This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Guard-Petter, J. Articles by Ingram, K. Search for Related Content PubMed PubMed Citation Articles by Guard-Petter, J. Articles by Ingram, K. Agricola Articles by Guard-Petter, J. Articles by Ingram, K.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol., 08 1995, 2845-2851, Vol 61, No. 8
Copyright © 1995, American Society for Microbiology

Characterization of lipopolysaccharide heterogeneity in Salmonella enteritidis by an improved gel electrophoresis method

J Guard-Petter, B Lakshmi, R Carlson and K Ingram
Southeast Poultry Research Laboratory, U.S. Department of Agriculture, Athens, Georgia, USA.

Salmonella enteritidis field isolates of different phage types and pathogenicities were assessed for changes in lipopolysaccharide (LPS) structure, using an improved method of polyacrylamide gel electrophoresis (PAGE) that revealed the same degree of structural detail as mass spectroscopy. The method allowed characterization of an LPS chemotype that may be associated, regardless of phage type, with increased virulence of S. enteritidis. The virulent variant SE6-E21, which efficiently contaminates eggs and yields high numbers of organisms from chick spleens, had an O-antigen/core ratio of 2.8, as determined from gels by densitometry, and 1.67 micrograms of mannose per microgram of 2-keto-3-deoxy-octulosonic acid (KDO), while the avirulent variant SE6-E5 had O-antigen/core ratios of 1.2 and 1.00. The association between O antigen and virulence was also seen on analysis of five new field isolates. One of the new field isolates generated a mixed population of smooth and semismooth variants in agreement with its mixed virulence in chicks. When LPS was purified from large-volume cultures, only the most virulent isolate yielded high amounts of O antigen (1.6 micrograms of mannose per microgram of KDO), while the other isolates had ratios characteristic of semismooth variants (< or = 1.0 microgram of mannose per microgram of KDO), including the isolate of mixed virulence. These results indicate that the improved PAGE method might provide a rapid, sensitive, in vitro assessment of field isolate virulence prior to the performance of definitive infectivity trials.