischio tubercolosi in ambiente sanitario. Valutazione del rischio e sorveglianza sanitaria.

Tuberculosis screening is recommended for all health care workers. We evaluated the prevalence of latent tuberculosis infection among 939 hospital workers of Tor Vergata University teaching hospital in Rome, Italy, in the period 2007-2013, by using the QuantiFERON Gold In-Tube (QFT) test. The mean age of subjects tested was 31 years. The prevalence of positive subjects (cut-off 0.35 UI/ml) was 5.5% (46/939) and the mean age of those who tested positive was 39 years. The low rate of positivity may be partly related to the higher reliability of QFT in comparison to tuberculin skin testing.

DNA Vaccines: A Strategy for Developing Novel Multivalent TB Vaccines.

Multivalent DNA vaccines that are delivered by electroporation (EP) through muscle tissue provide a novel method for eliciting immunity against tuberculosis (TB) as well as a broad range of diseases including HIV and cancers. Proper plasmid construction containing suitable protective TB antigens capable of evoking desired vaccine-induced responses would lead to the appropriate induction of both humoral and cellular immunity. DNA vaccines are safe and of low cost in comparison to traditional vaccines while also providing potentially effective prophylactic or therapeutic modalities against currently untreatable diseases. Here, we describe the steps for developing a rational multivalent TB DNA vaccine delivered with intramuscular EP in mice.

A Higher Activation Threshold of Memory CD8+ T Cells Has a Fitness Cost That Is Modified by TCR Affinity during Tuberculosis.

T cell vaccines against Mycobacterium tuberculosis (Mtb) and other pathogens are based on the principle that memory T cells rapidly generate effector responses upon challenge, leading to pathogen clearance. Despite eliciting a robust memory CD8+ T cell response to the immunodominant Mtb antigen TB10.4 (EsxH), we find the increased frequency of TB10.4-specific CD8+ T cells conferred by vaccination to be short-lived after Mtb challenge. To compare memory and naïve CD8+ T cell function during their response to Mtb, we track their expansions using TB10.4-specific retrogenic CD8+ T cells. We find that the primary (naïve) response outnumbers the secondary (memory) response during Mtb challenge, an effect moderated by increased TCR affinity. To determine whether the expansion of polyclonal memory T cells is restrained following Mtb challenge, we used TCRß deep sequencing to track TB10.4-specific CD8+ T cells after vaccination and subsequent challenge in intact mice. Successful memory T cells, defined by their clonal expansion after Mtb challenge, express similar CDR3ß sequences suggesting TCR selection by antigen. Thus, both TCR-dependent and -independent factors affect the fitness of memory CD8+ responses. The impaired expansion of the majority of memory T cell clonotypes may explain why some TB vaccines have not provided better protection.

Avaliação de biomarcadores para diagnóstico e monitoramento do tratamento da tuberculose pulmonar / Biomarker assessment for diagnosis and monitoring of treatment of pulmonary tuberculosis

INTRODUÇÃO: A tuberculose (TB), doença crônica infecciosa causada por Mycobacterium tuberculosis, é considerada um grave problema de saúde pública no país. A caracterização de antígenos protéicos e/ou lipídios que induzem uma resposta imunológica no hospedeiro, torna-se um importante passo para o desenvolvimento de novas ferramentas de diagnóstico e resposta terapêutica. Dentre os diferentes antígenos, em especial a mammalian cell entry protein 1A (proteína Mce1A), e os fosfolipídios da parede celular do bacilo como a cardiolipina (CL), os fosfatidilinositol (FI), fosfatidilcolina (FC), fosfatidiletanolamina (FE) e o sulfatide (SL), são, em sua maioria altamente imunogênicos, podendo então ser úteis no sorodiagnóstico. Portanto, o objetivo do estudo é avaliar a produção de anticorpos anti- Mce1A...

INTRODUCTION: Tuberculosis (TB), chronic infectious disease caused by Mycobacterium tuberculosis, is still a serious public health problem in the country. The characterization of protein and/or lipids antigens that induce an immune response in the host, it is an important step in the development of new diagnostic tools and monitoring TB treatment response. Among the different antigens, particularly mammalian cell entry protein 1A (Mce1A protein), and phospholipids from the cell wall of bacillus such as cardiolipin (CL), phosphatidylinositol (PI), phosphatidylcholine (PTC), phosphatidylethanolamine (PE) and sulfatide (SL), are highly immunogenic and can be used for improvement of the serodiagnosis. Therefore, the aim of the study is to evaluate the production of anti-Mce1A...

Impact and cost-effectiveness of new tuberculosis vaccines in low- and middle-income countries.

