Determination of the attachment of Photobacterium damselae subsp. piscicida to fish cells using an enzyme linked immunosorbent assay

Abstract

This paper describes the application of a modified ELISA, which offers a simple and semi-quantitative method to examine the attachment of P. damselae subsp. piscicida to CHSE-214 cells. The suitability of the ELISA procedure to assess this attachment was first confirmed by comparing the results of the ELISA with levels of attachment seen by microscopic examination. Significant differences were observed in the levels of adhesion to CHSE-214 among 32 P. damselae subsp. piscicida isolates from different species of fish and geographically different regions. Exposure of bacteria to low pH (pH 4-6) did not enhance their abilities to adhere to CHSE-214. However, treatment of two representative isolates, Italian I736 and Japanese SP92144, with seven different monosaccharides, revealed differences in their abilities to bind to the cells. Attachment of isolate SP92144 was significantly enhanced by treatment with both N-acetylneuraminic acid and L-fructose, while N-acetyl-D-galactosamine significantly decreased its ability to adhere. The attachment of strain I736 increased significantly when treated with N-acetylneuraminic acid.