THE INFLUENCE OF INCUBATION CONDITIONS ON THE ADHERENCE OF ORAL ENTEROBACTERIACEAE TO HELA-CELLS

The adherence of 12 oral isolates and 4 type strains of Enterobacteria ceae (equally representing Enterobacter cloacae, Klebsiella pneumoniae , Escherichia coli and Citrobacter freundii) to HeLa cell monolayers f ollowing five different incubation conditions (sucrose, D-mannose, ser um, MEM and Candida albicans GDH 1957) was investigated. Incubation wi th sucrose and D-mannose resulted in the greatest and least adherence, respectively. The presence of preadherent C. albicans GDH 1957 on the HeLa cells tended to enhance the adherence of certain strains of E. c loacae and C. freundii, but had no overall impact on Enterobacteriacea e adherence. While heterogeneity of behaviour existed between strains within species, E. cloacae was the most, and K. pneumoniae the least, adherent species irrespective of incubation conditions. Haemagglutinat ion assays indicated the presence of mannose-resistant type 1 fimbriae associated with all Enterobacteriaceae. In clinical terms, the variat ions in adherence properties observed in vitro may contribute to an un derstanding of the different prevalence rates of oral Enterobacteriace ae reported in the literature.