Dynamics of Cough Frequency in Adults Undergoing Treatment for Pulmonary Tuberculosis

Background

Cough is the major determinant of tuberculosis transmission. Despite this, there is a paucity of information regarding characteristics of cough frequency throughout the day and in response to tuberculosis therapy. Here we evaluate the circadian cycle of cough, cough frequency risk factors, and the impact of appropriate treatment on cough and bacillary load.

Methods

We prospectively evaluated human immunodeficiency virus-negative adults (n = 64) with a new diagnosis of culture-proven, drug-susceptible pulmonary tuberculosis immediately prior to treatment and repeatedly until treatment day 62. At each time point, participant cough was recorded (n = 670) and analyzed using the Cayetano Cough Monitor. Consecutive coughs at least 2 seconds apart were counted as separate cough episodes. Sputum samples (n = 426) were tested with microscopic-observation drug susceptibility broth culture, and in culture-positive samples (n = 252), the time to culture positivity was used to estimate bacillary load.

Results

The highest cough frequency occurred from 1 pm to 2 pm, and the lowest from 1 am to 2 am (2.4 vs 1.1 cough episodes/hour, respectively). Cough frequency was higher among participants who had higher sputum bacillary load (P < .01). Pretreatment median cough episodes/hour was 2.3 (interquartile range [IQR], 1.2-4.1), which at 14 treatment days decreased to 0.48 (IQR, 0.0-1.4) and at the end of the study decreased to 0.18 (IQR, 0.0-0.59) (both reductions P < .001). By 14 treatment days, the probability of culture conversion was 29% (95% confidence interval, 19%-41%).

Conclusions

Coughs were most frequent during daytime. Two weeks of appropriate treatment significantly reduced cough frequency and resulted in one-third of participants achieving culture conversion. Thus, treatment by 2 weeks considerably diminishes, but does not eliminate, the potential for airborne tuberculosis transmission.

Genetic diversity of Mycobacterium tuberculosis in Peru and exploration of phylogenetic associations with drug resistance

Background

There is limited available data on the strain diversity of M tuberculosis in Peru, though there may be interesting lessons to learn from a setting where multidrug resistant TB has emerged as a major problem despite an apparently well-functioning DOTS control programme.

Methods

Spoligotyping was undertaken on 794 strains of M tuberculosis collected between 1999 and 2005 from 553 community-based patients and 241 hospital-based HIV co-infected patients with pulmonary tuberculosis in Lima, Peru. Phylogenetic and epidemiologic analyses permitted identification of clusters and exploration of spoligotype associations with drug resistance.

Results

Mean patient age was 31.9 years, 63% were male and 30.4% were known to be HIV+. Rifampicin mono-resistance, isoniazid mono-resistance and multidrug resistance (MDR) were identified in 4.7%, 8.7% and 17.3% of strains respectively. Of 794 strains from 794 patients there were 149 different spoligotypes. Of these there were 27 strains (3.4%) with novel, unique orphan spoligotypes. 498 strains (62.7%) were clustered in the nine most common spoligotypes: 16.4% SIT 50 (clade H3), 12.3% SIT 53 (clade T1), 8.3% SIT 33 (LAM3), 7.4% SIT 42 (LAM9), 5.5% SIT 1 (Beijing), 3.9% SIT 47 (H1), 3.0% SIT 222 (clade unknown), 3.0% SIT1355 (LAM), and 2.8% SIT 92 (X3). Amongst HIV-negative community-based TB patients no associations were seen between drug resistance and specific spoligotypes; in contrast HIV-associated MDRTB, but not isoniazid or rifampicin mono-resistance, was associated with SIT42 and SIT53 strains.

Conclusion

Two spoligotypes were associated with MDR particularly amongst patients with HIV. The MDR-HIV association was significantly reduced after controlling for SIT42 and SIT53 status; residual confounding may explain the remaining apparent association. These data are suggestive of a prolonged, clonal, hospital-based outbreak of MDR disease amongst HIV patients but do not support a hypothesis of strain-specific propensity for the acquisition of resistance-conferring mutations.

Postmortem findings and opportunistic infections in HIV-positive patients from a public hospital in Peru

There is a paucity of HIV autopsy data from South America and none that document the postmortem findings in patients with HIV/AIDS in Peru. The purpose of this autopsy study was to determine the spectrum of opportunistic infections and the causes of mortality in HIV-positive patients at a public hospital in Lima. Clinico-epidemiological information regarding HIV infection in Peru is also reviewed. Sixteen HIV-related hospital postmortems, performed between 1999 and 2004, were included in this retrospective analysis. The primary cause of death was established in 12 patients: one died of neoplasia and 11 of infectious diseases, including 3 from pulmonary infection, 7 from disseminated infection, and 2 from central nervous system infection (one case had dual pathology). Opportunistic infections were identified in 14 cases, comprising cytomegalovirus, histoplasmosis, cryptococcosis, toxoplasmosis, Pneumocystis pneumonia, aspergillosis, tuberculosis, varicella zoster virus, and cryptosporidiosis. Fourteen patients had at least one AIDS-related disease that had been neither clinically suspected nor diagnosed premortem. Moreover, 82% of the diagnoses considered to be of important clinical significance had not been suspected antemortem. The spectrum and frequency of certain opportunistic infections differed from other South American autopsy studies, highlighting the importance of performing HIV/AIDS postmortems in resource-limited countries where locally specific disease patterns may be observed.

