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The risk and prognosis of tuberculosis (TB) are affected by both human and bacterial genetic factors. To identify interacting human and bacterial genetic loci, we leveraged paired human andMycobacterium tuberculosis(M.tb) genomic data from 1000 Tanzanian TB patients. Through a genome-to-genome approach, we identified two pairs of human andM.tbgenetic variants that are significantly associated. One of the human genetic variants maps to the intron ofPRDM15, a gene involved in apoptosis regulation. The other human variant maps to an intergenic region close toTIMM21andFBXO15. In addition, we observed that a group of linkedM.tbepitope variants were significantly associated with HLA-DRB1 variation. This suggests that even though epitope variation is rare inM.tbin general, specific epitopes might still be under immune selective pressure. Overall, our study pinpoints sites of genomic conflicts between humans andM.tb, suggesting bacterial escape from host selection pressure.

In settings with high tuberculosis (TB) endemicity, various genotypes of the Mycobacterium tuberculosis complex (MTBC) often differ in prevalence. However, the factors leading to these differences remain poorly understood. Here we studied the MTBC population in Dar es Salaam, Tanzania over a six-year period, using 1,082 unique patient-derived MTBC whole-genome sequences (WGS) and associated clinical data. We show that the TB epidemic in Dar es Salaam is dominated by multiple genotypes introduced to Tanzania from different parts of the world during the last 300 years. The most common MTBC genotypes deriving from these introductions exhibited differences in transmission rates and in the duration of the infectious period, but little differences in overall fitness, as measured by the effective reproductive number. Moreover, measures of disease severity and bacterial load indicated no differences in virulence between these genotypes during active TB. Instead, the combination of an early introduction and a high transmission rate accounted for the high prevalence of L3.1.1, the most dominant MTBC genotype in our setting. Yet, a longer co-existence with the host population did not always result in a higher transmission rate, suggesting that distinct life-history traits have evolved in the different MTBC genotypes. Taken together, our results point to bacterial factors as important determinants of the TB epidemic in Dar es Salaam.Author summaryTuberculosis (TB) is the deadliest human infectious disease caused by one single agent, Mycobacterium tuberculosis (Mtb). The origins of Mtb have been traced to East Africa millennia ago, where it likely became adapted to infect and transmit in humans. Here we show that in Dar es Salaam, Tanzania, an East African setting with a very high burden of TB, infections are caused by distinct Mtb genotypes introduced in recent evolutionary times from different parts of the world. These genotypes differed in traits important to Mtb transmission in the Dar es Salaam host population; while some Mtb genotypes transmitted more efficiently during a certain period of time, others elicited that patients would be infectious for longer periods. These traits evolved independently in the different Mtb genotypes and could not be explained by the time of co-existence between the host population and the pathogen. This suggests that bacterial factors are important determinants of the TB epidemic. More generally, we demonstrate that distinct pathogenic life history characteristics can co-exist in one host population.

Background Patients with clinically suspected tuberculosis are often treated empirically, as diagnosis - especially of extrapulmonary tuberculosis - remains challenging. This leads to an overtreatment of tuberculosis and to underdiagnosis of possible differential diagnoses. Methods This open-label, parallel-group, superiority randomized controlled trial is done in a rural and an urban center in Tanzania. HIV-positive and -negative adults (≥18 years) with clinically suspected extrapulmonary tuberculosis are randomized in a 1:1 ratio to an intervention- or control group, stratified by center and HIV status. The intervention consists of a management algorithm including extended focused assessment of sonography for HIV and tuberculosis (eFASH) in combination with chest X-ray and microbiological tests. Treatment with anti-tuberculosis drugs is started, if eFASH is positive, chest X-ray suggests tuberculosis, or a microbiological result is positive for tuberculosis. Patients in the control group are managed according national guidelines. Treatment is started if microbiology is positive or empirically according to the treating physician. The primary outcome is the proportion of correctly managed patients at 6 months (i.e patients who were treated with anti-tuberculosis treatment and had definite or probable tuberculosis, and patients who were not treated with anti-tuberculosis treatment and did not have tuberculosis). Secondary outcomes are the proportion of symptom-free patients at two and 6 months, and time to death. The sample size is 650 patients. Discussion This study will determine, whether ultrasound in combination with other tests can increase the proportion of correctly managed patients with clinically suspected extrapulmonary tuberculosis, thus reducing overtreatment with anti-tuberculosis drugs. Trial registration PACTR, Registration number: PACTR201712002829221, registered December 1st 2017.

