Chem 8157

I would say that this is a semi-quantitative method. Since the electrochemical measurement gives a value for the respiration activity and then compares that to the cut-off value of 90%, this is more than just a qualitative method. Depending on how accurately respiration can be measured in each case, one could even rank the antibiotics in terms of their effectiveness. For example, one antibiotic could result in a 50% decrease in respiration activity in 15 minutes, while another could result in a 15% decrease in 15 minutes - if this method can measure the difference accurately, then we could say that the first antibiotic is faster or more effective than the second (while a qualitative method would say only that they were both effective).

I think this is a qualitative method. Because the method is to determine whether the antibiotic would affect microorgnism or not. There is no value measured by this method to show how effective it will be.

The way in which example 16.7.1 is written as decreased respiration equaling activity

In my opinion, although the test has a cut-off value which is 90%, the focus is about whether the microorganism is alive or already dead. So basically it's a "yes" or "no" question, which means it's qualitative.

I agree with Meng and Li. It is a qualitative assay. The 90% respiration is a cut-off value to show a "yes" or "no" result. So the result is whether the antibiotic compounds are against the microorganism or not. It is a yes or no question. The research is not focus on what concentration will affect microorganism growth or other numerical parameters. It is only in the absence or presence of antibiotic compounds

While I can appreciate the earlier posts about this being a semi-quantitative method, I would still call this a qualitative method. The respiration cut off value is only there to distinguish between a positive or negative response. No larger conclusion is being made about the inhibitor based on that 90% value, it is like the previous response said before it is simply a "yes" or "no" evaluation. If we apply the standard that if a number is involved in making the determination then it is a semi-quantitative method, then there would never be a qualitative method, because at some point all methods have to rely on empirical data.

I'm not sure why my previous post got cut off but here is the complete one:

The way in which example 16.7.1 is written as decreased respiration equaling activity

I agree with Jon Dozier's opinion. I think it's a qualitative method. We cannot use that 90% to determine any level about how effective the antibiotic is against the microorganism. It's more complicated to determine the relationship between 90% and the efficiency. Different antibiotic has different properties. Some condition is helpful for one antibiotic to react with the microorganism while does nothing to help other antibiotic. We don't know the specific test condition. There is difference between in vivo and in vitro. So I think we can only deal with 90% a "yes/no" cutoff value. It's a qualitative method.

I am going to have to echo the opinions of those supporting the qualitative position. The new method is only used to determine if the microorganism is susceptible to the antibiotic. The 90% is simply the demarcation point between the yes and no qualitative points

I also think this is a qualitative screening. This method only uses the respiration cut off value to determine the antibiotic effect. If this is a quantitative or semiquantitative method, one should provide quantitative data such as the relationship between antibiotic amounts to the respiration activities.

SUMMARY AND COMMENTS
The method, as described, is definitely qualitative. The outcome should be whether the microorganisms are dead or alive.

On the other hand, if the goal was to measure the respiratory activity, the method could be either quantitative or semi-quantitative, depending on the specific conditions of the assay.