Proposition of a safe Mycobacterium tuberculosis complex denaturation method that does not compromise the integrity of DNA for whole-genome sequencing.

Whole-genome sequencing plays now a leading role in epidemiologic studies of tuberculosis. DNA extraction of Mycobacterium tuberculosis complex (MTBC) requires complete inactivation of the strains, to be handled for further molecular procedures. In this study we compared two chloroform-based denaturation methods (one with a step of heat killing, one without) to a traditional heat inactivation method. Our results showed that 40% of the strains of MTBC treated by the traditional protocol resulted in a positive culture whereas no culture was observed with the two chloroform-based protocols. The DNA extracts obtained with chloroform-based protocols preparation were successfully used for whole-genome sequencing. We recommend inactivation with our rapid and efficient denaturation method using chloroform without heat killing which met our expectations and biosecurity requirements.