Rapid molecular assay and strain typing methods of extrapulmonary tuberculosis

Abstract

Objective To evaluate the effect of Mycobacterium tuberculosis Direct Assay (MTD) for rapid detecting Mycobacterium tuberculosis rRNA and Multi-locus PCR for M.bovis BCG strain typing in patients with suspected extra-pulmonary tuberculosis. Methods From June 2010 to December 2011,47 children and 75 adult patients with suspected extra-pulmonary tuberculosis in Shanghai public health clinical center were recruited.Also 48 non-tuberculosis patients were taken as a negative control.Clinical specimens from these patients were collected.Acid fast stain,solid culture,liquid culture,and MTD were used to detect all clinical specimens simultaneously.Screen tuberculosis strains of the culture isolates by MPT64 antigen assay and use Multi-locus PCR for the BCG strain genotyping of the isolates without MPT64 antigen.SPSS16.0 was used to analyse the results. Results The sensitivity for acid fast stain,solid culture,liquid culture and MTD test was 10.7% (13/122),11.5% (14/122),16.4% (20/122) and 37.7% (46/122),respectively.And the specificity of MTD was 100.0%.Six clinical isolates from children were identified as BCG by Multi-locus PCR typing,the same with chemical tests. Conclusions The MTD assay and the MGIT960 liquid culture are effective and reliable method for diagnosing extra-pulmonary tuberculosis.And Multi-locus PCR can be assisted for the early diagnosis of extra-pulmonary tuberculosis patients with suspected BCG infection.(Chin J Lab Med,2013,36:620-624) Key words: Mycobacterium tuberculosis; RNA; ribosomal; Bacterial typing techniques; Polymerase chain reaction