Article Abstract:
Gas chromatography analysis of whole-cell fatty acid profiles has limited differentiation ability for strains of verotoxigenic Escherichia coli and Salmonella enteritidis. The variation in the fatty acid profiles in repeat preparations from the same strain is similar to that in subgroups. This limits the use of fatty acid profiles to subgroup verotoxigenic E. coli and S. enteritidis strains. The variation is due to the differences in the phenotypic expression of the fatty acids by bacterial cells grown under constant standard conditions.
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Article Abstract:
Greater heat tolerance in Salmonella enteritidis phage type 4 isolates appears to be associated with better survival on surfaces. In addition, culture of heat-tolerant isolates to stationary phase increased their acid and hydrogen peroxide tolerance, and further increased their heat tolerance. Extended culture of heat-sensitive isolates increased their heat tolerance, but only slightly increased their acid tolerance and had no effect on hydrogen peroxide tolerance. Surface survival was not affected by extended culture.
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Article Abstract:
A new gel electrophoresis method may allow for the efficient detection of virulent Salmonella enteritidis isolates before infectivity trials. The polyacrylamide gel electrophoresis (PAGE) technique characterized changes in lipopolysaccharide (LPS) structure at the same level of detail as characterized by mass spectroscopy. In an assay of field isolates of various phage types and pathogenicities, an increase in the O-antigen to core ratio was associated with an increase in virulence.
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