Nonspecific reactions of a commercial enzyme-linked immunosorbent assay kit (TECRA) for detection of staphylococcal enterotoxins in foods
| Autor: | C E Park, M K Rayman, M Akhtar |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Staphylococcus aureus
Enzyme-Linked Immunosorbent Assay Enterotoxin medicine.disease_cause Applied Microbiology and Biotechnology Sensitivity and Specificity Microbiology Sepharose Enterotoxins Affinity chromatography medicine False Positive Reactions Chromatography Ecology biology medicine.diagnostic_test Chemistry biology.organism_classification Proteus mirabilis Latex fixation test Evaluation Studies as Topic Immunoassay Food Microbiology Enterobacter cloacae Food Analysis Food Science Biotechnology Research Article |
| Zdroj: | Applied and environmental microbiology. 58(8) |
| ISSN: | 0099-2240 |
| Popis: | A staphylococcal enterotoxin visual immunoassay kit (TECRA) has recently become commercially available. Since the kit is an enzyme-linked immunosorbent assay system equipped with polyvalent antisera against staphylococcal enterotoxin types A to E (SEA to SEE) and the test is simple and rapid to perform (4 h), it has been widely used for screening purposes. In this study, the sensitivity of the kit for detection of SEA, SEB, and SEC in ham, cheese, and mushrooms was similar to those of kits based on an enzyme immunoassay and reversed passive latex agglutination: 0.75 to 1.0 ng of SEA per ml, 0.5 to 0.75 ng of SEB per ml, and 1.0 to 1.25 ng of SEC per ml. However, the TECRA kit showed nonspecific reactions with food samples contaminated by microorganisms other than Staphylococcus aureus, such as Enterobacter agglomerans, Enterobacter cloacae, Proteus mirabilis, Pseudomonas aeruginosa, and Serratia marcescens. The substance contributing to the false-positive results differed from true staphylococcal enterotoxins in that it was (i) heat labile (completely inactivated by heating for 2 min at 100 degrees C, whereas true staphylococcal enterotoxins were inactivated by about 10% with this treatment), (ii) lower in molecular weight than staphylococcal enterotoxins, and (iii) not bound 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 problem of false-positive results with the TECRA kit could be resolved by heat treatment (2 min at 100 degrees C) or by cleanup procedures involving metal chelate affinity chromatography with copper chelate Sepharose for 4 h before use of the TECRA kit. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|