T cell activation markers (TAM) expressed by antigen-specific T cells constitute promising candidates to attest the presence of an active infection by Mycobacterium tuberculosis (Mtb). Reciprocally, their modulation may be used to assess antibiotic treatment efficacy and eventually attest disease resolution. We hypothesized that the phenotype of Mtb-specific T cells may be quantitatively impacted by the load of bacteria present in a patient. We recruited 105 Tanzanian adult tuberculosis (TB) patients and obtained blood before and after 5 months of antibiotic treatment. We studied relationships between patients’ clinical characteristics of disease severity and microbiological as well as molecular proxies of bacterial load in sputum at the time of diagnosis. Besides, we measured by flow cytometry the expression of CD38 or CD27 on CD4+ T cells producing interferon gamma (IFN-γ) and/or tumor necrosis factor-alpha (TNF-α) in response to a synthetic peptide pool covering the sequences of Mtb antigens ESAT-6, CFP-10 and TB10.4. Reflecting the difficulty to extrapolate bacterial burden from a single end-point read-out, we observed statistically significant, but weak, correlations between Xpert MTB/RIF, MBLA and time to culture positivity. Unlike CD27, the resolution of CD38 expression by antigen-specific T cells was observed readily following 5 months of antibiotic therapy. In addition, only the intensity of CD38-TAM signals measured at diagnosis significantly correlated with Mtb 16S RNA recovered from patients’ sputa. Altogether, our data support CD38-TAM as an accurate marker of infection resolution and a sputum-independent proxy of bacterial load.

Background Patients with suspected extrapulmonary tuberculosis are often treated empirically. We hypothesized that extended focused assessment with sonography for human immunodeficiency virus (HIV) and tuberculosis (eFASH), in combination with other tests, would increase the proportion of correctly managed patients with suspected extrapulmonary tuberculosis. Methods This trial in adults with suspected extrapulmonary tuberculosis was performed in a rural and an urban hospital in Tanzania. Participants were randomized 1:1 to intervention or routine care, stratified by site and HIV status. All participants underwent clinical evaluation, chest radiography, and testing with sputum Xpert MTB/RIF and urine Xpert MTB/RIF Ultra assays. The intervention was a management algorithm based on results of eFASH plus microbiology, adenosine deaminase (ADA), and chest radiography. The primary outcome was the proportion of correctly managed patients. The presence of positive microbiological or ADA results defined definite tuberculosis. An independent end-point review committee determined diagnoses of probable or no tuberculosis. We evaluated outcomes using logistic regression models, adjusted for randomization stratification factors. Results From September 2018 to October 2020, a total of 1036 patients were screened and 701 were randomized (350 to the intervention and 351 to the control group). Of participants in the intervention group, 251 (72%) had a positive eFASH outcome. In 258 (74%) of the intervention and 227 (65%) of the control participants antituberculosis was initiated treatment at baseline. More intervention participants had definite tuberculosis (n = 124 [35%]), compared with controls (n = 85 [24%]). There was no difference between groups for the primary outcome (intervention group, 266 of 286 [93%]; control group, 245 of 266 [92%]; odds ratio, 1.14 [95% confidence interval: .60–2.16]; P = .68). There were no procedure-associated adverse events. Conclusions eFASH did not change the proportion of correctly managed patients but increased the proportion of those with definite tuberculosis. Clinical Trials Registration Pan African Registry: PACTR201712002829221.

T cell activation markers (TAM) expressed by antigen-specific T cells constitute promising candidates to attest the presence of an active infection by

Genome-wide association studies rely on the statistical inference of untyped variants, called imputation, to increase the coverage of genotyping arrays. However, the results are often suboptimal in populations underrepresented in existing reference panels and array designs, since the selected single nucleotide polymorphisms (SNPs) may fail to capture population-specific haplotype structures, hence the full extent of common genetic variation. Here, we propose to sequence the full genome of a small subset of an underrepresented study cohort to inform the selection of population-specific add-on SNPs, such that the remaining array-genotyped cohort could be more accurately imputed. Using a Tanzania-based cohort as a proof-of-concept, we demonstrate the validity of our approach by showing improvements in imputation accuracy after the addition of our designed addon SNPs to the base H3Africa array.

