Evaluating the non-tuberculous mycobacteria effect in the tuberculosis infection diagnosis.
The aim of the present study was to determine the role of previous non-tuberculous mycobacteria sensitisation in children as a factor of discordant results between tuberculin skin test (TST) and an in vitro T-cell based assay (T-SPOT.TB; Oxford Immunotec, Oxford, UK). We enrolled 21 non-bacille Calmette-Guérin-vaccinated paediatric patients for suspicious of latent tuberculosis infection (LTBI). These patients yielded a positive TST and a negative T-SPOT.TB. Cells were stimulated with Mycobacterium avium sensitin (having cross-reaction with Mycobacterium intracellulare and Mycobacterium scrofulaceum) and the presence of reactive T-cells was determined by an ex vivo ELISPOT. From the 21 patients, in 10 cases (47.6%), we obtained a positive ELISPOT result after stimulation with M. avium sensitin, in six (28.6%) cases, the result was negative and in the remaining five (23.8%) cases, the result was indeterminate. In conclusion, previous non-tuberculous mycobacteria sensitisation induces false-positive results in the TST for diagnosing LTBI and the use of gamma-interferon tests could avoid unnecessary chemoprophylaxis treatment among a child population.
Latorre
I
I
Servei de Microbiologia, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Carretera del Canyet s/n, 08916 Badalona Barcelona Spain.
De Souza-Galvão
M
M
Ruiz-Manzano
J
J
Lacoma
A
A
Prat
C
C
Altet
N
N
Ausina
V
V
Domínguez
J
J
D000293:Adolescent; D001424:Bacterial Infections; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D055985:Latent Tuberculosis; D008297:Male; D009161:Mycobacterium / Q000378:metabolism*; D009162:Mycobacterium avium / Q000276:immunology*; D012189:Retrospective Studies; D014374:Tuberculin Test / Q000379:methods; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology*
D007371:Interferon-gamma