| Summary: | 碩士 === 國立交通大學 === 環境工程系所 === 92 === III
Over the past years, E. coli and P. phosphorium were used as
laboratory bacterium to conduct mixture toxicity research of organic
toxins developed to study the toxicity of organic toxicants in our group.
The study was found, when toxicants have a small slope tend to act
synergistically while have a large slope may produce antagonistic effect.
From the results of this study, it was found that the proportion of
synergism was likely to be observed high when the combination of
antibiotics which were different mechanism and small dose-response
curve slopes.
The emergence and escalation of antimicrobial resistance in the
Gram-positive cocci (including enterococci and staphylococci) has been
observed, especially Methicillin- resistant Staphylococcus aures (MRSA).
This research used MSSA and MRSA as the test bacterium, chose six types
of antibiotic, and divided into four categories based on its
bacteria-suppressing mechanism. The post-categorized results were used
to proceed mixture toxicity testing of the Time-kill curve, and to observe
its growth-suppression situation of the MRSA and MSSA, as well as
discussing prediction method Mtox7 Model 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 Time-kill curve between different objects and different toxic materials,
in addition to comparing test results.
From the results of the study, we were found that synergism was
produced with the combination of antibiotics which were different
mechanism and small dose-response curve slopes. Comparison with two
different method, Mtox7 model predicted the combined effect and
time-kill curve was in defining the effects of antibiotics combination in
treatment, we also can get most the same result and the possibility of the
same result about 87.2%. This shows that the parameter as the slope of
dose-response curve is good at application on predicting the combined
therapeutic effects of mixtures of antibiotics. 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.
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