Production of TNF-α, IL-12(p40) and IL-17 Can Discriminate between Active TB Disease and Latent Infection in a West African Cohort

Background

Mycobacterium tuberculosis (MTb) infects approximately 2 billion people world-wide resulting in almost 2 million deaths per year. Determining biomarkers that distinguish different stages of tuberculosis (TB) infection and disease will provide tools for more effective diagnosis and ultimately aid in the development of new vaccine candidates. The current diagnostic kits utilising production of IFN-γ in response to TB antigens can detect MTb infection but are unable to distinguish between infection and disease. The aim of this study was to assess if the use of a longer term assay and the analysis of multiple cytokines would enhance diagnosis of active TB in a TB-endemic population.

Methods

We compared production of multiple cytokines (TNF-α, IFN-γ, IL-10, IL-12(p40), IL-13, IL-17 and IL-18) following long-term (7 days) stimulation of whole-blood with TB antigens (ESAT-6/CFP-10 (EC), PPD or TB10.4) from TB cases (n = 36) and their Mycobacterium-infected (TST+; n = 20) or uninfected (TST−; n = 19) household contacts (HHC).

Results and Conclusions

We found that TNF-α production following EC stimulation and TNF-α and IL-12(p40) following TB10.4 stimulation were significantly higher from TB cases compared to TST+ HHC, while production of IFN-γ and IL-13 were significantly higher from TST+ compared to TST- HHC following PPD or EC stimulation. Combined analysis of TNF-α, IL-12(p40) and IL-17 following TB10.4 stimulation resulted in 85% correct classification into TB cases or TST+ HHC. 74% correct classification into TST+ or TST− HHC was achieved with IFN-γ alone following TB10.4 stimulation (69% following EC) and little enhancement was seen with additional cytokines. We also saw a tendency for TB cases infected with M. africanum to have increased TNF-α and IL-10 production compared to those infected with M. tuberculosis. Our results provide further insight into the pathogenesis of tuberculosis and may enhance the specificity of the currently available diagnostic tests, particularly for diagnosis of active TB.     

Decay Kinetics of an Interferon Gamma Release Assay with Anti-Tuberculosis Therapy in Newly Diagnosed Tuberculosis Cases

Background

Qualitative and quantitative changes in IGRA response offer promise as biomarkers to monitor Tuberculosis (TB) drug therapy, and for the comparison of new interventions. We studied the decay kinetics of TB-specific antigen T-cell responses measured with an in-house ELISPOT assay during the course of therapy.

Methods

Newly diagnosed sputum smear positive TB cases with typical TB chest radiographs were recruited. All patients were given standard anti-TB treatment. Each subject was followed up for 6 months and treatment outcomes were documented. Blood samples were obtained for the ESAT-6 and CFP-10 (EC) ELISPOT at diagnosis, 1-, 2-, 4- and 6-months. Qualitative and quantitative reversion of the ELISPOT results were assessed with McNemar test, conditional logistic regression and mixed-effects hierarchical Poisson models.

Results

A total of 116 cases were recruited and EC ELISPOT was positive for 87% (95 of 109) at recruitment. There was a significant decrease in the proportion of EC ELISPOT positive cases over the treatment period (p<0.001). Most of the reversion occurred between the start and first month of treatment and at completion at 6 months. ESAT-6 had higher median counts compared to CFP-10 at all time points. Counts for each antigen declined significantly with therapy (p<0.001). Reverters had lower median SFUs at the start of treatment compared to non-Reverters for both antigens. Apart from the higher median counts for non-Reverters, no other risk factors for non-reversion were found.

Conclusions

TB treatment induces qualitative and quantitative reversion of a positive in-house IGRA in newly diagnosed cases of active TB disease. As this does not occur reliably in the majority of cured individuals, qualitative and quantitative reversion of an IGRA ELISPOT has limited clinical utility as a surrogate marker of treatment efficacy.     

