Caregiver willingness to give TPT to children living with drug-resistant TB patients

BACKGROUND Pediatric household contacts (HHCs) of patients with multidrug-resistant TB (MDR-TB) are at high risk of infection and active disease. Evidence of caregiver willingness to give MDR-TB preventive therapy (TPT) to children is limited.METHODS This was a cross-sectional study of HHCs of patients with MDR-TB to assess caregiver willingness to give TPT to children aged <13 years.RESULTS Of 743 adult and adolescent HHCs, 299 reported caring for children aged <13 years of age. The median caregiver age was 35 years (IQR 27-48); 75% were women. Among caregivers, 89% were willing to give children MDR TPT. In unadjusted analyses, increased willingness was associated with TB-related knowledge (OR 5.1, 95% CI 2.3-11.3), belief that one can die of MDR-TB (OR 5.2, 95% CI 1.2-23.4), concern for MDR-TB transmission to child (OR 4.5, 95% CI 1.6-12.4), confidence in properly taking TPT (OR 4.5, 95% CI 1.6-12.6), comfort telling family about TPT (OR 5.5, 95% CI 2.1-14.3), and willingness to take TPT oneself (OR 35.1, 95% CI 11.0-112.8).CONCLUSIONS A high percentage of caregivers living with MDR- or rifampicin-resistant TB patients were willing to give children a hypothetical MDR TPT. These results provide important evidence for the potential uptake of effective MDR TPT when implemented.

Acceptability of a first-line anti-tuberculosis formulation for children: qualitative data from the SHINE trial

SETTING: We conducted a qualitative exploration into the palatability and acceptability of a novel fixed-dose combination (FDC) anti-tuberculosis drug. This study was nested in the SHINE (Shorter treatment for minimal TB in children) trial, which compares the safety and efficacy of treating non-severe drug-susceptible tuberculosis (TB) with a 6 vs. 4 months anti-tuberculosis regimen in children aged 0-16 years. Participants were recruited in Cape Town, South Africa.OBJECTIVE: To describe the palatability and acceptability of a FDC of rifampicin, isoniazid and pyrazinamide among South African children and their caregivers in the SHINE trial.METHODS: We conducted 20 clinic observations of treatment administration, during which we conducted 16 semi-structured interviews with children and their caregivers. Data were organised thematically to report on experiences with administering and ingesting the FDC.RESULTS: Children and caregivers' experiences varied from delight to disgust. In general, participants said that the FDC compared favourably to other formulations. Pragmatic challenges such as dissolving the FDC and the time required to administer the FDC impeded caregivers' ability to integrate treatment into their daily routines. Drug manipulation was common among caregivers to improve TB treatment administration.CONCLUSION: This novel FDC appears acceptable for children, albeit with practical challenges to administration. Scale-up of FDC use should include supplementary intervention components to support caregivers.

HIV testing uptake among the household contacts of multidrug-resistant tuberculosis index cases in eight countries

SETTING

The household contacts (HHCs) of multidrug-resistant tuberculosis (MDR-TB) index cases are at high risk of tuberculous infection and disease progression, particularly if infected with the human immunodeficiency virus (HIV). HIV testing is important for risk assessment and clinical management.

METHODS

This was a cross-sectional, multi-country study of adult MDR-TB index cases and HHCs. All adult and child HHCs were offered HIV testing if never tested or if HIV-negative >1 year previously when last tested. We measured HIV testing uptake and used logistic regression to evaluate predictors.

RESULTS

A total of 1007 HHCs of 284 index cases were enrolled in eight countries. HIV status was known at enrolment for 226 (22%) HHCs; 39 (4%) were HIV-positive. HIV testing was offered to 769 (98%) of the 781 remaining HHCs; 544 (71%) agreed to testing. Of 535 who were actually tested, 26 (5%) were HIV-infected. HIV testing uptake varied by site (median 86%, range 0-100%; P < 0.0001), and was lower in children aged <18 years than in adults (59% vs. 78%; adjusted for site P < 0.0001).

CONCLUSIONS

HIV testing of HHCs of MDR-TB index cases is feasible and high-yield, with 5% testing positive. Reasons for low test uptake among children and at specific sites-including sites with high HIV prevalence-require further study to ensure all persons at risk for HIV are aware of their status.

Resource utilization for multidrug-resistant tuberculosis household contact investigations (A5300/I2003)

BACKGROUND

Current guidelines recommend evaluation of the household contacts (HHCs) of individuals with multidrug-resistant tuberculosis (MDR-TB); however, implementation of this policy is challenging.

OBJECTIVE

To describe the resource utilization and operational challenges encountered when identifying and characterizing adult MDR-TB index cases and their HHCs.

DESIGN

Cross-sectional study of adult MDR-TB index cases and HHCs at 16 clinical research sites in eight countries. Site-level resource utilization was assessed with surveys.

