Examination of respiratory specimens improves microbiological diagnosis of patients with presumptive extrapulmonary tuberculosis

Objectives: Bacteriological confirmation of extrapulmonary tuberculosis (EPTB) is challenging for several reasons: the paucibacillary nature of the sample; scarce resources, mainly in middle and low-income countries; the need for hospitalization; and unfavorable outcomes. We evaluated the diagnostic role of respiratory specimen examination prospectively in a cohort of patients with presumptive EPTB. Methods: From July 2018 to January 2019, in a tuberculosis (TB)/HIV reference hospital, a cohort of 157 patients with presumed EPTB was evaluated. Xpert1 MTB/RIF Ultra or a culture-positive result was considered for bacteriologically confirmed TB. Results: Out of 157 patients with presumptive EPTB, 97 (62%) provided extrapulmonary and respiratory specimens and 60 (38%) extrapulmonary specimens only. Of the 60 patients with extrapulmonary samples, 5 (8%) were positive. Of those with respiratory and extrapulmonary samples, 27 (28%) were positive: 10 in both the respiratory and extrapulmonary samples, 6 in the extrapulmonary sample only, and 11 in the respiratory sample only. A respiratory specimen examination increased by 6-fold the chance of bacteriological confirmation of TB (odds ratio = 5.97 [1.11-47.17]). Conclusion: We conclude that respiratory samples should be examined in patients with presumptive EPTB. (C) 2021 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.

Automated summary

The study evaluated the diagnostic role of respiratory specimen examination in patients with presumptive EPTB, and found that examining respiratory samples can significantly increase the likelihood of bacteriological confirmation of TB. It is recommended that respiratory samples be examined in patients with presumptive EPTB for better diagnosis.