Normalising surface EMG of ten upper-extremity muscles in handcycling: Manual resistance vs. sport-specific MVICs

Muscular activity in terms of surface electromyography (sEMG) is usually normalised to maximal voluntary isometric contractions (MVICs). This study aims to compare two different MVIC-modes in handcycling and examine the effect of moving average window-size. Twelve able-bodied male competitive triathletes performed ten MVICs against manual resistance and four sport-specific trials against fixed cranks. sEMG of ten muscles [M. trapezius (TD); M. pectoralis major (PM); M. deltoideus, Pars clavicularis (DA); M. deltoideus, Pars spinalis (DP); M. biceps brachii (BB); M. triceps brachii (TB); forearm flexors (FC); forearm extensors (EC); M. latissimus dorsi (LD) and M. rectus abdominis (RA)] was recorded and filtered using moving average window-sizes of 150, 200, 250 and 300 ms. Sport-specific MVICs were higher compared to manual resistance for TB, DA, DP and LD, whereas FC, TD, BB and RA demonstrated lower values. PM and EC demonstrated no significant difference between MVIC-modes. Moving average window-size had no effect on MVIC outcomes. MVIC-mode should be taken into account when normalised sEMG data are illustrated in handcycling. Sport-specific MVICs seem to be suitable for some muscles (TB, DA, DP and LD), but should be augmented by MVICs against manual/mechanical resistance for FC, TD, BB and RA.     

Human Cytomegalovirus Vaccine Based on the Envelope gH/gL Pentamer Complex

Human Cytomegalovirus (HCMV) utilizes two different pathways for host cell entry. HCMV entry into fibroblasts requires glycoproteins gB and gH/gL, whereas HCMV entry into epithelial and endothelial cells (EC) requires an additional complex composed of gH, gL, UL128, UL130, and UL131A, referred to as the gH/gL-pentamer complex (gH/gL-PC). While there are no established correlates of protection against HCMV, antibodies are thought to be important in controlling infection. Neutralizing antibodies (NAb) that prevent gH/gL-PC mediated entry into EC are candidates to be assessed for in vivo protective function. However, these potent NAb are predominantly directed against conformational epitopes derived from the assembled gH/gL-PC. To address these concerns, we constructed Modified Vaccinia Ankara (MVA) viruses co-expressing all five gH/gL-PC subunits (MVA-gH/gL-PC), subsets of gH/gL-PC subunits (gH/gL or UL128/UL130/UL131A), or the gB subunit from HCMV strain TB40/E. We provide evidence for cell surface expression and assembly of complexes expressing full-length gH or gB, or their secretion when the corresponding transmembrane domains are deleted. Mice or rhesus macaques (RM) were vaccinated three times with MVA recombinants and serum NAb titers that prevented 50% infection of human EC or fibroblasts by HCMV TB40/E were determined. NAb responses induced by MVA-gH/gL-PC blocked HCMV infection of EC with potencies that were two orders of magnitude greater than those induced by MVA expressing gH/gL, UL128-UL131A, or gB. In addition, MVA-gH/gL-PC induced NAb responses that were durable and efficacious to prevent HCMV infection of Hofbauer macrophages, a fetal-derived cell localized within the placenta. NAb were also detectable in saliva of vaccinated RM and reached serum peak levels comparable to NAb titers found in HCMV hyperimmune globulins. This vaccine based on a translational poxvirus platform co-delivers all five HCMV gH/gL-PC subunits to achieve robust humoral responses that neutralize HCMV infection of EC, placental macrophages and fibroblasts, properties of potential value in a prophylactic vaccine.     

Sensitivity of IFN-γ Release Assay to Detect Latent Tuberculosis Infection Is Retained in HIV-Infected Patients but Dependent on HIV/AIDS Progression

Background

Detection and treatment of latent TB infection (LTBI) in HIV infected individuals is strongly recommended to decrease morbidity and mortality in countries with high levels of HIV.

Objective

To assess the validity of a newly developed in-house ELISPOT interferon-γ release assay (IGRA) for the detection of LTBI amongst HIV infected individuals, in comparison with the Tuberculin Skin Test (TST).

