BACKGROUND: Individuals infected with Mycobacterium tuberculosis (Mtb) may develop symptoms and signs of disease (tuberculosis disease) or may have no clinical evidence of disease (latent tuberculosis infection [LTBI]). Tuberculosis disease is a leading cause of infectious disease morbidity and mortality worldwide, yet many questions related to its diagnosis remain. METHODS: A task force supported by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America searched, selected, and synthesized relevant evidence. The evidence was then used as the basis for recommendations about the diagnosis of tuberculosis disease and LTBI in adults and children. The recommendations were formulated, written, and graded using the Grading, Recommendations, Assessment, Development and Evaluation (GRADE) approach. RESULTS: Twenty-three evidence-based recommendations about diagnostic testing for latent tuberculosis infection, pulmonary tuberculosis, and extrapulmonary tuberculosis are provided. Six of the recommendations are strong, whereas the remaining 17 are conditional. CONCLUSIONS: These guidelines are not intended to impose a standard of care. They provide the basis for rational decisions in the diagnosis of tuberculosis in the context of the existing evidence. No guidelines can take into account all of the often compelling unique individual clinical circumstances.

Tuberculosis (TB) is a major public health concern worldwide with over 2 billion people currently infected. The rise of strains of Mycobacterium tuberculosis (Mtb) that are resistant to some or all first and second line antibiotics, including multidrug-resistant (MDR), extensively drug resistant (XDR) and totally drug resistant (TDR) strains, is of particular concern and new anti-TB drugs are urgently needed. Curcumin, a natural product used in traditional medicine in India, exhibits anti-microbial activity that includes Mtb, however it is relatively unstable and suffers from poor bioavailability. To improve activity and bioavailability, mono-carbonyl analogs of curcumin were synthesized and screened for their capacity to inhibit the growth of Mtb and the related Mycobacterium marinum (Mm). Using disk diffusion and liquid culture assays, we found several analogs that inhibit in vitro growth of Mm and Mtb, including rifampicin-resistant strains. Structure activity analysis of the analogs indicated that Michael acceptor properties are critical for inhibitory activity. However, no synergistic effects were evident between the monocarbonyl analogs and rifampicin on inhibiting growth. Together, these data provide a structural basis for the development of analogs of curcumin with pronounced anti-mycobacterial activity and provide a roadmap to develop additional structural analogs that exhibit more favorable interactions with other anti-TB drugs.

The lack of capacity to provide laboratory confirmation of a diagnosis of tuberculosis disease (TB) is contributing to enormous gaps in the ability to find, treat and follow TB patients. WHO estimates that globally only about 57% of the notified new cases of pulmonary TB in 2012 and about 19% of rifampicin-resistant TB cases were laboratory confirmed. The Cepheid Xpert((R)) MTB/RIF assay has been credited with revolutionizing laboratory testing to aid in the diagnosis of TB and rifampicin-resistant TB. This semi-automated test can detect both the causative agent of TB and mutations that confer rifampicin resistance from clinical specimens within 2 h after starting the test. In this article, we review the performance of the test, its pathway to regulatory approval and endorsement, guidelines for its use and lessons learned from the implementation of the test in low-burden, high-resource countries and in high-burden, low-resource countries.

Since the discovery of streptomycin's bactericidal activity against Mycobacterium tuberculosis, aminoglycosides have been utilized to treat tuberculosis (TB). Today, the aminoglycosides kanamycin and amikacin are used to treat multidrug-resistant (MDR) TB, and resistance to any of the second-line injectable antibiotics, including kanamycin, amikacin, or capreomycin, is a defining characteristic of extensively drug-resistant (XDR) TB. Resistance to kanamycin and streptomycin is thought to be due to the acquisition of unlinked chromosomal mutations. However, we identified eight independent mutations in the 5' untranslated region of the transcriptional activator whiB7 that confer low-level resistance to both aminoglycosides. The mutations lead to 23- to 145-fold increases in whiB7 transcripts and subsequent increased expression of both eis (Rv2416c) and tap (Rv1258c). Increased expression of eis confers kanamycin resistance in these mutants, while increased expression of tap, which encodes an efflux pump, is a previously uncharacterized mechanism of low-level streptomycin resistance. Additionally, high-level resistance to streptomycin arose at a much higher frequency in whiB7 mutants than in a wild-type (WT) strain. Although whiB7 is typically associated with intrinsic antibiotic resistance in M. tuberculosis, these data suggest that mutations in an uncharacterized regulatory region of whiB7 contribute to cross-resistance against clinically used second-line antibiotics. As drug resistance continues to develop and spread, understanding the mechanisms and molecular basis of antibiotic resistance is critical for the development of rapid molecular tests to diagnose drug-resistant TB strains and ultimately for designing regimens to treat drug-resistant cases of TB.

Quality laboratory services are essential for high quality, cost-effective health care. The need to use a laboratory systems approach, focusing on quality management systems (QMS) and accreditation standards, | is now well recognized,1 as it can provide vital information for proper planning and utilization of health | resources, which is critical in resource-limited settings. Accreditation also provides the credibility necessary to assure program investments in laboratory | strengthening. | The Global Laboratory Initiative (GLI) of the Stop | TB Partnership has developed a tool to assist laboratories in implementing a QMS that meets ISO15189 | Medical Laboratory–Requirements for Quality and | Competence, the most widely used standard for laboratory accreditation. This standard defi nes the requirements for a laboratory QMS, but provides no | guidance on how to implement processes and procedures to meet these requirements.

