Open AccessSensitive In Situ Monitoring of a Recombinant Bioluminescent Yersinia enterocolitica Reporter Mutant in Real Time on Camembert Cheese
Author(s) -
Ariel Maoz,
Robert Mayr,
Geraldine Bresolin,
Klaus Neuhaus,
Kevin P. Francis,
Siegfried Scherer
Publication year - 2002
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.68.11.5737-5740.2002
Subject(s) - bioluminescence , operon , biology , yersinia enterocolitica , mutant , plasmid , bioreporter , transposable element , microbiology and biotechnology , transposon mutagenesis , mutagenesis , enterobacteriaceae , yersinia pseudotuberculosis , reporter gene , escherichia coli , bacteria , biochemistry , genetics , dna , gene , virulence , gene expression
Bioluminescent mutants of Yersinia enterocolitica were generated by transposon mutagenesis using a promoterless, complete lux operon (luxCDABE) derived from Photorhabdus luminescens, and their production of light in the cheese environment was monitored. Mutant B94, which had the lux cassette inserted into an open reading frame of unknown function was used for direct monitoring of Y. enterocolitica cells on cheeses stored at 10 degrees C by quantifying bioluminescence using a photon-counting, intensified charge-coupled device camera. The detection limit on cheese was 200 CFU/cm(2). Bioluminescence of the reporter mutant was significantly regulated by its environment (NaCl, temperature, and cheese), as well as by growth phase, via the promoter the lux operon had acquired upon transposition. At low temperatures, mutant B94 did not exhibit the often-reported decrease of photon emission in older cells. It was not necessary to include either antibiotics or aldehyde in the food matrix in order to gain quantitative, reproducible bioluminescence data. As far as we know, this is the first time a pathogen has been monitored in situ, in real time, in a "real-product" status, and at a low temperature.