TY - JOUR
T1 - Ethidium bromide efflux by Salmonella: modulation by metabolic energy, pH, ions and phenothiazines.
AU - Amaral, Leonard
AU - Cerca , Pedro
AU - Spengler , Gabriella
AU - Machado , Lisa
AU - Martins, Ana
AU - Couto, Isabel Maria dos Santos Leitão
AU - Bettencourt, Miguel Viveiros
AU - Fanning , Séamus
AU - Pagès, J-M.
PY - 2011/1/1
Y1 - 2011/1/1
N2 - The main efflux pump of Salmonella enterica serotype Enteritidis, which obtains its energy for the extrusion of noxious agents from the proton-motive force, was studied with the aid of an ethidium bromide (EtBr) semi-automated method under conditions that define the role of metabolic energy, ions and pH in the extrusion of the universal substrate EtBr. The results obtained in this study indicate that in minimal medium containing sodium at pH 5 efflux of EtBr is independent of glucose, whereas at pH 8 metabolic energy is an absolute requirement for the maintenance of efflux. In deionised water at pH 5.5, metabolic energy is required for the maintenance of efflux. The inhibitory effect of the ionophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) on efflux is shown to be minimised by low pH, and at high pH by metabolic energy. Similarly, thioridazine, an inhibitor of metabolic enzymes, inhibits efflux of EtBr only at pH 8 and the degree of inhibition is lessened by the presence of metabolic energy.
AB - The main efflux pump of Salmonella enterica serotype Enteritidis, which obtains its energy for the extrusion of noxious agents from the proton-motive force, was studied with the aid of an ethidium bromide (EtBr) semi-automated method under conditions that define the role of metabolic energy, ions and pH in the extrusion of the universal substrate EtBr. The results obtained in this study indicate that in minimal medium containing sodium at pH 5 efflux of EtBr is independent of glucose, whereas at pH 8 metabolic energy is an absolute requirement for the maintenance of efflux. In deionised water at pH 5.5, metabolic energy is required for the maintenance of efflux. The inhibitory effect of the ionophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) on efflux is shown to be minimised by low pH, and at high pH by metabolic energy. Similarly, thioridazine, an inhibitor of metabolic enzymes, inhibits efflux of EtBr only at pH 8 and the degree of inhibition is lessened by the presence of metabolic energy.
KW - Proton-motive force
KW - pH
KW - Metabolic energy
KW - Hydronium ions
KW - Efflux pump
KW - Thioridazine
KW - Salmonella Enteritidis
KW - Ions
KW - CCCP
U2 - 10.1016/j.ijantimicag.2011.03.014
DO - 10.1016/j.ijantimicag.2011.03.014
M3 - Article
C2 - 21565465
SN - 0924-8579
VL - 38
SP - 140
EP - 145
JO - International Journal Of Antimicrobial Agents
JF - International Journal Of Antimicrobial Agents
IS - 2
ER -