The effect of pH and culture system on the attachment of plasmid-bearing and plasmid-cured Yersinia enterocolitica to a polycarbonate membrane in a surface adhesion immunofluorescent technique

摘要

A rapid surface adhesion based immunofluorescence technique was used to isolate and detect Yersinia enterocolitica from inoculated enriched culture systems. The pathogen was isolated by surface adhesion to a polycarbonate membrane which was mounted on a glass slide and immersed in the enriched culture for 15 min. The pathogen was detected using a fluorescent labelled (FITC) monoclonal antibody which was specific for Y. enterocolitica serotype O:3 and then viewed using fluorescent microscopy. The effect of culture type (broth, meat homogenate and minced meat) and pH (5.00, 7.00, 9.00 and 11.00) on the adhesion of plasmid-bearing and plasmid-cured Y. enterocolitica to the polycarbonate membrane in this technique was determined. The pH had a significant effect (P < 0.05) in broth and meat homogenate cultures, with enhanced attachment of Y. enterocolitica (P + and P-) at pH 9.00 than at pH 5, 7 or 11. Culture type was also important, with differences observed in the numbers of Yersinia adhering to membranes immersed in broth, meat homogenate and minced beef. Differences in attachment were noted between plasmid-bearing and plasmid-cured Y. enterocolitica isolated from similar cultural environments. The reasons for these observed differences, and their implications for the surface adhesion immunofluorescent rapid method, are discussed.