鹽度及酸鹼度對霍亂弧菌O139吸附作用的影響   全文下載

Effects of Salinity and pH on the Adherence and Virulence of Vibrio cholerae O139

霍亂孤菌感染人體引起霍亂的第一步必須能吸附到小腸並進行拓殖（colonization）；然而，吸附作用受生長環境中許多生理化學因子的影響。本研究探討在不同鹽度與酸鹼度下生長，霍亂弧菌O139 的吸附力與毒力之變化。相較於在對照組培養基（0.5% NaCl及pH 7.0）的培養，O139菌株於不同鹽度及酸鹼度培養後，其對HeLa細胞株的吸附率分別於0%及5%NaCl下，明顯降低56% （P = 0.0007）與69% （P = 0.0008）；於pH 6及pH 5.5下，吸附率分別降低至91% （P = 0.016）和82% （P = 0.006）。經連續繼代培養後，其吸附力並無顯著變化（P = 0.182）；若將第十代的細菌接種回對照組培養基中，其吸附力回升至與對照其且相同。進行小鼠餵食及攻擊實驗，測定吸附力對O139 菌株致病力的影響，結果顯示在0% NaCl、5% NaCl及pH 5.5培養下，O139菌株對小鼠的存活率分別為50%、60%及20%。由這些結果推測，鹽度改變對菌株的吸附力及毒力造成的是可逆性抑制作用，且此影響強於酸鹼值的影響效應。

Vibrio cholerae must first adhere to and colonize the human small intestine in order to cause cholera and this adherence can be affected by several physicochemical factors. The purpose of this study was to examine the adherence and virulence of V. cholerae O139 that was grown in experimental broth media with different salinities and pH values. After the bacterial cells were incubated separately in these media, the adherence of V. cholerae O139 to HeLa cells was examined. By comparison with bacteria grown in a control medium with 0.5% NaCl and pH 7.0, the percentages of adhesion of bacteria grown in media with 0% and 5% NaCl were found to decline significantly by 56% (P = 0.0007) and 69% (P = 0.0008) respectively, and those in media with pH 6 and 5.5 decreased to 91% (P = 0.016) and 82% (P = 0.006) respectively. After the bacterial cells were sub-cultured in the experimental media serially, no difference in adherence was observed between the first, the fifth and the tenth generations (P = 0.182). However, after the tenth generation, when the treated bacterial cells were re-incubated in a control medium, the level of adherence was found to become similar to that of the control bacteria. In order to determine the effect of adherence on the pathogenicity of V. cholerae O139, mice were challenged with a double dose of the LD50 of the test strains incubated in 0% NaCl, 5% NaCl, and pH 5.5, and the survival of rates were at 50%, 60% and 20%, respectively. These results suggest that changes of salinity can cause a reversible inhibition effect on either adhesion or virulence of V. cholerae O139, and those effects resulting from changes in salinity are stronger than those of different pH values. 霍亂孤菌感染人體引起霍亂的第一步必須能吸附到小腸並進行拓殖（colonization）；然而，吸附作用受生長環境中許多生理化學因子的影響。本研究探討在不同鹽度與酸鹼度下生長，霍亂弧菌O139 的吸附力與毒力之變化。相較於在對照組培養基（0.5% NaCl及pH 7.0）的培養，O139菌株於不同鹽度及酸鹼度培養後，其對HeLa細胞株的吸附率分別於0%及5%NaCl下，明顯降低56% （P = 0.0007）與69% （P = 0.0008）；於pH 6及pH 5.5下，吸附率分別降低至91% （P = 0.016）和82% （P = 0.006）。經連續繼代培養後，其吸附力並無顯著變化（P = 0.182）；若將第十代的細菌接種回對照組培養基中，其吸附力回升至與對照其且相同。進行小鼠餵食及攻擊實驗，測定吸附力對O139 菌株致病力的影響，結果顯示在0% NaCl、5% NaCl及pH 5.5培養下，O139菌株對小鼠的存活率分別為50%、60%及20%。由這些結果推測，鹽度改變對菌株的吸附力及毒力造成的是可逆性抑制作用，且此影響強於酸鹼值的影響效應。