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Detection Yield and Tolerability of String Test for Diagnosis of Childhood Intrathoracic Tuberculosis

  • 2015/11/11
Type de publication
  • Articles
  • Nansumba M
  • Kumbakumba E
  • Orikiriza P
  • Muller Y
  • Nackers F
  • Debeaudrap P
  • Boum Y 2nd
  • Bonnet M
  • Tuberculose

BACKGROUND: Difficulty to obtain sputum in children complicates diagnosis of intrathoracic tuberculosis (TB). The intra-gastric string test (ST) used for retrieval of enteric pathogens might be an alternative specimen collection method, but requires further evaluation of its utility in TB diagnosis. We conducted a cross-sectional study comparing the TB detection yield and the tolerability of ST and sputum induction (SI) in children. METHODS: Two ST and SI procedures were performed in children (3-14 years of age) who were clinically suspected of having TB. The string was removed after a 2-hour gastric downtime and SI was done after a maximum of 20 minutes nebulization with 5% saline solution. LED-fluorescence microscopy and mycobacterial cultures were performed on all specimens and XpertMTB/RIF assay was performed on stored specimen sediments. Tolerability questionnaires were administered to parents of children. RESULTS: Of 137 included children (median age: 8.1 years; 33.3% with HIV infection), 14 (10.2%) were diagnosed with TB, 10 (71.4%) by ST and 12 (85.7%) by SI. Among 105 children with both ST and SI performed, 5 (4.8%) versus 4 (3.8%) were smear-positive using ST and SI, respectively (McNemar p= 1.00). Nine (8.6%) in each group had positive cultures (p= 1.00). Of 64 children tested with XpertMTB/RIF, 3 (4.7%) of the ST group versus 4 (6.3%) of the SI group were TB positive (p=1.00). No adverse serious events were reported. ST could not be performed in 22/137 (16.1%) children because they were unable to swallow the capsule. CONCLUSIONS: TB detection yield was comparable between ST and SI. The tolerability of ST in young children might be improved by the reduction of the size of the capsule