Submitted to: Applied and Environmental Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/21/2003
Publication Date: 3/1/2004
Citation: Debroy, C., Roberts, E., Kundrat, J., Davis, M.A., Briggs, C.E., Fratamico, P.M. 2004. Detection of escherichia coli serotypes 026 and 0113 by pcr amplification of the wzx and wzy genes. Applied and Environmental Microbiology. 2004. v. 70(3):1830-1832. Interpretive Summary: The bacterium, Escherichia coli, causes a variety of diseases in humans and animals, and non-harmful E. coli types, or serogroups, also exist. A procedure called serotyping is commonly performed to distinguish between the different E. coli types. This procedure relies on use of antisera raised in rabbits against different components found on the surface of the E. coli. Serotyping, however, can generally only be performed in specialized laboratories, is labor intensive, and may require several days to complete, and often serotyping results in cross reactivity of one antiserum with multiple E. coli serogroups, rendering identification difficult. Thus, due to the lack of simple and rapid methods for detection and identification of E. coli and to distinguish harmful and non-harmful E. coli, the incidence of disease caused by specific E. coli serogroups may be underestimated. Furthermore, epidemiological studies are difficult to perform. E. coli serogroups O26 and O113, referred to as enterohemorrhagic E. coli, have caused human diarrheal diseases. Thus, to develop a more rapid and simple method for detection and identification of these E. coli serogroups, a technique known as the polymerase chain reaction (PCR), based on amplification of genes involved in coding specific surface components of E. coli serogroups O26 and O113, was developed and used for detection of these organisms in apple juice. Thus, use of these specific PCR assays enhances the ability to detect, identify, and type E. coli O26 and E. coli O113 eliminating the use of the labor-intensive serotyping procedure.
Technical Abstract: Polymerase chain reaction (PCR)-based assays for detecting enterohemorrhagic Escherichia coli (EHEC) serogroups O26 and O113 were developed by targeting the wzx (O antigen flippase) and wzy (O antigen polymerase) genes in the O antigen gene clusters of each organism. The PCR assays were specific for the respective serogroups, as there was no amplification of DNA from non-O26 and non-O113 E. coli serogroups or from the other bacterial genera tested. Using the PCR assays, the organisms were detected in seeded apple juice inoculated at levels as low as 10 CFU/ml. Thus, the O26- and O113-specific PCR assays can potentially be used for typing E. coli serogroups O26 and O113 and to detect these EHEC in food, fecal, and environmental samples.