|CLOTILDE, LAURIE - Food And Drug Administration(FDA)|
|Bernard Iv, Clay|
|LIN, ANDREW - Food And Drug Administration(FDA)|
|LAUZON, CAROL - California State University|
|MULDOON, MARK - Romer Laboratories|
|XU, YICHUN - Sdix|
Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2014
Publication Date: 2/4/2015
Citation: Clotilde, L., Bernard Iv, C., Lin, A., Salvador, A., Lauzon, C., Muldoon, M., Xu, Y., Carter, J.M. 2015. Comparison of antibody- versus pcr-based assays for serotyping shiga toxin-producing escherichia coli recovered from various cattle operations. Foodborne Pathogens and Disease. 12(2):118-121.
Interpretive Summary: We now know that O157:H7 is not the only kind of E coli that causes problems. Many other types of E coli can produce the Shiga toxins that cause severe disease in humans. Shiga toxin producing E coli (STEC) can be detected and have their type determined using two general kinds of tests. One kind, an immunoassay, uses antibodies that are specific for binding to the complex carbohydrates coating the outside of the bacteria. The other kind is a genetic test, which is specific for the genes of these characteristics. We have attached both kinds of test to fluorescent magnetic microbeads, in such a way that we can run several tests at once using one small sample. In this paper we compared the two microbead methods and showed that the genetic test is slightly better than the immunoassay. Both of our tests were useful for typing E coli found in cattle feces from a variety of beef and dairy farming operations. Tests like these can help track and predict outbreaks of foodborne disease caused by STEC.
Technical Abstract: Serotyping of Shiga toxin-producing Escherichia coli (STEC) strains is contingent upon the availability of quality antisera. In this study, the serogroup of 161 STEC strains typed by conventional antisera and isolated from the fecal samples of California cattle were compared to two newly developed multiplexed PCR- and antibody-based microbead assays using the Luminex technology. Of the tested STEC strains, a total of 33, 21, 30, and 77 isolates belonging to 10, 10, 10, and 18 STEC serogroups were detected and serotyped by conventional antisera in cattle in dairy farms, feedlots, grazing irrigated pastures, and on the range, respectively. In the dairy farms and feedlots, E. coli O157 was the predominant serogroup, while in the cow-calf operations (i.e.,in irrigated pastures and on the range), STEC O26 and O125 were the predominant serogroups, respectively. The newly developed Luminex assays were capable of serotyping 11 STEC isolates that were previously determined untypeable for the O antigen using conventional antisera. Except for 14 isolates, results from the two Luminex assays agreed.