Module 2 Kitchen Lab

This week I attempted to make a homemade agar solution in order to grow a culture of the bacteria off my hand. While I didn't have the best luck in the world, I luckily got to do a similar experiment in my lab class! I'll show you my attempt to make my homemade agar, as well as the results I got from my lab. I think my biggest issue might have been the broth. It wasn't the powder type that the recipie called for, but a liquid. Maybe that had something to do with why I couldn't get bacteria to grow?

Here's what my broth looked like when it was still hot!

I didn't have a petri dish, so I poured the agar into this Tupperware container to cool.

I ended up swabbing my hand, because I wanted to compare it to the results I got in lab to see if they'd grow as well on my homemade solution.

Unfortunately.... no luck. The lid is supposed to stay on as a precaution, but with the blue lid, it was hard to see anything. I popped the lid off and still didn't see any colonies from where I streak. This pic is from day 4, so I would've expected to see something by now!

So instead, I'm going to try to analyze this plate that I made when I swabbed my hand in lab. There seem to be two main types of colonies. There are the large tan irregular shaped colonies, and beige punctiform circular colonies.Both are smooth and shiny, and opaque.

According to WHO (http://www.ncbi.nlm.nih.gov/books/NBK144001/), one of the main bacteria found on the hand is a resident bacteria called staphylococcus epidemis. Resident bacteria tend to be protective, and they actually help prevent other more harmful microbes from colonizing. They're very common to see on skin, and are actually the predominant species for our hands.

However, according to NIH (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2807625/), these bacteria can become opportunitstic pathogens in the right conditions. It's actually a really common cause of infection for indwelling medical devices, because it is found all over the skin! There is a lot of antibiotic restistnace for this microbe, so it can be really hard to treat.

Moral of the story with S. epidermis is that it's great on your hands and skin, but not so great anywhere else. I'm pretty sure one of these colonies above are S. epidemis, based on how common it seems!