Tuberculosis in household contacts of multidrug-resistant tuberculosis patients

SETTING

The burden of tuberculosis (TB) disease among household contacts of multidrug-resistant TB (MDR-TB) patients is poorly understood and might represent a target for transmission-interrupting interventions.

DESIGN

This retrospective cohort study, conducted in Lima, Peru, from June to September 2008, estimated the incidence of TB disease among household contacts of MDR-TB patients in 358 households.

RESULTS

Of 2112 household contacts in 80 households (22% of households), 108 (5%) developed TB disease during the study, giving an incidence rate of 2360 per 100 000 contact follow-up years for each of the first 3 years after exposure. Drug susceptibility tests (DST) were available for 50 diseased contacts, of whom 36 (80%) had MDR-TB. Forty-two pairs of index-contact DSTs were available, among which the contact had an identical or less resistant phenotype than the index case in 27 pairs. Multivariate Cox regression demonstrated that male contacts (hazard ratio [HR] 2.8, P < 0.05), with previous TB disease (HR 20.7, P < 0.001) and with associated (non-human immunodeficiency virus) comorbidities (HR 11.2, P < 0.001) were more likely to develop TB.

CONCLUSION

The high percentage of diseased household contacts highlights an opportunity for household-level interventions to prevent transmission, whether or not these cases were all attributable to the index case.

Improved diagnosis of pleural tuberculosis using the microscopic- observation drug-susceptibility technique

Tests for pleural tuberculosis are insensitive and expensive. We compared nonproprietary microscopic-observation drug-susceptibility (MODS) culture with Löwenstein-Jensen culture for evaluation of pleural specimens. MODS culture was associated with greatly increased diagnostic sensitivity and shorter time to diagnosis, compared with Löwenstein-Jensen culture (sensitivity of culture of biopsy specimens, 81% vs.51%; time to diagnosis, 11 days vs. 24 days; P < .001). The MODS technique is inexpensive, allows drug-susceptibility testing, and is a considerably improved diagnostic method for pleural tuberculosis.

The effect of surgery on the outcome of treatment for multidrug-resistant tuberculosis: a systematic review and meta-analysis

BACKGROUND

In 2014 only 50 % of multidrug-resistant tuberculosis (MDR-TB) patients achieved a successful treatment outcome. With limited options for medical treatment, surgery has re-emerged as an adjuvant therapeutic strategy. We conducted a systematic review and meta-analysis to assess the evidence for the effect of surgery as an adjunct to chemotherapy on outcomes of adults treated for MDR-TB.

METHODS

Databases and grey literature sources were searched using terms incorporating surgery and MDR-TB. No language or publication type limits were applied. Articles published pre-1990, without a comparator group, or reporting <10 surgical participants were excluded. Two-stage sifting in duplicate was employed. Data on WHO-defined treatment outcomes were abstracted into a standardised database. Study-level risk of bias was evaluated using standardised tools. Outcome-level evidence quality was assessed using GRADE. Forest plots were generated, random effects meta-analysis conducted, and heterogeneity assessed using the I(2) statistic.

RESULTS

Of 1024 unique citations identified, 62 were selected for full-text review and 15 retained for inclusion. A further four articles were included after bibliography/citation searching, and one additional unpublished manuscript was identified, giving 20 articles for final inclusion. Six were meta-analyses/systematic reviews and 14 were primary research articles (observational studies). From the 14 primary research articles, a successful outcome (cured/treatment completed) was reported for 81.9 % (371/453) and 59.7 % (1197/2006) in the surgical and non-surgical group respectively, giving a summary odds ratio of 2.62 (95 % confidence interval 1.94-3.54). Loss to follow-up and treatment failure were lower in the surgery group (both p = 0.01). Overall GRADE quality of evidence for all outcomes considered was "very low".

CONCLUSIONS

This meta-analysis suggests that surgery as an adjunct to chemotherapy is associated with improved treatment outcomes in MDR-TB patients. However, inherent limitations in observational study design, insufficient reporting, and lack of adjustment for confounders, led to grading of the evidence as very low quality. Data on rationale for surgical referral, subsequent outcomes and resource-limited settings are scarce, precluding evidence-based recommendations on the suitability of surgery by patient characteristics or setting. It is hoped that highlighted methodological and reporting gaps will encourage improved design and reporting of future surgical studies for MDR-TB.

