Bioluminescence method to evaluate antimicrobial agents against Mycobacterium avium

Area of Science:

• Microbiology
• Molecular Biology
• Antimicrobial Resistance

Background:

• Mycobacterium avium complex (MAC) poses a significant challenge in treating infections, particularly in immunocompromised individuals.
• Accurate and rapid susceptibility testing is crucial for effective antimicrobial therapy against MAC.
• Traditional methods for determining antimicrobial susceptibility can be time-consuming.

Purpose of the Study:

• To develop and validate a novel bioluminescence-based assay for evaluating antimicrobial susceptibility in Mycobacterium avium.
• To assess the utility of the firefly luciferase reporter system for rapid drug susceptibility testing of M. avium.

Main Methods:

• Transformation of Mycobacterium avium A5 with the pLUC10 plasmid encoding the firefly luciferase gene.
• Measurement of bioluminescence production in the transformed strain (A5(pLUC10)) using a microplate luminometer.
• Evaluation of antimicrobial susceptibility using the luciferase microplate assay in parallel with conventional broth macrodilution.

Main Results:

• The transformed strain A5(pLUC10) exhibited significantly higher bioluminescence compared to the parental strain.
• A rapid decrease in bioluminescence (< or = 10% of controls) was observed within 3 days in the presence of inhibitory drug concentrations.
• The results from the luciferase microplate assay showed a close correlation with Minimum Inhibitory Concentrations (MICs) determined by the conventional method.

Conclusions:

• The luciferase microplate assay provides a convenient and reliable method for evaluating in vitro antimicrobial activity against the M. avium complex.
• This bioluminescence-based approach offers a potentially faster alternative to conventional susceptibility testing for M. avium.
• The reporter strain A5(pLUC10) is a valuable tool for rapid antimicrobial susceptibility testing.