Methodology/Principal Findings

ESAT6/CFP10 (EC) ELISPOT assays were performed, together with a TST, in 285 HIV infected individuals recruited in HIV clinics in Dakar, Senegal, who had no signs of active TB at time of enrolment. Thirty eight of the subjects (13.3%) failed to respond to PHA stimulation and were excluded from the analysis. In the 247 remaining patients, response to PHA did not vary according to CD4 cell count categories (p = 0.51). EC ELISPOT was positive in 125 (50.6%) subjects, while 53 (21.5%) had a positive TST. Concordance between EC ELISPOT and TST was observed in 151 patients (61.1%) (kappa = 0.23). The proportion of subjects with a positive response to the EC ELISPOT assay decreased with declining CD4 counts (p trend = 0.001), but were consistently higher than the proportion of TST responders. In multivariate analysis, the risk of being EC-ELISPOT positive in HIV infected individuals was associated with age, CD4 count and HIV-1 strain.

Conclusion

Our study indicates that IGRAs using M. tuberculosis specific antigens are likely to retain their validity for the diagnosis of LTBI among HIV positive individuals, but may be impaired by T-cell anergy in severely immuno-suppressed individuals.     

Tributyltin-resistant bacteria from estuarine and freshwater sediments.

Resistance to tributyltin (TBT) was examined in populations from TBT-polluted sediments and nonpolluted sediments from an estuary and from fresh water as well as in pure cultures isolated from those sediments. The 50% effective concentrations (EC50s) for populations were higher at a TBT-polluted freshwater site than at a site without TBT, suggesting that TBT selected for a TBT-resistant population. In contrast, EC50s were significantly lower for populations from a TBT-contaminated estuarine site than for those from a site without TBT, suggesting that other factors in addition to TBT determine whether populations become resistant. EC50s for populations from TBT-contaminated freshwater sediments were nearly 30 times higher than those for populations from TBT-contaminated estuarine sediments. We defined a TBT-resistant bacterium as one which grows on trypticase soy agar containing 8.4 microM TBT, a concentration which prevented the growth of 90% of the culturable bacteria from these sediments. The toxicity of TBT in laboratory media was influenced markedly by the composition of the medium and whether it was liquid or solid. Ten TBT-resistant isolates from estuarine sediments and 19 from freshwater sediments were identified to the genus level. Two isolates, each a Bacillus sp., may be the first gram-positive bacteria isolated from fresh water in the presence of a high concentration of TBT. There was a high incidence of resistance to heavy metals: metal resistance indices were 0.76 for estuarine isolates and 0.68 for freshwater isolates.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tributyltin-resistant bacteria from estuarine and freshwater sediments.

Resistance to tributyltin (TBT) was examined in populations from TBT-polluted sediments and nonpolluted sediments from an estuary and from fresh water as well as in pure cultures isolated from those sediments. The 50% effective concentrations (EC50s) for populations were higher at a TBT-polluted freshwater site than at a site without TBT, suggesting that TBT selected for a TBT-resistant population. In contrast, EC50s were significantly lower for populations from a TBT-contaminated estuarine site than for those from a site without TBT, suggesting that other factors in addition to TBT determine whether populations become resistant. EC50s for populations from TBT-contaminated freshwater sediments were nearly 30 times higher than those for populations from TBT-contaminated estuarine sediments. We defined a TBT-resistant bacterium as one which grows on trypticase soy agar containing 8.4 microM TBT, a concentration which prevented the growth of 90% of the culturable bacteria from these sediments. The toxicity of TBT in laboratory media was influenced markedly by the composition of the medium and whether it was liquid or solid. Ten TBT-resistant isolates from estuarine sediments and 19 from freshwater sediments were identified to the genus level. Two isolates, each a Bacillus sp., may be the first gram-positive bacteria isolated from fresh water in the presence of a high concentration of TBT. There was a high incidence of resistance to heavy metals: metal resistance indices were 0.76 for estuarine isolates and 0.68 for freshwater isolates.(ABSTRACT TRUNCATED AT 250 WORDS)     

