Severe acute respiratory syndrome coronavirus 2 seroprevalence among patients with pulmonary tuberculosis.

OBJECTIVE: The objective of this study was to estimate the seroprevalence of severe acute respiratory syndrome coronavirus 2 antibodies in patients with tuberculosis. METHODS: This cross-sectional study was conducted at an outpatient tuberculosis clinic in Alvorada, RS, Brazil, with data collection between October and December 2020. Outpatients aged>18 years with active pulmonary tuberculosis, no prior history of coronavirus disease 2019, and no suspected coronavirus disease 2019 were included in the study. Whole blood samples were collected to perform the severe acute respiratory syndrome coronavirus 2 antibodies test. RESULTS: During the study period, 52 patients met the inclusion and were included in the analysis. Severe acute respiratory syndrome coronavirus 2 antibodies were positive in 16 (30.8%) patients. Male sex was more frequent among patients with negative severe acute respiratory syndrome coronavirus 2 antibodies than in patients with positive severe acute respiratory syndrome coronavirus 2 antibodies (86.1 vs. 56.3%, p=0.031). Contact with coronavirus disease 2019 case was more common in patients with positive severe acute respiratory syndrome coronavirus 2 antibodies compared with patients with negative severe acute respiratory syndrome coronavirus 2 antibodies (87.5 vs. 8.3%, p<0.0001). In a multivariate analysis, in a model including the variables such as male sex and contact with coronavirus disease 2019 case, only contact with coronavirus disease 2019 was independently associated with positive severe acute respiratory syndrome coronavirus 2 antibodies (OR 77.0, 95%CI 11.5-512.4, p<0.0001). CONCLUSION: This study revealed a seroprevalence of 30.8% severe acute respiratory syndrome coronavirus 2 among patients with tuberculosis.

Severe acute respiratory syndrome coronavirus 2 seroprevalence among patients with pulmonary tuberculosis

SUMMARY OBJECTIVE: The objective of this study was to estimate the seroprevalence of severe acute respiratory syndrome coronavirus 2 antibodies in patients with tuberculosis. METHODS: This cross-sectional study was conducted at an outpatient tuberculosis clinic in Alvorada, RS, Brazil, with data collection between October and December 2020. Outpatients aged>18 years with active pulmonary tuberculosis, no prior history of coronavirus disease 2019, and no suspected coronavirus disease 2019 were included in the study. Whole blood samples were collected to perform the severe acute respiratory syndrome coronavirus 2 antibodies test. RESULTS: During the study period, 52 patients met the inclusion and were included in the analysis. Severe acute respiratory syndrome coronavirus 2 antibodies were positive in 16 (30.8%) patients. Male sex was more frequent among patients with negative severe acute respiratory syndrome coronavirus 2 antibodies than in patients with positive severe acute respiratory syndrome coronavirus 2 antibodies (86.1 vs. 56.3%, p=0.031). Contact with coronavirus disease 2019 case was more common in patients with positive severe acute respiratory syndrome coronavirus 2 antibodies compared with patients with negative severe acute respiratory syndrome coronavirus 2 antibodies (87.5 vs. 8.3%, p<0.0001). In a multivariate analysis, in a model including the variables such as male sex and contact with coronavirus disease 2019 case, only contact with coronavirus disease 2019 was independently associated with positive severe acute respiratory syndrome coronavirus 2 antibodies (OR 77.0, 95%CI 11.5-512.4, p<0.0001). CONCLUSION: This study revealed a seroprevalence of 30.8% severe acute respiratory syndrome coronavirus 2 among patients with tuberculosis.

Association of Xpert MTB/RIF Cycle Threshold Values with Tuberculosis Treatment Outcomes.

PURPOSE: Considering the current recommendation of the World Health Organization to replace sputum smear microscopy with Xpert MTB/RIF as an initial diagnostic test for tuberculosis (TB), and that culture takes time to provide results, the cycle threshold (CT) of the Xpert test may be the only way to assess bacillary load. The objective of this study is to evaluate the association of bacillary load, measured by the Xpert CT, with the TB treatment outcomes. METHODS: In cohort study, Xpert CT values were evaluated in cured and non-cured (failure and death) patients. Multivariate analysis was performed to evaluate if CT is independently associated with TB treatment outcomes. RESULTS: During this study period, 155 patients (84 cured and 71 non-cured) met the inclusion and were included in the analysis. The mean CT value for Xpert MTB/RIF test was 20.7 ± 5.6 in cured patients and 17.1 ± 5.6 in non-cured patients (p < 0.0001). Previous TB was more frequent in non-cured (28.2%) than in cured patients (7.1%) (p < 0.0001). Non-cured patients were younger than cured ones (37.1 ± 13.3 vs 43.6 ± 16.2; p = 0.006). HIV was more frequent in non-cured (28.2%) than in cured patients (15.5%), although this difference was not statistically significant (p = 0.054). In multivariate analysis, CT values, age, previous TB, and HIV were independently associated with non-cure. CONCLUSIONS: Lower Xpert MTB/RIF CT values were independently associated with worse treatment outcomes. The information from even a single test performed before starting treatment proved to be a relatively good predictor of TB treatment outcome.

Evaluation of Xpert MTB/RIF Ultra performance for pulmonary tuberculosis (TB) diagnosis in a city with high TB incidence in Brazil.

