Predictors of Discordant Tuberculin Skin Test and QuantiFERON-TB Gold In-tube Results in Eastern China: A Population-based, Cohort Study

Spatial-temporal distribution characteristics of pulmonary tuberculosis in eastern China from 2011 to 2021

China is still among the 30 high-burden tuberculosis (TB) countries in the world. Few studies have described the spatial epidemiological characteristics of pulmonary TB (PTB) in Jiangsu Province. The registered incidence data of PTB patients in 95 counties of Jiangsu Province from 2011 to 2021 were collected from the Tuberculosis Management Information System. Three-dimensional spatial trends, spatial autocorrelation, and spatial-temporal scan analysis were conducted to explore the spatial clustering pattern of PTB. From 2011 to 2021, a total of 347,495 newly diagnosed PTB cases were registered. The registered incidence rate of PTB decreased from 49.78/100,000 in 2011 to 26.49/100,000 in 2021, exhibiting a steady downward trend (χ2 = 414.22, P < 0.001). The average annual registered incidence rate of PTB was higher in the central and northern regions. Moran's I indices of the registered incidence of PTB were all >0 (P< 0.05) except in 2016, indicating a positive spatial correlation overall. Local autocorrelation analysis showed that 'high-high' clusters were mainly distributed in northern Jiangsu, and 'low-low' clusters were mainly concentrated in southern Jiangsu. The results of this study assist in identifying settings and locations of high TB risk and inform policy-making for PTB control and prevention.

Prospective cohort study on tuberculosis incidence and risk factors in the elderly population of eastern China

Background

Tuberculosis continues to be a significant public health concern in China, particularly among the elderly population. This study aimed to assess the risk factors of tuberculosis among elderly individuals in China through a cohort study, focusing on this high-risk population.

Methods

The population-based census was strategically designed to cover diverse regions and demographics across the city. The survey captured demographic and lifestyle information, as well as a clinical examination. Participants were prospectively followed up over a specified duration to monitor the incidence of tuberculosis cases.

Results

After a follow-up period of more than 7 years, 246 individuals developed tuberculosis, resulting in an incidence rate of 92.21 per 100,000 person-years (95 % CI 81.2-104.3). In multivariate analysis, the following factors were found to have significant associations with active tuberculosis. Increasing age correlated with a higher risk of active tuberculosis (AHR = 1.03 per 1-year increase in age, 95%CI: 1.01, 1.04, P < 0.001). Males continued to have a higher risk compared to females (HR = 2.73, 95%CI: 2.08, 3.58, P < 0.001). Individuals with a normal Body Mass Index (BMI) faced nearly three times higher risk compared to their obese counterparts (HR = 2.87, 95 % CI: 1.51, 5.46, P = 0.001). Conversely, those with an underweight BMI had a ten-fold higher risk compared to the obese group (HR = 9.89, 95 % CI: 4.92, 19.85, P < 0.001). Elderly individuals who quit smoking had a 1.35-fold increased risk compared to non-smokers (HR = 1.35, 95%CI: 1.12, 1.64, P < 0.001).

Conclusions

Tuberculosis incidence among the elderly population in China remained alarmingly high. This finding emphasizes the urgent need for implementing proactive case detection measures specifically tailored to address the specific needs of this vulnerable demographic, particularly in individuals who are male, have a history of former or current smoking, and have a low BMI. Moreover, we must not underestimate the influence of former smoking on tuberculosis risk.

Exploration and improvement of QuantiFERON-TB assay in patients with indeterminate results in clinical practice: A head-to-head study

BACKGROUND

We implemented the QuantiFERON-TB Gold In-Tube (QFT-GIT) based on peripheral blood mononuclear cells (QFT-PBMCs) and QFT Gold Plus (QFT-Plus) in patients with indeterminate results, and use Mit-Nil value to identify false negatives and impaired cellular immunity.