Childhood Tuberculosis in a Sub-Saharan Tertiary Facility: Epidemiology and Factors Associated with Treatment Outcome

Childhood tuberculosis (TB) is a diagnostic challenge in developing countries, and patient outcome can be influenced by certain factors. We report the disease course, clinical profile and factors associated with treatment outcome in a tertiary facility of Kinshasa. Documentary and analytical studies were conducted using clinical and exploratory data for children aged up to 15 years who were admitted to the University Clinics of Kinshasa for TB. Data are presented as frequencies and averages, and binary and logistic regression analyses were performed. Of 283 children with TB, 82 (29.0%) had smear-negative TB, 40 (14.1%) had smear-positive TB, 159 (56.1%) had extra-pulmonary TB (EPTB), 2 (0.7%) had multidrug-resistant TB (MDR-TB), 167 (59.0%) completed treatment, 30 (10.6%) were cured, 7 (2.5%) failed treatment, 4 (1.4%) died, 55 (19.4%) were transferred to health centers nearest their home, and 20 (7.0%) were defaulters. In the binary analysis, reported TB contacts (p = 0.048), type of TB (p = 0.000), HIV status (p = 0.050), Ziehl-Nielsen test result (p = 0.000), Lowenstein culture (p = 0.004) and chest X-ray (p = 0.057) were associated with outcome. In the logistic regression, none of these factors was a significant predictor of outcome. Tertiary level care facilities must improve the diagnosis and care of patients with childhood TB, which justifies the development of alternative diagnostic techniques and the assessment of other factors that potentially affect outcome.     

Evaluation of the burden of unsuspected pulmonary tuberculosis and co-morbidity with non-communicable diseases in sputum producing adult inpatients

Background

A high burden of tuberculosis (TB) occurs in sub-Saharan African countries and many cases of active TB and drug-resistant TB remain undiagnosed. Tertiary care hospitals provide an opportunity to study TB co-morbidity with non-communicable and other communicable diseases (NCDs/CDs). We evaluated the burden of undiagnosed pulmonary TB and multi-drug resistant TB in adult inpatients, regardless of their primary admission diagnosis, in a tertiary referral centre.

Methodology/Principal Findings

In this prospective study, newly admitted adult inpatients able to produce sputum at the University Teaching Hospital, Lusaka, Zambia, were screened for pulmonary TB using fluorescent smear microscopy and automated liquid culture. The burden of pulmonary TB, unsuspected TB, TB co-morbidity with NCDs and CDs was determined. Sputum was analysed from 900 inpatients (70.6% HIV infected) 277 (30.8%) non-TB suspects, 286 (31.8%) TB suspects and 337 (37.4%) were already receiving TB treatment. 202/900 (22.4%) of patients had culture confirmed TB. TB co-morbidity was detected in 20/275 (7.3%) NCD patients, significantly associated with diabetes (P = 0.006, OR 6.571, 95%CI: 1.706–25.3). 27/202 (13.4%) TB cases were unsuspected. There were 18 confirmed cases of MDR-TB, 5 of which were unsuspected.

Conclusions/Significance

A large burden of unsuspected pulmonary TB co-morbidity exists in inpatients with NCDs and other CDs. Pro-active sputum screening of all inpatients in tertiary referral centres in high TB endemic countries is recommended. The scale of the problem of undiagnosed MDR-TB in inpatients requires further study.     

Interferon-Gamma Release Assay Performance of Pleural Fluid and Peripheral Blood in Pleural Tuberculosis

Background

The diagnosis of pleural tuberculosis (TB) remains to be difficult. Interferon-gamma release assay (IGRA) is a promising method for diagnosing TB in low TB burden countries. The release of interferon-gamma (IFN-γ) by T lymphocytes increases at a localized site of infection with Mycobacterium tuberculosis antigen. This study aimed to examine the clinical accuracy of T-SPOT.TB on pleural fluid and peripheral blood for the diagnosis of pleural TB in high TB burden country.

