title: Spatiotemporal progression of localized bacterial peritonitis before and after open abdomen lavage monitored by in vivo bioluminescent imaging.
abstract: BACKGROUND
  Bacterial peritonitis is a life-threatening abdominal infection associated with high morbidity and mortality. The rat is a popular animal model for studying peritonitis and its treatment, but longitudinal monitoring of the progression of peritonitis in live animals has been impossible until now and thus required a large number of animals. Our objective was to develop a noninvasive in vivo imaging technique to monitor the spatiotemporal spread of bacterial peritonitis.
  
  
  METHODS
  Peritonitis was induced in 8 immunocompetent male Wistar rats by placing fibrin clots containing 5x10(8) cells of both Bacteroides fragilis (American Type Tissue Culture [ATCC)] 25,285 and bioluminescent Escherichia coli Xen14. After 1 or 2 days, infected clots were removed and open abdomen lavage was performed. In vivo bioluminescent imaging was used to monitor the spread of peritonitis.
  
  
  RESULTS
  Bioluminescent in vivo imaging showed an increase in the area of spread, and the number of E. coli tripled into the rat's abdominal cavity on day 1 after clot insertion; however, on day 2, encapsulation of the clot confined bacterial spread. Bioluminescent E. coli respread over the peritoneal cavity after lavage; within 10 days, however, in vivo imaging showed a decrease of 3-4 orders of magnitude in bacterial load.
  
  
  CONCLUSIONS
  Bioluminescent in vivo imaging can be effectively used to monitor the spatiotemporal behavior of the peritonitis during 3 different stages of the disease process: initiation, treatment, and follow-up. Imaging allows researchers to repeatedly image the same animal, thereby reducing variability and providing greater confidence in determining treatment efficacies for therapeutic interventions using a small number of animals.
authors.affiliation: Department of Biomedical Engineering, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands. p.k.sharma@med.umcg.nl
authors.forename: Prashant K
authors.initials: PK
authors.lastname: Sharma
authors.forename: Eefje
authors.initials: E
authors.lastname: Engels
authors.forename: Wim
authors.initials: W
authors.lastname: Van Oeveren
authors.forename: Rutger J
authors.initials: RJ
authors.lastname: Ploeg
authors.forename: C
authors.initials: C
authors.lastname: van Henny der Mei
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Busscher
authors.forename: Gooitzen M
authors.initials: GM
authors.lastname: Van Dam
authors.forename: Gerhard
authors.initials: G
authors.lastname: Rakhorst
mesh_terms: D000818:Animals; D001441:Bacteroides fragilis / Q000302:isolation & purification*; D003952:Diagnostic Imaging / Q000379:methods; D018450:Disease Progression; D004926:Escherichia coli / Q000302:isolation & purification*; D049453:Luciferases, Bacterial; D049408:Luminescent Agents; D008297:Male; D010533:Peritoneal Lavage; D010538:Peritonitis / Q000382:microbiology* / Q000473:pathology / Q000628:therapy; D051381:Rats; D017208:Rats, Wistar
chemical_list: D049408:Luminescent Agents; D049453:Luciferases, Bacterial