METHODS

One hundred seventy-one out of 2480 patients who had a QFT-GIT test were prospectively recruited and classified as high Nil (n = 35), low Mit (n = 75) and control (n = 61) cohorts. Head-to-head comparisons, i.e., QFT-PBMCs vs. QFT-GIT in high Nil cohort, QFT-Plus vs. QFT-GIT in low Mit cohort, and QFT-PBMCs vs. QFT-GIT in controls, were performed. Lymphocyte subsets counts were conducted in low Mit and control cohorts.

RESULTS

A significant reduction of positive rate only occurred in Mit-Nil < 6 IU/ml (p < 0.001). QFT-PBMCs yielded 100 % valid results and had a significant Nil decline in high Nil cohort (0.98 ± 1.06 vs. 9.55 ± 0.64 IU/ml, p < 0.0001), while correlated well with QFT-GIT for qualitative (Cohen's k = 0.93) and quantitative (TB-Ag [R2 = 0.91] and Mit [R2 = 0.94]) analyses. QFT-Plus produced 61.3 % valid results and had a significant Mit increase in low Mit cohort (0.82 ± 0.95 vs. 0.17 ± 0.11 IU/ml, p < 0.0001). Mit-Nil value significantly correlated with lymphocyte subsets counts (R:0.49-0.56, p < 0.0001), separately corresponding to thresholds of 4.26, 5.33, 5.55 and 5.81 IU/ml for predicting decreased total lymphocyte, T lymphocyte, CD4+ and CD8+ cells.

CONCLUSIONS

QFT that replacing whole blood with PBMCs should be recommended to handle high Nil samples, and QFT-Plus can declined the frequency of low Mit results. In addition, Mit-Nil < 6 and 5.81 IU/ml are potential thresholds to identify the risk of false negatives and impaired cellular immunity, respectively.

Evaluation of ESAT6-CFP10 Skin Test for Mycobacterium tuberculosis Infection among Persons Living with HIV in China

Recent global guidelines recommend Mycobacterium tuberculosis antigen-based skin tests, such as the ESAT6-CFP10 (EC) skin test, as acceptable alternatives to the tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube test (QFT). However, the diagnostic value of these tests among persons living with HIV (PLHIV) is unknown. We aimed to assess the diagnostic accuracy of the EC among a cohort of PLHIV in China. We recruited PLHIV in Jiangsu Province, China, to assess sensitivity and specificity of the EC test. Participants were tested with the QFT, TST, and EC skin test. Results were stratified by age, M. tuberculosis BCG vaccination, and CD4 count. The sensitivity and specificity of the EC skin test was assessed using distinct cutoffs of the QFT and TST. Of 350 PLHIV enrolled in the study, 58 (16.6%), 89 (25.4%), and 59 (16.9%) tested positive with the EC test, the QFT, and the TST, respectively. Positivity increased with CD4 count; however, these trends were similar across tests. At a 5-mm cutoff, EC skin test specificity was high (99.6%, 95% confidence interval [CI] 95% CI = 97.7 to 100.0); however, sensitivity was moderate (81.4%; 95% CI = 66.6 to 91.6). After stratifying by BCG, the sensitivity and specificity were 86.4% (95% CI = 65.1 to 97.1) and 99.1% (95% CI = 95.0 to 100.0) among vaccinated PLHIV and 76.2% (95% CI = 52.8 to 91.8) and 100.0% (95% CI = 97.2 to 100.0) among unvaccinated PLHIV, respectively. Among PLHIV, the diagnostic value of the EC skin test remained high, regardless of BCG vaccination or CD4 count. The EC skin test performed comparably to TST and may be a valid alternative diagnostic test to use in settings or populations with high HIV prevalence and BCG vaccination. To our knowledge, this is the first study to evaluate the novel ESAT6-CFP10 skin test among PLHIV. Among 350 PLHIV, the test displayed high specificity and sensitivity, a finding which did not markedly differ based on BCG vaccination and CD4 count.

Spatiotemporal Changes in Pulmonary Tuberculosis Incidence in a Low-Epidemic Area of China in 2005-2020: Retrospective Spatiotemporal Analysis

BACKGROUND

In China, tuberculosis (TB) is still a major public health problem, and the incidence of TB has significant spatial heterogeneity.

