Immunochromatographic Strip Assay for Detection of Cronobacter sakazakii in Pure Culture.

Cronobacter sakazakii (C. sakazakii) is a foodborne pathogen, posing a high risk of disease to infants and immunocompromised individuals. In order to develop a quick, easy, and sensitive assay for detecting C. sakazakii, a rabbit anti-C. sakazakii immunoglobulin G (IgG) was developed using sonicated cell protein from C. sakazakii. The developed anti-C. sakazakii (IgG) was of good quality and purity, as well as species-specific. The developed rabbit anti-C. sakazakii IgG was attached to the surface of a sulforhodamine B-encapsulated liposome to form an immunoliposome. A test strip was then prepared by coating goat anti-rabbit IgG onto the control line and rabbit anti-C. sakazakii IgG onto the test line, respectively, of a plastic-backed nitrocellulose membrane. A purple color signal both on the test line and the control line indicated the presence of C. sakazakii in the sample, whereas purple color only on the control line indicated the absence of C. sakazakii in the sample. This immunochromatographic strip assay could produce results in 15 min with a limit of detection of 107 CFU/ml in C. sakazakii culture. The immunochromatographic strip assay also showed very good specificity without cross-reactivity with other tested Cronobacter species. Based on these results, the developed immunochromatographic strip assay is efficient for the detection of C. sakazakii and has high potential for on-site detection.