Chronology of Morphological Forms of Mycobacterium bovis Rapid-Growing Strain

The study aimed to examine the changes observed in the morphology of rapid-growing tuberculosis pathogen strain, degree of pathogenicity, sensitized properties, and content of lipids, which depend on the pH of the medium, for 180 inoculations of 1-3 days culture. The reversion of non-acid-resistant forms of Mycobacterium bovis of the rapid-growing strain to bacterial acid-resistant forms occurred because of the following reasons: formation of non-acid-resistant grains in thread-like M. bovis, transformation and fragmentation of non-acid-resistant thread-like forms into acid-resistant rod-shaped bacteria, and output from non-acid-resistant thread-like M. bovis acid-resistant forms. It was found that increasing the number of passages of M. bovis of the rapid-growing strain through the medium at pH 6.7 led to a probable decrease (p<0.05) in the content of total lipids; fractions of phospholipids, triacylglycerols, and sterin ethers; and an increase in the number of diacylglycerols, sterins, and free fatty acids (FFAs). It is established that the decrease in saturated and long-chain fatty acids and the increase in unsaturated and short-chain fatty acids were accompanied by the loss of virulence of mycobacteria. Of the 19 FFAs, nine tended to disappear from the cell wall.