Methods

168 subjects with pleural effusion were enrolled prospectively and examined with T-SPOT.TB on pleural fluid and peripheral blood samples simultaneously.

Results

The receiver operating characteristic (ROC) curve and cut-off value of pleural fluid T-SPOT.TB was established according to spot forming cells (SFC) between culture/biopsy-confirmed pleural TB group and no pleural TB group. The sensitivity of pleural fluid T-SPOT.TB and peripheral blood T-SPOT.TB was similar (96.3% and 92.7%, respectively) (P= 0.691). In contrast, the specificity of pleural fluid T-SPOT.TB (94.5%) was significantly higher than that of peripheral blood T-SPOT.TB (76.1%) (P=0.002). 2% (2/98) of pleural fluid T-SPOT.TB results were indeterminate.

Conclusion

The diagnostic accuracy of peripheral blood T-SPOT.TB is low in high TB burden countries due to latent tuberculosis infection. Pleural fluid T-SPOT.TB is a relatively useful and supplementary test to explore pleural TB in high TB burden countries, but its diagnostic accuracy needs to be validated in further large scale research.     

Treatment Outcome of Tuberculosis Patients under Directly Observed Treatment Short Course and Factors Affecting Outcome in Southern Ethiopia: A Five-Year Retrospective Study

Tuberculosis (TB) is one of the major public health and socio-economic issues in the 21^st century globally. Assessment of TB treatment outcomes, and monitoring and evaluation of its risk factors in Directly Observed Treatment Short Course (DOTS) are among the major indicators of the performance of a national TB control program. Hence, this institution-based retrospective study was conducted to determine the treatment outcome of TB patients and investigate factors associated with unsuccessful outcome at Dilla University Referral Hospital, southern Ethiopia. Five years (2008 to 2013) TB record of TB clinic of the hospital was reviewed. A total 1537 registered TB patients with complete information were included. Of these, 942 (61.3%) were male, 1015 (66%) were from rural areas, 544 (35.4%) were smear positive pulmonary TB (PTB+), 816 (53.1%) were smear negative pulmonary TB (PTB-) and 177(11.5%) were extra pulmonary TB (EPTB) patients. Records of the 1537 TB patients showed that 181 (11.8%) were cured, 1129(73.5%) completed treatment, 171 (11.1%) defaulted, 52 (3.4%) died and 4 (0.3%) had treatment failure. The overall mean treatment success rate of the TB patients was 85.2%. The treatment success rate of the TB patients increased from 80.5% in September 2008-August 2009 to 84.8% in September 2012–May 2013. Tuberculosis type, age, residence and year of treatment were significantly associated with unsuccessful treatment outcome. The risk of unsuccessful outcome was significantly higher among TB patients from rural areas (AOR = 1.63, 95% CI: 1.21–2.20) compared to their urban counterparts. Unsuccessful treatment outcome was also observed in PTB- patients (AOR = 1.77, 95% CI: 1.26–2.50) and EPTB (AOR = 2.07, 95% CI: 1.28–3.37) compared to the PTB+ patients. In conclusion, it appears that DOTS have improved treatment success in the hospital during five years. Regular follow-up of patients with poor treatment outcome and provision of health information on TB treatment to patients from rural area is recommended.     

Estimating the burden of tuberculosis among foreign-born persons acquired prior to entering the U.S., 2005-2009

Background

The true burden of reactivation of remote latent tuberculosis infection (reactivation TB) among foreign-born persons with tuberculosis (TB) within the United States is not known. Our study objectives were to estimate the proportion of foreign-born persons with TB due reactivation TB and to describe characteristics of foreign-born persons with reactivation TB.

