All of the T-streak showed growth however, not all of the bacteria formed colonies. Pseudomonas aeruginosa had no colonies therefore, the colony morphology were not applicable. The error could have been to not spreading the bacteria enough using the T-streak method. P.aeruginosa, Enterobacter aerogenes, Escherichia coli and, Klebsiella pneumoniae all tested as gram negative. The lab manual confirmed the experiments findings to be correct and each one were pink colored on the slide under a microscope. If the result had varied from gram negative a reason could include leaving the decolorizer on the slide for one minute instead of ten seconds. Doing this could make the slide appear any color other than pink. The results could also have varied …show more content…
P.aeruginosa, E. coli, and K. pneumoniae were all non-motile and the lab manual confirmed it to be incorrect. E. aerogenes results were motile which were confirmed by the lab manual. P.aeruginosa and E. coli should have been motile. The results could have been incorrect due to contamination of bacteria or not enough bacteria were used to get an adequate result. This could result from the bacteria not be spread throughout the medium causing the sample to look non-motile. The oxygen requirement test showed all four of the bacteria to have facultative anaerobic results. The lab manual confirmed all the bacterium except P.aeruginosa. P.aeruginosa should have obligated aerobic results. The results varied due to contamination of the bacteria used to cause a misconception. P.aeruginosa had an obligate aerobic result because it lives with the presence of oxygen and dies without it. The results could have varied due to contamination of the bacterium.
The color of the EMB matched the lab manual except for the manual did not specify E. coli to have purple and green colors. The results could have varied if enough bacteria had not been scraped on the petri plate to show the
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.
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
This test is used to detect if the bacteria contains any deoxyribonuclease activity. Because no color change was observed from blue to clear my unknown bacteria displayed a negative result.
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.
The main idea of this experiment was to correctly identify the unknown bacteria, #3. Identification of unknown bacteria yields multiple benefits in many different areas in the research of microorganisms. In this experiment I performed many different test dealing with things such as the presence of enzymes, fermentation abilities and different chemical reactions. Observations made from the tests were then compared to a gram negative unknown chart in order to identify the bacteria. Based off of my results and the chart, I concluded the bacteria #3 was the bacteria Escherichia coli. E. coli is most commonly found in the intestines of warm blooded organisms. Most E. coli strands are non pathogenic however, there are strands
There are many differents ways to identify a bacterial unknown and many different situations where identification would be beneficial. One way to identify bacterial unknowns is to perform biochemical tests. In this experiment multiple biochemical tests were done, by performing these tests on the bacterial unknown received the two different bacteria were then identified. The citrate test is done to test the ability of organisms to use citrate as a carbon source. This test uses Simmons citrate agar, the agar contains sodium citrate as the only carbon source and has bromothymol blue as the pH indicator. The organisms that use citrate as a carbon source use the enzyme to transport the citrate into the cell. The cells converts ammonium dihydrogen
This report will go in depth with the tests used, results yielded, and rationale behind each. Procedures: On the first day of the lab, I was presented with an unknown bacteria labeled simply as 6C. I first observed
pneumoniae I believe I have a subspeciesof K. pneumoniae perhaps K. pheumoniae ozaenae or K. pneumoniae rhinoscleromatis. Indole, MR-VP and Citrate will vary among different subspecies according to bergey's manual of determinative bacteriology. The reason why I decided on K. pneumoniae over E. aerogenes is because of the gelatin and motile test. According to bergey's manual, Enterobacter liquefies gelatin very slowly and in addition E. aerogenes will test positive for motility. To further differentiate K. pneumoniae from Enterobacter and narrow down the exact species of K. pneumoniae the urea hydrolysis assay could have been the determining factor. Subspecies ozaenae and rhinosclermatis will result in a negative reaction for VP but bergey’s Manual indicates a positive reaction for
The bacteria that was contained within Unknown tube #12 is believed to be Pseudomonas aeruginosa, Figure 1. The bacteria tested to be Gram Stain negative, producing a pink, red color retained from the staining process. When the species of bacteria was plated on nutrient media, the cells produced an irregular and spreading configuration as shown in Figure 2. This same plating test provided the margins and elevation, lobate and hilly, respectively. The specimen was stabbed in a Fluid Thioglycollate Medium (FTM) tube using an inoculated loop of the bacteria. The results of this experimentation indicate the type of oxygen requirement of the bacteria. The test found the bacteria to be aerobic as colonies of the bacteria began to form along the top of the FTM tube (Manual 2017).
