GENETICS AND EPIDEMIOLOGY OF CFA/I PLASMIDS OF E. COLI

  • Murray, Barbara E, (PI)

Project: Research project

Description

Enterotoxigenic Escherichia coli (ETEC) are an important cause of
travelers' and infantile diarrhea worldwide particularly in underdeveloped
and/or tropical countries. The major thrust of this proposal is to
investigate one of the major virulence factors of ETEC, colonization factor
antigen (CFA)/I, a plasmid mediated adherence fimbria found on certain of
ETEC. CFA/I plasmids have been examined for the possibility of other
associated phenotypic markers including antibiotic resistance, production
of heat stable or heat labile toxin, fermentation of carbonhydrates,
production of colicin and of and of hemolysin and by molecular weight
determinations. These plasmlids will be will further characterized by
agarose gel electrophoresis os restriction endonuclease digestion fragments
and by hybridization of pTx, a CFA/I:ST plasmid transferred from a strain
isolated during a nonsocomial outbreak of diarrhea. In addition, the
ability of different bacteria to express CFA/I and the stability of pTx in
different strains is being investigated. Finally, cloning of CFA/I subunit
and of CFA/I fimbria will be done using restriction endonuclease cleavage
fragments of a CFA/I plasmid, which are then ligated into appropriate
cloning vectors and transformed into an E. coli K12 which has been shown to
be able to express CFA/I. The DNA segments(s) necessary for synthesis of
the fimbriae will be determined by transposon insertion-deletion
interruption of CFA/I production. The immediate goals of this proposal are
to delineate the homogeneity or heterogeneity of CFA/I plasmids, to clone
the CFA/I gene(s) using hosts which are capable of CFA/I expression, and to
develop a sensitive and specific DNA probe using this clone. The long
range goal (for future studies) will be to use this CFA/I probe in field
studies in order to define the true epidemiology of CFA/I as it relates to
ETEC. Such a strain also has potential as a live vaccine strain but the
worldwide prevalence of this fimbrial antigen should first be established.
StatusFinished
Effective start/end date9/30/838/31/86

Funding

  • National Institutes of Health

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Molecular Epidemiology
Plasmids
Escherichia coli
Enterotoxigenic Escherichia coli
DNA Restriction Enzymes
Hot Temperature
Infantile Diarrhea
Colicins
Escherichia coli K12
Hemolysin Proteins
DNA Probes
Virulence Factors
Microbial Drug Resistance
Fermentation
Disease Outbreaks
Electrophoresis
Organism Cloning
Digestion
Diarrhea
Epidemiology

Keywords

  • Medicine(all)
  • Immunology and Microbiology(all)