OBJECTIVE

This study aimed to investigate the temporal trends and spatial patterns of pulmonary tuberculosis (PTB) in a low-epidemic area of eastern China, Wuxi city, from 2005 to 2020.

METHODS

The data of PTB cases from 2005 to 2020 were obtained from the Tuberculosis Information Management System. The joinpoint regression model was used to identify the changes in the secular temporal trend. Kernel density analysis and hot spot analysis were used to explore the spatial distribution characteristics and clusters of the PTB incidence rate.

RESULTS

A total of 37,592 cases were registered during 2005-2020, with an average annual incidence rate of 34.6 per 100,000 population. The population older than 60 years had the highest incidence rate of 59.0 per 100,000 population. In the study period, the incidence rate decreased from 50.4 to 23.9 per 100,000 population, with an average annual percent change of -4.9% (95% CI -6.8% to -2.9%). The incidence rate of pathogen-positive patients increased during 2017-2020, with an annual percent change of 13.4% (95% CI 4.3%-23.2%). The TB cases were mainly concentrated in the city center, and the incidence of hot spots areas gradually changed from rural areas to urban areas during the study period.

CONCLUSIONS

The PTB incidence rate in Wuxi city has been declining rapidly with the effective implementation of strategies and projects. The populated urban centers will become key areas of TB prevention and control, especially in the older population.

Spatial-temporal analysis of pulmonary tuberculosis among students in the Zhejiang Province of China from 2007-2020

Background

Pulmonary tuberculosis (PTB) is a serious chronic communicable disease that causes a significant disease burden in China; however, few studies have described its spatial epidemiological features in students.

Methods

Data of all notified PTB cases from 2007 to 2020 in the student population were collected in the Zhejiang Province, China using the available TB Management Information System. Analyses including time trend, spatial autocorrelation, and spatial-temporal analysis were performed to identify temporal trends, hotspots, and clustering, respectively.

Results

A total of 17,500 PTB cases were identified among students in the Zhejiang Province during the study period, accounting for 3.75% of all notified PTB cases. The health-seeking delay rate was 45.32%. There was a decreasing trend in PTB notifications throughout the period; clustering of cases was seen in the western area of Zhejiang Province. Additionally, one most likely cluster along with three secondary clusters were identified by spatial-temporal analysis.

Conclusion

Although was a downward trend in PTB notifications among students during the time period, an upward trend was seen in bacteriologically confirmed cases since 2017. The risk of PTB was higher among senior high school and above than of junior high school. The western area of Zhejiang Province was the highest PTB risk settings for students, and more comprehensive interventions should be strengthened such as admission screening and routine health monitoring to improve early identification of PTB.

Predictive performance of interferon-gamma release assays and the tuberculin skin test for incident tuberculosis: an individual participant data meta-analysis

BACKGROUND

Evidence on the comparative performance of purified protein derivative tuberculin skin tests (TST) and interferon-gamma release assays (IGRA) for predicting incident active tuberculosis (TB) remains conflicting. We conducted an individual participant data meta-analysis to directly compare the predictive performance for incident TB disease between TST and IGRA to inform policy.

METHODS

We searched Medline and Embase from 1 January 2002 to 4 September 2020, and studies that were included in previous systematic reviews. We included prospective longitudinal studies in which participants received both TST and IGRA and estimated performance as hazard ratios (HR) for the development of all diagnoses of TB in participants with dichotomised positive test results compared to negative results, using different thresholds of positivity for TST. Secondary analyses included an evaluation of the impact of background TB incidence. We also estimated the sensitivity and specificity for predicting TB. We explored heterogeneity through pre-defined sub-group analyses (e.g. country-level TB incidence). Publication bias was assessed using funnel plots and Egger's test. This review is registered with PROSPERO, CRD42020205667.

