A high-throughput screening assay based on automated microscopy for monitoring antibiotic susceptibility of Mycobacterium tuberculosis phenotypes

BackgroundEfficient high-throughput drug screening assays are necessary to enable the discovery of new anti-mycobacterial drugs. The purpose of our work was to develop and validate an assay based on live-cell imaging which can monitor the growth of two distinct phenotypes of Mycobacterium tuberculosis and to test their susceptibility to commonly used TB drugs.ResultsBoth planktonic and cording phenotypes were successfully monitored as fluorescent objects using the live-cell imaging system IncuCyte S3, allowing collection of data describing distinct characteristics of aggregate size and growth. The quantification of changes in total area of aggregates was used to define IC50 and MIC values of selected TB drugs which revealed that the cording phenotype grew more rapidly and displayed a higher susceptibility to rifampicin. In checkerboard approach, testing pair-wise combinations of sub-inhibitory concentrations of drugs, rifampicin, linezolid and pretomanid demonstrated superior growth inhibition of cording phenotype.ConclusionsOur results emphasize the efficiency of using automated live-cell imaging and its potential in high-throughput whole-cell screening to evaluate existing and search for novel antimycobacterial drugs.

Automated summary

The study demonstrates the effectiveness of using automated live-cell imaging to monitor different growth phenotypes of Mycobacterium tuberculosis and evaluate their susceptibility to anti-TB drugs. Results show that the cording phenotype is more susceptible to drugs like rifampicin, indicating the potential advantage of this method in screening and evaluating anti-tuberculosis drugs.