Makakole Sesupo C, Sturm A Willem
Department of Medical Microbiology and MRC Genital Ulcer Disease Research Unit, Faculty of Medicine, University of Natal, Durban, South Africa.
J Med Microbiol. 2001 May;50(5):449-455. doi: 10.1099/0022-1317-50-5-449.
To investigate if temperature affects the interaction of Haemophilus ducreyi with human epithelial cells, nine strains were used to evaluate the adhesion kinetics of the organism at 33 degrees C and 37 degrees C. The effect of the free toxin on the epithelial cells at those temperatures was also assessed. The cyto-adherence kinetics of H. ducreyi to the epithelial cells was significantly greater at 33 degrees C (10 times more) than at 37 degrees C in all seven clinical isolates tested. There was a significant difference in cell-associated H. ducreyi at 33 degrees C as compared with 37 degrees C. Control strains showed similar adhesion properties at both temperatures. However, the virulent strain CIP542 adhered in larger amounts than the avirulent strain A77. Electron microscopy revealed that there was more tissue necrosis at the lower than the higher temperature. The effect of the free toxin was the same at each temperature. However, strain A77 had significantly lower toxicity than strain CIP542 and the clinical isolates. These results suggest that H. ducreyi displays a temperature-dependent interaction with human epithelial cells, and this feature may play a role in the virulence of the organism in vivo. While the overall toxic effect of viable bacteria depends on the metabolic activity of the bacteria and is, therefore, higher at 33 degrees C than at 37 degrees C withthe same initial inoculum, the effect of the extracted toxin at molecular level with fixed concentrations is a temperature-independent event.
为研究温度是否影响杜克雷嗜血杆菌与人类上皮细胞的相互作用，使用了9株菌株来评估该菌在33℃和37℃时的黏附动力学。还评估了在这些温度下游离毒素对上皮细胞的影响。在所有测试的7株临床分离株中，杜克雷嗜血杆菌在33℃时对上皮细胞的细胞黏附动力学显著高于37℃时（高10倍）。33℃时与细胞相关的杜克雷嗜血杆菌与37℃时相比存在显著差异。对照菌株在两个温度下表现出相似的黏附特性。然而，强毒株CIP542的黏附量比无毒株A77多。电子显微镜显示，较低温度下的组织坏死比高温时更多。游离毒素在每个温度下的作用相同。然而，菌株A77的毒性显著低于菌株CIP542和临床分离株。这些结果表明，杜克雷嗜血杆菌与人类上皮细胞表现出温度依赖性相互作用，这一特征可能在该菌的体内毒力中起作用。虽然活菌的总体毒性作用取决于细菌的代谢活性，因此在相同初始接种量的情况下，33℃时比37℃时更高，但固定浓度的提取毒素在分子水平上的作用是与温度无关的事件。