Testing positive for VP narrowed the bacteria choices to B. subtilis and B. cereus. I conducted the Oxidase test next and the results were unclear. After trying multiple times I concluded that the test was positive. To verify my conclusion it conducted a DNase test to verify my choice. The DNase test came back with a halo meaning the DNase test was positive.
There were four possible organisms my unknown could have been: Citrobacter freundii, Enterobacter cloacae, Proteus mirabilis, and Staphylococcus epidermidis. Out of the four, I slowly narrowed my options down to only one of those organisms. Once the tests were done, I had narrowed the possibilities of my unknown organism to be Citrobacter freundii.
Pseudomonas aeruginosa is characterized by aerobic, gram negative, motile, non-spore forming bacilli (rods).1 A trait that differentiates P. aeruginosa from other gram-negative bacteria is the fact that it produces indophenol oxidase, which is an enzyme that renders them positive in an oxidase test.1 The type of flagella this organism is known to possess is called a polar flagella, meaning a single flagellum at one pole of the rod.1 This means the motility of the organism is quite limited and can travel only in one direction. In spite of this, the single flagellum, as well as the presence of pili, are major contributions to the motility of Pseudomonas aeruginosa.1 The Pseudomonas genus, the genus from which P. aeruginosa originates from, is known to be an environmental bacteria; hence why this organism is very common in soil, water, and even fresh fruits and vegetables.1 A common characteristic of environmental bacteria, P. aeruginosa being of no exception, is the ways in which they grow. P. aeruginosa grows and thrives in biofilms which are groups of adhering bacteria in aqueous environments. These biofilms eventually begin to produce a slimy substance resembling glue which allows them to spread and stick to other materials/locations. Not only does P. aeruginosa require minimal nutritional requirements, but the entire Pseudomonas genus type does as well.1 Due to P. aeruginosa (usually) only needing acetate as carbon and ammonia as nitrogen,
The identification of the unknown began with a gram-negative result during the gram stain testing; gram-negative results are pink in color, because the structure of the cell does not hold Gram’s crystal violet stain as well as gram-positive bacteria does. Gram-positive bacteria are purple in color, compared to the pink in the gram-negative cells because of the safranin. The unknown, Pseudomonas aeruginosa, was a gram-negative aerobe, which was the first piece of evidence used to narrow down to the identification of the unknown. The morphology of the unknown was short rods organized in pairs, and they were about 1 micrometer wide and 3 micrometers long. It also showed true motility, which
coli. E. coli should be motile because of the presence of peritrichous flagella, but the test had a negative result. There were some other inconsistencies such as L. lactis testing negative in the lactose tubes and A. faecalis testing negative for the presence of oxidase. There inconsistencies are most likely due to human error during the lab. These errors could include misuse of equipment, improper sterilization methods, faulty equipment, or a mixture of all of them.
In the world of microbiology it is vitally important to be able to discern the identities of microorganisms. Not only is it important in a lab setting but as well as in healthcare in general. Properly identify what strain of bacteria a person has will aid in the proper medicine and dose given. Throughout the semester we have learned about different types of bacteria and certain test that can clearly identify them. The purpose of this lab report is to identify a Gram-positive or Gram-negative bacterium. Using all the knowledge of procedures and lab techniques identify the unknown and discuss all the tests you performed.