Dados do Trabalho

Título

ACCURACY OF XPERT MTB/RIF ULTRA VS. LIQUID CULTURE IN SPUTUM SAMPLES FROM CHILDREN IN A MULTICENTRIC BRAZILIAN STUDY

Introdução

Mycobacterial culture for tuberculosis (TB) diagnosis remains the “gold standard” method despite having a lower sensitivity in children due to the paucibacillary nature of TB, and the long time waiting for a result. In this line, the World Health Organization (WHO) endorses the use of the molecular biology technique Xpert MTB/RIF Ultra (GeneXpert® Cepheid) as the initial diagnostic test in all children suspected of having TB.

Objetivo (s)

We aimed to evaluate the accuracy of Xpert MTB/RIF Ultra versus liquid culture in sputum samples collected from children.

Material e Métodos

Cross-sectional study in 22 Brazilian local sites. Children between 6 months to <15 years old were prospectively enrolled in two different types of health services (hospital and specialized outpatient clinics) from December 2021 to mid May 2023. All participants underwent sputum collection, and the same sample analyzed by Xpert MTB/RIF Ultra and liquid culture (using the Mycobacteria Growth Indicator Tube - MGIT method). The positivity of molecular biology technique was defined as: not detected or detected (high, medium, low, very low, trace). Diagnostic accuracy was calculated using the epiR package to estimate sensitivity and specificity values. Exact method was used to calculate 95% confidence intervals for all estimates.

Resultados e Conclusão

486 participants were screened and 406 were included, with a median age of 3.8 (IQR: 1.7-7.0). 229/406 (56.4%) had valid Xpert MTB/RIF Ultra and MGIT results and 11/406 had culture contamination. 88.6% (203/229) of the participants had induced sputum collection. 216/229 (94.3%) participants had negative TB results in both techniques (Xpert MTB/RIF Ultra and MGIT), 7/229 (3.1%) were TB positive in MGIT and Xpert MTB/RIF Ultra (2 high, 1 medium, 2 low and 2 trace detection), 4/229 (1.7%) had TB detection in Xpert MTB/RIF Ultra (all trace-positive) and were negative in MGIT, and 2/229 (0.9%) were positive in MGIT and negative in Xpert MTB/RIF Ultra. Specificity was 77.8% (95%CI, 40.0-97.2) and the sensitivity was 98.2% (95%CI, 95.4-99.5). These partial results indicate, at the moment, that the Xpert MTB/RIF Ultra presents high sensitivity but an inferior ability to identify non-ill patients. However, this is an ongoing study and more participants will be included and tested.

Palavras-chave

sputum, accuracy, tuberculosis, children.

Agradecimentos

This work was supported by the PROADI-SUS in collaboration with Hospital Moinhos de Vento.