24 páginas, 3 figuras, 1 tabla. The sequence data generated by this study has been deposited on SRA (https://www.ncbi.nlm.nih.gov/sra) under the accession number PRJNA670836. Extended data is available here: https://github.com/fmenardo/MTBC_L1_L3. DOI: https://doi.org/10.5281/zenodo.4609804 (Menardo, 2021)., Background: Lineage 1 (L1) and 3 (L3) are two lineages of the Mycobacterium tuberculosis complex (MTBC) causing tuberculosis (TB) in humans. L1 and L3 are prevalent around the rim of the Indian Ocean, the region that accounts for most of the world's new TB cases. Despite their relevance for this region, L1 and L3 remain understudied. Methods: We analyzed 2,938 L1 and 2,030 L3 whole genome sequences originating from 69 countries. We reconstructed the evolutionary history of these two lineages and identified genes under positive selection. Results: We found a strongly asymmetric pattern of migration from South Asia toward neighboring regions, highlighting the historical role of South Asia in the dispersion of L1 and L3. Moreover, we found that several genes were under positive selection, including genes involved in virulence and resistance to antibiotics. For L1 we identified signatures of local adaptation at the esxH locus, a gene coding for a secreted effector that targets the human endosomal sorting complex, and is included in several vaccine candidates. Conclusions: Our study highlights the importance of genetic diversity in the MTBC, and sheds new light on two of the most important MTBC lineages affecting humans., This work was supported by the Swiss National Science Foundation (grants 310030_188888, CRSII5_177163, IZRJZ3_164171 and IZLSZ3_170834) and the European Research Council (309540 EVODRTB and 883582-ECOEVODRTB).

Background: The current screening tools for tuberculosis (TB) are inadequate resulting in insufficient TB case detection and continued community transmission of TB.As the world in geared into finding missing TB cases, new strategies are called for to aid in rapid identification of TB cases. This study aimed to evaluate the role C-reactive protein (CRP)in triaging for who to get a definitive test for active pulmonary TB diagnosis in urban Tanzania.Methods: A case–control study was conducted among pulmonary TB (PTB) patients and contacts without active PTB. The diagnosis of PTB was performed using GeneXpert MTB/RIF assay and culture. Blood was collected from cases and controls for measuring CRP levels during recruitment. We compared socio-demographic characteristics, clinical and laboratory parameters obtained during recruitment and performed diagnostic accuracy analyses for CRP. Results: Out of all 193 study participants who were involved in final analysis, 147 (76.2%) were males. Pulmonary TB cases had significantly lower median BMI than controls (median 17.4 kg/m2 [IQR: 15.8–19.2 kg/m2] vs., 24.9 kg/m2 [IQR: 22.1–28.5 kg/m2), p < 0.001). There was no statistical difference in prevalence of HIV between PTB cases and controls i.e., 13.33% vs., 11.7%, p = 0.48. CRP was significantly higher in PTB cases vs., controls (median 67.8 mg/L, [IQR: 36.5– 116.9 mg/L] vs., 1.55 mg/L, [IQR: 0.59–6.0mg/L], p = 0.003). Furthermore, CRP at cut-off ≥ 10mg/L were associated with best combination of sensitivity, specificity and area under the curve of 89.9%, 95% CI: 82.2-95.0, 80.9%, CI: 71.4-88.2 and 0.85, 95%CI: 0.80-0.90 respectively. A multivariate logistic regression model adjusted for fever, night sweats and body mass index showed that CRP above 10mg/L was significantly associated with PTB, aOR 5.2, 95% CI 1.2-22.8. Conclusions: CRP at cut-off ≥ 10mg/L can be used to screen pulmonary TB. These findings can be used to improve TB screening algorithm by incorporating CRP in combination with TB symptoms to identify patients who need further confirmatory TB tests. However, additional prospective studies are required to support our findings and contribute into policy recommendations on use of CRP in a screening algorithm for pulmonary TB.