Genomic signatures of pre-resistance in Mycobacterium tuberculosis

Recent advances in bacterial whole-genome sequencing have resulted in a comprehensive catalog of antibiotic resistance genomic signatures in Mycobacterium tuberculosis. With a view to pre-empt the emergence of resistance, we hypothesized that pre-existing polymorphisms in susceptible genotypes (pre-resistance mutations) could increase the risk of becoming resistant in the future. We sequenced whole genomes from 3135 isolates sampled over a 17-year period. After reconstructing ancestral genomes on time-calibrated phylogenetic trees, we developed and applied a genome-wide survival analysis to determine the hazard of resistance acquisition. We demonstrate that M. tuberculosis lineage 2 has a higher risk of acquiring resistance than lineage 4, and estimate a higher hazard of rifampicin resistance evolution following isoniazid mono-resistance. Furthermore, we describe loci and genomic polymorphisms associated with a higher risk of resistance acquisition. Identifying markers of future antibiotic resistance could enable targeted therapy to prevent resistance emergence in M. tuberculosis and other pathogens.

Designing and Evaluating Interventions to Halt the Transmission of Tuberculosis

To reduce the incidence of tuberculosis, it is insufficient to simply understand the dynamics of tuberculosis transmission. Rather, we must design and rigorously evaluate interventions to halt transmission, prioritizing those interventions most likely to achieve population-level impact. Synergy in reducing tuberculosis transmission may be attainable by combining interventions that shrink the reservoir of latent Mycobacterium tuberculosis infection (preventive therapy), shorten the time between disease onset and treatment initiation (case finding and diagnosis), and prevent transmission in key settings, such as the built environment (infection control). In evaluating efficacy and estimating population-level impact, cluster-randomized trials and mechanistic models play particularly prominent roles. Historical and contemporary evidence suggests that effective public health interventions can halt tuberculosis transmission, but an evidence-based approach based on knowledge of local epidemiology is necessary for success. We provide a roadmap for designing, evaluating, and modeling interventions to interrupt the process of transmission that fuels a diverse array of tuberculosis epidemics worldwide.

Novel developments in the epidemic of human immunodeficiency virus and tuberculosis coinfection

Tuberculosis (TB) disease remains one of the highest causes of mortality in HIV-infected individuals, and HIV-TB coinfection continues to grow at alarming rates, especially in sub-Saharan Africa. Surprisingly, a number of important areas regarding coinfection remain unclear. For example, increased risk of TB disease begins early in the course of HIV infection; however, the mechanism by which HIV increases this risk is not well understood. In addition, there is lack of consensus on the optimal way to diagnose latent TB infection and to manage active disease in those who are HIV infected. Furthermore, effective point-of-care testing for TB disease remains elusive. This review discusses key areas in the epidemiology, pathogenesis, diagnosis, and management of active and latent TB in those infected with HIV, focusing attention on issues related to high- and low-burden areas. Particular emphasis is placed on controversial areas where there are gaps in knowledge and on future directions of study.

Challenges with scale-up of GeneXpert MTB/RIF® in Uganda: a health systems perspective

BACKGROUND

Many high burden countries are scaling-up GeneXpert® MTB/RIF (Xpert) testing for tuberculosis (TB) using a hub-and-spoke model. However, the effect of scale up on reducing TB has been limited. We sought to characterize variation in implementation of referral-based Xpert TB testing across Uganda, and to identify health system factors that may enhance or prevent high-quality implementation of Xpert testing services.

METHODS

We conducted a cross-sectional study triangulating quantitative and qualitative data sources at 23 community health centers linked to one of 15 Xpert testing sites between November 2016 and May 2017 to assess health systems infrastructure for hub-and-spoke Xpert testing. Data sources included a standardized site assessment survey, routine TB notification data, and field notes from site visits.

RESULTS

Challenges with Xpert implementation occurred at every step of the diagnostic evaluation process, leading to low overall uptake of testing. Of 2192 patients eligible for TB testing, only 574 (26%) who initiated testing were referred for Xpert testing. Of those, 54 (9.4%) were Xpert confirmed positive just under half initiated treatment within 14 days (n = 25, 46%). Gaps in required infrastructure at 23 community health centers to support the hub-and-spoke system included lack of refrigeration (n = 14, 61%) for sputum testing and lack of telephone/mobile communication (n = 21, 91%). Motorcycle riders responsible for transporting sputum to Xpert sites operated variable with trips once, twice, or three times a week at 10 (43%), nine (39%) and four (17%) health centers, respectively. Staff recorded Xpert results in the TB laboratory register at only one health center and called patients with positive results at only two health centers. Of the 15 Xpert testing sites, five (33%) had at least one non-functioning module. The median number of tests per day was 3.57 (IQR 2.06-4.54), and 10 (67%) sites had error/invalid rates > 5%.

CONCLUSIONS

Although Xpert devices are now widely distributed throughout Uganda, health system factors across the continuum from test referral to results reporting and treatment initiation preclude effective implementation of Xpert testing for patients presenting to peripheral health centers. Support for scale up of innovative technologies should include support for communication, coordination and health systems integration.

