Chemical Testing And Its Effect On The Growth Of An Agar Slant And Broth

The following tests according to the lab manual were performed: gram stain, fermentation tubes, methyl red, vogues proskauer, sulfur, indole, motility and growing it up on MacConkey agar. The gram stain was performed incorrectly the first time. This is because the decolorizer was not on the bacterium slide for long enough, giving a false outcome.

This experiment was centered on metabolic and biochemical testing procedures. The rationale of performing these tests was to distinguish six different microbes from one another and to compare how their metabolic and biochemical processes differ from species to species to determine the unknown sample.

The colonies were smooth, translucent, and had a white brownish color. The Gram stain resulted in Gram positive cocci. After the Gram stain was completed, the bacteria were streaked on a Mannitol-Salt Agar plate and a Catalase test was performed. After these test were completed a Phenol Red Dextrose Fermentation tube was inoculated, and a SIM Tube inoculated.

Next I performed a KOH test to further confirm that my organism was a Gram-negative species. For the KOH test, I added 3 drops of 10% potassium hydroxide (KOH) to a small drop of distilled water onto a clean microscope slide, transferred a visible clump of organism to the KOH solution using my inoculating loop. I than mixed the cells into the solution using small, circular motions for 60 seconds and then lifted up the loop to look for what appears to be a “stringing” affect which means it’s confirmed that it is gram- negative species. Next, I created a streak plate using nutrient agar so that I could see pure culture of my organism. I aseptically obtained a loop full of my organism and gently inoculated one quarter of the nutrient agar plate by running the loop back and forth across the surface. I then flame sterilized the inoculating loop, allowing it to cool for 10 seconds, and then streaked the organism from quadrant I into quadrant II using a zigzag motion technique. I repeated those steps streaking from quadrant II to quadrant III and then streaking from quadrant III to quadrant IV. Once completed, I put the streak plate in the incubator at 37° for 24-48 hours. 48 hours later, I check my streak plate and it had a lot of growth on it. I was able to determine that the organism was definitely an off white color, opaque. The IV quadrant was the quadrant that best

There are many reasons for knowing the identity of microorganisms. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all of the methods that I have been learned so far in the microbiology laboratory class for the identification of an unknown bacterium.

This experiment was conducted to find the genus and species of an unknown bacteria prescribed by the lab teacher, which was unknown bacteria GA3 in my case. Identification of unknown bacteria techniques are used on an every day basis to figure out what type of bacteria it is and to find the best method of how to treat a patient with this bacteria (1). All five “I’s” of Microbiology were used in the testing for the unknown culture. Inoculation was used several times to put the unknown culture into agar plates or into biochemical test tubes. After Inoculation of these tubes or plates, they always were placed into the incubator for further growth and development. Isolation was used to make sure we got the correct bacteria we were testing for. After each further isolation, we gram stained the culture and inspected the culture under a microscope to further help in the identification process of the unknown bacteria. Multiple tests were done on the unknown culture to make sure we were confident in what kind of bacteria the unknown was.

There are many reasons for knowing the identity of microorganisms. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all of the methods that have been learned so far in the microbiology laboratory class for the identification of unknown bacteria. The identification process can be completed with a series of deferential stains and biochemical tests. Creating a dichotomous key helps to limit the amount of biochemical tests done on an unknown organism and by observation

The first step to identifying the unknown bacteria residing on the blood agar plate sent in from Khokana was to do a Gram stain on it. This is an important first step because it dictates further testing that will be necessary to arrive at a final conclusive result. Viewing the fixed and stained slide under the microscope revealed round chains of bacteria in a purple color signaling Gram-positive streptococci. A catalase test was performed with no bubbling present indicating a negative result. This further confirmed the shape and arrangement seen under microscopy. With this mind, the coagulase test was not done, as it would be of no use since that specifies for staphylococcus, specifically for Staphylococcus aureus. For streptococcus, an examination of hemolysis was necessary at this point. Shifting attention back to the original blood agar plate, gamma hemolysis was noted, thus narrowing the field down to two choices left. The unknown bacteria was either Streptococcus bovis or Entercoccus faecalis. This also means the Optochin and Bacitracin sensitivity tests would not be needed as those pinpoint alpha- and

This experiment was given to us to utilized previous knowledge learned throughout the semester to identify a gram negative unknown bacterium. We had to first learn the difference between a gram negative and a gram positive organism. We started off with doing gram stains to determine whether it was positive or negative. Based on the gram stains, a gram positive stains purple and a gram negative stains pink. A gram positive stains purple because the cell walls is made of a thick peptidoglycan layer and doesn’t

The purpose of this study was to identify the unknown bacterium using biochemical tests and various methods that had been learned from previous the microbiology laboratory class. Identifying the unknown bacterium was determined by separating and differentiating possible

The bases of this experiment was to discover the identify of the unknown from three possible specimens: Klebsiella pneumonia, Escherichia coli, and Enterobacter aerogenes. Utilizaing the T streak technique, the bacteria was isolated into pure colonies for further study. The Gram Stain method was used to identity the morhphology of the bacteria such as the shape and whether the bacteria was Gram positive or Gram negative. Biochemical test were also used to help identify the unknown bacteria. The biochemical test used was the Triple Sugar Iron Agar, Sulfur Indole Motility test, Methyl Red test, Voges-Proskauer test, Citrate test, Urease test, and the Gelatin test. After observing the morphology of the bacteria using the Gram Stain method and utilizing all the possible biochemical test, the bacteria was identified to be Enterobacter aerogenes.

I have completed the testing on the organism you provided to me that was obtained from one of your patients, patient #17. Upon culturing the specimen and conducting the gram staining procedure, I was able to determine the microorganism is a Gram-negative rod shaped organism. The culture plate showed no evidence of hemolysis. Once I determined its bacterial classification, I then proceeded to order additional laboratory tests specifically used for Gram-negative organisms. The tests included:

Sample 70A was a given as a pure bacteria. With this pure bacterium I immediately made a streak plate to get my single colonies and conducted a Gram stain. After completed the steps as instructed in the Laboratory manual, it was determined that Sample 70A bacteria was a Gram-positive rods. The bacteria was purple in color, this indicate that the crystal violet was not countered with the safranin leaving bacteria stain with the crystal violet (Leboffe and Pierce). The cells were cylinder in shape clarifying them as rods.

In the experiment we conducted there were many method in which we could have used to help us manipulate and identify bacterium on different agar plates. First part of the experiment involved the manipulation of the bacterial growth where we used different streaking methods to see which method was best suited to give me colonies. We have used 2 types of bacteria Escherichia coli (E. coli) and Yakult (Lactobacillus casei). E. coli is a bacteria that is rod shaped, Gram negative and is a genus of enterobacteriacae, the rate of its growth varies on if the right conditions are met which include the right PH, temperature, energy source and nutrient. Yakult consists of probiotic bacteria which is good bacteria that is beneficial to our digestive system and in each bottle of

The purpose of the two experiments was to determine the fundamental effects that temperature has on the growth and survival of bacteria. During the first experiment five different bacterial broth cultures of Escherichia coli, Pseudomonas fluorescens, Enterococcus faecalis, Bacillus subtilis and Bacillus stearothermophilus were individually incubated at temperatures of 5, 25, 37, 45 and 55°C for one week in an aim to distinguish the effect temperature has on growth and survival of the five different species. After one week they were observed for distinguishable changes by the turbidity showing an indication of bacterial growth, or the clarity an indication of no survival.