FINDINGS

We obtained data from 13 studies out of 40 that were considered eligible (N = 32,034 participants: 36% from countries with TB incidence rate ≥100 per 100,000 population). All reported data on TST and QuantiFERON Gold in-Tube (QFT-GIT). The point estimate for the TST was highest with higher cut-offs for positivity and particularly when stratified by bacillus Calmette-Guérin vaccine (BCG) status (15 mm if BCG vaccinated and 5 mm if not [TST^{5/15 mm}]) at 2.88 (95% CI 1.69-4.90). The pooled HR for QFT-GIT was higher than for TST at 4.15 (95% CI 1.97-8.75). The difference was large in countries with TB incidence rate <100 per 100,000 population (HR 10.38, 95% CI 4.17-25.87 for QFT-GIT VS. HR 5.36, 95% CI 3.82-7.51 for TST^{5/15 mm}) but much of this difference was driven by a single study (HR 5.13, 95% CI 3.58-7.35 for TST^{5/15 mm} VS. 7.18, 95% CI 4.48-11.51 for QFT-GIT, when excluding the study, in which all 19 TB cases had positive QFT-GIT results). The comparative performance was similar in the higher burden countries (HR 1.61, 95% CI 1.23-2.10 for QFT-GIT VS. HR 1.72, 95% CI 0.98-3.01 for TST^{5/15 mm}). The predictive performance of both tests was higher in countries with TB incidence rate <100 per 100,000 population. In the lower TB incidence countries, the specificity of TST (76% for TST^{5/15 mm}) and QFT-GIT (74%) for predicting active TB approached the minimum World Health Organization target (≥75%), but the sensitivity was below the target of ≥75% (63% for TST^{5/15 mm} and 65% for QFT-GIT). The absolute differences in positive and negative predictive values between TST^{15 mm} and QFT-GIT were small (positive predictive values 2.74% VS. 2.46%; negative predictive values 99.42% VS. 99.52% in low-incidence countries). Egger's test did not show evidence of publication bias (0.74 for TST^{15 mm} and p = 0.68 for QFT-GIT).

INTERPRETATION

IGRA appears to have higher predictive performance than the TST in low TB incidence countries, but the difference was driven by a single study. Any advantage in clinical performance may be small, given the numerically similar positive and negative predictive values. Both IGRA and TST had lower performance in countries with high TB incidence. Test choice should be contextual and made considering operational and likely clinical impact of test results.

FUNDING

YH, IA, and MXR were supported by the National Institute for Health and Care Research (NIHR), United Kingdom (RP-PG-0217-20009). MQ was supported by the Medical Research Council [MC_UU_00004/07].

Positive rate and risk factors of latent tuberculosis infection among persons living with HIV in Jiangsu Province, China

Objective

To analyze the latent tuberculosis infection (LTBI) among persons living with HIV(PLWH) in Jiangsu Province, to explore the factors affecting the positive rate of LTBI, and to take appropriate measures to control tuberculosis (TB) infection.

Methods

A cross-sectional study was conducted among PLWH in Jiangsu Province from June to July 2021. All PLWH in Jiangsu Province were used as the study population. Currently, the diagnosis of LTBI lacks a "gold standard" and can only be assisted by the immunological method. In this study, Tuberculin skin test (TST), ESAT6-CFP10 test (EC), and QuantiFERON-TB gold in-tube (QFT) were used to detect the positive rate of LTBI among PLWH and to analyze their risk factors.

Results

A total of 340 prisoners were included, 89.7% were male, the median age was 38 years [Interquartile Range (IQR):32-46 years], these patients were on Antiviral Therapy (ART), and median CD4 counts was 376 (IQR: 261-496), 103 (30.3%) were positive in at least one test, LTBI by TST was 16.5%, LTBI by EC was 15.9%, LTBI by QFT was 26.2%. Univariate analysis showed the results for TST, EC, and QFT were not affected by CD4 counts (p>0.05), and multivariate analysis showed that a history of incarceration was associated with an increased risk of positive TST (adjusted odds ratio [aOR]=1.98;95% CI,1.03-3.82), EC (aOR=2.65;95% CI,1.37-5.12) and QFT (aOR=2.01;95%CI,1.12-3.57), in addition, female gender was associated with increased risk of positive TST (aOR=3.66;95%CI,1.60-8.37) and EC (aOR=3.43;95%CI,1.46-8.07), and contact history of TB patients was associated with increased risk of TST (aOR= 2.54;95%CI,1.23-5.22) and QFT (aOR=2.03;95%CI,1.03-3.99), and ethnic minorities (aOR=0.26;95%CI,0.12-0.57), longer duration of incarceration was associated with an increased risk of positive QFT (aOR=1.12;95%CI,1.02-1.24). Conclusions Female gender, and ethnic minorities, history of incarceration, longer duration of incarceration, and contact history of TB patients are risk factors for LTBI among PLWH in Jiangsu Province, and attention should be paid to TB control in this population.