INTRODUCTION: Since 2018, World Health Organization (WHO) recommended the Xpert MTB/RIF Ultra use for pulmonary and extrapulmonary TB diagnosis, and suggested that Xpert Ultra should be tested in various populations, with different geographical and epidemiological settings. METHODS: Cross-sectional study with prospective data collection. Outpatients aged >18 years with respiratory symptoms suggestive of pulmonary TB were invited to participate. Sensitivity, specificity, positive and negative predictive values of the test were calculated and compared with the traditional Xpert MTB/RIF. RESULTS: During the study period, 180 patients met the inclusion and were included in the analysis. Xpert MTB/RIF Ultra test was positive in 33 patients (18.3%), and RIF resistance was detected in 1 (3.1%) patient. Considering culture as the gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value of Xpert MTB/RIF Ultra were 100.0% (95% CI 85.2-100.0), 93.6% (95% CI 88.6-96.9), 69.7% (95% CI 55.8-80.7), and 100.0% (95% CI 87.2-100.0), respectively. The area under the ROC curve was 0.97 for the Xpert MTB/RIF Ultra test (95% CI 0.93 to 0.99; p < 0.0001). There was no difference statistically significant between sensitivities and specificities of Xpert MTB/RIF and Xpert MTB/RIF Ultra (p > 0.05). CONCLUSIONS: This is the first study in Brazil to evaluate the accuracy of Xpert MTB/RIF Ultra in individuals with presumptive pulmonary TB. The test showed an excellent sensitivity and a high specificity, demonstrating that it is a useful tool for pulmonary TB diagnosis.

Association of Radiological Findings with the Xpert MTB/RIF Test in Patients with Suspected Pulmonary Tuberculosis.

PURPOSE: Tuberculosis (TB) treatment is often carried out empirically, based on clinical and radiological findings. Chest X-ray (CXR) has good sensitivity but poor specificity in TB diagnosis. Xpert MTB/RIF (Mycobacterium tuberculosis/Rifampicin) is increasingly used in many countries as the initial diagnostic test for TB. The aim of the present study was to evaluate the association of radiological findings with the Xpert MTB/RIF test in patients with suspected pulmonary TB. METHODS: Cross-sectional study in an outpatient TB clinic. Sputum AFB smear, culture, Xpert MTB/RIF, and CXR were collected in patients with suspected pulmonary TB. RESULTS: During the study period, 312 patients met the inclusion criteria and were included in the analysis. Among Xpert MTB/RIF-positive cases, the radiographic patterns were classified as typical of TB, compatible of TB, and normal in 78 (70.3%), 31 (27.9%), and 2 (1.8%) patients, respectively. CXRs were classified as typical of TB, compatible of TB, and normal in 20 (10.0%), 25 (12.4%), and 152 (75.6%) patients, respectively, in Xpert MTB/RIF-negative cases. CONCLUSIONS: We found an association between radiographic patterns and Xpert MTB/RIF results in patients with suspected pulmonary TB. These results confirm the current recommended diagnosis algorithm.

Impact of introduction of Xpert MTB/RIF test on tuberculosis (TB) diagnosis in a city with high TB incidence in Brazil.

BACKGROUND: Xpert MTB/RIF is increasingly used in many countries as the initial diagnostic test for tuberculosis (TB). Few studies have evaluated the effect of Xpert on TB diagnosis under programmatic conditions in Brazil. The aim of the present study was to evaluate the impact of introduction of Xpert MTB/RIF on TB diagnosis in a city with high TB incidence in Brazil. METHODS: We included patients evaluated with conventional diagnostic tests during one year before Xpert introduction (pre-Xpert group) and patients evaluated using Xpert during one year after the test introduction (post-Xpert group). RESULTS: 620 patients met the inclusion criteria (208 in the pre-Xpert group and 412 in the post-Xpert group) and were included in the analysis. The time until TB diagnosis was shorter in post-Xpert group (0.7 day, IQR: 0.5-1.0 day) than in pre-Xpert group (2.0 days, IQR: 2.0-2.0 days) (p<0.0001). Atypical disease characteristics, such as less weight loss, fever, dyspnea, night sweats, and hemoptysis; a negative sputum smear; a negative culture, and a chest X-ray atypical of TB were more common in post-Xpert group than in pre-Xpert group (p<0.0001 for all). CONCLUSIONS: We found that the implementation of the Xpert MTB/RIF assay, under programmatic conditions, improve and facilitate TB diagnosis, especially in cases with atypical disease manifestations. These results are likely to be generalizable to settings with a similar high TB incidence.

Diagnostic performances of the Xpert MTB/RIF in Brazil.

BACKGROUND AND OBJECTIVES: As for all tests, the diagnostic performances of Xpert MTB/RIF might be different in settings with different tuberculosis prevalence. Aim of the study is to evaluate the performances of Xpert MTB/RIF to diagnose tuberculosis in Brazil, where 407 culture-confirmed tuberculosis patients were retrospectively enrolled in Rio Grande do Sul, between 2015 and 2016. METHODS: Sensitivity, specificity, positive and negative predictive values of the test were calculated and a logistic regression analysis was performed to assess the role played by explanatory variables in the occurrence of true positive and negative diagnostic results. RESULTS: Sensitivity of Xpert MTB/RIF was 100.0%, specificity 92.8%; positive and negative predictive values were 71.4% and 100.0%, respectively. In the HIV- infected sub-group specificity was 59.3%. In the multivariate logistic regression analysis, true positivity was associated with increasing age (1.0; p-value: 0.02) while true positivity and negativity were negatively associated with alcohol abuse. CONCLUSIONS: Xpert is sensitive and specific in the Brasilian settings.