When unknown 32 was tested with the oxidase test, it was found oxidase negative. The catalase test tests for the presence of catalase which breaks down hydrogen peroxide and oxidase dismutase. A small amount of hydrogen peroxide is dropped onto a slide of unknown 32 and resulted in bubbles. This result shows that unknown 32 is catalase positive since it broke down hydrogen peroxide and oxidase dismutase which resulted in water and oxygen. This eliminated Enterococcus spp.…
The catalase test is used to differentiate staphylococci (catalase-positive) from streptococci (catalase-negative). The enzyme, catalase, protects the bacteria from the toxic by-products of oxygen metabolism. This enzyme is produced by bacteria that respires using oxygen. The catalase-positive bacteria include strict aerobes. Catalase-negative bacteria may be anaerobes, or they may be facultative anaerobes do not respire using oxygen as a terminal electron acceptor. The test reaction is very fast and obvious bubbles will be seen. 30% Hydrogen peroxide will be drop on a glass slide. The inoculum of 24 hours fresh culture will be picked by using sterile loop and placed on the slide that contain H²O² drop. Bubble formation on the slide will show…
The purpose of this experiment was to isolate two unknown bacteria and perform a series of selective and differential tests to correctly identify each. After the bacteria was isolated a series of differential and selective tests following the dichotomous key attached were used to identify each bacteria. The Gram-positive bacteria were identified as Staphylococcus aureus with a positive confirmatory test, mannitol salt agar, showing consistent results as well for S. aureus. The Gram-negative bacteria were Pseudomonas aeruginosa with a positive confirmatory…
The purpose of this lab was to determine the identity of an unknown bacteria slant culture. The unknown was identified using differential tests to determine its metabolic and morphology characteristics. Results from the differential tests indicated that unknown culture 5 is Staphylococcus aureus.…
The purpose of this experiment is to distinguish and indentify an unknown bacterium. There are several tests that can help one eliminate and narrow down the options. The most useful test, and the very first one done, is a gram stain. This test will tell whether the bacterium is gram-positive or gram-negative. After the type of gram stain is identified, the tester has a wide array of differentiating tests at their disposal. Based on the results from these tests, and the numerous others that are available, one can accurately establish the identity of an unknown bacterium.…
Explain in detail the procedure that you followed (including amount of substrate, enzyme etc, and the whole procedure including incubation times) (3 Points)…
The pathogenic species of staphylococcus ferment mannitol and produce acid which turns the pH indicator…
Tubes were kept in the ice bath for 30 minutes. The tubes were then heat shocked at 42℃ for 90 seconds. The tubes were then returned to the ice bath for one minute. 1 ml of LB broth was added to each tube for outgrowth and placed in an incubator set at 37℃ for 45 minutes. The cells were then spread on a grow plate of LB-amp-arabinose and placed in an incubator at 37℃ overnight.…
Each was isolated on different plates to have a primary culture, SBAP 1 and SBAP 2. In SBAP 1, a split plate was done, by inoculating the B hemolytic colonies and the tan colonies from the CHOC. It gave a mixed growth, so the tan colonies were inoculated to SBAP 2 in order to isolate the tan colonies without being mixed with the other colony. In SBAP 2, the split plate of γ-hemolytic colonies and tan colonies from the CHOC. After incubation, the tan colonies showed irregular colony morphology which has a formation of halo clearing on the sides of the…
After the gram stain test I carried out a catalase test. This test was carried out to investigate if my unknown was streptococci (negative) or staphylococci (positive) and or micrococci (positive). The catalase test result indicated that my unknown was negative because no bubbles formed when I placed a loop of the organism into hydrogen peroxide.…
The purpose of this lab is to isolate a bacterial population from the normal throat flora. A streak plate method will be used to obtain a pure culture of a Gram positive coccus genus of bacteria. Several biochemical tests will be performed to aid in the identification of this unknown bacterium. Biochemical tests are a series of tests used to identify certain bacterium The various tests that are used in this lab are the catalase test, oxidase test, blood hemolytic test, MSA, blood agar, and PEA/ab sens test. A known Gram positive coccus bacteria will be used alongside an isolated Gram positive unknown bacteria for comparison to aid in the ability to identify the isolated organism to the genus level.…
The second experiment with MSA plates did not turn out as expected. The class control MSA plate for S. pneumonia showed no growth at all and no color change. The lack of growth could be partially explained by the fact that MSA is a selective medium, selecting for staphylococci because of the high salt content, and the lack of color change could be due to the fact that pathogenic species preferentially ferment mannitol and produce acid changing the media color from red to yellow. Another explanation is the possibility of the class control sample showing no growth or color change could be as simple as it being a bad culture. The MSA plates for S. aureas showed both growth and extreme fermentation while the S. epidermis sample showed…
Description: The history of Glo Germ Gel, the simulated germ product I will be using for my experiment.…
In conclusion, it was found that the gram positive bacterium was indeed Staphylococcus aureus and the gram negative bacterium was Klebsiella pneumoniae. One problem that was difficult to overcome was maintaining sterile technique while inoculating both agar plates and test tubes. The isolation was difficult to do because two attempts were…
For comparison purpose, I used two bacteria for this experiment. They are E. coli, a gram negative bacteria and Staphylococcus, a gram positive bacteria. I prepared a heat fixed smear of both bacteria. First, I used crystal violet as my primary stain, put few drops of it on the smear and let it sit for 30 seconds.…