Expert: Walter Hintz - 3/21/2010

Question
QUESTION: To Mr. Hintz: Expert
My school is having a science fair in 5 weeks. For my project I want to, essentially, produce a strain of bacteria that is resistant to household cleaners, such as Lysol. The reason I want to do this is because I understand that there are certain bacteria that we need and when one of these cleaners kills all the bacteria it kills even the good bacteria, this potentially increases the likelihood of getting sick because it is possible that the next bacteria to land on the surface will be bad, and may take over the entire surface. The help I need is to Know which strains of bacteria are good. Another issue is that I go to a private school that does not have a lab or an incubator, even though the community college is just down the street from my house I can not receive assistance from them because we end school at 6 o'clock on Mondays and Wednesdays and at 8:30 an Tuesdays and Thursdays, and we also have school on Sundays until 3 o'clock, in other words because of time restraints. I saw in one of your answers to a similar question a recipe for media(gelatin and beef bullion) I am going to assume that this is the equivalent of nutrient agar, is this correct? Even if this is correct my teacher said that I would need to prepare the petri dish for a change in acidity or any other environmental change, how would I do this? Would bacteria grow if it is not placed in an incubator,and if so how long would it take? is there any way to make sure no parasitic bacteria get in the dish if I don't have a sterile lab(I am very careful, and I have a steady hand)? I am able to acquire sterile cotton swabs and gloves. I know this is a difficult project, if you don't think it is feasible please tell me, and please suggest a different variation or project that I can do.the latest I can hand in the project outline is on Tuesday, I am truly sorry about the last minute nature of this question, but I just thought of it 2 days ago, after shooting down other ideas which were either impossible, or I was unable to come up with an experiment for the topic. i should probably mention that I am in tenth grade, so you know a range of what to think about if this experiment is not possible. I have no experience working with bacteria, this is another reason I want to use a safe or good bacteria.
Thank you so much for your time, I really appreciate it.

ANSWER: Hi Zvi
First of all I will tell you that you cannot just develop a  new species of strain of bacteria. New strains come about only through the process of microevolution. Suppose you have a culture of 10 million bacteria and all except one are sensitive to a household germ killer. This one has a different genetic make up and survives to reproduce while all the others die.  Unless there is a resistant one there will be no new strain and the presence of a resistant strain depends upon mutations. At this late date the only thing I can suggest is that you pursue a study on the effectiveness  of germicides.  We are told that washing hands with soap is just as effective as these liquid hand cleaners you can buy now. I have wondered about these wipes you can find in grocery stores to wipe shopping carts. Do they really work. This is a workable idea.
As to cultures the gelatin and broth I suggested is like nutrient agar and you can culture bacteria at warm room temperature without an incubator. It just may take a little longer then 24 hours. I do not know why your teacher mentioned pH changes. Bacteria will grow fine a a pH of 7.0
If you decide to do a bacti project like the one I suggested it would be a quantitative study not a qualitative one and you would be swabbing hands so you just to be careful that a hand swab is all that is introduced to the media.
The more I thing about testing these shopping cart wipes the better I like the idea.
If you decide to do a bacti study let me know and I will help you. I was a diagnostic bacteriologist for the US Army.
It is not as sensational as developing a new species but it will work
   walter

---------- FOLLOW-UP ----------

QUESTION: To Mr. Hintz: Expert
First of all, thank you very much for your answer, it is truly helpful.
Second, just so you don't get the wrong impression of what my teacher knows, my original idea, which I should have been more clear about, was to change the pH or temperature.
Third, the reason I originally wanted to do this was to show the principal of the school that evolution does happen, because when we started to learn about evolution he did not let the teacher teach it to us, rather we had to learn it from the book, because it "goes against our religious beliefs". What really bothered me about his whole speech was his statement "science is not the search for truth, it is the search for convenience",this I know to be an untruth. (After this statement it did not surprise me that on a test which he gave us he wrote "textile" rather than "material" because he thought we would think material means fabric.) While we were "learning" evolution it was discussing why pesticides become less effective over time, this is where my idea came from.
Fourth, my sister (who is in medical school) said that if I try to make the media from scratch it will not be sterile, thereby not being an effective media because of parasitic bacteria. In order to counter this issue can you suggest where I might be able to buy the agar?
Fifth, in order to get proper results for the project you suggested (which I plan on doing) I would need to use the same hand correct? If I use multiple hands to test different products it will not be accurate because everyone reacts differently to different products, correct? (Or would it not matter because the bacteria reacts the same?)
Sixth, by "Quantitative not Qualitative" you mean I am looking for how much bacteria rather than what type, correct?
Seventh, and last, which cleaning products should I use, I only use soap and water, and I don't know what products there are out there?
Again thank you for your time and I really appreciate the effort you are putting in to help me along.

ANSWER: Hi again Zvi
You are certainly in a pickle here as a scientific minded individual in an unscientific school. Let me tell you first that there is nothing you can do to convince the school authorities that evolution occurs so do not bother to try. Although I am not Jewish I taught science part time for a year in a conservative Girls Hebrew Academy. I was not allowed to answer any questions about evolution or sex.
As for your project. You can buy small amounts of bacti media from Carolina biological supply of Ward's natural science establishment. I do not know where you live but if you have a large hospital nearby you could beg a few agar plates form them. You sister is a medical student so maybe she could get you some.
With the project I suggested whose  hands you check are not important. In fact the more hands you use the better. You are only testing the effectiveness of soap or an antiseptic cleaner. You would merely have be sure that the hands had not been washed for a while. I would suggest the first thing in the morning. You could use the right hand for soap and the left for antiseptic. Just be sure to test more then once.
Stick with a single brand of soap and a single brand of hand sanitizer. There are three brands of sanitizer Purcell, Loyola and Dial that I am aware of.
I suggested a quantitative study because for a qualitative study you would have to have methods of further identifying the colonies. You have to use staining methods etc.
When recording you data you can describe the colonies however and that might be be a good idea
 Keep me informed as to what you are doing. When you decide upon a hypothesis and an experimental design let me know.
As to the evolution controversy just keep your mouth shut and do your thing. I wise person told me once not to argue with somebody if you think they're nuts. Its a waste of time

---------- FOLLOW-UP ----------

QUESTION: To Mr. Hintz: Expert
Thank you very much for your prompt response.
As to what my hypothesis will be, I think it will be "What works better hand soap, or antiseptic sanitizer?". My constant will be a dirty unwashed hand, and my two variables will be hand soap and hand sanitizer. I still need to ask my teacher if he approves of this idea, but I am pretty sure he will approve.
I will surely take you advice to stay quiet.
Thank you again for all the help you have given me, and I will try to keep you informed like you asked. In order to keep you informed should I continue to contact you through here?

Answer
Hi Zv1; In the scientific method the question is the problem.  If other words the Problem you are testing is "Which is more effective hand soap or sanitizer?"
The hypothesis is a statement as to what you think the answer will be
e.g. "Hand soap is more effective in removing bacteria then sanitizer" or you can word it the other way with sanitizer being more effective then soap. It makes no difference which way you state it because negative information is just as valuable and answers he problem.
Be sure you run the test more then once