Py-MAB-Tof detection and Identification of microorganisms in urine

Abstract

Rapid detection and identification of bacteria and other microorganisms has become a field where new analytical methods are needed. An approach, based on the use of pyrolysis coupled to mass spectrometry (Py-MS), for the detection and identification of bacteria in urine and other aqueous samples is described. In this procedure, the sample is placed on a direct insertion probe and pyrolysis is conducted directly into the ion source of the mass spectrometer. Ionization is achieved with a metastable atom bombardment source (MAB). In contrast to electron ionization, this novel ionization source, by providing discrete ionization energies, allows selective ionization and control over fragmentation. The MAB source is coupled to a time-of-flight (Tof) mass analyzer that provides high sensitivity and fast spectral acquisition. Experiments conducted with a number of uropathogenic bacteria, such as Escherichia coli, Citrobacter freundii, Proteus mirabilis and Pseudomonas aeruginosa, reveal that they provide discernable fingerprints when analyzed in urine samples by Py-MAB-Tof. Results can be obtained in minutes and the sensitivity is such that 10 4 bacteria on the pyrolysis probe are required for analysis.