Rapid, Sensitive Assay for Staphylococcal Enterotoxin and a Comparison of Serological Methods

Abstract

Reversed passive hemagglutination was used to assay enterotoxin in culture filtrates and in food samples. With cells tanned and then sensitized with antitoxin globulin and preserved with either formaldehyde or pyruvic aldehyde, as little as 0.0007 ,ug of enterotoxin was detectable. The results of hemagglutination tests compared well with those obtained by quantitative precipitin tests or by immunodiffusion, but hemagglutination was 50 to 100 times more sensitive than the immunodiffusion technique. In addition, results of the hemagglutination test were available within a few hours, and neither elimination of interfering proteins from food extracts nor concentration of the sample, both of which are necessary for immunodiffusion, was required for this procedure.

Toxigenicity inStaphylococcus aureusand Coagulase-Negative Staphylococci: Epidemiological and Molecular Aspects

“…RPHG (Reverse Passive Hemagglutination), which uses the adsorption of specifi c antibodies in red blood cells, was the fi rst method employed to be regarded as truly sensitive as it is capable of detecting 1 ng/g of enterotoxin present in food. The disadvantages of method are nonspecifi c hemagglutination and the diffi culty in adsorbing certain antibodies on the surface of red blood cells [87].…”

Rapid Solid-Phase Radioimmunoassay for Staphylococcal Enterotoxin A

“…Solid-phase radioimmunoassay is the fastest, simplest radioimmunoassay system available and is quantitatively reliable and specific in a variety of media. There are more sensitive methods, e.g., the familiar micro-Ouchterlony procedure of Casman and Bennett (2) and the reverse passive hemagglutination which is subject to cross-reaction and not quantitatively reliable (10). However, they are cumbersome both in time and in the required processing of specimens before use.…”