[The quantitation of Pseudomonas aeruginosa elastase in suppurative chronic otitis media using a sensitive ELISA...

A sensitive sandwich ELISA method has been developed in order to quantitate the Pseudomonas aeruginosa elastase (PE) of ear discharge from chronic suppurative otitis media (CSOM) patients. Samples were incubated with EDTA-2Na before ELISA in order to inhibit the PE activity which hydrolyzes anti-PE IgG antibody into smaller molecular fragments. Quantitation of PE in middle ear effusions (MEE) from 10 patients with chronic otitis media with effusion (OME) were also performed. In CSOM, 12 of 14 samples revealed a significant amount of PE from 0.6 microliter/ml to 62.1 microliters/ml, which was significantly higher than those in MEE (p less than 0.05). In MEE, 8 of 10 samples were under the detection limit. Two samples in CSOM with Pseudomonas aeruginosa infection had high levels of PE. The quantitation was linear, with a concentration from 5 ng PE/sample to 500 ng PE/sample. This ELISA system is a sensitive method for quantitation of PE requiring only very small samples.