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[Detection of Mycobacterium tuberculosis in sputum using PCR and chemoluminescent display]
J C Rodríguez1, E Fuentes, G Royo
1Laboratorio de Microbiología, Hospital General Universitario de Elche, Universidad de Alicante.
Background:
Polymerase chain reaction (PCR) using a probe with revealed chemoluminescence applied to the rapid diagnosis of pulmonary tuberculosis was used to detect Mycobacterium tuberculosis in sputum samples.
Methods:
The sputum samples were treated with proteinase K, SDS, NaOH and CTAB. A fragment of the IS6110 sequence of Mycobacterium tuberculosis detected by a probe marked with digoxigenin and revealed chemoluminescence was amplified.
Results:
The detection limit of the technique was situated at 10 mycobacteria per sample. Of 120 samples with a positive culture, 88 were positive by chemoluminescence probe (73.3%). The sensitivity decreased to 68.6% (35/51) in samples with negative staining and positive culture.
Conclusions:
The application of molecular biology techniques are a good diagnostic alternative in samples with negative staining and clinical suspicion of tuberculosis. Our system is a cheaper alternative than the commercial systems and is applicable in laboratories unable to use radioactive isotopes.