RT Journal Article SR Electronic(1) A1 WALKER, SAM L. A1 SOJKA, MARCJANNA A1 DIBB-FULLER, MICHAEL A1 WOODWARD, MARTIN J.YR 1999 T1 Effect of pH, temperature and surface contact on the elaboration of fimbriae and flagella by Salmonella serotype Enteritidis JF Journal of Medical Microbiology, VO 48 IS 3 SP 253 OP 261 DO https://doi.org/10.1099/00222615-48-3-253 PB Microbiology Society, SN 1473-5644, AB Summary Survival of enteric pathogens exposed to various environmental stresses depends upon a number of protective responses, some of which are associated with induction of virulence determinants. Flagella and fimbriae are putative virulence determinants of Salmonella spp. and ELISAs specific for the detection of flagella and SEF21, SEF14 and SEF17 fimbriae were used to assess the effect of temperature and pH upon their elaboration by isolates of Salmonella serotype Enteritidis in planktonic growth and on the surface of two-dimensional gradient agar plates. For three phage type 4 isolates of Enteritidis of comparative clinical provenance, similar phenotypes for the elaboration of these surface antigens were observed. SEF14 fimbriae were elaborated in planktonic growth at 37°C, but not 20°C, at pH 4.77 and above but not at pH 4.04; whereas on agar gradient plates SEF14 fimbriae were elaborated poorly but with best yields at pH 4.04. SEF17 fimbriae were elaborated in planktonic growth at 20°C, but not at 37°C, at pH 6.18 and above but not at pH 5.09 or below; whereas on agar gradient plates SEF17 fimbriae were elaborated well even at pH 4.65. SEF21 fimbriae were expressed very poorly under all conditions tested. Planktonic growth at 37°C induced least flagella whereas growth at 20°C, and particularly surface growth at lower pH values, induced a ‘hyper-flagellate’ phenotype. Single colonies allowed to form on gradient agar plates were shown to generate different colonial morphologies which were dependent on initial pH. These results demonstrate that the physicochemical environment is an important determinant of bacterial response, especially the induction of putative virulence factors., UL https://www.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-48-3-253