RESULTS

Between October 2015 and April 2016, 308 index cases and 1018 HHCs were enrolled. Of 280 index cases with sputum collected, 94 were smear-positive (34%, 95%CI 28-39), and of 201 with chest X-rays, 87 had cavitary disease (43%, 95%CI 37-50) after a mean duration of treatment of 8 weeks. Staff required 512 attempts to evaluate the 308 households, with a median time per attempt of 4 h; 77% (95%CI 73-80) of HHCs were at increased risk for TB: 13% were aged <5 years, 8% were infected with the human immunodeficiency virus, and 79% were positive on the tuberculin skin test/interferon-gamma release assay. One hundred and twenty-one previously undiagnosed TB cases were identified. Issues identified by site staff included the complexity of personnel and participant transportation, infection control, personnel safety and management of stigma.

CONCLUSION

HHC investigations can be high yield, but are labor-intensive.

Pediatric tuberculous meningitis: Model-based approach to determining optimal doses of the anti-tuberculosis drugs rifampin and levofloxacin for children

Pediatric tuberculous meningitis (TBM) is a highly morbid, often fatal disease. Standard treatment includes isoniazid, rifampin, pyrazinamide, and ethambutol. Current rifampin dosing achieves low cerebrospinal fluid (CSF) concentrations, and CSF penetration of ethambutol is poor. In adult trials, higher-dose rifampin and/or a fluoroquinolone reduced mortality and disability. To estimate optimal dosing of rifampin and levofloxacin for children, we compiled plasma and CSF pharmacokinetic (PK) and outcomes data from adult TBM trials plus plasma PK data from children. A population PK/pharmacodynamic (PD) model using adult data defined rifampin target exposures (plasma area under the curve (AUC)0-24 = 92 mg*h/L). Levofloxacin targets and rifampin pediatric drug disposition information were literature-derived. To attain target rifampin exposures, children require daily doses of at least 30 mg/kg orally or 15 mg/kg intravenously (i.v.). From our pediatric population PK model, oral levofloxacin doses needed to attain exposure targets were 19-33 mg/kg. Our results provide data-driven guidance to maximize pediatric TBM treatment while we await definitive trial results.

Beyond accuracy: creating a comprehensive evidence base for TB diagnostic tools

The need for a strong and comprehensive evidence base to support decision making with regard to the implementation of new and improved diagnostic tools and approaches has been highlighted by a number of stakeholders; these include members of the New Diagnostics Working Group (NDWG) and the Subgroup for Introducing New Approaches and Tools of the Stop TB Partnership. To compile such evidence in a systematic manner, we have developed an impact assessment framework (IAF) which links evidence on inputs to outcomes. The IAF comprises five interconnected layers: effectiveness analysis, equity analysis, health systems analysis, scale-up analysis and policy analysis. It can be used by new diagnostics developers and other interested research teams to collect as much policy-relevant data as possible prior to, during and after the demonstration phase of tool development. The evidence collated may be used by international and national policy makers to support adoption, implementation and scale-up decisions. The TREAT TB (Technology, Research, Education and Technical Assistance for TB) initiative uses the IAF in its operational research and field evaluations of new tools and approaches for TB diagnosis. It has also been incorporated into the NDWG's recent publication: 'Pathways to better diagnostics for tuberculosis: a blueprint for the development of TB diagnostics'. This article describes the IAF and the process of improving it and suggests next steps in overcoming the challenges in its implementation.

Transcriptome and proteome analysis of ovaries of arrhenotokous and thelytokous Venturia canescens

Under arrhenotoky, unfertilized haploid eggs develop as males but under thelytoky they develop into diploid females after they have undergone diploidy restoration. In the parasitoid wasp Venturia canescens both reproductive modes occur. Thelytoky is genetically determined but the underlying genetics of diploidy restoration remain unknown. In this study we aim to identify the genes and/or proteins that control thelytoky. cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis of total ovarian RNA and two-dimensional protein electrophoresis in combination with mass spectrometry revealed putative transcripts and proteins involved in arrhenotokous and thelytokous development. The detected tubulin and actin protein differences are most likely functionally related to the two types of reproduction.

Annual meeting of the Tuberculosis Surveillance and Research Unit, 2008

The Tuberculosis Surveillance and Research Unit (TSRU) held its last annual meeting in Helsinki, Finland, from 1 to 4 April 2008. Several topics of current interest for tuberculosis (TB) research and new research projects were presented and discussed in depth by 60 delegates from Europe, Africa and Asia. This paper summarises some of the highlights of the meeting which may be of interest to epidemiologists and managers active in the field of TB.