Mycobacterium tuberculosis Infection among 1,659 Silicosis Patients in Zhejiang Province, China

Silicosis is a well-established risk factor for Mycobacterium tuberculosis infection. This study aimed to estimate the burden and risk factors of M. tuberculosis infection. Silicosis patients from Zhejiang Province were screened for M. tuberculosis by sputum culture, chest radiographs, whole-blood gamma interferon (IFN-γ) release assay (QuantiFERON-TB Gold In-Tube [QFT-GIT]), and tuberculin skin test (TST). Potential risk factors for M. tuberculosis were identified. Data for 1,659 patients were obtained from 1,684 participants. Of these, 1,656 (99.8%) were men, and the average age was 58 (54 to 63) years. The prevalence of active tuberculosis (ATB) was 6,340/100,000 (6.34%) people; the proportion of patients with latent tuberculosis infection (LTBI) was 50.6%. Age (odds ratio [OR] = 1.059, 95% confidence interval [CI] = 1.020 to 1.099, P = 0.003), being underweight (OR = 2.320, 95% CI = 1.057 to 5.089, P = 0.036), and having a history of exposure to TB patients (OR = 4.329, 95% CI = 1.992 to 9.434, P < 0.001) were associated with ATB; BCG vaccination could reduce ATB risk in silicosis patients (OR = 0.541, 95% CI = 0.307 to 0.954, P = 0.034). Among patients without ATB, the QFT-GIT positivity rate was 40.5%, which was affected by silicosis severity, while that of TST was 57.2%. BCG vaccination was an independent factor for LTBI risk reduction (OR = 0.612, 95% CI = 0.468 to 0.801, P < 0.001). The quantitative results of QFT-GIT decreased with silicosis stage (H = 6.037; P = 0.048). In conclusion, M. tuberculosis prevalence was high in silicosis patients. BCG vaccination reduced the risk of both ATB and LTBI in silicosis patients. IMPORTANCE This study evaluated the prevalence of Mycobacterium tuberculosis infection in silicosis patients in mainland China and identified the potential risk factors for both active tuberculosis (ATB) and latent tuberculosis infection (LTBI). We believe that our study makes a significant contribution to the literature because we demonstrated that M. tuberculosis prevalence was high among silicosis patients. BCG vaccination was an independent factor that reduced the risk of M. tuberculosis infection in patients with silicosis. Furthermore, we show that the prevalence of LTBI in patients with silicosis may have been underestimated by immunological detection methods. This study can help to identify targeted subgroups prioritized for M. tuberculosis control and to reduce the risk of disease development.

Selection of the cutoff value of the tuberculin skin test for diagnosing students who need preventive treatment: A school-based cross-sectional study

Objective

Tuberculosis outbreaks in schools are common in China. This study aimed to introduce and evaluate a new screening process to help control outbreaks.

Methods

Screening information of students in three schools with tuberculosis outbreaks was collected. QuantiFERON-TB gold in-tube (QFT) results were used as the reference standard to determine the cutoff value of the tuberculin skin test (TST) for diagnosing students who need to have preventive medication.

