Rapid detection of Pseudomonas aeruginosa by phage-capture system coupled with micro-Raman spectroscopy

The early and accurate identification of medically relevant microorganisms like Pseudomonas aeruginosa is of great importance for human health. Current pathogen identification is routinely performed using conventional microbiological methods which are unable to detect fastidious organism that are difficult to culture and occur at low concentrations without time consuming multiple cultivation steps. This study reports the development of a novel rapid and cultivation-free method for highly sensitive and rapid detection of Pseudomonas aeruginosa based on the coupling of phage-capture system with optical techniques, namely FTIR and visible micro-Raman spectroscopies. Commercial latex beads were functionalized with the entire structure of engineered phage clones and used as bacterial capture and concentrating system. The rapid concentration of bacteria enhanced the detection of the Raman scattering signal by increasing the location concentration that is being processed. This method can be used to detect a low level of P. aeruginosa (10cells/ml) from clinical samples without the use of selective media or additional biochemical tests. The sample testing process, including data acquisition, required a time less than one hour. The proposed system represents a proof of concept study for development of sensitive phage-based biosensors for rapid and specific one-step detection of pathogenic bacteria.