Identification and characterization of a phase-variable nonfimbrial Salmonella typhimurium gene that alters O-antigen production

Lola Y. Kwan, Richard E. Isaacson

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Salmonella typhimurium 798, which was isolated from a pig, is known to phase vary from a nonadhesive to an adhesive phenotype. Cells of the adhesive phenotype adhere to porcine enterocytes, are more readily phagocytized by porcine neutrophils and macrophages, and once phagocytized can survive intracellularly, while cells of the nonadhesive phenotype die rapidly. The effect of phenotypic switching also can be visualized by changes in colony morphologies and the presence of between 10 and 15 proteins in the envelopes of cells in the adhesive phenotype. Mutants previously constructed with cells in the adhesive phenotype and the transposon TnphoA were screened to identify mutants lacking one or more of the unique proteins. One mutation was cloned and sequenced, and the mutation was shown to be in rfaL (O-antigen ligase). Expression of O antigen was shown to be phase variable. The adhesive strain expressed an O antigen that was at least eightfold longer than that for the nonadhesive strain and by virtue of O-antigen production was resistant to porcine complement. The mutant survived intracellularly in phagocytic cells as well as its wild-type parent.

Original languageEnglish (US)
Pages (from-to)5725-5730
Number of pages6
JournalInfection and immunity
Volume66
Issue number12
StatePublished - Dec 1 1998

Fingerprint Dive into the research topics of 'Identification and characterization of a phase-variable nonfimbrial Salmonella typhimurium gene that alters O-antigen production'. Together they form a unique fingerprint.

Cite this