TB-PRACTECAL: study protocol for a randomised, controlled, open-label, phase II-III trial to evaluate the safety and efficacy of regimens containing bedaquiline and pretomanid for the treatment of adult patients with pulmonary multidrug-resistant tuberculosis

BACKGROUND

Globally rifampicin-resistant tuberculosis disease affects around 460,000 people each year. Currently recommended regimens are 9-24 months duration, have poor efficacy and carry significant toxicity. A shorter, less toxic and more efficacious regimen would improve outcomes for people with rifampicin-resistant tuberculosis.

METHODS

TB-PRACTECAL is an open-label, randomised, controlled, phase II/III non-inferiority trial evaluating the safety and efficacy of 24-week regimens containing bedaquiline and pretomanid to treat rifampicin-resistant tuberculosis. Conducted in Uzbekistan, South Africa and Belarus, patients aged 15 and above with rifampicin-resistant pulmonary tuberculosis and requiring a new course of therapy were eligible for inclusion irrespective of HIV status. In the first stage, equivalent to a phase IIB trial, patients were randomly assigned one of four regimens, stratified by site. Investigational regimens include oral bedaquiline, pretomanid and linezolid. Additionally, two of the regimens also included moxifloxacin (arm 1) and clofazimine (arm 2) respectively. Treatment was administered under direct observation for 24 weeks in investigational arms and 36 to 96 weeks in the standard of care arm. The second stage of the study was equivalent to a phase III trial, investigating the safety and efficacy of the most promising regimen/s. The primary outcome was the percentage of unfavourable outcomes at 72 weeks post-randomisation. This was a composite of early treatment discontinuation, treatment failure, recurrence, lost-to-follow-up and death. The study is being conducted in accordance with ICH-GCP and full ethical approval was obtained from Médecins sans Frontières ethical review board, London School of Hygiene and Tropical Medicine ethical review board as well as ERBs and regulatory authorities at each site.

DISCUSSION

TB-PRACTECAL is an ambitious trial using adaptive design to accelerate regimen assessment and bring novel treatments that are effective and safe to patients quicker. The trial took a patient-centred approach, adapting to best practice guidelines throughout recruitment. The implementation faced significant challenges from the COVID-19 pandemic. The trial was terminated early for efficacy on the advice of the DSMB and will report on data collected up to the end of recruitment and, additionally, the planned final analysis at 72 weeks after the end of recruitment.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02589782. Registered on 28 October 2015.

Ebola exposure, illness experience, and Ebola antibody prevalence in international responders to the West African Ebola epidemic 2014-2016: A cross-sectional study

BACKGROUND

Healthcare and other front-line workers are at particular risk of infection with Ebola virus (EBOV). Despite the large-scale deployment of international responders, few cases of Ebola virus disease have been diagnosed in this group. Since asymptomatic or pauci-symptomatic infection has been described, it is plausible that infections have occurred in healthcare workers but have escaped being diagnosed. We aimed to assess the prevalence of asymptomatic or pauci-symptomatic infection, and of exposure events, among returned responders to the West African Ebola epidemic 2014-2016.

METHODS AND FINDINGS

We used snowball sampling to identify responders who had returned to the UK or Ireland, and used an online consent and questionnaire to determine their exposure to EBOV and their experience of illness. Oral fluid collection devices were sent and returned by post, and samples were tested using an EBOV IgG capture assay that detects IgG to Ebola glycoprotein. Blood was collected from returnees with reactive samples for further testing. Unexposed UK controls were also recruited. In all, 300 individuals consented, of whom 268 (89.3%) returned an oral fluid sample (OFS). The majority had worked in Sierra Leone in clinical, laboratory, research, and other roles. Fifty-three UK controls consented and provided samples using the same method. Of the returnees, 47 (17.5%) reported that they had had a possible EBOV exposure. Based on their free-text descriptions, using a published risk assessment method, we classified 43 (16%) as having had incidents with risk of Ebola transmission, including five intermediate-risk and one high-risk exposure. Of the returnees, 57 (21%) reported a febrile or diarrhoeal illness in West Africa or within 1 mo of return, of whom 40 (70%) were not tested at the time for EBOV infection. Of the 268 OFSs, 266 were unreactive. Two returnees, who did not experience an illness in West Africa or on return, had OFSs that were reactive on the EBOV IgG capture assay, with similar results on plasma. One individual had no further positive test results; the other had a positive result on a double-antigen bridging assay but not on a competitive assay or on an indirect EBOV IgG ELISA. All 53 controls had non-reactive OFSs. While the participants were not a random sample of returnees, the number participating was high.

CONCLUSIONS

This is the first study, to our knowledge, of the prevalence of EBOV infection in international responders. More than 99% had clear negative results. Sera from two individuals had discordant results on the different assays; both were negative on the competitive assay, suggesting that prior infection was unlikely. The finding that a significant proportion experienced "near miss" exposure events, and that most of those who experienced symptoms did not get tested for EBOV at the time, suggests a need to review and standardise protocols for the management of possible exposure to EBOV, and for the management of illness, across organisations that deploy staff to outbreaks.