Results

A total of 1,232 students and teachers from three different schools that all had more than three student patients with tuberculosis were included in this study. In total, 308 (25.0%) students had an induration diameter ≥10 mm; among students in a class different from the index case, the infection rate was 24.4% (264/1,084), which was lower than the rate among students in the same class (29.7%) (P = 0.157). Students in the same class as the index tuberculosis case had a much higher QFT positivity compared to those in a different class (58.1% vs. 7.7%, P < 0.0001). Diagnostic agreement between TST ≥10 mm and QFT was 36.6%. The diagnostic value reached the highest when the induration diameter of TST was ≥9 mm, with a sensitivity and specificity of 94.1% (95% CI: 89.4%–97.1%) and 27.6% (95% CI: 24.9%–30.4%), respectively. The area under the curve (AUC) was 0.664 (95% CI: 0.637–0.690, P < 0.0001).

Conclusion

In tuberculosis outbreaks in schools, if there are three or more cases of students with tuberculosis in a class or if the moderate or strong TST positivity rate is much higher than the normal range in the region, attention should be paid to those with moderately positive TST results. Interferon-gamma release assays (IGRAs) are recommended to be conducted following TST on the day of reading the results, especially among students sharing the same class with the index case. In resource-poor areas lacking IGRAs, the induration diameter of TST can be appropriately reduced from 15 to 9 mm to enhance the sensitivity of TST.

Analysis of the diagnostic efficacy of the QuantiFERON-TB Gold In-Tube assay for preoperative differential diagnosis of spinal tuberculosis

Background

Differential diagnosis of spinal tuberculosis is important for the clinical management of patients, especially in populations with spinal bone destruction. There are few effective tools for preoperative differential diagnosis in these populations. The QuantiFERON-TB Gold In-Tube (QFT-GIT) test has good sensitivity and specificity for the diagnosis of tuberculosis, but its efficacy in preoperative diagnosis of spinal tuberculosis has rarely been investigated.

Method

A total of 123 consecutive patients with suspected spinal tuberculosis hospitalized from March 20, 2020, to April 10, 2022, were included, and the QFT-GIT test was performed on each patient. We retrospectively collected clinical data from these patients. A receiver operating characteristic (ROC) curve was plotted with the TB Ag-Nil values. The cutoff point was calculated from the ROC curve of 61 patients in the study cohort, and the diagnostic validity of the cutoff point was verified in a new cohort of 62 patients. The correlations between TB Ag-Nil values and other clinical characteristics of the patients were analyzed.

Results

Of the 123 patients included in the study, 51 had confirmed tuberculosis, and 72 had non-tuberculosis disease (AUC=0.866, 95% CI: 0.798-0.933, P&lt;0.0001). In patients with spinal tuberculosis, the QFT-GIT test sensitivity was 92.16% (95% CI: 80.25%-97.46%), and the specificity was 67.14% (95% CI: 54.77%-77.62%). The accuracy of diagnostic tests in the validation cohort increased from 77.42% to 80.65% when a new cutoff point was selected (1.58 IU/mL) from the ROC curve of the study cohort. The TB Ag-Nil values in tuberculosis patients were correlated with the duration of the patients’ disease (r=0.4148, P=0.0025).

Conclusion

The QFT-GIT test is an important test for preoperative differential diagnosis of spinal tuberculosis with high sensitivity but low specificity. The diagnostic efficacy of the QFT-GIT test can be significantly improved via application of a new threshold (1.58 IU/mL), and the intensity of the QFT-GIT test findings in spinal tuberculosis may be related to the duration of a patient’s disease.

The effect of BCG vaccination and risk factors for latent tuberculosis infection among college freshmen in China

OBJECTIVES

In this study, we aimed to verify whether Bacillus Calmette-Guérin (BCG) can protect first-year college students against Mycobacterium tuberculosis (MTB) infection by the recombinant fusion protein ESAT6-CFP10 skin test (ECST) or the tuberculin skin test (TST).

METHODS

We conducted a cross-sectional study to assess risk factors for latent tuberculosis infection (LTBI). Vaccine effectiveness of BCG against LTBI, measured by ECST and TST separately, was assessed using multivariable logistic regression.

