Week 3, Day 4

May 31, 2013

Today in lab our professor brought in some MRSA (methicillin resistant Staphylococcus areus) and MSSA (methicillin sensitive Staphylococcus areus) Petri dishes for us to observe. The MRSA samples were incubated on mannitol-salt agar plates.

 In one of the samples we observed a mupirocin antibiotic disk in the agar. The bacteria in the dish was sensitive to the mupirocin and did not grow around the disk. Another dish contained a sample of bacteria that was avoiding (was sensitive to) a oxycillin antibiotic disk. Because this disk inhibited the growth of the bacteria, it indicates that the culture was MSSA and not MRSA.

                                                           

After viewing the MRSA and MSSA culture dishes we retrieved the yogurt tubes from the day before. The milk had solidified and the bacterial growth had formed yogurt in the tubes.  We were able to sample it and determine which brand of yogurt was better.

 We also observed the UV light treated bacteria water Petri dish and the untreated sample. The untreated sample had a great deal of bacteria cultures growing on, while the treated sample only had a few cultures growing on the Petri dish. Our professor told us that usually the UV treated water would have no bacterial cultures.

We also studied our food purity test from the day before. The meats that were present in the hamburger extract had reacted to the goat anti-albumins and produced precipitates, whereas the goat anti-albumins for the meats not present in the hamburger did not react with the extract at all. This test allows us to identify which meats were present in the hamburger extract, which will give us an idea of the purity of the sample.

  We finished up lab for the mini session by watching the movie 'Contagion,' and how it applied to Microbiology and our field of nursing.