Each day, approximately 27,000 people become ill with tuberculosis (TB), and 4,000 die from this disease. Pulmonary TB is the main clinical form of TB, and affects the lungs with a considerably heterogeneous manifestation among patients. Immunomodulation by an interplay of host-, environment-, and pathogen-associated factors partially explains such heterogeneity. Microbial communities residing in the host's airways have immunomodulatory effects, but it is unclear if the inter-individual variability of these microbial communities is associated with the heterogeneity of pulmonary TB. Here, we investigated this possibility by characterizing the microbial composition in the sputum of 334 TB patients from Tanzania, and by assessing its association with three aspects of disease manifestations: sputum mycobacterial load, severe clinical findings, and chest x-ray (CXR) findings. Compositional data analysis of taxonomic profiles based on 16S-rRNA gene amplicon sequencing and on whole metagenome shotgun sequencing, and graph-based inference of microbial associations revealed that the airway microbiome of TB patients was shaped by inverse relationships between Streptococcus and two anaerobes: Selenomonas and Fusobacterium. Specifically, the strength of these microbial associations was negatively correlated with Faith's phylogenetic diversity (PD) and with the accumulation of transient genera. Furthermore, low body mass index (BMI) determined the association between abnormal CXRs and community diversity and composition. These associations were mediated by increased abundance of Selenomonas and Fusobacterium, relative to the abundance of Streptococcus, in underweight patients with lung parenchymal infiltrates and in comparison to those with normal chest x-rays. And last, the detection of herpesviruses and anelloviruses in sputum microbial assemblage was linked to co-infection with HIV. Given the anaerobic metabolism of Selenomonas and Fusobacterium, and the hypoxic environment of lung infiltrates, our results suggest that in underweight TB patients, lung tissue remodeling toward anaerobic conditions favors the growth of Selenomonas and Fusobacterium at the expense of Streptococcus. These new insights into the interplay among particular members of the airway microbiome, BMI, and lung parenchymal lesions in TB patients, add a new dimension to the long-known association between low BMI and pulmonary TB. Our results also drive attention to the airways virome in the context of HIV-TB coinfection.

Lineage 1 (L1) and 3 (L3) are two lineages of theMycobacterium tuberculosiscomplex (MTBC), causing tuberculosis (TB) in humans. L1 and L3 are endemic to the Rim of the Indian Ocean, the region that accounts for most of the world’s new TB cases. Despite their relevance for this region, L1 and L3 remain understudied. Here we analyzed 2,938 L1 and 2,030 L3 whole genome sequences originating from 69 countries. We show that South Asia played a central role in the dispersion of these two lineages to neighboring regions. Moreover, we found that L1 exhibits signatures of local adaptation at theesxHlocus, a gene coding for a secreted effector that targets the human endosomal sorting complex, and is included in several vaccine candidates. Our study highlights the importance of genetic diversity in the MTBC, and sheds new light on two of the most important MTBC lineages affecting humans.

Objectives To describe the prevalence of respiratory pathogens in tuberculosis (TB) patients and in their household contact controls, and to determine the clinical significance of respiratory pathogens in TB patients. Methods We studied 489 smear-positive adult TB patients and 305 household contact controls without TB with nasopharyngeal swab samples within an ongoing prospective cohort study in Dar es Salaam, Tanzania, between 2013 and 2015. We used multiplex real-time PCR to detect 16 respiratory viruses and seven bacterial pathogens from nasopharyngeal swabs. Results The median age of the study participants was 33 years; 61% (484/794) were men, and 21% (168/794) were HIV-positive. TB patients had a higher prevalence of HIV (28.6%; 140/489) than controls (9.2%; 28/305). Overall prevalence of respiratory viral pathogens was 20.4% (160/794; 95%CI 17.7–23.3%) and of bacterial pathogens 38.2% (303/794; 95%CI 34.9–41.6%). TB patients and controls did not differ in the prevalence of respiratory viruses (Odds Ratio [OR] 1.00, 95%CI 0.71–1.44), but respiratory bacteria were less frequently detected in TB patients (OR 0.70, 95%CI 0.53–0.94). TB patients with both respiratory viruses and respiratory bacteria were likely to have more severe disease (adjusted OR [aOR] 1.6, 95%CI 1.1–2.4; p 0.011). TB patients with respiratory viruses tended to have more frequent lung cavitations (aOR 1.6, 95%CI 0.93–2.7; p 0.089). Conclusions Respiratory viruses are common for both TB patients and household controls. TB patients may present with more severe TB disease, particularly when they are co-infected with both bacteria and viruses.