Methods

We conducted a cross-sectional study of patients with an M. tuberculosis isolate genotyped by the U.S. National TB Genotyping Service, 2005–2009. TB cases were attributed to reactivation TB if they were not a member of a localized cluster of cases. Localized clusters were determined by a spatial scan statistic of cases with isolates with matching TB genotype results. Crude odds ratios and 95% confidence intervals were used to assess relations between reactivation TB and select factors among foreign-born persons.

Main Results

Among the 36,860 cases with genotyping and surveillance data reported, 22,151 (60%) were foreign-born. Among foreign-born persons with TB, 18,540 (83.7%) were attributed to reactivation TB. Reactivation TB among foreign-born persons was associated with increasing age at arrival, incidence of TB in the country of origin, and decreased time in the U.S. at the time of TB diagnosis.

Conclusions

Four out of five TB cases among foreign-born persons can be attributed to reactivation TB and present the largest challenge to TB elimination in the U.S. TB control strategies among foreign-born persons should focus on finding and treating latent tuberculosis infection prior to or shortly after arrival to the United States and on reducing the burden of LTBI through improvements in global TB control.     

Classification and characterisation of extracellular vesicles-related tuberculosis subgroups and immune cell profiles

Around the world, tuberculosis (TB) remains one of the most common causes of morbidity and mortality. The molecular mechanism of Mycobacterium tuberculosis (Mtb) infection is still unclear. Extracellular vesicles (EVs) play a key role in the onset and progression of many disease states and can serve as effective biomarkers or therapeutic targets for the identification and treatment of TB patients. We analysed the expression profile to better clarify the EVs characteristics of TB and explored potential diagnostic markers to distinguish TB from healthy control (HC). Twenty EVs-related differentially expressed genes (DEGs) were identified, and 17 EVs-related DEGs were up-regulated and three DEGs were down-regulated in TB samples, which were related to immune cells. Using machine learning, a nine EVs-related gene signature was identified and two EVs-related subclusters were defined. The single-cell RNA sequence (scRNA-seq) analysis further confirmed that these hub genes might play important roles in TB pathogenesis. The nine EVs-related hub genes had excellent diagnostic values and accurately estimated TB progression. TB's high-risk group had significantly enriched immune-related pathways, and there were substantial variations in immunity across different groups. Furthermore, five potential drugs were predicted for TB using CMap database. Based on the EVs-related gene signature, the TB risk model was established through a comprehensive analysis of different EV patterns, which can accurately predict TB. These genes could be used as novel biomarkers to distinguish TB from HC. These findings lay the foundation for further research and design of new therapeutic interventions aimed at treating this deadly infectious disease.     

High Prevalence of Pulmonary Tuberculosis but Low Sensitivity of Symptom Screening among HIV-Infected Pregnant Women in South Africa

Symptom screening is a recommended component of intensified case-finding (ICF) for pulmonary tuberculosis (TB) among HIV-infected individuals. Symptomatic individuals are further investigated to either exclude or diagnose pulmonary TB, thus reducing the number of individuals requiring costly laboratory investigation. Those with laboratory evaluations negative for pulmonary TB or who lack symptoms may be eligible for antiretroviral therapy (ART) and/or TB isoniazid preventive therapy (IPT). A four-part symptom screen has been recommended by the World Health Organization (WHO) for identifying TB suspects and those unlikely to have TB. A meta-analysis of studies among HIV-infected individuals calculated a sensitivity of 90.1% for the four-part symptoms screen - of any of cough, fever, night sweats, or weight loss - among patients in clinical care, making it an effective tool for identifying most patients with TB. An important population for intensified case-finding not included in that meta-analysis was HIV-infected pregnant women. We undertook a cross-sectional survey among HIV-infected pregnant women receiving prenatal care at community clinics in South Africa. We obtained a four-symptom review and sputum smear microscopy and mycobacterial culture on all participants. Among 1415 women, 226 (16%) had a positive symptom screen, and 35 (2.5%) were newly diagnosed with culture-positive TB. Twelve were on TB treatment at the time of screening, yielding 47 (3.3%) women with prevalent TB. Symptom screening among women without known TB had a sensitivity of 28% and specificity of 84%. The poor performance of symptom screening to identify women with TB suggests that other approaches may be needed for intensified case-finding to be effective for this population.     

