title: An automated system for rapid non-destructive enumeration of growing microbes.
abstract: BACKGROUND
  The power and simplicity of visual colony counting have made it the mainstay of microbiological analysis for more than 130 years. A disadvantage of the method is the long time required to generate visible colonies from cells in a sample. New rapid testing technologies generally have failed to maintain one or more of the major advantages of culture-based methods.
  
  
  RESULTS
  We present a new technology and platform that uses digital imaging of cellular autofluorescence to detect and enumerate growing microcolonies many generations before they become visible to the eye. The data presented demonstrate that the method preserves the viability of the microcolonies it detects, thus enabling generation of pure cultures for microbial identification. While visual colony counting detects Escherichia coli colonies containing about 5x10(6) cells, the new imaging method detects E. coli microcolonies when they contain about 120 cells and microcolonies of the yeast Candida albicans when they contain only about 12 cells. We demonstrate that digital imaging of microcolony autofluorescence detects a broad spectrum of prokaryotic and eukaryotic microbes and present a model for predicting the time to detection for individual strains. Results from the analysis of environmental samples from pharmaceutical manufacturing plants containing a mixture of unidentified microbes demonstrate the method's improved test turnaround times.
  
  
  CONCLUSIONS
  This work demonstrates a new technology and automated platform that substantially shortens test times while maintaining key advantages of the current methods.
authors.affiliation: Rapid Micro Biosystems, Inc., Bedford, Massachusetts, United States of America.
authors.forename: Roanna
authors.initials: R
authors.lastname: London
authors.forename: Julie
authors.initials: J
authors.lastname: Schwedock
authors.forename: Andrew
authors.initials: A
authors.lastname: Sage
authors.forename: Heather
authors.initials: H
authors.lastname: Valley
authors.forename: Jamie
authors.initials: J
authors.lastname: Meadows
authors.forename: Michael
authors.initials: M
authors.lastname: Waddington
authors.forename: Don
authors.initials: D
authors.lastname: Straus
mesh_terms: D001331:Automation; D002176:Candida albicans / Q000302:isolation & purification*; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000302:isolation & purification*; D005453:Fluorescence