BackgroundHuman tuberculosis (TB) is caused by seven phylogenetic lineages of theMycobacterium tuberculosiscomplex (MTBC), Lineage 1–7. Recent advances in rapid genotyping of MTBC based on single nucleotide polymorphisms (SNP), allow for rapid and phylogenetically robust strain classification, paving the way for defining genotype-phenotype relationships in clinical settings. Such studies have revealed that, in addition to host and environmental factors, different strains of the MTBC influence the outcome of TB infection and disease. In Tanzania, such molecular epidemiological studies of TB however are scarce in spite of a high TB burden.Methods and FindingsHere we used a SNP-typing method to genotype a nationwide collection of 2,039 MTBC clinical isolates obtained from new and retreatment TB cases diagnosed in 2012 and 2013. Four lineages, namely Lineage 1–4 were identified. The distribution and frequency of these lineages varied across the regions but overall, Lineage 4 was the most frequent (n=866, 42.5%), followed by Lineage 3 (n=681, 33.4%) and 1 (n=336, 16.5%), with Lineage 2 being the least frequent (n=92, 4.5%). A total of 64 (3.1%) isolates could not be assigned to any lineage. We found Lineage 2 to be associated with female sex (adjusted odds ratio [aOR] 2.25; 95% confidence interval [95% CI] 1.38 – 3.70, pConclusionsThis study provides novel insights into the influence of pathogen-related factors on the TB epidemic in Tanzania.

Background Differences in rural and urban settings could account for distinct characteristics in the epidemiology of tuberculosis (TB). We comparatively studied epidemiological features of TB and helminth co-infections in adult patients from rural and urban settings of Tanzania. Methods Adult patients (≥ 18 years) with microbiologically confirmed pulmonary TB were consecutively enrolled into two cohorts in Dar es Salaam, with ~ 4.4 million inhabitants (urban), and Ifakara in the sparsely populated Kilombero District with ~ 400 000 inhabitants (rural). Clinical data were obtained at recruitment. Stool and urine samples were subjected to diagnose helminthiases using Kato-Katz, Baermann, urine filtration, and circulating cathodic antigen tests. Differences between groups were assessed by χ2, Fisher’s exact, and Wilcoxon rank sum tests. Logistic regression models were used to determine associations. Results Between August 2015 and February 2017, 668 patients were enrolled, 460 (68.9%) at the urban and 208 (31.1%) at the rural site. Median patient age was 35 years (interquartile range [IQR]: 27–41.5 years), and 454 (68%) were males. Patients from the rural setting were older (median age 37 years vs. 34 years, P = 0.003), had a lower median body mass index (17.5 kg/m2 vs. 18.5 kg/m2, P

BACKGROUND A quarter of the world's population is estimated to be infected with Myobacterium tuberculosis (Mtb). Infection is detected by immune response to M. tuberculosis antigens using either tuberculin skin test (TST) and interferon gamma release (IGRA's), tests which have low sensitivity in immunocompromised. IL-7 is an important cytokine for T-cell function with potential to augment cytokine release in in-vitro assays. This study aimed to determine whether the addition of IL-7 in interferon-gamma release assays (IGRAs) improves its diagnostic performance of Mtb infection. METHODS 44 cases with confirmed TB and 45 household contacts without TB were recruited and 1ml of blood was stimulated in two separate IGRA's tube set: one set of standard Quantiferon TB gold tubes mitogen, TB antigen and TB Nil; one set of customized Quantiferon TB gold tubes with added IL-7. Following IFN-γ and IP-10 release was determined using ELISA. RESULTS We found that the addition of IL-7 led to significantly higher release of IFN-γ in individuals with active TB from 4.2IU/ml (IQR 1.4-6.9IU/ml) to 5.1IU/ml (IQR 1.5-8.1IU/ml, p = 0.0057), and we found an indication of a lower release of both IFN-γ and IP-10 in participants with negative tests. CONCLUSIONS In TB cases addition of IL-7 in IGRA tubes augments IFN-γ but not IP-10 release, and seems to lower the response in controls. Whether IL-7 boosted IGRA holds potential over standard IGRA needs to be confirmed in larger studies in high and low TB incidence countries.