Successful Tuberculosis Treatment Outcomes among HIV/TB Coinfected Patients Down-Referred from a District Hospital to Primary Health Clinics in Rural South Africa

BackgroundHIV and tuberculosis (TB) coinfection remains a major public health threat in sub-Saharan Africa. Integration and decentralization of HIV and TB treatment services are being implemented, but data on outcomes of this strategy are lacking in rural, resource-limited settings. We evaluated TB treatment outcomes in TB/HIV coinfected patients in an integrated and decentralized system in rural KwaZulu-Natal, South Africa.MethodsWe retrospectively studied a cohort of HIV/TB coinfected patients initiating treatment for drug-susceptible TB at a district hospital HIV clinic from January 2012-June 2013. Patients were eligible for down-referral to primary health clinics(PHCs) for TB treatment completion if they met specific clinical criteria. Records were reviewed for patients’ demographic, baseline clinical and laboratory information, past HIV and TB history, and TB treatment outcomes.ResultsOf 657(88.7%) patients, 322(49.0%) were female, 558(84.9%) were new TB cases, and 572(87.1%) had pulmonary TB. After TB treatment initiation, 280(42.6%) were down-referred from the district level HIV clinic to PHCs for treatment completion; 377(57.4%) remained at the district hospital. Retained patients possessed characteristics indicative of more severe disease. In total, 540(82.2%) patients experienced treatment success, 69(10.5%) died, and 46(7.0%) defaulted. Down-referred patients experienced higher treatment success, and lower mortality, but were more likely to default, primarily at the time of transfer to PHC.ConclusionDecentralization of TB treatment to the primary care level is feasible in rural South Africa. Treatment outcomes are favorable when patients are carefully chosen for down-referral. Higher mortality in retained patients reflects increased baseline disease severity while higher default among down-referred patients reflects failed linkage of care. Better linkage mechanisms are needed including improved identification of potential defaulters, increased patient education, active communication between hospitals and PHCs, and tracing of patients lost to follow up. Decentralized and integrated care is successful for carefully selected TB/HIV coinfected patients and should be expanded.     

Incidence of tuberculosis among reported AIDS cases in Quebec from 1979 to 1996

BACKGROUND: The impact of HIV infection on tuberculosis (TB) rates in Quebec has not been fully established. Because concurrent HIV infection is the single most important factor in TB reactivation, the authors used Quebec AIDS surveillance data to quantify the extent of TB among reported AIDS cases and to identify the characteristics of AIDS patients with TB. METHODS: The study population comprised people aged 15 years and over with AIDS diagnosed between Jan. 1, 1979, and Dec. 31, 1996, and reported by Mar. 13, 1997. Patients with TB (all forms) and those without TB were compared. Multivariate logistic regression analysis was used to examine the independent effect of each variable on the AIDS-TB cases. The authors also compared the number of AIDS-TB cases with the number of TB cases to estimate the effect of HIV infection on TB incidence. RESULTS: Of the 4684 people with AIDS reported in Quebec, 242 (5.2%) had active TB at some point during the course of their illness. During 1992-1995, 9.6% of the people with TB in Montreal, and 5.8% in the province of Quebec, also had HIV infection. Those with AIDS and TB were predominantly male (75.2%), manual workers (40.1%) and residents of Montreal (86.4%) and were born in an HIV-endemic country (63.8%). The multivariate analysis indicated that AIDS patients who were born in HIV-endemic countries in the Caribbean, sub-Saharan Africa or other developing regions were 21.8 times (95% confidence interval [CI] 19.5-28.5), 17.9 times (95% CI 12.7-27.1) and 4.9 times (95% CI 3.5-7.0) more likely to have TB than those born in Canada; manual workers and unemployed people with AIDS were 1.6 times (95% CI 1.3-2.0) and 2.0 times (95% CI 1.5-2.6) more likely to have TB than professional workers; and people who acquired HIV infection through heterosexual contact were 2.1 times (95% CI 1.6-3.1) more likely to have TB than men who acquired it through sexual contact with other men. INTERPRETATION: AIDS seems to contribute significantly to the number of TB cases. The results of this study reinforce the importance of offering HIV testing to people in high-risk groups, such as those born in a country where HIV and TB is endemic.     

