Diagnosing pulmonary tuberculosis by pooling induced sputum

Etiologic Investigation of Patients Diagnosed with Bacteriologically Unconfirmed Tuberculosis in Tanzania

Globally, half of patients with pulmonary tuberculosis (PTB) are diagnosed clinically without bacteriologic confirmation. In clinically diagnosed PTB patients, we assessed both the proportion in whom PTB could be bacteriologically confirmed by reference standard diagnostic tests and the prevalence of diseases that mimic PTB. We recruited adult patients beginning treatment of bacteriologically unconfirmed PTB in Moshi, Tanzania, in 2019. We performed mycobacterial smear, Xpert MTB/RIF Ultra, and mycobacterial culture, fungal culture, and bacterial culture on two induced sputum samples: fungal serology and computed tomography chest scans. We followed participants for 2 months after enrollment. We enrolled 36 (63%) of 57 patients with bacteriologically unconfirmed PTB. The median (interquartile range) age was 55 (44-67) years. Six (17%) were HIV infected. We bacteriologically confirmed PTB in 2 (6%). We identified pneumonia in 11 of 23 (48%), bronchiectasis in 8 of 23 (35%), interstitial lung disease in 5 of 23 (22%), pleural collections in 5 of 23 (22%), lung malignancy in 1 of 23 (4%), and chronic pulmonary aspergillosis in 1 of 35 (3%). After 2 months, 4 (11%) were dead, 21 (58%) had persistent symptoms, 6 (17%) had recovered, and 5 (14%) were uncontactable. PTB could be bacteriologically confirmed in few patients with clinically diagnosed PTB and clinical outcomes were poor, suggesting that many did not have the disease. We identified a high prevalence of diseases other than tuberculosis that might be responsible for symptoms.

Comparable detection of nasopharyngeal swabs and induced sputum specimens for viral nucleic acid detection of suspected novel coronavirus (SARS-Cov-2) patients in Fayoum governorate, Egypt

Background

The most commonly utilized samples for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) are nasopharyngeal swabs (NPS) and oropharyngeal swabs. However, there are some drawbacks. For SARS-CoV-2 detection, induced sputum might be analyzed and may be equivalent to pharyngeal swabs. This study was done to assess the potential superiority of induced sputum over NPS for SARS-CoV-2 detection. Sixty symptomatic COVID-19 patients who attended Fayoum University Hospitals in Fayoum Governorate, Egypt, were included in this cross-sectional descriptive study. Paired NPS and induced sputum samples were collected from each subject on the third and tenth days after symptoms began for RT-qPCR SARS-COV2 diagnosis.

Results

At day 3, 52 (86.7%) of NPS and 48 (80.00%) of induced sputum specimens had positive RT-qPCR results with a significant statistical difference (P = 0.001). At day 10, 41 induced sputum samples (68.3%) were negative, while 19 (31.7%) were positive. Only three (5.0%) of the 19 positive induced sputum samples tested positive for NPS. NPS samples had a higher viral load than induced sputum samples at day 3 [25 (41.7%) vs. 23 (38.3%)]. At day 10, induced sputum samples had a higher viral load than NPS [9 (15.0%) vs. 6 (10.0%)]. A statistically significant positive correlation between the viral load value of the NPS and the induced sputum sample at day 3 (r = 0.497, p = 0.00) denoting similarity in the results of the two types of samples. By ROC analysis, the highest area under the curve for the overall CT value of the induced sputum was (0.604), with a statistically significant difference (p value = 0.0418).

Conclusion

In the early stages of the disease, induced sputum and NPS tests had comparable results, but NPS yielded more false negative results later in the disease course than an induced sputum sample, which yielded higher sample positivity and viral load than NPS. Furthermore, induced sputum collection is a straightforward, non-invasive, and risk-free method. As a result, induced sputum could be useful for COVID-19 confirmation in patients with radiologically or epidemiologically suspected COVID-19 who have a negative NPS or in difficult-to-diagnose COVID-19 patients.

Screening performance of C-reactive protein for active pulmonary tuberculosis in HIV-positive patients: A systematic review with a meta-analysis

Background

Tuberculosis (TB) is the leading infectious cause of mortality worldwide. In the last years, resistant strains of the etiological agent, Mycobacterium tuberculosis, have emerged, thus demanding more triage tests to identify active pulmonary TB (PTB) patients and to evaluate their disease severity. Therefore, acute-phase reaction serum tests are required for monitoring TB patients, among WHO symptom screening recommendations. C-reactive protein (CRP) is a non-specific inflammatory biomarker that has been recently proposed for TB screening and can be quantitatively analyzed through cost-effective point-of-care assays. A previous meta-analysis found CRP to be highly sensitive and moderately specific for active PTB with confirmed HIV infection.

Methods

We performed a meta-analysis update of diagnostic tests, pooling sensitivities, and specificities in order to assess the accuracy of CRP as a potential test for the screening of HIV-associated PTB in outpatients. We searched MEDLINE, Web of Science, and SCOPUS for eligible articles before 19 October 2021.

Results

We identified 13 eligible studies with HIV-positive patients with PTB. At a CRP threshold of 10 mg/L, CRP pooled sensitivity was 87% (76%–93%) and pooled specificity was 67% (49%–81%), with an area under the curve (AUC) of 0.858. Using a CRP threshold of 8 mg/L, pooled sensitivity was 82% (72%–89%) and pooled specificity was 82% (67%–92%), with an AUC of 0.879. We found that CRP has a high sensitivity in the screening of PTB in HIV-positive outpatients, consistent with findings reported previously.

Conclusions

Regardless of pooled specificity, better results were found using the CRP threshold of 8 mg/L as a test screening of PTB, meeting the need of further approaching specific TB diagnostic methods and reducing resource consumption.