RESULTS

A total of 7351 college freshmen accepted ECST, whereas 7228 accepted TST. A total of 263 (3.58%) tested positive with ECST and 581 (8.04%) tested positive with TST. BCG was significantly associated with LTBI (ECST: adjusted odds ratio (aOR) = 0.26; 95% CI 0.09 to 0.73; TST: aOR = 0.25; 95% CI 0.13 to 0.49). The BCG protective effect on freshmen living in rural areas (ECST: aOR = 0.16; 95% CI 0.04 to 0.55; TST: aOR = 0.12; 95% CI 0.04 to 0.33) is better than that of freshmen living in cities (ECST: aOR = 0.53; 95% CI 0.07 to 4.03; TST: aOR = 0.44; 95% CI 0.17 to 1.16).

CONCLUSIONS

Protection against LTBI was strongly associated with BCG vaccination. A novel skin test (ECST) may underestimate the protective effects of BCG in college freshmen. BCG has better protection in areas with a slightly higher incidence of LTBI.

Tuberculosis reinfection and relapse in eastern China: A prospective study using whole-genome sequencing

OBJECTIVES

Tuberculosis recurrence after an initial successful treatment episode can occur from either reinfection or relapse. In a population-based sample and whole genome sequencing (WGS) in eastern China, we aimed to evaluate risk factors for tuberculosis recurrence, and assess the proportion of recurrence due to either reinfection or relapse.

METHODS

Successfully treated pulmonary tuberculosis patients with sputum culture positive results were recruited from five cities in Jiangsu Province from 2013-2015 and followed for two years for tuberculosis recurrence. Among patients developing a second tuberculosis episode, WGS was performed to distinguish relapse or reinfection through a distance threshold of 6-single-nucleotide polymorphisms (SNP). We analyzed risk factors for recurrence and epidemiological characteristics of different types of recurrent patients.

RESULTS

Of 1,897 successful treated tuberculosis patients, 7.4% (141/1879) developed recurrent tuberculosis. Compared with non-recurrent tuberculosis, patients were at higher risk of recurrence in older age (Adjusted Odds Ratio [AOR], 1.02 for each additional year; 95% CI, 1.01-1.03, P=0.003), patients previously treated for tuberculosis (AOR=2.22; 95% CI, 1.52-3.26, P<0.001), or with bilateral cavities (AOR, 1.56; 95% CI, 1.05-2.32, P=0.029). Among 27.0% (38/141) recurrent tuberculosis patients with successfully sequenced pairs, relapse was substantially more common than reinfection (71.1% versus 28.9%, P=0.014).

CONCLUSIONS

Endogenous relapse was significantly more common than exogenous reinfection in the first two years after treatment in eastern China. Prioritization of high-risk groups for recurrence, such as the elderly, with a previous tuberculosis diagnosis, or with bilateral cavities, may provide opportunities to reduce post-tuberculosis morbidity.

Upregulation of PD-1 expression on circulating CD8+ but not CD4+ T cells is associated with tuberculosis infection in health care workers

Background

Health care workers (HCWs) are at risk for occupationally acquired Mycobacterium tuberculosis infection and tuberculosis (TB) disease due to repeated exposure to workplace tubercle bacilli. To determine whether continual mycobacterial stimulation correlates with increased expression of inhibitory T cell receptors, here we compared PD-1 receptor expression on surfaces of circulating T cells between naïve (uninfected) HCWs and HCWs with latent TB infection (LTBI).

Result

Data collected from 133 medical workers who met study selection criteria were included in the final analysis. QuantiFERON-TB Gold In-​Tube (QFT-GIT) testing yielded positive results for 32 HCWs, for an overall LTBI rate of 24.1%. Multivariate analysis identified HCW length of service > 15 years as an independent risk factor for a positive QFT-GIT result. In addition, comparisons of blood T cell subgroup profiles between QFT- and QFT+ groups indicated QFT+ subjects possessed greater proportions of mature (TM), transitional memory (TTM) and effector memory (TEM) CD4+ T cell subgroups and lower proportions of naïve T cells (TN). Moreover, the QFT+ group percentage of CD8+ T cells with detectable surface PD-1 was significantly higher than the corresponding percentage for the QFT- group. Meanwhile, no statistical intergroup difference was observed in percentages of CD4+ T cells with detectible surface PD-1.