The lengthy course of treatment with currently used antimycobacterial drugs and the resulting emergence of drug-resistant strains have intensified the need for alternative therapies against Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis. We show that Mtb and Mycobacterium marinum use ABL and related tyrosine kinases for entry and intracellular survival in macrophages. In mice, the ABL family tyrosine kinase inhibitor, imatinib (Gleevec), when administered prophylactically or therapeutically, reduced both the number of granulomatous lesions and bacterial load in infected organs and was also effective against a rifampicin-resistant strain. Further, when coadministered with current first-line drugs, rifampicin or rifabutin, imatinib acted synergistically. These data implicate host tyrosine kinases in entry and intracellular survival of mycobacteria and suggest that imatinib may have therapeutic efficacy against Mtb. Because imatinib targets host, it is less likely to engender resistance compared to conventional antibiotics and may decrease the development of resistance against coadministered drugs.

BACKGROUND: The identification of Mycobacterium tuberculosis vaccines that elicit a protective immune response in the lungs is important for the development of an effective vaccine against tuberculosis. METHODS AND PRINCIPAL FINDINGS: In this study, a comparison of intranasal (i.n.) and subcutaneous (s.c.) vaccination with the BCG vaccine demonstrated that a single moderate dose delivered intranasally induced a stronger and sustained M. tuberculosis-specific T-cell response in lung parenchyma and cervical lymph nodes of BALB/c mice than vaccine delivered subcutaneously. Both BCG and a multicomponent subunit vaccine composed of nine M. tuberculosis recombinant proteins induced strong antigen-specific T-cell responses in various local and peripheral immune compartments. Among the nine recombinant proteins evaluated, the alanine proline rich antigen (Apa, Rv1860) was highly antigenic following i.n. BCG and immunogenic after vaccination with a combination of the nine recombinant antigens. The Apa-induced responses included induction of both type 1 and type 2 cytokines in the lungs as evaluated by ELISPOT and a multiplexed microsphere-based cytokine immunoassay. Of importance, i.n. subunit vaccination with Apa imparted significant protection in the lungs and spleen of mice against M. tuberculosis challenge. Despite observed differences in the frequencies and location of specific cytokine secreting T cells both BCG vaccination routes afforded comparable levels of protection in our study. CONCLUSION AND SIGNIFICANCE: Overall, our findings support consideration and further evaluation of an intranasally targeted Apa-based vaccine to prevent tuberculosis.

Comparative genomic sequencing is shedding new light on bacterial identification, taxonomy and phylogeny. An in silico assessment of a core gene set necessary for cellular functioning was made to determine a consensus set of genes that would be useful for the identification, taxonomy and phylogeny of the species belonging to the subclass Actinobacteridae which contained two orders Actinomycetales and Bifidobacteriales. The subclass Actinobacteridae comprised about 85% of the actinobacteria families. The following recommended criteria were used to establish a comprehensive gene set; the gene should (i) be long enough to contain phylogenetically useful information, (ii) not be subject to horizontal gene transfer, (iii) be a single copy (iv) have at least two regions sufficiently conserved that allow the design of amplification and sequencing primers and (v) predict whole-genome relationships. We applied these constraints to 50 different Actinobacteridae genomes and made 1,224 pairwise comparisons of the genome conserved regions and gene fragments obtained by using Sequence VARiability Analysis Program (SVARAP), which allow designing the primers. Following a comparative statistical modeling phase, 3 gene fragments were selected, ychF, rpoB, and secY with R(2)>0.85. Selected sets of broad range primers were tested from the 3 gene fragments and were demonstrated to be useful for amplification and sequencing of 25 species belonging to 9 genera of Actinobacteridae. The intraspecies similarities were 96.3-100% for ychF, 97.8-100% for rpoB and 96.9-100% for secY among 73 strains belonging to 15 species of the subclass Actinobacteridae compare to 99.4-100% for 16S rRNA. The phylogenetic topology obtained from the combined datasets ychF+rpoB+secY was globally similar to that inferred from the 16S rRNA but with higher confidence. It was concluded that multi-locus sequence analysis using core gene set might represent the first consensus and valid approach for investigating the bacterial identification, phylogeny and taxonomy.

We investigated the in vitro production of the antimicrobial peptide hepcidin by cells of the innate immune system that harbor Mycobacterium tuberculosis. Stimulation of mouse lung macrophages with M. tuberculosis or IFN-gamma + M. tuberculosis induced hepcidin mRNA. In human alveolar A549 epithelial cells, lipoglycans of M. tuberculosis, in particular mannose-capped lipoarabinomannan and phosphatidyl-myo-inositol mannosides, were strong inducers of hepcidin mRNA. In mouse dendritic cells, hepcidin mRNA was increased by subcellular fractions and culture filtrate proteins of M. tuberculosis and by TLR2 and TLR4 agonists, but not by TLR9 agonists, IL-1-alpha, IL-6 or TNF-alpha. Flow cytometry evaluation of human peripheral blood mononuclear cells demonstrated that CD11c(+) myeloid dendritic cells stimulated with killed M. tuberculosis or live M. bovis BCG produced hepcidin. The production of the antimicrobial peptide hepcidin by cells that interact with M. tuberculosis suggests a host defense mechanism against mycobacteria.