PLoS ONE, 13 (4), ISSN:1932-6203

Objectives We evaluated the diagnostic performance of the novel next-generation Xpert MTB/RIF Ultra (Xpert Ultra) in comparison to Xpert MTB/RIF (Xpert) assay for the detection of paediatric pulmonary tuberculosis in high burden settings. Methods From May 2011 to September 2012, children with suspected pulmonary tuberculosis were enrolled at two Tanzanian sites and sputum samples were examined using sputum smear, Xpert and culture. Xpert Ultra was tested between January and June 2017 using sputum pellets, which had been stored at −80°C. The diagnostic accuracy of Ultra versus Xpert was determined using well-defined case definitions as reference standard. Results In total, 215 children were included. The median age was 5.4 years, the HIV prevalence was 52% and 13% had culture-confirmed pulmonary tuberculosis. When only the first available sample of each patient was analysed, the sensitivity of Xpert Ultra was 64.3 % (95% CI: 44.1 to 81.4) while that of Xpert was 53.6% (95%CI: 33.9 to 72.5). The specificity of Xpert Ultra based on analysis of all available samples was 98.1% (95%CI: 93.4 to 99.7), that of Xpert was 100%. Conclusions Xpert Ultra was found to have a higher sensitivity, but slightly reduced specificity compared to Xpert in detecting pulmonary tuberculosis in children.

Background Helminth infections can negatively affect the immunologic host control, which may increase the risk of progression from latent Mycobacterium tuberculosis infection to tuberculosis (TB) disease and alter the clinical presentation of TB. We assessed the prevalence and determined the clinical relevance of helminth co-infection among TB patients and household contact controls in urban Tanzania. Methodology Between November 2013 and October 2015, we enrolled adult (≥18 years) sputum smear-positive TB patients and household contact controls without TB during an ongoing TB cohort study in Dar es Salaam, Tanzania. We used Baermann, FLOTAC, Kato-Katz, point-of-care circulating cathodic antigen, and urine filtration to diagnose helminth infections. Multivariable logistic regression models with and without random effects for households were used to assess for associations between helminth infection and TB. Principal findings A total of 597 TB patients and 375 household contact controls were included. The median age was 33 years and 60.2% (585/972) were men. The prevalence of any helminth infection among TB patients was 31.8% (190/597) and 25.9% (97/375) among controls. Strongyloides stercoralis was the predominant helminth species (16.6%, 161), followed by hookworm (9.0%, 87) and Schistosoma mansoni (5.7%, 55). An infection with any helminth was not associated with TB (adjusted odds ratio (aOR) 1.26, 95% confidence interval (CI): 0.88–1.80, p = 0.22), but S. mansoni infection was (aOR 2.15, 95% CI: 1.03–4.45, p = 0.040). Moreover, S. mansoni infection was associated with lower sputum bacterial load (aOR 2.63, 95% CI: 1.38–5.26, p = 0.004) and tended to have fewer lung cavitations (aOR 0.41, 95% CI: 0.12–1.16, p = 0.088). Conclusions/Significance S. mansoni infection was an independent risk factor for active TB and altered the clinical presentation in TB patients. These findings suggest a role for schistosomiasis in modulating the pathogenesis of human TB. Treatment of helminths should be considered in clinical management of TB and TB control programs., Author summary Tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis, and parasitic worm infections are typical diseases of poverty. They often overlap geographically, and can occur in the same individual. Parasitic worm infections contribute to the down-regulation of the essential immune response against TB, and therefore can increase progression from latent M. tuberculosis infection to active TB. We conducted a case-control study in Dar es Salaam, the economic capital of Tanzania, where TB and helminths constitute a considerable burden. We found that infection with the blood fluke Schistosoma mansoni was associated with active TB, while none of the other parasitic worms showed such an association. Interestingly, TB patients infected with S. mansoni had significantly lower sputum bacterial load at diagnosis and tended to have fewer lung cavitations compared with TB patients without any parasitic worm infection. Diagnosis and treatment of parasitic worm infections, particularly schistosomiasis, should be considered during the management of TB patients and in the context of TB control programs. This could help to reduce the TB burden in settings where TB and parasitic worms co-exist.

