Abstract
The TECRA kit, a commercial staphylococcal enterotoxin visual immunoassay kit, is an enzyme-linked immunosorbent assay system which utilizes polyvalent antisera against staphylococcal enterotoxin types A to E. The test is simple and rapid to perform (4 h) and has therefore been widely used for screening purposes. In this study, the TECRA kit produced a number of false-positive reactions with seafood; 25% of 218 samples of seven types of seafood gave false-positive results, particularly shellfish such as mussels (85%), clams (32%), oysters (23%), winkles (20%), and squid (13%). Some nonshellfish samples also gave false-positive results with the TECRA kit (smelt [20%] and trout [10%]). The substance contributing to the false-positive results differed from true staphylococcal enterotoxins in that it was: (i) heat labile, being completely inactivated by heating for 3 min at 70 degrees C, compared with 5% inactivation of true staphylococcal enterotoxins by the same heat treatment, (ii) in a selective reaction with normal rabbit or calf serum (nonspecific reactions were completely abolished by these sera, whereas staphylococcal enterotoxins were not affected), and (iii) incapable of binding to a copper-chelate Sepharose gel (all of the substance remained in the unbound wash fraction, whereas staphylococcal enterotoxins were quantitatively bound to the gel). The false-positive reactions occurring with seafood were not associated with substances produced by microorganisms, since the bacterial isolates from the samples did not give positive results with the TECRA kit.(ABSTRACT TRUNCATED AT 250 WORDS)
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Evenson M. L., Hinds M. W., Bernstein R. S., Bergdoll M. S. Estimation of human dose of staphylococcal enterotoxin A from a large outbreak of staphylococcal food poisoning involving chocolate milk. Int J Food Microbiol. 1988 Dec 31;7(4):311–316. doi: 10.1016/0168-1605(88)90057-8. [DOI] [PubMed] [Google Scholar]
- Lachica R. V., Genigeorgis C., Hoeprich P. D. Metachromatic agar-diffusion methods for detecting staphylococcal nuclease activity. Appl Microbiol. 1971 Apr;21(4):585–587. doi: 10.1128/am.21.4.585-587.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Park C. E., Akhtar M., Rayman M. K. Nonspecific reactions of a commercial enzyme-linked immunosorbent assay kit (TECRA) for detection of staphylococcal enterotoxins in foods. Appl Environ Microbiol. 1992 Aug;58(8):2509–2512. doi: 10.1128/aem.58.8.2509-2512.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Park C. E., El Derea H. B., Rayman M. K. Evaluation of staphylococcal thermonuclease (TNase) assay as a means of screening foods for growth of staphylococci and possible enterotoxin production. Can J Microbiol. 1978 Oct;24(10):1135–1139. doi: 10.1139/m78-185. [DOI] [PubMed] [Google Scholar]
- Park C. E., Szabo R. Evaluation of the reversed passive latex agglutination (RPLA) test kits for detection of staphylococcal enterotoxins A, B, C, and D in foods. Can J Microbiol. 1986 Sep;32(9):723–727. doi: 10.1139/m86-131. [DOI] [PubMed] [Google Scholar]
- Porath J., Carlsson J., Olsson I., Belfrage G. Metal chelate affinity chromatography, a new approach to protein fractionation. Nature. 1975 Dec 18;258(5536):598–599. doi: 10.1038/258598a0. [DOI] [PubMed] [Google Scholar]
- Rose S. A., Bankes P., Stringer M. F. Detection of staphylococcal enterotoxins in dairy products by the reversed passive latex agglutination (SET-RPLA) kit. Int J Food Microbiol. 1989 Feb;8(1):65–72. doi: 10.1016/0168-1605(89)90081-0. [DOI] [PubMed] [Google Scholar]
- Wieneke A. A. Comparison of four kits for the detection of staphylococcal enterotoxin in foods from outbreaks of food poisoning. Int J Food Microbiol. 1991 Dec;14(3-4):305–312. doi: 10.1016/0168-1605(91)90122-6. [DOI] [PubMed] [Google Scholar]