OBJECTIVE: To evaluate the performance of the Gen-Probe Amplified MTD® Test (AMTD) for childhood tuberculosis (TB) diagnosis compared to conventional culture. DESIGN: We retrospectively studied 121 childhood cases (73 males; median age 7 years, range 1-16). Pulmonary samples (104/152, 68%) included gastric aspirates (n = 53), induced sputum samples (n = 43), bronchial aspirates and bronchoalveolar lavage (n = 8). Extra-pulmonary samples (48/152, 32%) included lymph nodes (n = 34) and other sterile fluids (n = 14). Specimens were examined using acid-fast bacilli (AFB) microscopy, AMTD and bacterial culture using BACTEC™ MGIT™ 960 and Löwenstein-Jensen (LJ) media. RESULTS: A clinical diagnosis of TB was made in 50/121 (41%) children (43/50 pulmonary disease). AFB microscopy was positive in 6%; Mycobacterium tuberculosis was recovered by culture from 16/50 (32%) and AMTD was positive in 29/50 (58%). AMTD sensitivity, specificity, positive predictive value and negative predictive value compared to culture were respectively 100%, 85%, 50% and 100%. For pulmonary vs. extra-pulmonary disease, the performance of AMTD compared to culture was respectively 100%, 77%, 46% and 100% vs. 100%, 97.5%, 75% and 100%. CONCLUSIONS: Nucleic acid amplification tests are more sensitive and very specific methods for the rapid detection of M. tuberculosis. The AMTD technique increases TB detection in children compared to conventional culture.
OBJECTIVE: To evaluate the performance of the Gen-Probe Amplified MTD® Test (AMTD) for childhood tuberculosis (TB) diagnosis compared to conventional culture. DESIGN: We retrospectively studied 121 childhood cases (73 males; median age 7 years, range 1-16). Pulmonary samples (104/152, 68%) included gastric aspirates (n = 53), induced sputum samples (n = 43), bronchial aspirates and bronchoalveolar lavage (n = 8). Extra-pulmonary samples (48/152, 32%) included lymph nodes (n = 34) and other sterile fluids (n = 14). Specimens were examined using acid-fast bacilli (AFB) microscopy, AMTD and bacterial culture using BACTEC™ MGIT™ 960 and Löwenstein-Jensen (LJ) media. RESULTS: A clinical diagnosis of TB was made in 50/121 (41%) children (43/50 pulmonary disease). AFB microscopy was positive in 6%; Mycobacterium tuberculosis was recovered by culture from 16/50 (32%) and AMTD was positive in 29/50 (58%). AMTD sensitivity, specificity, positive predictive value and negative predictive value compared to culture were respectively 100%, 85%, 50% and 100%. For pulmonary vs. extra-pulmonary disease, the performance of AMTD compared to culture was respectively 100%, 77%, 46% and 100% vs. 100%, 97.5%, 75% and 100%. CONCLUSIONS: Nucleic acid amplification tests are more sensitive and very specific methods for the rapid detection of M. tuberculosis. The AMTD technique increases TB detection in children compared to conventional culture.
Authors: Juliana Maria Azevedo de Lyra; Magda Maruza; Mirela Verza; Maria Madileuza Carneiro; Maria de Fátima Militão de Albuquerque; Maria Lúcia Rossetti; Ricardo Ximenes; Maria Cynthia Braga; Norma Lucena-Silva Journal: Mem Inst Oswaldo Cruz Date: 2014-08-29 Impact factor: 2.743