Diagnostic Value of T-Cell Interferon-γ Release Assays on Cerebrospinal Fluid for Tuberculous Meningitis

Diagnosis of tuberculous meningitis (TBM) remains a challenge. This study aimed to evaluate the performance of T-SPOT.TB test on cerebrospinal fluid mononuclear cells (CSFMCs) for suspected TBM patients. 43 consecutive patients with suspected TBM were enrolled in the study from June 2011 to September 2014. T-SPOT.TB was performed on both CSFMCs and peripheral blood mononuclear cells (PBMCs). The final diagnosis of TBM was independent of the T-SPOT.TB result. The diagnostic sensitivity, specificity, predictive value, and likelihood ratio of T-SPOT.TB on CSFMCs and PBMCs were analyzed. Of the 43 patients, 12 (27.9%) were finally diagnosed with TBM, 28 (65.1%) with non-TBM, and 3 (7.0%) with indeterminate diagnoses. Of 40 cases with definite diagnoses, the sensitivity and specificity were 92.0% and 96.0% for T-SPOT.TB on CSFMCs, and 83.0% and 82.0% for T-SPOT.TB on PBMCs, respectively. The positive predictive value (PPV) and negative predictive value (NPV) of T-SPOT.TB on CSFMCs were 85.0% and 96.0%, respectively. The PPV and NPV were 67.0% and 92.0% for T-SPOT.TB on PBMCs. The difference of T-SPOT.TB between CSFMCs and PBMCs was not significant so far as sensitivity, specificity, PPV, and NPV were concerned (P>0.05 for each). However, T-SPOT.TB on CSFMC and CSFMC: PBMC in TBM cases seemed higher than that in non-TBM cases. Our study further showed that T-SPOT.TB on CSFMCs might be a rapid and accurate diagnostic test for TBM. CSFMC: PBMC T-SPOT.TB ratio might be useful for the early diagnosis of TBM.     

Investigation outcomes of tuberculosis suspects in the health centers of Addis Ababa, Ethiopia

Background

Little is known about the prevalence of tuberculosis (TB) and HIV among TB suspects in primary health care units in Ethiopia.

Methods

In the period of February to March, 2009, a cross sectional survey was done in 27 health centers of Addis Ababa to assess the prevalence of TB and HIV among TB suspects who have > = 2 weeks symptoms of TB such as cough, fever and weight loss. Diagnosis of TB and HIV was based on the national guidelines. Information concerning socio-demographic variables and knowledge of the respondents about TB was collected using pretested questionnaire.

Results

Of the 545 TB suspects, 506 (92.7%) of them participated in the study. The prevalence of both pulmonary and extra pulmonary TB was 46.0% (233/506). The smear positivity rate among pulmonary TB suspect was 21.3%. Of the TB suspects, 298 (58.9%) of them were tested for HIV and 27.2% (81/298) were HIV seropositive. Fifty percent of the HIV positive TB suspects had TB. TB suspects who had a contact history with a TB patient in the family were 9 times more likely to have TB than those who did not have a contact history, [OR = 9.1, (95%CI:4.0, 20.5)]. Individuals who had poor [OR = 5.2, (95%CI: 2.3, 11.2)] and fair knowledge [OR = 3.7, (95%CI: 1.3, 10.4)] about TB were more likely to have TB than individuals who had good knowledge.

Conclusion

In conclusion, the prevalence of TB among TB suspects with duration of 2 or more weeks is high. Fifty percent of the HIV positive TB suspects had TB. Case finding among TB suspects with duration of 2 or more weeks should be intensified particularly among those who have a contact history with a TB patient.