Characterization of Yersinia species by protein profiling using automated microfluidic capillary electrophoresis

Abstract

Yersinia pestis is a biological agent of high risk to national security due to its ability to be easily disseminated and transmitted among humans. If Y. pestis was to be utilized in a deliberate disease outbreak it would be essential to rapidly and accurately identify the agent. Current identification methods for Yersinia species are limited by their reliance on cultivation, the time taken to achieve results and/or the use of protocols that are not amenable for field use. Faster identification methods are urgently required. Microfluidic capillary electrophoresis was used to identify seven Yersinia species based on their protein profiles. Further objectives included determining if Yersinia species could be detected in mixtures of milk products and Escherichia coli, determining if Yersinia could be detected in a blinded identification and reproducibility across two platforms. Two characteristic protein bands were detected at 50 kilodaltons (kDa) and between 50 and 75 kDa for the Yersinia species. Individual Yersinia species could be differentiated from one another and distinguished from E. coli, Bacillus anthracis Sterne strain and Dipel (containing Bacillus thuringiensis). Due to the high protein content of milk products Yersinia could not be detected when mixed with these but was detected when mixed with E. coli. Species were correctly identified with 96% success in blinded procedures using 12 individuals. Whilst protein profile patterns were reproducible across platforms there was some discrepancy in protein sizing. This study demonstrates that protein profiling using microfluidic capillary electrophoresis is able to rapidly and reproducibly identify and characterize Yersinia species. Results show this technique is a powerful front-line, rapid and broad range screening method capable of identifying and differentiating biological agents, hoax agents and environmental bacterial species.