Background Culture contamination with environmental bacteria is a major challenge in tuberculosis (TB) laboratories in hot and humid climate zones. We studied the effect of cetylpyridinium chloride (CPC) preservation on culture results and performance of Xpert MTB/RIF. Methods Consecutive sputum samples from microscopy smear-positive TB patients were collected. Two-hundred samples were equally split in two aliquots, one aliquot was treated with CPC and stored at ambient temperature for 7 days. The second aliquot was immediately processed. Samples were decontaminated for 20, 15 or 10 min, and subsequently cultured on Löwenstein-Jensen medium. Furthermore, 50 samples were stored for 7, 14 and 21 days, and 100 CPC-pretreated samples tested by Xpert MTB/RIF. Results CPC pretreated samples showed a higher culture yield compared to non-treated sputum samples across all decontamination times: 94% vs. 73% at 10 min (p = 0.01), 94% vs. 64% at 15 min (p = 0.004), and 90% vs. 52% at 20 min (p

BackgroundXpert® MTB/RIF (Xpert) has suboptimal sensitivity for the diagnosis of pulmonary tuberculosis in children. The next-generation Xpert MTB/RIF Ultra assay (Xpert Ultra) is substantially more sensitive than Xpert and may allow improved detection of paediatric tuberculosis. We evaluated the diagnostic accuracy of Xpert Ultra versus Xpert in the detection of pulmonary tuberculosis in children.MethodsFrom May 2011 to September 2012, children with presumptive pulmonary tuberculosis were enrolled at two „Tanzanian research sites in the EDCTP-funded TB CHILD project. Sputum samples were collected and examined for tuberculosis using sputum smear, Xpert and culture. Xpert Ultra analysis was performed between January and June 2017 at both sites using decontaminated sputum pellets which had been stored at −80°C. The diagnostic accuracy of Xpert and Xpert Ultra was determined using well-defined case definitions as reference standard.ResultsIn total, 215 children were included in the analysis. The median age was 5.4 years (IQR, 1.5 to 9.9), the HIV prevalence was 52%, and 28 children (13%) had culture-confirmed pulmonary tuberculosis. When only the first available sample of each patient was considered, the sensitivity of Xpert Ultra was 64.3% (95% CI: 44.1 to 81.4) while that of Xpert was 53.6% (95% CI: 33.9 to 72.5). The specificity of Xpert Ultra based on the analysis of all available samples was 98.1% (95% CI: 93.4 to 99.7), whereas that of Xpert was 100%.ConclusionIn settings with a high burden of tuberculosis and HIV, Xpert Ultra had a better sensitivity than Xpert in children. However, the specificity was slightly lower than that of Xpert. Thus, Xpert Ultra has the potential to increase the reliability and the speed of tuberculosis diagnosis in children.

Background Fine needle aspiration biopsy has become a standard approach for diagnosis of peripheral tuberculous lymphadenitis. The aim of this study was to compare the performance of Xpert MTB/RIF and Ustar EasyNAT TB IAD nucleic acid amplification assays, against acid-fast bacilli microscopy, cytology and mycobacterial culture for the diagnosis of TB lymphadenitis in children from a TB-endemic setting in Tanzania. Methods Children of 8 weeks to 16 years of age, suspected of having TB lymphadenitis, were recruited at a district hospital in Tanzania. Fine needle aspirates of lymph nodes were analysed using acid-fast bacilli microscopy, liquid TB culture, cytology, Xpert MTB/RIF and EasyNAT. Latent class analysis and comparison against a composite reference standard comprising “culture and/or cytology” was done, to assess the performance of Xpert MTB/RIF and EasyNAT for the diagnosis of TB lymphadenitis. Results Seventy-nine children were recruited; 4 were excluded from analysis. Against a composite reference standard of culture and/or cytology, Xpert MTB/RIF and EasyNAT had a sensitivity and specificity of 58 % and 93 %; and 19 % and 100 % respectively. Relative to latent class definitions, cytology had a sensitivity of 100 % and specificity of 94.7 %. Conclusions Combining clinical assessment, cytology and Xpert MTB/RIF may allow for a rapid and accurate diagnosis of childhood TB lymphadenitis. Larger diagnostic evaluation studies are recommended to validate these findings and on Xpert MTB/RIF to assess its use as a solitary initial test for TB lymphadenitis in children.

The EasyNAT assay was evaluated for the detection of tuberculosis in sputum smears from presumptive pulmonary tuberculosis (TB) patients in an African high-TB and high-HIV setting. The sensitivity of the EasyNAT assay was 66.7%, and the specificity and positive predictive value were 100% for the culture-positive patients. The sensitivity was only 10% in the smear-negative and culture-positive patients.

