Rapid and spontaneous loss of phthiocerol dimycocerosate (PDIM) from Mycobacterium tuberculosis grown in vitro: implications for virulence studies.

ABSTRACT: Isolated in vitro more than half a century ago, the H37Rv strain of Mycobacterium tuberculosis still remains the strain of choice for the majority of laboratories conducting in vivo studies of TB pathogenesis. In this report we reveal that H37Rv is highly prone to losing the ability to synthesize the cell wall lipid phthiocerol dimycocerosate (PDIM) during extended periods of in vitro culture. In addition, H37Rv stocks that have been held in vitro for even a short length of time should be thought of as a heterogeneous population of PDIM-positive and PDIM-negative cell types. We demonstrate that after weekly subculture of PDIM-positive isolates over a period of 20 weeks, the proportion of PDIM-negative cells rises above 30 %. That PDIM biosynthesis is negatively selected in vitro is evident

SUBMITTER: Domenech P 

PROVIDER: S-EPMC5154741 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature