Viable, but Non-Culturable, State of a Green Fluorescence Protein-Tagged Environmental Isolate of Salmonella Typhi in Groundwater and Pond Water

FEMS Microbiol Lett. 1999 Jan 1;170(1):257-64. doi: 10.1111/j.1574-6968.1999.tb13382.x.


An environmental isolate of Salmonella typhi was chromosomally marked with a gfp gene encoding green fluorescence protein (GFP) isolated from Aequorea victoria. The hybrid transposon mini Tn5 gfp was transconjugated from E. coli to S. typhi, resulting in constitutive GFP production. The survival of S. typhi GFP155 introduced into groundwater and pond water microcosms was examined by GFP-based plate counts, total cell counts, and direct viable counts. A comparison between GFP-based direct viable counts and plate counts was a good method for verifying the viable, but non-culturable (VBNC), state of S. typhi. The entry into a VBNC state of S. typhi was shown in all microcosms. S. typhi survived longer in groundwater than in pond water as both a culturable and a VBNC state.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriological Techniques
  • Colony Count, Microbial
  • Conjugation, Genetic
  • Culture Media
  • DNA Transposable Elements
  • Fresh Water
  • Green Fluorescent Proteins
  • Luminescent Proteins / genetics*
  • Luminescent Proteins / metabolism
  • Micropore Filters
  • Salmonella typhi / genetics
  • Salmonella typhi / growth & development*
  • Salmonella typhi / isolation & purification*
  • Sterilization
  • Water Microbiology*


  • Culture Media
  • DNA Transposable Elements
  • Luminescent Proteins
  • Green Fluorescent Proteins