OBJECTIVE We examined the effect of an instructional video about the production of diagnostic sputum on case detection of tuberculosis (TB), and evaluated the acceptance of the video. TRIAL DESIGN Randomized controlled trial. METHODS We prepared a culturally adapted instructional video for sputum submission. We analyzed 200 presumptive TB cases coughing for more than two weeks who attended the outpatient department of the governmental Municipal Hospital in Mwananyamala (Dar es Salaam, Tanzania). They were randomly assigned to either receive instructions on sputum submission using the video before submission (intervention group, n = 100) or standard of care (control group, n = 100). Sputum samples were examined for volume, quality and presence of acid-fast bacilli by experienced laboratory technicians blinded to study groups. RESULTS Median age was 39.1 years (interquartile range 37.0-50.0); 94 (47%) were females, 106 (53%) were males, and 49 (24.5%) were HIV-infected. We found that the instructional video intervention was associated with detection of a higher proportion of microscopically confirmed cases (56%, 95% confidence interval [95% CI] 45.7-65.9%, sputum smear positive patients in the intervention group versus 23%, 95% CI 15.2-32.5%, in the control group, p

Summary Background Following endorsement by the World Health Organisation, the Xpert MTB/RIF assay has been widely incorporated into algorithms for the diagnosis of adult tuberculosis (TB). However, data on its performance in children remain scarce. This prospective, multi-centre study evaluated the performance of Xpert MTB/RIF to diagnose pulmonary tuberculosis in children. Methods Children older than eight weeks and younger than 16 years with suspected pulmonary tuberculosis were enrolled at three TB endemic settings in Tanzania and Uganda, and assigned to five well-defined case definition categories: culture-confirmed TB, highly probable TB, probable TB, not TB, or indeterminate. The diagnostic accuracy of Xpert MTB/RIF was assessed using culture-confirmed TB cases as reference standard. Results In total, 451 children were enrolled. 37 (8%) had culture-confirmed TB, 48 (11%) highly probably TB and 62 probable TB (13%). The Xpert MTB/RIF assay had a sensitivity of 68% (95% CI, 50%–82%) and specificity of 100% (95% CI, 97%–100%); detecting 1.7 times more culture-confirmed cases than smear microscopy with a similar time to detection. Xpert MTB/RIF was positive in 2% (1/48) of highly probable and in 3% (2/62) of probable TB cases. Conclusions Xpert MTB/RIF provided timely results with moderate sensitivity and excellent specificity compared to culture. Low yields in children with highly probable and probable TB remain problematic.

Background This study established evidence about the diagnostic performance of trained giant African pouched rats for detecting Mycobacterium tuberculosis in sputum of well-characterised patients with presumptive tuberculosis (TB) in a high-burden setting. Methods The TB detection rats were evaluated using sputum samples of patients with presumptive TB enrolled in two prospective cohort studies in Bagamoyo, Tanzania. The patients were characterised by sputum smear microscopy and culture, including subsequent antigen or molecular confirmation of Mycobacterium tuberculosis, and by clinical data at enrolment and for at least 5-months of follow-up to determine the reference standard. Seven trained giant African pouched rats were used for the detection of TB in the sputum samples after shipment to the APOPO project in Morogoro, Tanzania. Results Of 469 eligible patients, 109 (23.2%) were culture-positive for Mycobacterium tuberculosis and 128 (27.3%) were non-TB controls with sustained recovery after 5 months without anti-TB treatment. The HIV prevalence was 46%. The area under the receiver operating characteristic curve of the seven rats for the detection of culture-positive pulmonary tuberculosis was 0.72 (95% CI 0.66–0.78). An optimal threshold could be defined at ≥2 indications by rats in either sample with a corresponding sensitivity of 56.9% (95% CI 47.0–66.3), specificity of 80.5% (95% CI 72.5–86.9), positive and negative predictive value of 71.3% (95% CI 60.6–80.5) and 68.7% (95% CI 60.6–76.0), and an accuracy for TB diagnosis of 69.6%. The diagnostic performance was negatively influenced by low burden of bacilli, and independent of the HIV status. Conclusion Giant African pouched rats have potential for detection of tuberculosis in sputum samples. However, the diagnostic performance characteristics of TB detection rats do not currently meet the requirements for high-priority, rapid sputum-based TB diagnostics as defined by the World Health Organization.