COMPARISON OF CULTURE AND ACID-FAST BACILLI STAIN TO PCR FOR DETECTION OF MYCOBACTERIUM-TUBERCULOSIS IN CLINICAL-SAMPLES

The major drawback in effective use of polymerase chain reaction (PCR) for detectinng Mycobacterium tuberculosis (MTB) in clinical samples i s the presence of PCR inhibitors and unique cell components of the org anism that complicate DNA extraction and subsequent PCR amplification. A PCR assay with a unique multistep DNA extraction method that minimi zes these problems was compared in a prospective study to acid-fast ba cilli stain (AFBS) and culture for detecting MTB in clinical samples. A total of 254 clinical specimens in two separate studies were process ed for MTB by these techniques. While PCR and culture were 100% sensit ive and specific, culture required up to 8 weeks of incubation and add itional time to perform biochemical testing to identify the isolated m icro-oganism. Acid-fast bacilli slain had a specificity of about 87% a nd did not differentiate among Mycobacterial species. In contrast, the results from PCR were available within 48 h and did not require addit ional testing to attain a final result. Polymerase chain reaction was highly reliable for detection and confirmation and interpretation of p ositive AFBS results. The assay was easy to perform with a turn around time of about 2 days. (C) 1998 Academic Press.