Citation:

DONOHUE, M. J., J. BEST, W. SMALLWOOD, M. KOSTICH, M. R. RODGERS, AND J. A. SHOEMAKER. DIFFERENTIATION OF AEROMONAS ISOLATES OBTAINED FROM DRINKING WATER DISTRIBUTION SYSTEM USING MATRIX-ASSISTED LASER DESCRIPTION/IONIZATION-MASS SPECTROMETRY (MALDI-MS). Analytical Chemistry. American Chemical Society, Washington, DC, 79(5):1939-1946, (2007).

Impact/Purpose:

This particular task is comprised of 4 subtasks: 1.) Characterization of Potential Viral Biomarkers by Mass Spectrometry; 2.) Characterization of Parasites by Mass Spectrometric Techniques;

3.) Rapid Discrimination of Bacterial Indicators of Fecal Contamination and Bacterial Pathogens by Mass Spectrometric Techniques; and 4.) Investigation of Aeromonas Virulence Factors Using Mass Spectrometry.

The purpose of this research project is to use mass spectrometric techniques, such as electrospray ionization (ESI), capillary electrophoresis (CE) and matrix assisted laser desorption ionization (MALDI) mass spectrometry, to provide "protein mass fingerprinting" and protein sequencing information for viruses, bacteria and protozoa that cause waterborne disease. These protein mass fingerprinting libraries will be evaluated to determine whether mass spectrometric techniques can identify protein fingerprints related to the infectivity/viability of selected microorganisms and whether they can differentiate between infective / non-infective genus and strains of the selected microorganisms. The characteristic proteins identified by mass spectrometry as markers of infectivity/viability or strain differentiation can then be used to develop more sensitive microbiological drinking water methods.

Description:

The genus Aeromonas is one of several medically significant genera that have gained prominence due to their evolving taxonomy and controversial role in human diseases. In this study, matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) was used to analyze the whole cells of both reference strains and unknown Aeromonas isolates obtained from water distribution systems. A library of over 45 unizue m/z signatures was created from 40 strains that are representative of the seventeen recognized species of Aeromonas, as well as three reference strains from genus Vibrio and two reference strains from Plesiomonas shigelloides. The library was used to help speciate 52 isolates of Aeromonas. The environmental isolates were broken up into two blind studies. Group 1 contained isolates that had a recognizable phenotypic profile and Group 2 contained isolates that had an atypical phenotypic profile. MALDI-MS analysis of the water isolates in Group 1 matched the phenotypic identification in all cases. In Group 2, the MALDI-MS based determination confirmed the identity of 18 of the 27 isolates. These results demonstrate the MALDI-MS analysis can rapidly and accurately classify species of the genus Aeromonas, making it a powerful tool especially suited for environmental monitoring and detection of microbial hazards in drinking water.

Record Details: