Staphylococcus Aureus! New Project and Article Assignments

  Staphylococcus Aureus

This week in the internship I finally figured out what my #7 unknown bacteria was! It was Staphylococcus Aureus! My MSA came back with bacteria growing so it was MSA positive. I then tested my bacteria broth with the following broths: glucose, lactose, mannitol, tryptone, TSI(agar), and TSB+6.5NaCl(sodium chloride). All the results(color changes and bacteria growth) proved that my bacteria was in fact Staphylococcus Aureus. A very resistant bacteria to antibiotics that can be found in the respiratory tract and on the skin. Staph aureus can cause skin infections, respiratory disease like sinusitis, food poisoning, and possible life threatening diseases like: pneumonia, meningitis, osteomyelitis, endocartitis, and toxic shock syndrome(TSS). 

To the left you can see my test tubes after they spent 24 hours in the incubator with color changes to yellow and some bacteria growth in the TSI. To the right you can see my MSA medium with the bacteria growing in it. This proves that my bacteria was able to grow in a high salt environment. The yellow was what you were looking for here.        

 Isolated Streak (Notice the different kinds of Spots)

Now that I found out that my bacteria was Staphylococcus Aureus, Josh gave me an assignment to look up a few articles and type a review on one. The article I chose to review is called "Staphylococcus Aureus small colony variants are susceptible to light activated microbial agents" by Sarah Tubby. Michael Wilson, John A. Wright, Ping Zhang, and Sean P. Nair. So far it's very interesting because I'm learning why Staph aureus is so resistant to antibiotics and this new method that has potential to eliminate S. aureus. Oh, yeah and I was assigned a brand new bacteria to solve and test on. I have done an isolated streak and have done the gram stain so far but something very interesting was noticed by Josh on my isolated streak. It actually had two different types of bacteria growing in it! How weird! So Josh told me to test the both bacteria in TSB and incubate them. Well that's what I've done so far and hopefully next week I will figure out what it is. Also I'm really looking forward to the field trip this Friday to the Arizona Museum of Natural History even though I have class at that time. Hmm not really sure what to do, but I will figure something out!

First Week as Stem Intern! Unknown Bacteria "X" Mini Project

   This past week has been my first week as a STEM intern. I started Monday at noon and my journey began with some very long and informative safety videos. Although they were boring they are important and essential. After the videos I had to find out what an "isolation streak" and a "lawn streak" were. I then had to actually do an isolation and lawn streak with mystery bacteria #7 given to me by Josh. My first attempts on the streaks were not very good due to me literally stabbing the TSA. I tried it again and my second attempt were much better after Josh demonstrated how to do it properly. Drawing the “T” on the bottom of the dish really helped as well. I put my first and second attempts of streaks in the incubator for 24 hours to see my results.

These are my first and second attempts for the isolation streak. “T” definitely help

My second attempt (right) seemed to have grown some type of mold quite obviously.

On Tuesday I had to find out what a “gram stain” was and figure out how to do a gram stain on my unknown bacteria. So I found out that a gram stain is a way to figure out what type of cell wall (gram negative or gram positive) and shape the bacteria has to differentiate it from other bacteria to narrow down what type of bacteria it is. So the process was to grab a slide and put a drop of water on it. I then grabbed some bacteria and smeared it on the slide on the water. I got an oil lamp and heated the slide by passing it on top of the fire until the water dried up and left only the bacteria. After that I put a drop of crystal violet on the bacteria and left it for 30 seconds and rinsed it off with water. Next I covered the bacteria with Gram’s Iodine for one minute and rinsed. The decolorizer was next for 15-30 seconds and rinse. Last was the Safranin for about a minute and rinse off. Blot dry with the bibulous paper and finally put the slide under the microscope and look for the cell morphology. Mine turned out to be a gram positive coccus.

I had figured out that my cell morphology was coccus, which is circular shaped cells. I also found out through the gram stain that my unknown bacteria was gram positive since it was purple. From that information I followed the positive gram cocci chart and the next step was to do a catalase test. The catalase test purpose is to identify if the bacteria generates the enzyme catalase. I needed some hydrogen peroxide for this test. I grabbed a slide and made two circles one for the test and the other for control. I put a drop of distilled water on both circles and smeared some inoculum (bacteria). I put one or two drops of hydrogen peroxide on the Test circle and none on the control. The reason for this is to see if the hydrogen peroxide will make the bacteria bubble or not. If the bacteria does bubble then it means that it is catalase positive. The C circle is to compare with T circle.  My bacteria did bubble so it is catalase positive.

Now that the bacteria have been identified to have positive catalase enzymes, the next step is to do glucose fermentation. I simply transferred a few drops from by unknown bacteria tube to the glucose tube and put it in the incubator for 24 hours. The next day I grabbed my glucose tube from the incubator and saw that it turned bright yellow. This means that my bacteria is a positive acid and it did not produce any gas. Finally I did an MSA test today to see if my bacteria can withstand a high salt concentration environment. I did an isolated streak on an MSA medium today and placed it in the incubator for 24 hours. Next week I will check my results. Overall I have really enjoyed this mini project so far because it’s really “hands on” learning and it’s interesting to see how many test are done on a bacteria. The other interns seem really cool as well and seem to be enjoying their projects too.

First Week as a S-STEM Scholar, Human Chimeras

So this is my first week as a S-STEM Scholar and my first time doing a blog ever! I'm very excited to be a part of this STEM program and to be one of the scholars chosen this semester and I want to thank the STEM staff for choosing me. Well I don't have much to blog about this week but the internship interview I had on Monday with Josh and Matt. The interview was good and I hope I'm chosen to be an intern for the program. In the interview I was motivated to look into biological research and that's what I did. I found an interesting article about human chimeras. A chimera is a mythological term given to animals with other animals' parts like a lion with a snake for it's tail. Chimeras were only thought as these mythological creatures until recently as doctors are finding characteristics of chimeras in humans. This article states that there was a case of a mother that had recently given birth to a child but blood test showed that she was not the child's biological mother. She continued to take blood test but they soon found out that she was a fraternal twin and that the twin literally "absorbed into her" and the "combined tissue created a composite body". Another woman had the same problem when she needed a kidney from  her children but then found out they did not have her DNA. I found this article very interesting as I never imagined this ever happening and it's quite fascinating. There are links below to the the article.

http://io9.com/5911357/theres-a-good-chance-youre-a-human-chimera