The effect of early versus late treatment initiation after diagnosis on the outcomes of patients treated for multidrug-resistant tuberculosis: a systematic review

BACKGROUND

Globally it is estimated that 480 000 people developed multidrug-resistant tuberculosis (MDR-TB) in 2014 and 190 000 people died from the disease. Successful treatment outcomes are achieved in only 50 % of patients with MDR-TB, compared to 86 % for drug susceptible disease. It is widely held that delay in time to initiation of treatment for MDR-TB is an important predictor of treatment outcome. The objective of this review was to assess the existing evidence on the outcomes of multidrug- and extensively drug-resistant tuberculosis patients treated early (≤4 weeks) versus late (>4 weeks) after diagnosis of drug resistance.

METHODS

Eight sources providing access to 17 globally representative electronic health care databases, indexes, sources of evidence-based reviews and grey literature were searched using terms incorporating time to treatment and MDR-TB. Two-stage sifting in duplicate was employed to assess studies against pre-specified inclusion and exclusion criteria. Only those articles reporting WHO-defined treatment outcomes were considered for inclusion. Articles reporting on fewer than 10 patients, published before 1990, or without a comparison of outcomes in patient groups experiencing different delays to treatment initiation were excluded.

RESULTS

The initial search yielded 1978 references, of which 1475 unique references remained after removal of duplicates and 28 articles published pre-1990. After title and abstract sifting, 64 papers underwent full text review. None of these articles fulfilled the criteria for inclusion in the review.

CONCLUSIONS

Whilst there is an inherent logic in the theory that treatment delay will lead to poorer treatment outcomes, no published evidence was identified in this systematic review to support this hypothesis. Reports of programmatic changes leading to reductions in treatment delay exist in the literature, but attribution of differences in outcomes specifically to treatment delay is confounded by other contemporaneous changes. Further primary research on this question is not considered a high priority use of limited resources, though where data are available, improved reporting of outcomes by time to treatment should be encouraged.

Development of low-cost inverted microscope to detect early growth of Mycobacterium tuberculosis in MODS culture

Background

The microscopic observation drug susceptibility (MODS) assay for rapid, low-cost detection of tuberculosis and multidrug resistant tuberculosis depends upon visualization of the characteristic cording colonies of Mycobacterium tuberculosis in liquid media. This has conventionally required an inverted light microscope in order to inspect the MODS culture plates from below. Few tuberculosis laboratories have this item and the capital cost of $5,000 for a high-end microscope could be a significant obstacle to MODS roll-out.

Methodology

We hypothesized that the precise definition provided by costly high-specification inverted light microscopes might not be necessary for pattern recognition.

Significance

In this work we describe the development of a low-cost artesenal inverted microscope that can operate in both a standard or digital mode to effectively replace the expensive commercial inverted light microscope, and an integrated system that could permit a local and remote diagnosis of tuberculosis.

Infrequent MODS TB culture cross-contamination in a high-burden resource-poor setting

One obstacle to wider use of rapid liquid culture-based tuberculosis diagnostics such as the microscopic observation drug susceptibility (MODS) assay is concern about cross-contamination. We investigated the rate of laboratory cross-contamination in MODS, automated MBBacT, and Lowenstein-Jensen (LJ) cultures performed in parallel, through triangulation of microbiologic (reculturing stored samples), molecular (spoligotype/RFLP), and clinical epidemiologic data. At least 1 culture was positive for Mycobacterium tuberculosis for 362 (11%) of 3416 samples; 53 were regarded as potential cross-contamination suspects. Cross-contamination accounted for 17 false-positive cultures from 14 samples representing 0.41% (14/3416) and 0.17% (17/10248) of samples and cultures, respectively. Positive predictive values for MODS, MBBacT (bioMérieux, Durham, NC), and LJ were 99.1%, 98.7%, and 99.7%, and specificity was 99.9% for all 3. Low rates of cross-contamination are achievable in mycobacterial laboratories in resource-poor settings even when a large proportion of samples are infectious and highly sensitive liquid culture-based diagnostics such as MODS are used.

Convergent evolution and topologically disruptive polymorphisms among multidrug-resistant tuberculosis in Peru

BACKGROUND

Multidrug-resistant tuberculosis poses a major threat to the success of tuberculosis control programs worldwide. Understanding how drug-resistant tuberculosis evolves can inform the development of new therapeutic and preventive strategies.

METHODS

Here, we use novel genome-wide analysis techniques to identify polymorphisms that are associated with drug resistance, adaptive evolution and the structure of the phylogenetic tree. A total of 471 samples from different patients collected between 2009 and 2013 in the Lima suburbs of Callao and Lima South were sequenced on the Illumina MiSeq platform with 150bp paired-end reads. After alignment to the reference H37Rv genome, variants were called using standardized methodology. Genome-wide analysis was undertaken using custom written scripts implemented in R software.

