Science Buddies: "Ask an Expert"

I need a safe pathogen to use to test swimmer's ear in the lab. I have found I can not use Pseudomonas aeruginosa. I can not start my science fair project till I find a pathogen I can use. I want to test various PH and cholorine levels in water. Preferably in a test tube. I need help urgently. I am behind already.

Hi Thomas,
Welcome to the Ask an Expert forums. It sounds as if you need a substitute for a pathogen. A pathogen is, by definition, unsafe and not suitable for a science fair project unless you are working in a university setting with experienced researchers.
Can you tell us a little more about what you had planned? If it is not feasible to study swimmers' ear, maybe we can help you to adapt your project to something more suitable.

Chris

I was planning to conduct the experiment at Saint Mary's College in Orinda, California. My teacher knows one of the biology professors there and our class will be going there in the second semester to I think conduct labs. My teacher wants me to try to do this experiment and not have to change to a completely different experiment. The original plan was to test the bacteria in a test tube filled with water and with varying levels of pH and chlorine, to simulate pool conditions. The professor at SMC is taking many days to return my replies and the forms for the project are do on monday, so that is why i have come to this site.

Sounds like you need a related bacterium to "stand in" for P. aeruginosa. Basically, something similar to P. aeruginosa, but less dangerous to work with--is that right? It's gram-negative and aerobic, so you'll want something with those same characteristics. Preferably something closely related to P. aeruginosa.

I did a google search for "non-pathogenic pseudomonas" and got this as a hit: http://209.85.173.104/search?q=cache:5v ... =firefox-a

It lists five Pseudomonas species that are apparently not pathogenic (although it says some might be animal pathogens). Maybe one of these would be appropriate for your project? I'm not saying that definitely one of these would work--I don't know anything about them--but you could do some further research and see if one of them or another Pseudomonas species would be a good stand-in.

Alternatively, streptococcus and staphyulococcus apparently can also cause swimmer's ear (http://www.medicinenet.com/otitis_externa/article.htm)--maybe a bacteria like one of these would be an option?

I'm pretty confident with a little research you can find a Pseudomonas, staphylococcus or streptococcus that would be appropriate for your lab work. Good luck!