Conclusions

Our data demonstrated that upregulated PD-1 expression on circulating CD8+, but not CD4+ T cells, was associated with latent TB infection of HCWs. As compared to other hospitals, occupational TB infection risk in our hospital was substantially mitigated by implementation of multitiered infection control measures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00433-9.

A risk score for prediction of poor treatment outcomes among tuberculosis patients with diagnosed diabetes mellitus from eastern China

Persons living with diabetes (PLWD) with newly diagnosed tuberculosis are at greater risk of poor treatment outcomes. Identifying and prioritizing high-risk subgroups of PLWD and tuberculosis for tuberculosis programs to target has been rarely performed. We investigated risk factors for poor tuberculosis treatment outcomes among PLWD and developed a predictive risk score for tuberculosis control prioritization. Among PLWD diagnosed with tuberculosis, demographic, clinical, and tuberculosis treatment outcome data were collected. Poor treatment outcomes included treatment failure, death, default, and transfer. Multivariable logistic regression modeling was used to analyze risk factors of poor treatment outcomes. Risk scores were derived based on regression coefficients to classify participants at low-, intermediate-, and high-risk of poor treatment outcomes. Among 335 PLWD newly diagnosed with tuberculosis, 109 were cured and 172 completed treatment. Multivariable logistic regression found that risk factors of poor treatment outcomes included bacteriologically-positivity, low body mass index, no physical activity, and pulmonary cavitation. Rates of poor treatment outcomes in low- (0-2), intermediate- (3-4), and high-risk (5-8) groups were 4.2%, 10.5%, and 55.4% (Ptrend < 0.0001), respectively. The risk score accurately discriminated poor and successful treatment outcomes (C-statistic, 0.85, 95% CI 0.78-0.91). We derived a simple predictive risk score that accurately distinguished those at high- and low-risk of treatment failure. This score provides a potentially useful tool for tuberculosis control programs in settings with a double burden of both tuberculosis and diabetes.

Sensitivity, specificity, and safety of a novel ESAT6-CFP10 skin test for tuberculosis infection in China: two randomized, self-controlled, parallel-group phase 2b trials

BACKGROUND

Diagnostics to identify tuberculosis infection are limited. We aimed to assess the diagnostic accuracy and safety of the novel ESAT6-CFP10 (EC) skin test for tuberculosis infection in Chinese adults.

METHODS

We conducted two randomized, parallel-group clinical trials in healthy participants and tuberculosis patients. All participants were tested with the T-SPOT.TB test, then received EC skin test and tuberculin skin test (TST). The diameter of skin indurations and/or redness at injection sites were measured at different time periods. A Bacillus Calmette Guerin (BCG) model was also established to assess the diagnosis of tuberculosis infection using EC skin test.

RESULTS

In total, 777 healthy participants and 96 tuberculosis patients were allocated to receive the EC skin test at 1.0μg/0.1ml or 0.5μg/0.1ml. The area under the curve was 0.95 (95% CI, 0.91-0.97) from the EC skin test at a dose of 1.0μg/0.1ml at 24-72 hours. Compared to the T-SPOT.TB test, the EC skin test demonstrated similar sensitivity (87.5, 95% CI 77.8-97.2 versus 86.5, 95% CI 79.5-93.4) and specificity (98.9, 95% CI 96.0-99.9 versus 96.1, 95% CI 93.5-97.8). Among BCG vaccinated participants, the EC skin test had high consistency with the T-SPOT.TB test (96.3, 95% CI, 92.0-100.0). No serious adverse events related to the EC skin test were observed.

CONCLUSIONS

The EC skin test demonstrated both high specificity and sensitivity at a dose of 1.0μg/0.1ml, comparable to the T-SPOT.TB test. The diagnostic accuracy of the EC skin test was not impacted by BCG vaccination.