Optical Molecular Diagnostics and System Technology

Aim: To countermeasure the global spread of β-lactamases, we developed a rapid molecular test for the highly variable OXA-β-lactamases that allows minimizing the time to effective treatment. Methods: OXA-mRNA was specifically enriched from total RNA using groupspecific biotinylated DNA probes and streptavidin-coated magnetic beads. Phylogenetic OXA groups were distinguished by PCR product size. Results: This mRNA fishing method is highly sensitive, yielding specific results from as little as 1 ng total RNA. It enables discrimination of OXA-extended substrate spectrum β-lactamases and carbapenemases and the semiquantitative detection of highly expressed ISAba1-controlled variants. Conclusion: Targeting mRNA with specific probes on magnetic beads will allow for adaptation to automated systems, such as point-of-care diagnostics.