[Isolation of mycobacteria L forms as a prognostic criterion of recurrence and aggravation of tuberculosis in patients with extended residual tuberculous lesions of the lungs].

To elucidate the role of tubercle bacilli L-forms in tuberculosis relapsing and aggravation in patients with extended residual lesions in the lungs, 117 patients mainly with extended and neglected destructive tuberculosis of the lungs were observed for a period of 5 to 7 years with using microbiological and clinico-roentgeno-laboratory examinations. Analysis of the immediate and remote results of the treatment showed that in the group of the abacillary patients according to the routine microbiological investigations who continued to isolate L-forms of tubercle bacilli at the background of remaining destructive cavities in the lungs aggravations and relapses amounted to 46.6 per cent. The etiological role of the L-forms was proved by absolute identity of the biological properties of the L-form revertants isolated from in vitro subcultures and tubercle bacilli, isolated from the patients during the process relapsing.