Sensitivity of immunoperoxidase and immunofluorescence staining for detecting chlamydia in conjunctival scrapings and in cell culture.

The sensitivities of Giemsa, immunofluorescence, and immunoperoxidase staining for the detection of Chlamydia psittaci inclusions in conjunctival scrapings and in irradiated McCoy cell monolayers were compared. Conjunctival specimens were obtained from a cat colony in which a trachoma-like disease, feline chlamydial keratoconjunctivitis, was endemic. The two immunochemical techniques were found to be of equal sensitivity and 50% to 100% more sensitive than Giemsa stain. Permanent preparations of immunoperoxidase stained material can be made and can be read using a simple light microscope. These features make the technique more useful than immunofluorescence staining, which gives temporary preparations that must be examined with a specialised fluorescence microscope.