Reactivity of a dual amplified chlamydia immunoassay with different serovars of Chlamydia trachomatis

A study was undertaken with different serovars (D, E, F, L2, MoPn) of Chlam ydia trachomatis to determine the analytical sensitivity of a new dual ampl ified immunoassay (IDELA PCE Chlamydia) for detecting chlamydial lipopolysa ccharide. IDEIA PCE Chlamydia incorporates a polymer conjugate consisting o f multiple copies of antibody and enzyme molecules to provide signal amplif ication. The test was also assessed with different protein A producing stra ins of Staphylococcus aureus in order to assess whether the use of a multip le antibody conjugate increased nonspecific binding. The detection limits v aried for each serovar with a detection limit of 38 IFU/ml obtained with se rovar F and 237 IFU/ml obtained with serovar D. The incorporation of the po lymer conjugate resulted in a 2-5 fold increase in analytical sensitivity c ompared to an earlier version of the test using a conventional conjugate. N o increase in cross reactivity with protein A producing strains of S. aureu s was obtained. The new dual amplified test format offers potential as a se nsitive low-cost screening assay for C. trachomatis infections.