To help reach the target of tuberculosis (TB) disease elimination by 2050, vaccine development needs to occur now. We estimated the impact and cost-effectiveness of potential TB vaccines in low- and middle-income countries using an age-structured transmission model. New vaccines were assumed to be available in 2024, to prevent active TB in all individuals, to have a 5-y to lifetime duration of protection, to have 40-80% efficacy, and to be targeted at "infants" or "adolescents/adults." Vaccine prices were tiered by income group (US $1.50-$10 per dose), and cost-effectiveness was assessed using incremental cost per disability adjusted life year (DALY) averted compared against gross national income per capita. Our results suggest that over 2024-2050, a vaccine targeted to adolescents/adults could have a greater impact than one targeted at infants. In low-income countries, a vaccine with a 10-y duration and 60% efficacy targeted at adolescents/adults could prevent 17 (95% range: 11-24) million TB cases by 2050 and could be considered cost-effective at $149 (cost saving to $387) per DALY averted. If targeted at infants, 0.89 (0.42-1.58) million TB cases could be prevented at $1,692 ($634-$4,603) per DALY averted. This profile targeted at adolescents/adults could be cost-effective at $4, $9, and $20 per dose in low-, lower-middle-, and upper-middle-income countries, respectively. Increased investments in adult-targeted TB vaccines may be warranted, even if only short duration and low efficacy vaccines are likely to be feasible, and trials among adults should be powered to detect low efficacies.

Assessment of the novel T-cell activation marker-tuberculosis assay for diagnosis of active tuberculosis in children: a prospective proof-of-concept study.

BACKGROUND: The diagnosis of paediatric tuberculosis is complicated by non-specific symptoms, difficult specimen collection, and the paucibacillary nature of the disease. We assessed the accuracy of a novel immunodiagnostic T-cell activation marker-tuberculosis (TAM-TB) assay in a proof-of-concept study to identify children with active tuberculosis. METHODS: Children with symptoms that suggested tuberculosis were prospectively recruited at the NIMR-Mbeya Medical Research Center in Mbeya, and the Ifakara Health Institute in Bagamoyo, Tanzania, between May 10, 2011, and Sept 4, 2012. Sputum and peripheral blood mononuclear cells were obtained for Mycobacterium tuberculosis culture and performance assessment of the TAM-TB assay. The children were assigned to standardised clinical case classifications based on microbiological and clinical findings. FINDINGS: Among 290 children screened, we selected a subgroup of 130 to ensure testing of at least 20 with culture-confirmed tuberculosis. 17 of 130 children were excluded because of inconclusive TAM-TB assay results. The TAM-TB assay enabled detection of 15 of 18 culture-confirmed cases (sensitivity 83·3%, 95% CI 58·6-96·4). Specificity was 96·8% (95% CI 89·0-99·6) in the cases that were classified as not tuberculosis (n=63), with little effect from latent tuberculosis infection. The TAM-TB assay identified five additional patients with highly probable or probable tuberculosis, in whom M tuberculosis was not isolated. The median time to diagnosis was 19·5 days (IQR 14-45) for culture. INTERPRETATION: The sputum-independent TAM-TB assay is a rapid and accurate blood test that has the potential to improve the diagnosis of active tuberculosis in children. FUNDING: European and Developing Countries Clinical Trials Partnership, German Federal Ministry of Education and Research, and Swiss National Science Foundation.

The double burden: a new-age pandemic meets an ancient infection.

Tuberculosis is responsible for significant morbidity and mortality in the tropics. Active TB develops when host defences are impaired. Epidemiological evidence and studies addressing the double burden of communicable and non-communicable diseases demonstrate a clear association between diabetes and susceptibility to TB, treatment failure and complications. The immune mechanisms involved in host-pathogen interactions in co-morbid TB-diabetes are not well defined and require further investigation. This combined with the increase in diabetes predominately in low- and middle-income countries where TB is prevalent has major health implications.

Pre-placement screening for tuberculosis in healthcare workers.

BACKGROUND: Healthcare workers (HCWs) are at occupational risk of contracting and transmitting tuberculosis (TB). Despite national guidance, the optimal process for the pre-placement screening of new entrant HCWs for TB in the UK is not certain, nor the appropriateness of using a one-step interferon gamma release assay (IGRA) screening programme. AIMS: To assess the potential for an IGRA-only TB screening programme for new entrant HCWs, and identify cost savings achieved through this process. METHODS: We conducted a retrospective analysis of IGRA and tuberculin skin tests (TST) within our occupational health service over a 3-year period. HCWs with markedly discordant test results (IGRA negative, TST positive) were followed up to determine whether they developed active TB. We also estimated the yearly cost savings if the existing two-step process was replaced with an IGRA-only programme. RESULTS: Totally, 96/1258 (8%) HCWs had positive IGRA results; 788 TSTs were performed for newly screened IGRA-negative HCWs without Bacille Calmette-Guérin scars, among which 597 (76%) tested negative (TST <6 mm). None of the 10 individuals with grossly discordant test results (TST >15 mm) developed active TB during the study period. We calculated savings of £20,453 if the two-step process was replaced with an IGRA-only programme. CONCLUSIONS: The absence of disease progression in individuals with markedly discordant results in this study suggest that an IGRA-only screening programme for new HCWs in the UK is feasible, and may be safe although our follow-up period was insufficient. Our results also suggest that substantial cost savings can be made by using this programme.