title: Evaluation of Escherichia coli viability by flow cytometry; a method for determining bacterial responses to antibiotic exposure.
abstract: BACKGROUND
  In this study, we check for the presence of specific resistance genes by PCR and then we used flow cytometry to evaluate antibiotic-induced effects in different strains of Escherichia coli.
  
  
  METHODS
  The presence of resistance genes was investigated by PCR in 10 strains of Escherichia coli isolated from Foglia River. Bacterial responses to different antibiotics were also tested with flow cytometry techniques by evaluating both the degree of decrease in viability and the light scatter changes in all of the strains.
  
  
  RESULTS
  PCR revealed that only one strain exhibits the presence of one resistance gene. Despite this, analyses of strains using flow cytometry evidenced the presence of viable subpopulations after antibiotic treatment. Furthermore, analyses of scatter signals revealed profound changes in the Forward Scatter (FSC) and Side Scatter (SSC) of the bacterial populations as a consequence of antibiotic exposure, confirming the viability and membrane potential data. The riverine strains were in general less sensitive to antibiotics than the reference strain (ATCC 25922).
  
  
  CONCLUSIONS
  Antibiotic resistance is a widespread phenomena. The multiparametric approach based on flow cytometry used in this study, providing results about different aspects (cell viability, membrane potential, light scatter changes), may overcome the limitation of PCR and could represent an adequate method for the evaluation of bacteria responses to antibiotic exposure. This article is protected by copyright. All rights reserved.
authors: Department of Earth, Life and Environmental Sciences, University of Urbino "Carlo Bo", 61029, Urbino, Italy.
authors: Paola
authors: P
authors: Boi
authors: Department of Biomolecular Science, University of Urbino "Carlo Bo", 61029, Urbino, Italy.
authors: Anita
authors: A
authors: Manti
authors: Department of Biomolecular Science, University of Urbino "Carlo Bo", 61029, Urbino, Italy.
authors: Anna
authors: A
authors: Pianetti
authors: Department of Biomolecular Science, University of Urbino "Carlo Bo", 61029, Urbino, Italy.
authors: Luigia
authors: L
authors: Sabatini
authors: Department of Biomolecular Science, University of Urbino "Carlo Bo", 61029, Urbino, Italy.
authors: Davide
authors: D
authors: Sisti
authors: Department of Biomolecular Science, University of Urbino "Carlo Bo", 61029, Urbino, Italy.
authors: Marco
authors: M
authors: Rocchi
authors: Department of Biomolecular Science, University of Urbino "Carlo Bo", 61029, Urbino, Italy.
authors: Francesca
authors: F
authors: Bruscolini
authors: Department of Biomolecular Science, University of Urbino "Carlo Bo", 61029, Urbino, Italy.
authors: Luca
authors: L
authors: Galluzzi
authors: Department of Biomolecular Science, University of Urbino "Carlo Bo", 61029, Urbino, Italy.
authors: Stefano
authors: S
authors: Papa
keywords: Escherichia coli; antibiotic effects; flow cytometry