[Identification of L-forms of Mycobacterium tuberculosis complex by polymerase chain reaction (PCR)]

Polymerase chain reaction (PCR) was used to verify the tuberculous origin of L-forms isolated from clinical non-respiratory samples from patients with extrapulmonary tuberculosis. PCR was made by using cultured L-forms obtained from negative and positive cultures. PCR used a total of 60 cultured L-forms different in the morphology of colonies and the rate of growth. The total count of L-forms yielding positive amplification with M. tuberculosis complex-specific primers was 51 (85%). L-form passages were subjected to PCR analysis. A total of 14 third-generation L-forms were examined. They turned out to be positive. Thus, the fact that L-forms isolated from nonrespiratory clinical samples from patients with tuberculosis are most commonly L-forms of M. tuberculosis was genetically substantiated.