September 7, 2009 22 Comments
The Infectious Disease group at Merck have (finally) published a couple of papers related to the bacterial “fitness test” we developed at Elitra Pharmaceuticals. Check out the paper “A Staphylococcus aureus Fitness Test Platform for Mechanism-Based Profiling of Antibacterial Compounds” in the current issue of Cell Chemistry & Biology, which describes the design of this innovative experiment.
The S. aureus fitness test a product of work we did at Elitra Pharmaceuticals, extending the invention by Allyn Forsyth* to engineer bacterial strains (via antisense) to control the expression of individual genes and therefore become more sensitive to antimicrobial compounds acting through specific targets. By pooling a collection of engineered strains corresponding to all of the essential genes of S. aureus and screening antimicrobial compounds, we were able to discover targets for antimicrobial compounds whose mechanism of action had not yet been determined. We later collaborated with Merck to apply the fitness test to, among other things, their library of natural products. Merck acquired the technology platform after Elitra shut down.
My particular contribution to the experiment was in coming up with the method for using unique fluorescently-labeled PCR primers corresponding to each of the individual essential gene bacterial strains and resolving them on a gel (capillary) using a multiplexing strategy. I continue to believe that this approach is superior to using microarrays (an alternative successfully used by other groups) since the sensitivity of capillary eletrophoresis allowed for semi-quantitative analysis of the multiplex PCR results, and was quite flexible to iterations on the pooling and multiplex PCR design.
Congratulations to the Merck team for these publications and their commitment to the project.