抗生素對金黃色葡萄球菌之混合毒性效應研究

Abstract

抗生素對金黃色葡萄球菌之混合毒性效應研究 學生：葉書豪 指導教授：陳重元 國立交通大學環境工程研究所 摘要 過去，曾以大腸桿菌和螢光菌為實驗菌種，針對有機毒物做混合毒性研究，依有機毒物之致毒機制以及劑量-反應曲線的斜率作為主要分類工具，歸納出一個結論，就是當劑量-反應曲線斜率為小斜率時，且在毒性物質為不同作用機制的情況下，產生毒性加強（synergism）的比例很高。 本研究是以金黃色葡萄球菌為試驗菌種，選擇了二十九種抗生素，依其對細菌抑制作用的機制將其分為五大類，利用分類後的結果，進行平板法混合毒性試驗，觀察其對金黃色葡萄球菌之生長抑制情形，探討混合毒性模式之預測方法，並與過去以混濁度法所做的有機毒物試驗結果相比較，是否不同物種、不同毒性物質間，其預測準則之可應用性，並以混濁度法及Time-kill curve方法做試驗，與平板法所得的結果相比較。 由本研究之平板法實驗結果顯示，由兩種作用機制不同，且其劑量-反應曲線斜率小於一的抗生素混合併用下，產生協同作用（synergism）的機率最大，可高達80%。同時以混濁度法和Time-kill curve兩種試驗方法所做混合抗生素之試驗結果，與平板法有一致性。以這三種混合毒性試驗做比較，平板法是一種較方便且可同時做多組試驗的方法，Time-kill curve則可讓我們瞭解菌種實際的抑制情形，而與混濁度法的一致性，可證明毒理學應用於藥理學之可行性。 運用毒理學與藥理學之相似性，使得本研究之成果能有效地預測混合效應之模式，在藥理學的應用上，則能用於控制病菌感染，在現今醫學界普遍面臨致病菌具高抗藥性，且有些病菌無法以單一抗生素來抑制，所以混合抗生素試驗之研究，即為一迫切且可行的方法，本研究之主要目的為以兩種抗生素混合，使其產生協同作用（synergism）之療效。 關鍵詞：金黃色葡萄球菌、混濁度法、平板法、Time-kill curve、劑量-反應曲線、協同作用

The Effects of Antibiotics on Mixture Toxicity to Staphylococcus aureus Student: Yeh Shu-Hao Advisor: Dr. Chen Chung-Yuan Institude of Environmental Engineering National Chaio Tung University ABSTRACT E. coli and P. phosphorium were used as laboratory bacterium in the past to conduct mixture toxicity research of organic toxins. The toxic mechanism of the organic toxins and the slope of the dose-response curve were used as main grouping tools to generalize a conclusion. When a small slope rate appeared on the dose-response curve while toxic materials were under different mechanism conditions, the proportion of synergism produced was very high. This research used Staphylococcus aureus as the laboratory bacterium, chose twenty-nine types of antibiotic, and divided into five categories based on its bacteria-suppressing mechanism. The post-categorized results were used to proceed mixture toxicity testing of the agar plate test, and to observe its growth-suppression situation of the Staphylococcus aureus, as well as discussing prediction method of the mixture toxicity model and to make comparison with previous test results done on organic toxic materials using turbidity method, together with checking the applicability of prediction principles between different objects and different toxic materials, in addition to comparing test results derived from turbidity method and time-kill curve, with the agar plate test result. The agar plate test result of this research indicated that although the two mechanisms had different functions, the highest possibility of synergism, as high as 80%, was produced under the combination of antibiotics when the slope rate of the dose-response cure was smaller than 1. At the same time, the mixture antibiotic test result using turbidity method and time-kill curve was consistent with the result derived from the agar plate test. When making a comparison between these three mixture toxicity tests, the agar plate test was more convenient as well as capable of conducting multiple testing at one time; time-kill curve allowed us to understand the actual suppression situation of the bacterium, and was consistent with the turbidity method, able to substantiate the feasibility of applying toxicology to pharmacology. The use of the similarity between toxicology and pharmacology, allowed this research result to effectively predict the model of combined effects. Its application in pharmacology can be applicable on controlling bacterium infections. Today's medical field commonly faces bacteria capable of high-tolerance, in addition to some of the bacteria unable to be suppressed by a single antibiotic, hence for the research on mixture antibiotic testing, an urgently needed and workable method. The main objective of this research is to combine two types of antibiotics, and for them to form effective treatment by producing synergism. Key words : Staphylococcus aureus, turbidity method, agar plate test, time-kill curve, dose-response curve, synergism.