Experiment Case

The objective of this experiment was to identify the organism I chose of the unknown bacteria (#10). Applying all of the methods that had been taught so far in the microbiology laboratory class did this experiment. Three staining techniques were used to help figure out what the unknown bacteria was. The three stains used were the Gram stain, Acid Fast stain, and Spore stain in lab. Each of these stains helped when figuring out what the unknown bacteria was by showing under a microscope if the unknown bacteria were negative or positive. While doing the Gram stain one is looking to see if the unknown bacteria was pink which means it is negative or purple which means the unknown bacteria is positive. The Gram stain ended up being a pink, which meant the unknown bacteria, was negative. Gram staining is useful in separating bacteria into two groups: Gram positive or Gram negative. Gram positive bacteria have a cell wall composed almost entirely of peptidoglycan, present in many layers. Gram negative bacteria have a cell wall with only a thin layer of peptidoglycan beneath an outer cell wall membranous layer. The next stain done was the Acid Fast stain and was looking to see if it appeared blue which means the unknown bacteria is negative or red which means the unknown bacteria is positive. The Acid Fast stain is primarily used to detect members of the genus Mycobacterium and Nocardia. If the stain is red it contains mycolic acid, which is rare. The Acid Fast stain was blue, which meant the unknown bacterium was negative. The last stain is was the Spore stain so if it was green that meant the unknown bacteria was positive and if it was red that meant the unknown bacteria was negative. The Spore stain is used to identify bacterial cells that can produce endospores. The endospore stain is used to tell apart vegetative cells of bacteria from endospores. The Spore stain came out being negative also. All three stains that were performed came out negative. Doing all of these stains to identify unknown bacteria is important. Staining the unknown bacteria allows one to look under a microscope to see stain color and morphology.

The results after staining showed that all the bacteria staining came out negative. After viewing the unknown bacteria under the microscope in oil immersion the morphology came very apparent. The morphology of the unknown bacteria was rods. After figuring out the morphology and staining the results showed that the unknown bacteria picked was Enterobacter Aerogenes.