ABSTRACT
OBJECTIVE: The aim of study was to develop a rapid assay, dye labelled monoclonal antibody assay (DLMAA), using non-radioactive organic synthetic dyes for identification of Toxic Shock Syndrome Toxin-1 (TSST-1) producing strains of Staphylococcus aureus. MATERIALS AND METHODS: The assay protocol required only two simple steps; addition of TSST-1 antigen to a nitrocellulose membrane and then adding a colloidal dye labelled antibody (D/A) suspension detection reagent. RESULTS: The sensitivity and specificity of the assay was determined relative to positive and negative strains compared to an ELISA assay. Overall 100% agreement was found between both assays. The sensitivity for detection of TSST-1 was 30 ng. CONCLUSION: The DLMAA did not require handling and disposal of radioactive materials. It is a rapid qualitative technique for detection of TSST-1 toxin at room temperature within a short time.
ABSTRACT
AIMS: To develop a competitive agglutination inhibition assay (CAIA) for the detection of anti-Toxic Shock Syndrome Toxin-1 (TSST-1) antibody in serum samples using a commercially available reverse passive agglutination assay (RPLA) kit. METHODS AND RESULTS: TSST-1 toxin and sera were incubated together, so that anti-toxin IgG would complex with the toxin. Latex particles sensitized with rabbit IgG anti-TSST-1 were added to test for un-complexed toxin. The sensitivity and specificity of the CAIA assay was determined relative to positive and negative ELISA results. The sensitivity (proportion of positive ELISA sera which tested positive by CAIA) was 66% whilst the specificity (proportion of ELISA negative sera which tested negative by CAIA) was 75%. Seven sera (14%) were negative by ELISA but positive for CAIA and 12 (18.8%) were positive for ELISA but negative for CAIA, suggesting some interference with the assays. Statistical analysis showed no significant difference between the methods in terms of the numbers of individuals testing positive (chi2, P = 0.04). CONCLUSIONS: The CAIA assay allowed detection of anti-TSST-1 within 18 h and was simple to read visually. SIGNIFICANCE AND IMPACT OF THE STUDY: The method is a useful test for individual serum samples and a preliminary investigation for medical screening of suspected toxic shock syndrome and is applicable in situations where antibody assays are not routinely used for anti-TSST-1 and also where sophisticated equipment (e.g. microtitre plate reader) is not available.