This may seem a weird experiment to have done – but 2 weeks ago Ean Ean snipped off some hair from my armpit directly into a Petri dish to see what we grew. The reason for this behaviour was that my T-shirts and jumpers tend to develop a lot of holes in the armpit areas and we wondered what bacteria was doing the damage. I do have reasonably hairy armpits!
Pictures below of the bacteria we grew – they are small round bacteria – this is known as coccus (cocci in pleural).
The Gram staining (by Rhys today) shows that the bacteria are Gram Positive.
A brief internet search shows that common axillary bacteria include Corynebacterium and Propionibacterium. Another bacteria that is often present but in smaller number is Staphylococcus.
Corynebacterium is a genus of bacteria that are gram-positive and aerobic. They are bacilli, and in some phases of life they are, more particularly, club-shaped, which inspired the genus name. The principal features of the Corynebacterium genus were described by Collins and Cummins in 1986. They are gram-positive, catalase-positive, non-spore-forming, non-motile, rod-shaped bacteria that are straight or slightly curved. Propionibacterium is a gram-positive, anaerobic, rod-shaped genus of bacteria named for their unique metabolism: They are able to synthesize propionic acid by using unusual transcarboxylase enzymes. Staphylococcus is a genus of Gram-positive bacteria. Under the microscope, they appear round, and form in grape-like clusters. The Staphylococcus genus includes at least 40 species (Wikipedia).
My bacteria appear to be Staphylococci – round and blue.
Preparing sample for microscopy today:
1. The Petri dish culture – axillary (armpit) hairs are visible!
2. The spatula was used to scrape off the bacterial culture into this container and then it was mixed with small amount water:
3. Small drop put onto a slide:
4. This is then dried:
Unstained heat-fixed slide, with 63x objective:
Gram stained slide, x32 objective:
Gram stained slide, x63 objective: