Quantifying Viable M. tuberculosis Safely Obviating the Need for High Containment Facilities

Area of Science:

• Microbiology
• Infectious Diseases
• Public Health

Background:

• Mycobacterium tuberculosis (MTB) requires Biosafety Level-3 (BSL-3) containment, posing risks and high costs for diagnostics.
• Limited infrastructure in low- and middle-income countries restricts access to essential tuberculosis diagnostics.
• Developing cost-effective and safe diagnostic methods is crucial for global tuberculosis control.

Purpose of the Study:

• To describe a method for inactivating Mycobacterium tuberculosis in sputum samples.
• To ensure inactivation does not compromise bacterial quantification for diagnostic purposes.
• To eliminate the need for BSL-3 containment for tuberculosis molecular bacterial load assays (TB-MBLA).

Main Methods:

• Sputum samples were inactivated using heat treatment.
• Sputum samples were inactivated using guanidine thiocyanate (GTC).
• The quantification of viable bacteria was assessed after inactivation procedures.

Main Results:

• Both heat treatment and GTC inactivation rendered sputum samples safe for handling.
• Inactivation methods did not significantly affect the quantification of viable Mycobacterium tuberculosis.
• The described method enables TB-MBLA without requiring BSL-3 laboratory facilities.

Conclusions:

• Sputum inactivation offers a safe and cost-effective alternative for TB-MBLA.
• This approach significantly improves accessibility of tuberculosis diagnostics in resource-limited settings.
• The method supports global efforts to control tuberculosis by overcoming infrastructure barriers.