title: Comparison of solid-phase cytometry and the plate count method for the evaluation of the survival of bacteria in pharmaceutical oils.
abstract: OBJECTIVE
  To compare the survival of four bacterial strains (Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Pseudomonas aeruginosa) in pharmaceutical oils, including jojoba oil/tea tree oil, carbol oil, jojoba oil and sesame oil.
  
  
  RESULTS
  Oils were spiked with the test bacteria in a concentration of 10(4) CFU ml(-1). Bacteria were extracted from oils with phosphate-buffered saline containing 0.5% Tween 20. Aliquots of the pooled water layers were analysed by solid-phase cytometry and plate counting. Plate counts dropped to zero for all test strains exposed for 24 h to three of the four oils. In contrast, significant numbers of viable cells were still detected by SPC, except in the jojoba oil/tea tree oil mixture and partly in sesame oil.
  
  
  CONCLUSIONS
  Exposure of bacteria for 24 h to the two oils containing an antimicrobial led to a loss of their culturability but not necessarily of their viability. The antibacterial activity of the jojoba oil/tea tree oil mixture supersedes that of carbol oil.
  
  
  CONCLUSIONS
  These in vitro data suggest that the jojoba oil/tea tree oil mixture more than carbol oil inhibits bacterial proliferation when used for intermittent self-catherization.
authors.affiliation: Laboratory for Pharmaceutical Microbiology, University of Ghent, Ghent, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: De Prijck
authors.forename: E
authors.initials: E
authors.lastname: Peeters
authors.forename: H J
authors.initials: HJ
authors.lastname: Nelis
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D015169:Colony Count, Microbial / Q000379:methods; D047569:Laser Scanning Cytometry / Q000379:methods; D050296:Microbial Viability / Q000187:drug effects*; D010938:Plant Oils / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010938:Plant Oils