Development of a colloidal gold-based immunochromatographic test strip for the rapid, on-site detection of Pseudomonas aeruginosa in clinical samples

Background: Current procedures for the detection of Pseudomonas aeruginosa require sophisticated equipment, skilled technicians, and a great deal of time. Immunochromatography assays (ICA) are simple and rapid diagnostic procedures that can be performed and interpreted on the spot or at the bedside without a machine. Methods: We developed a rapid, 1-step immunochromatographic test strip that is well suited to the on-site detection of P. aeruginosa with high sensitivity and specificity. In brief, a monoclonal antibody targeting the outer membrane protein F (OprF) of P. aeruginosa, 3C3B5, was conjugated to colloidal gold and used as a detection antibody. An OprF polyclonal antibody was developed as the capture antibody. Eighty-three clinical samples were examined for P. aeruginosa by rapid 1-step ICA and compared with Multiplex-polymerase chain reation (M-PCR). Results: The detection limit of this method is 5 x 10(5) CFU/ml for P. aeruginosa and 10 ng/ml for the OprF protein. The immunochromatographic strip test demonstrated a slightly lower sensitivity (84.8%), but a similar specificity (100%), to multi-PCR, which is an accurate method for the detection of P. aeruginosa in the laboratory. We observed no cross-reactivity with non-P. aeruginosa bacterial microbes. The detection of P. aeruginosa by the ICA strip can be completed within 5-10 min and is at least 10-fold faster than M-PCR. Conclusions : The ICA test strip developed in this study has proved to be a rapid, simple, effective and economical method for the detection of P. aeruginosa infection in clinical samples. To our knowledge, this is the first report of an ICA method being used to detect P. aeruginosa.