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Name: Kayla
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I am doing a science fair project on deodorants and anti-perspirants- to see which one hinders bacterial growth more effectively. Here's my problem, I cannot find what kind of bacteria (mainly) flourishes in the axilla (armpit) region. I have been on many different search engines- medical pages- and microbiology pages, and unfortuantely cannot come up with any answers. My school's science fair is March 3rd- so I am in desperate need of an answer!!! I need to be able to order the type of bacteria soon. Thank you.

Try Staphylococcus epidermidis-it is a common organism that grows on the skin. It is not pathogenic (disease-causing) and can be used by students. You could try culturing your own armpit-use a sterile q-tip. Spread the q-tip on the agar plate and then take some of your antiperspirant or deodorant and make a dot in the middle of the plate. Incubate the plate and see if the bacteria are repelled or are resistant. I would measure the size of the zone so you can compare each type of deodorant, etc. You could also check if different people's bacteria are more or less resistant, ie if the same deodorant works for everyone. Each person's bacterial population are a little different. This would require volunteers who would be willing to stick a q-tip in their armpit! If you decide to do this, I would sample the armpit when it is moist, before a shower (dry, clean skin won't have as much bacteria). Good luck.

Van Hoeck

Hi Kayla...

As you probably know sweat glands are of 2 types, one of them, the one called apocrine is usually associated with hair follicles and continously secret fatty sweat in the gland tubule.When, due to many factors the tubule wall contracts the fatty secretion is expelled to the skin, where local bacteria break it down into fatty acids that have pungent and disagreable odor. These glands are concentrated at the underarm (axilla) and genital region. Now for your question: bacteria are a general name for micro-organisms that are found at all ecosystems ( but for the completely sterile ones)and even in some habitats where no other forms of life can exist. There are bacteria that causes and spread diseases, and bacteria that are very useful. The moist areas of the skin like the armpits can have a large number of bacteria. As i found (reported at Internet by Dr. Neal Chamberlain, specialist of Microbiology at the Kirksville College of Medicine), the most common bacteria on the skin are: Proprionobacterium acnes, Staphylcoccus epidermidis, Corynebacterium, Micrococcus, Peptostreptococcus and various Neisseria species. You mentioned your intention to order some bacteria samples to make your tests, but maybe it will be easier to make yourself a culture of the commom bacteria, just looking around... and good luck at the fair!
Thanks for asking NEWTON

(Dr.Mabel Rodrigues)

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