RESULTS

High quality homoplastic single nucleotide polymorphisms were observed in genes known to confer drug resistance as well as genes in the Mycobacterium tuberculosis ESX secreted protein pathway, pks12, and close to toxin/anti-toxin pairs. Correlation of homoplastic variant sites identified that many were significantly correlated, suggestive of epistasis. Variation in genes coding for ESX secreted proteins also significantly disrupted phylogenetic structure. Mutations in ESX genes in key antigenic epitope positions were also found to disrupt tree topology.

CONCLUSION

Variation in these genes have a biologically plausible effect on immunogenicity and virulence. This makes functional characterization warranted to determine the effects of these polymorphisms on bacterial fitness and transmission.

What can we offer to 3 million MDRTB household contacts in 2016?

The diagnosis of multidrug resistant tuberculosis (MDR-TB) in any individual is the beginning of a prolonged and difficult therapeutic journey. It also marks the moment from which to begin consideration of how to manage close contacts. Preventive therapy for drug-susceptible latent tuberculosis infection has been demonstrated to be effective at reducing the risk of future disease; the stakes are higher when considering prevention of MDR-TB because treatment of active disease is more prolonged and toxic and much less effective. This has encouraged exploration of the potential utility of preventive therapy, with second-line agents, in reducing future incident drug-resistant TB.Three clinical trials of preventive therapy for contacts of patients with MDR-TB are starting in 2015/16; results will not be available until at least 2020, so what should be offered to exposed contacts in the interim?A recent policy brief, arising from a global consultation meeting of international experts, recommended preventive therapy based upon very limited available observational data. However the many known unknowns associated with this approach, include the high proportion of index-contact pairs with discordant drug susceptibility profiles and (even if susceptibilities are shared) the lack of data supporting the use of the selected agents in the treatment of latent infection (rather than active disease).It is important to acknowledge that the alternative to offering preventive therapy is not doing nothing. On the contrary, identified contacts should be maintained under close, active surveillance for 24 months, enabling early detection of active disease in the small proportion amongst whom this may occur. Such patients should benefit from less extensive disease at diagnosis and early access to individualized therapeutic regimens with improved treatment outcomes. Moreover the vast majority of contacts that do not develop disease will benefit from avoidance of potentially toxic, unnecessary therapy.Whether preventive therapy or close observation are implemented, national programmes should maintain a register of all contacts, interventions and 24 month outcomes; these will provide important performance metrics for programmatic management of MDRTB. If harmonized and standardized internationally, such a register could rapidly yield a wealth of observational data, to complement the trial results of the future.

Alternative methods of diagnosing drug resistance--what can they do for me?

During the last decade considerable attention has been focussed upon the development of new technologies and methodologies for detection of drug resistance in Mycobacterium tuberculosis. There is a growing acknowledgement that the redundancy in testing a full panel of first-line drugs is an unaffordable indulgence; since only resistance at baseline to either (or both) of the two most potent agents, isoniazid (H) and rifampicin (R), would usually prompt therapeutic modification there is a shift towards initial RH (or R alone for selected genotypic technologies) drug susceptibility testing (DST) followed, if necessary by further extended first and second line agent (currently phenotypic) DST. Most of the new drug susceptibility tests endorsed by the World Health Organization since 2007 deliver rapid RH (or R alone for selected genotypic technologies) DST. Targeting of patient groups with risk factors for drug resistance increases the proportion of tests that identify drug resistance, but in many settings at least as many patients with drug resistant disease will have no identifiable risk factors--equity of care demands that universal RH DST at baseline should be the goal. We review the bewildering array of choices facing TB program directors and attempt to provide objective information to help in deciding what tools may be best suited to different environments.

Microscopic observation drug susceptibility assay for tuberculosis screening before isoniazid preventive therapy in HIV-infected persons

BACKGROUND

Active tuberculosis (TB) must be excluded before initiating isoniazid preventive therapy (IPT) in persons infected with human immunodeficiency virus (HIV), but currently used screening strategies have poor sensitivity and specificity and high patient attrition rates. Liquid TB culture is now recommended for the detection of Mycobacterium tuberculosis in individuals suspected of having TB. This study compared the efficacy, effectiveness, and speed of the microscopic observation drug susceptibility (MODS) assay with currently used strategies for TB screening before IPT in HIV-infected persons.

METHODS

A total of 471 HIV-infected IPT candidates at 3 hospitals in Lima, Peru, were enrolled in a prospective comparison of TB screening strategies, including laboratory, clinical, and radiographic assessments.

