Navigating a Path to Rifampicin Resistance in Tuberculosis

Area of Science:

• Microbiology
• Genetics
• Infectious Diseases

Background:

• Antibiotic resistance in bacteria often originates from tolerant subpopulations.
• The mechanism of resistance development in Mycobacterium tuberculosis (tuberculosis cause) from tolerant cells remains unclear.

Purpose of the Study:

• To investigate whether antibiotic resistance in Mycobacterium tuberculosis arises from pre-existing tolerant subpopulations.
• To determine the contribution of classical tolerance and differentially detectable (DD) bacilli to rifampicin resistance.

Main Methods:

• Utilized a robotic transwell microtiter system for parallel culture of Mycobacterium tuberculosis.
• Employed deep sequencing of a barcoded library to track bacterial subpopulations.
• Investigated classical tolerance (prolonged minimum duration of killing) and DD bacilli (viable but unculturable on plates).

Main Results:

• Rifampicin resistance in Mycobacterium tuberculosis preferentially arises from both classical tolerant and DD bacilli subpopulations.
• Resistance emerged earlier in the DD bacilli population compared to the classical tolerant population.
• Barcoded libraries and parallel culturing are effective for studying minority bacterial subpopulations.

Conclusions:

• Antibiotic resistance in Mycobacterium tuberculosis is significantly influenced by tolerant subpopulations.
• Differentially detectable (DD) bacilli play a crucial role in the early development of rifampicin resistance.
• Advanced techniques like barcoded libraries offer new avenues for understanding resistance mechanisms in bacterial pathogens.