Area de Nutrición y Bromatología, Departamento de Higiene y Tecnología de los Alimentos, Universidad de León, Spain.
Int J Food Microbiol. 2010 Feb 28;137(2-3):130-6. doi: 10.1016/j.ijfoodmicro.2009.11.022. Epub 2009 Dec 3.
There is a lack of work comparing the influence of various poultry chemical decontaminants on the membrane fluidity of pathogenic bacteria. In order to assess the possible role of physical membrane changes on bacterial adaptation to decontaminants, fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) was measured in Listeria monocytogenes and Salmonella enterica strains before and after growth in the presence of increasing sub-lethal concentrations of decontaminants (trisodium phosphate - TSP, acidified sodium chlorite - ASC, citric acid - CA and peroxyacids - PA). Higher (P<0.05) anisotropy values (lower membrane fluidity) were observed, both before and after exposure to decontaminants, in strains of L. monocytogenes (average 0.206+/-0.008) than in those of S. enterica (0.188+/-0.013). Cells exposed to sub-inhibitory concentrations of acid decontaminants (CA or PA) showed higher (P<0.05) anisotropy values and percentages of survival to acid stress than unexposed cells, suggesting that adaptation to these compounds is related to changes in membrane fluidity. Minimal changes in anisotropy values were observed after growth in presence of TSP or ASC. After treatment with strong concentrations of acid decontaminants (0.05 and 1% ASC, 5% and 10% CA, and 0.1 and 0.25% PA) the highest anisotropy values (highest membrane rigidity) were shown by cells previously grown with sub-inhibitory concentrations of CA or PA, suggesting that the synergistic effects of successive applications of various acids should be minimized. Because of the relationship between high membrane rigidity and high resistance to different stresses, the fact that it is essential to ensure adequate, inhibitory, CA or PA concentrations during poultry decontamination treatments is underlined.
目前缺乏比较各种禽类化学消毒剂对病原菌膜流动性影响的工作。为了评估物理膜变化对细菌适应消毒剂的可能作用，在存在递增亚致死浓度消毒剂（磷酸三钠-TSP、酸化亚氯酸钠-ASC、柠檬酸-CA 和过氧酸-PA）的情况下，测量了单核细胞增生李斯特菌和肠炎沙门氏菌菌株在生长前后 1,6-二苯基-1,3,5-己三烯（DPH）的荧光各向异性。在暴露于消毒剂前后，单核细胞增生李斯特菌菌株（平均 0.206+/-0.008）的各向异性值（较低的膜流动性）均高于肠炎沙门氏菌菌株（0.188+/-0.013）（P<0.05）。与未暴露细胞相比，暴露于亚抑菌浓度酸性消毒剂（CA 或 PA）的细胞显示出更高（P<0.05）的各向异性值和对酸胁迫的存活率，表明对这些化合物的适应与膜流动性的变化有关。在存在 TSP 或 ASC 的情况下生长后，各向异性值仅发生最小变化。在用强浓度酸性消毒剂（0.05 和 1%ASC、5% 和 10%CA，以及 0.1 和 0.25%PA）处理后，先前用亚抑菌浓度 CA 或 PA 生长的细胞显示出最高的各向异性值（最高的膜刚性），表明各种酸的连续应用的协同效应应最小化。由于高膜刚性与对不同应激的高抗性之间存在关系，因此在禽类消毒处理期间，确保 CA 或 PA 的足够、抑制浓度是至关重要的。