RESULTS

Of 435 patients who provided 2 sputum samples, M. tuberculosis was detected in 27 (6.2%) by MODS culture, 22 (5.1%) by Lowenstein-Jensen culture, and 7 (1.6%) by smear. Of patients with any positive microbiological test result, a MODS culture was positive in 96% by 14 days and 100% by 21 days. The MODS culture simultaneously detected multidrug-resistant TB in 2 patients. Screening strategies involving combinations of clinical assessment, chest radiograph, and sputum smear were less effective than 2 liquid TB cultures in accurately diagnosing and excluding TB (P<.01). Screening strategies that included nonculture tests had poor sensitivity and specificity.

CONCLUSIONS

MODS culture identified and reliably excluded cases of pulmonary TB more accurately than other screening strategies, while providing results significantly faster than Lowenstein-Jensen culture. Streamlining of the ruling out of TB through the use of liquid culture-based strategies could help facilitate the massive up-scaling of IPT required to reduce HIV and TB morbidity and mortality.

Falls, poisonings, burns, and road traffic injuries in urban Peruvian children and adolescents: a community based study

OBJECTIVES

To identify individual and household characteristics associated with serious falls, poisonings, burns and road traffic injuries (RTIs) for children in Lima, Peru.

METHODS

5061 households consisting of 10,210 children were included in this community based, cross-sectional study in San Juan de Miraflores (SJM), a low income, urban district of Lima, Peru. Households were eligible if there was a consenting adult and at least one resident child aged < or =18 years. A door to door survey was conducted in SJM, collecting childhood injury, demographic, and socioeconomic data. Analysis was done at the individual and household level for injuries severe enough to have required medical consultation.

RESULTS

The greatest burden of injury was from falls and RTIs. For individuals, male gender and age were the most important predictors of injuries. Households in which multiple injuries were reported were more likely to be poor (odds ratio (OR) 1.66, 95% CI 1.24 to 2.22) and overcrowded (OR 1.88, 95% CI 1.20 to 2.94). The occurrence of serious falls, poisonings, burns, and pedestrian RTIs significantly increased the likelihood of a second serious injury in the home (adjusted ORs ranged between 1.88 and 2.99).

CONCLUSION

All children from households in which an unintentional injury has occurred appear to have an increased likelihood of future injury; such high risk households may be readily identifiable in the clinical setting. Interventions in this environment designed to prevent subsequent injuries merit further investigation.

Accuracy of diabetes screening methods used for people with tuberculosis, Indonesia, Peru, Romania, South Africa

Objective

To evaluate the performance of diagnostic tools for diabetes mellitus, including laboratory methods and clinical risk scores, in newly-diagnosed pulmonary tuberculosis patients from four middle-income countries.

Methods

In a multicentre, prospective study, we recruited 2185 patients with pulmonary tuberculosis from sites in Indonesia, Peru, Romania and South Africa from January 2014 to September 2016. Using laboratory-measured glycated haemoglobin (HbA1c) as the gold standard, we measured the diagnostic accuracy of random plasma glucose, point-of-care HbA1c, fasting blood glucose, urine dipstick, published and newly derived diabetes mellitus risk scores and anthropometric measurements. We also analysed combinations of tests, including a two-step test using point-of-care HbA1cwhen initial random plasma glucose was ≥ 6.1 mmol/L.

Findings

The overall crude prevalence of diabetes mellitus among newly diagnosed tuberculosis patients was 283/2185 (13.0%; 95% confidence interval, CI: 11.6–14.4). The marker with the best diagnostic accuracy was point-of-care HbA1c (area under receiver operating characteristic curve: 0.81; 95% CI: 0.75–0.86). A risk score derived using age, point-of-care HbA1c and random plasma glucose had the best overall diagnostic accuracy (area under curve: 0.85; 95% CI: 0.81–0.90). There was substantial heterogeneity between sites for all markers, but the two-step combination test performed well in Indonesia and Peru.

Conclusion

Random plasma glucose followed by point-of-care HbA1c testing can accurately diagnose diabetes in tuberculosis patients, particularly those with substantial hyperglycaemia, while reducing the need for more expensive point-of-care HbA1c testing. Risk scores with or without biochemical data may be useful but require validation.

Second-line anti-tuberculosis drug concentrations for susceptibility testing in the MODS assay

Multidrug-resistant tuberculosis (TB) threatens TB control worldwide. The microscopic observation drug susceptibility (MODS) assay is a low-cost, high-performance TB diagnostic tool for rapid liquid culture and direct isoniazid and rifampicin drug susceptibility testing (DST). The objective of this study was to explore the potential for extending the MODS assay to rapid second-line DST and to identify critical concentrations of candidate drugs for prospective testing. Sputum samples from 94 TB culture-positive patients receiving second-line TB agents were cultured following standardised MODS protocols, with a range of titrations of antimicrobial drugs added. Critical concentrations were determined using a modified Kaplan-Meier survival curve analysis. Candidate critical concentrations were determined for capreomycin (10 μg·mL(-1)), ciprofloxacin (1.25 μg·mL(-1)), cycloserine (40 μg·mL(-1)), ethambutol (10 μg·mL(-1)), ethionamide (5 μg·mL(-1)), kanamycin (5 μg·mL(-1)), para-aminosalicylic acid (10 μg·mL(-1)) and streptomycin (10 μg·mL(-1)). No cut-off point was identified for the other second-line drugs or for pyrazinamide. At particular concentrations of some second-line TB drugs this novel Kaplan-Meier analysis clearly differentiated populations that were susceptible or resistant. These candidate critical concentrations should now be tested in a range of epidemiological settings to define the performance of direct, second-line TB DST with MODS, offering potential low-cost second-line TB DST capacity.

