16 research outputs found
Comparative antibacterial potential of selected aldehyde-based biocides and surfactants against planktonic Pseudomonas fluorescens
The antimicrobial efficacy of two aldehydebased biocides (glutaraldehyde, GTA, and orthophthalaldehyde, OPA) and two surfactants (cetyltrimethyl ammonium bromide, CTAB, and sodium dodecyl sulphate,
SDS) was tested against planktonic Pseudomonas fluorescens. The antimicrobial effects were evaluated by respiratory activity as a measure of the oxygen uptake
rate, adenosine triphosphate (ATP) release, outer membrane proteins (OMP) expression and cellular colour changes. The results were compared with the bacterial
characteristics without chemical treatment. Tests in the presence of bovine serum albumin (BSA), in order to mimic a disinfection process in the real situation under dirty conditions, were performed according to the
European Standard EN-1276. P. fluorescens was completely inactivated with OPA (minimum bactericidal concentration, MBC = 0.5 mM) and CTAB (MBC = 5 mM) and was resistant to GTA and SDS. Only CTAB promoted cellular disruption and consequent
ATP release. The antimicrobial action of the
chemicals tested was significantly reduced when BSA was introduced into the bacterial cultures, increasing markedly the MBC values. Additionally, the presence of BSA
acted as a disruption protective agent when CTAB was applied and stimulated the bacterial respiratory activity when lower concentrations of SDS were tested. The
OMP of the bacterial cells was affected by the application of both surfactants. OMP expression remained unaltered after biocide treatment. Bacterial colour change was
noticed after treatment with biocides and surfactants. In summary, P. fluorescens was extremely resistant to GTA and SDS, with antimicrobial action being quenched
markedly by the reaction with BSA.Instituto de Biotecnologia e QuÃmica Fina (IBQF).Fundação para a Ciência e a Tecnologia (FCT) - (Project CHEMBIO - POCI/BIO/61872/2004
Niche segregation in two closely related species of stickleback along a physiological axis: Explaining multidecadal changes in fish distribution from iron-induced respiratory impairment
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