Microbiology- Identifying Unknowns: Micro. Lueteus

For the first day, I received my unknown bacteria number 110 and I stared to observe that tube. The tube has normal color, creamy, and little bit cloudy. First, I made two new slants to get the strong and alive bacteria for further text. One tube was incubated at 250C and other at 370C. Next, I started to do my Gram Stain. After I finished the smear, heat fix, and cover the slide with all chemical, I saw the pink color stick onto the slide. I knew that this bacterium is gram negative. Then, I looked up the slide though the microscope form 10X -> 40X ->oil ->100X. I saw the bacteria which have rod shape with chains and pairs. I want make sure one more time that bacteria are gram negative or positive, so I stared to set up EMB and PEA plates to get the result for the next class.

The first test executed was the fermentation of carbohydrates. The objective of this particular test is to identify the ability of microorganisms to ferment a specific carbohydrate (Reiner, 2012). The test can be used to identify three different ways in which bacteria can ferment simple carbohydrates. Bacteria can be tested for acidity, alkalinity, whether or not it remains neutral and gas formation (Reiner, 2012). To conduct the carbohydrate fermentation test, a pH indicator, bromocresol purple, is used to indicate an acidic characteristic (Reiner, 2012). Bromocrescol purple indicates carbohydrate fermentation media by turning a deep purple if it’s an uninoculated media, yellow if it’s acidic and purple if it’s alkaline (Reiner, 2012). Durham tubes are placed inside the tubes containing the media and bacteria to detect gas production (Reiner, 2012). Three different carbohydrates were tested for fermentation during this test: glucose, sucrose and lactose for each of the

I achieved an isolated Gram negative bacteria because I modified the four-quadrant streak style and time. I believe that my Gram negative bacteria were a fast grower and would over grow the Gram positive. On the 4th day I was able to successfully isolate my Gram negative, and proceeded to run the SIM test and the TSI test as instructed. Both tests produced black precipitants, indicating sulfur reduction. This narrowed down my possible Gram negative bacteria to four bacteria. As I continued to analyze the SIM test the results showed motility, which was confirmed by my TA and indole production. With this test I was able to narrow it down to 2 bacteria. I think did another Gram stain to confirm no contamination, once confirmed, I decided to do

For this experiment, we were given three gram staining slides as well as a petri dish with five different types of incubated microorganisms that were divided. The five different organisms on the petri dish being observed were Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Klebsiella pneumonia, and yeast known as Candida albicans. On the surface of the

Overall, the experiments objective was complete because the unknown bacteria was identified through the steps provided. The hypothesis stated that if the bacteria is gram-positive than

I also performed the MRVP test. This test differentiates between organisms by detecting fermentative end-products following growth in a buffered peptone-glucose broth. In the Methyl Red test, the low pH of 4 is indicated by a red medium.

According to page 24 of the lab manual, Gram-positive bacteria are able to grow on a PEA medium but not EMB-lactose (Holbrook & Leicht, 2013). Therefore, further testing had to be done that would identify the gram-positive or gram-negative state in the Catalase and Oxidase test. The result of the KOH Test, also Table 1, as gram-positive, because the bacterium we tested did not form a string. Because of the mixture of identities the Catalase test and Oxidase test were used (Figure 2). These both resulted in a very strong gram-positive reaction. During the Catalase test, after placing a drop of H2O2 on our slide, an immediate strong reaction of bubbles formed. This confirms our specimen as catalase-positive bacteria. The Oxidase test showed strong reaction in the gram-positive designated areas confirming, with the Catalase test, that the bacteria most likely is gram-positive. This concludes the observational-based testing

Day 1: different agar plates were divided into four sections and the four microbes were streaked and incubated overnight ( at 37 °C)

Observing under 1000X magnification, the gram stain depicts pink bacilli, as seen in Figure 1. Figure 2 depicts the growth of a brown bacteria on a MacConkey Agar plate. Figure 3 depicts the growth of a similarly brown bacteria surrounded by a very thin clear area on a blood agar plate. As seen in Figure 4, the slant of gram-negative isolate appears mainly clear, with a slight green tint. Figure 5 shows the methyl red test, which produced no color change. Figure 6 shows the Voges-proskauer test, which also produced no color change. Figure 7 depicts the lactose test, which produced no color change and no gas. The Indole test resulted in a red ring and the Hydrogen Sulfide, H2S, test resulted in a black precipitate, both of which can

The purpose of this final laboratory experiment was to allow the student to apply the knowledge learned from the exercises performed during the laboratory sessions. The knowledge accumulated from these exercises dealt with performing multiple tests used to characterize and differentiate between microorganisms. Not only did the student learn how to perform these tests, but also learned the ability to interpret the results in order to identify a microorganism. By the end of the final laboratory period, the student was expected to be able to correctly isolate and identify the two microorganisms, one Gram-positive and one Gram-negative, from a mixed culture the student receives. The mixed culture I received was number 21. From

The purpose of the gram stain test is to see if an organism is gram negative or gram positive based on it’s color and shape. Using an inoculating loop and inserting it into the incinerator for 10 seconds, it was sterilized. A small drop of water was then applied onto a clean glass slide by using the now sterile inoculating loop. The loop was used to spread the organism back and forth on the slide until a good portion of the glass is covered. The organism and water were left to dry completely before heat fixing the glass slide. After heat fixing, over a sink crystal violet was applied to the glass slide for one minute. It was then rinsed with water and iodine was applied for one minute. The slide was then rinsed with water and 95% ethanol was

In this experiment individuals were given a plate with two unknown specimens. Each group completed a gram stain followed by a series of other test in order to identify the unknown bacteria. Each student conducted separate testing’s on one unknown in order to specifically identify the strain.

There are many different physiological tests one can used to identify bacteria. For this project, one can use a spore stain to see if a bacteria can produce spores in response to nutrient depletion.(Intrieri, 2014) There is also the catalase tests, which show whether bacteria possesses the enzyme catalase, which can handle reactive oxygen species (Intrieri, 2014). There is also the oxidase test, which tests for the presence of oxidase in a bacteria, which indicates the bacteria contains cytochrome c (Intrieri, 2014). Another useful test to differentiate bacteria is the Entero-Plueri Test®, which performs multiple tests in one setting, like

Before I performed any experiments, however, I made educated guesses/hypotheses regarding the identities of each unknown microorganism. Firstly, my assigned sample, B2 and the other bacterial sample F7 were transparent before the gram test so I could not make a hypothesis about them without any information to base it off of. However, I assumed that A4 is a type of algae due to the small flagella (used for water navigation) and green color it possessed and that F10 is a eukaryote of some sort due to its cells ' constant movement. Before performing the complete identification tests on the B2 sample, I could not make guesses regarding their results because I lacked information about the basic properties of the bacteria that gram-staining and ocular

(4 marks) What is the use of negative staining? (2 marks) c) Most genera of bacteria will lose the red carbolfuchsin stain when decolourized using acid alcohol but those that are "acid-fast" retain the bright red colour in ZiehlNielsen Acid-Fast stain. What could be the explanation for this colour differences. (3 marks) You are given a bacterial sample and your task is to find out whether the bacteria are motile or not. Suggest three (3) lab procedures that enable you to test on the bacterial sample. (3 marks)