Multicomponent Strategy with Decentralized Molecular Testing for Tuberculosis

BACKGROUND

Effective strategies are needed to facilitate the prompt diagnosis and treatment of tuberculosis in countries with a high burden of the disease.

METHODS

We conducted a cluster-randomized trial in which Ugandan community health centers were assigned to a multicomponent diagnostic strategy (on-site molecular testing for tuberculosis, guided restructuring of clinic workflows, and monthly feedback of quality metrics) or routine care (on-site sputum-smear microscopy and referral-based molecular testing). The primary outcome was the number of adults treated for confirmed tuberculosis within 14 days after presenting to the health center for evaluation during the 16-month intervention period. Secondary outcomes included completion of tuberculosis testing, same-day diagnosis, and same-day treatment. Outcomes were also assessed on the basis of proportions.

RESULTS

A total of 20 health centers underwent randomization, with 10 assigned to each group. Of 10,644 eligible adults (median age, 40 years) whose data were evaluated, 60.1% were women and 43.8% had human immunodeficiency virus infection. The intervention strategy led to a greater number of patients being treated for confirmed tuberculosis within 14 days after presentation (342 patients across 10 intervention health centers vs. 220 across 10 control health centers; adjusted rate ratio, 1.56; 95% confidence interval [CI], 1.21 to 2.01). More patients at intervention centers than at control centers completed tuberculosis testing (adjusted rate ratio, 1.85; 95% CI, 1.21 to 2.82), received a same-day diagnosis (adjusted rate ratio, 1.89; 95% CI, 1.39 to 2.56), and received same-day treatment for confirmed tuberculosis (adjusted rate ratio, 2.38; 95% CI, 1.57 to 3.61). Among 706 patients with confirmed tuberculosis, a higher proportion in the intervention group than in the control group were treated on the same day (adjusted rate ratio, 2.29; 95% CI, 1.23 to 4.25) or within 14 days after presentation (adjusted rate ratio, 1.22; 95% CI, 1.06 to 1.40).

CONCLUSIONS

A multicomponent diagnostic strategy that included on-site molecular testing plus implementation supports to address barriers to delivery of high-quality tuberculosis evaluation services led to greater numbers of patients being tested, receiving a diagnosis, and being treated for confirmed tuberculosis. (Funded by the National Heart, Lung, and Blood Institute; XPEL-TB ClinicalTrials.gov number, NCT03044158.).

Study protocol: a cluster randomized trial to evaluate the effectiveness and implementation of onsite GeneXpert testing at community health centers in Uganda (XPEL-TB)

BACKGROUND

Delays in diagnosis and treatment of tuberculosis (TB) remain common in high-burden countries. To improve case detection, substantial investments have been made to scale-up Xpert MTB/RIF (Xpert), a cartridge-based nucleic acid amplification test that can detect TB within 2 hours, as a replacement for sputum smear microscopy. However, the optimal strategy for implementation of Xpert testing remains unclear.

METHODS

The Xpert Performance Evaluation for Linkage to Tuberculosis Care (XPEL-TB) trial uses an ultra-pragmatic, hybrid type II effectiveness-implementation design to assess the effectiveness and implementation of a streamlined strategy for delivery of Xpert testing in real-world settings. Twenty health centers with TB microscopy units were selected to participate in the trial, with ten health centers randomized to the intervention strategy (onsite molecular testing using GeneXpert Edge, process redesign to facilitate same-day TB diagnosis and treatment, and performance feedback) or routine care (onsite sputum smear microscopy plus referral of sputum samples to Xpert testing sites). The primary outcome is the number of patients with microbiologically confirmed TB who were initiated on treatment within 14 days of presentation to the health center, which reflects successful completion of the TB diagnostic evaluation process. Secondary outcomes include health outcomes (6-month vital status), as well as measures of the reach, adoption, and implementation of the intervention strategy.

DISCUSSION

The design elements and implementation approach for the XPEL-TB trial were intentionally selected to minimize disruptions to routine care procedures, with the goal of limiting their influence on key primary and secondary outcomes. Trial findings may result in increased support and funding for rapid, onsite molecular testing as the standard-of-care for all patients being evaluated for TB.

TRIAL REGISTRATION

US National Institutes of Health's ClinicalTrials.gov, NCT03044158. Registered 06 February 2017. Pan African Clinical Trials Registry, PACTR201610001763265. Registered 03 September 2016.