Prediction of delayed treatment response in pulmonary tuberculosis: use of time to positivity values of Bactec cultures

New drugs that can shorten tuberculosis (TB) treatment and target drug resistant strains are urgently needed. A test which could predict patients at risk of a delayed response to treatment would facilitate clinical trials of new anti-tuberculosis drugs. A widely-used test for the assessment of response to treatment is sputum smear examination. Patients who are smear positive after 2 and 3 months of treatment are said to have delayed and significantly delayed treatment responses respectively. Time to positivity (TTP) values of Bactec cultures, from the first 2 weeks of treatment were used to predict delayed and significantly delayed treatment responses in patients with first time pulmonary tuberculosis. Changes in TTP values early in treatment were transformed to a response ratio (r). Values of r that were less than a threshold value (r(c)) indicated patients who were at risk of having delayed or significantly delayed response to treatment. Accuracy of prediction was sensitive to the timing of sputum sampling and adherence to therapy in the first 2 weeks. Based on TTP data from the first 2 weeks of treatment, significantly delayed treatment response could be predicted with a sensitivity of 75% and a specificity of 62% while the positive (PPV) and negative predictive values (NPV) were 14% and 97% respectively. While the high NPV indicates that a large proportion of patients with a satisfactory response to treatment can be reliably identified, the low PPV value underlines the need to use TTP in conjunction with other markers of disease activity to predict unfavourable treatment response in tuberculosis treatment.

Differentiation of Mycobacterium tuberculosis complex by PCR amplification of genomic regions of difference

Differentiation of members of the Mycobacterium tuberculosis complex by conventional mycobacteriological methods is time consuming, making surveillance of species-specific disease difficult. A two-step, multiplex polymerase chain reaction (PCR) method based on genomic regions of difference (RD1, RD1(mic), RD2(seal), RD4, RD9 and RD12) was developed for the differentiation of M. canettii, M. tuberculosis, M. africanum, M. microti, M. pinnipedii, M. caprae, M. bovis and M. bovis BCG. The size of the respective multiplex PCR amplification products corresponded to the presence of the different M. tuberculosis complex members. This method allows for rapid differentiation, making it suitable for routine laboratories and surveillance purposes.

Replacement of the lysine residue in the consensus ATP-binding sequence of the AddA subunit of AddAB drastically affects chromosomal recombination in transformation and transduction of Bacillus subtilis

The ATP-dependent deoxyribonuclease enzyme complex (AddAB) of Bacillus subtilis possesses two consensus ATP-binding sequences, located in the N-terminal region of both subunits. The highly conserved lysine residues in both consensus ATP-binding sequences were replaced by glycine, resulting in the mutant enzyme complexes AddAB-A-K36G (AddA*B) and AddAB-B-K14G (AddAB*). The mutation in subunit AddA reduced DNA repair and chromosomal transformation, and abolished bacteriophage PBS1-mediated transduction. This mutation also resulted in a complete loss of the ATP-dependent exonuclease and helicase activity. In contrast, the mutation in subunit AddB had only marginal effects. The recF and addAB genes are not required for transformation with plasmid DNA, but have overlapping activities in transformation with chromosomal DNA. By contrast to RecF, the AddAB enzyme is essential for PBS1-mediated transduction. However, recF has a more important function with respect to DNA repair than addAB.

Cosmid contigs from the tuberous sclerosis candidate region on chromosome 9q34

Tuberous sclerosis (TSC) is a heterogeneous multisystem disorder with loci on 9q34 (TSC1) and 16p13.3 (TSC2). The TSC2 gene has recently been isolated, while the TSC1 gene has been mapped to a 5-cM region between the markers D9S149 and D9S114. In our effort to localise and clone TSC1, we have obtained three adjacent cosmid contigs that cover the core of the candidate region. The three contigs comprise approximately 600 kb and include 80 cosmids, 2 P1 clones, 1 YAC, 5 anonymous markers and 4 sequence-tagged sites. The ABO blood group locus, the Surfeit gene cluster, the dopamine beta-hydroxylase gene (DBH) and VAV2, a homologue of the vav oncogene, have all been mapped within the contigs. Exon trapping and mutation screening experiments, aimed at identifying the TSC1 gene, are currently in progress.

Refined localization of TSC1 by combined analysis of 9q34 and 16p13 data in 14 tuberous sclerosis families

Tuberous sclerosis (TSC) is a heterogeneous trait. Since 1990, linkage studies have yielded putative TSC loci on chromosomes 9, 11, 12 and 16. Our current analysis, performed on 14 Dutch and British families, reveals only evidence for loci on chromosome 9q34 (TSC1) and chromosome 16p13 (TSC2). We have found no indication for a third locus for TSC, linked or unlinked to either of these chromosomal regions. The majority of our families shows linkage to chromosome 9. We have refined the candidate region for TSC1 to a region of approximately 5 cM between ABL and ABO.