Unknown lab report e coli

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Unknown lab report e coli

Broth culture 16 was randomly selected by our group and subjected to qualitative tests for taxonomic identification. We suggest that culture 16 is an example of Escherichia coli.

Changes in protocol or interpretation are noted where they were implemented, but strict adherence to the manual prevailed. Microscope, incubator, and deionizer functioned correctly throughout testing period, with stains, dishes, agars, and test reagents readily available.

Lab procedures are considered orthodox and usage thereof is noted chronologically.

Unknown lab report e coli

It appeared turbid, reflecting Unknown lab report e coli substantial amount of growth. To determine that the stock culture was pure, we performed a streak plate using loops of the stock broth on a fresh dish of nutrient agar and then incubated it for 48 hours at Standard Temperature and Pressure; 37C, 1 ATM STP.

A Gram stain was then carried out to differentiate the unknown sample from a broad class to a more specific category of bacteria. The Gram stain distinguishes between Gram-positive and Gram-negative bacteria based on the composition of the cell walls.

Gram-positive bacteria appear purple and Gramnegative bacteria appear pink after staining. The first Gram stain produced unsatisfactory results and was then repeated with a clear indication of negativity. Light pink staining was evident on the cells in the field of view FOV and a search of the slide revealed uniformity in the sample.

From these results we concluded that unknown 16 was Gram-negative in nature, and therefore it could possibly be any of the following bacteria: Alcaligenes faecalis, Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, Proteus vulgaris, or Pseudomonas fluorescens.

We then conducted a negative stain to reveal the shape of the cell and any extracellular features such as the presence of a capsule. The first negative stain was unsuccessful and was therefore repeated. The second stain yielded cocci and coccobacilli shaped cells occurring singly and also arranged in irregular clusters.

These appeared somewhat sparsely distributed at x with oil immersion. A simple stain was then performed because previously in lab, the negative stain made it hard to visualize the bacteria.

The simple stain was prepared using a sample of bacteria from the 24 hour old broth culture. The appearance of the microbe was again coccus and coccobacillus in shape, yet clusters were grouped in greater numbers, and their concentration was higher for the same FOV.

From the results obtained by the negative and simple stain, we assumed that the unknown sample might be Alcaligenes faecalis, due to the shape of the cells and their clustered pattern. This revealed moist, colorless, and opaque streaks of colonies the size of pinpricks in quadrant one, diminishing to one 3 mm round colony in the fourth quadrant that had billowing or irregular edges.

All colonies appeared to be the same color, size, and shape. We concluded that the stock broth culture was pure. The KOH test revealed an extremely fine filament which adhered to a toothpick and stretched three to five mm before breaking from tension.

The larger smear of bacteria when mixed with KOH turned nearly opaque and produced a more prominent filament that again retained adhesion to the toothpick for three to five mm before breaking.

Based on the results of the Gram stain and the KOH Gram test we concluded that our unknown sample was a Gram-negative. To determine if our unknown sample was Alcaligenes faecalis, we decided to perform an oxidase test. Some gram-negative species of bacteria are oxidase positive while others, such as those in the Enterobacteriaceae family, are oxidase negative, so we prepared a tryptic soy agar plate and made a single streak-line inoculation using the 72 hour old stock broth culture.

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We incubated this plate for 24 hours. This test revealed that the unknown sample was oxidasenegative and therefore unlikely to be Alcaligenes faecalis. This led us to believe that our unknown may be Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, or Proteus vulgaris.

We inoculated three Durham tubes containing glucose, sucrose, and lactose, with a loop of our stock broth culture that was hours old and incubated the tubes for 48 hours.

We inoculated the TGYA shake tube with the stock broth culture and incubated this for 48 hours. We concluded that the bacterial sample was a facultative anaerobe because it grew at the bottom of the shake tube in the absence of oxygen and also toward the top of the tube where oxygen was present.

These results further supported our claim that our unknown was not Alcaligenes faecalis because it is an obligate aerobe and also it eliminated the possibility of our unknown being Pseudomonas fluorescens because it too is an obligate aerobe.

The results of our Durham tube test showed that the unknown sample was able to utilize various carbohydrate fermentation pathways. All three test tubes containing Glucose, Sucrose, and Lactose were positive for the presence of acid and gas production.

A positive result was determined by the color change of the medium from red to yellow and the presence of a gas bubble within the Durham tube. From these results we concluded that our unknown sample could not be Proteus mirabilis or Proteus vulgaris due to the fact that neither of these bacteria is able to ferment lactose.

Unknown Lab Report Essay. The purpose of this lab is to isolate a bacterial population from the normal throat flora - Unknown Lab Report Essay introduction. A streak plate method will be used to obtain a pure culture of a Gram positive coccus genus of bacteria. Microbiology Unknown Lab Report. DEANA ISSAWI. MICROBIOLOGY INTRODUCTION. Bacteria lies everywhere and affects multiple people therefore knowing the causes of . Here is an excellent example of how to write an unknown lab report in Microbiology class. Please note that due to formatting issues the flow charts had to be.

We determined that the broth culture specimen was either Escherichia coli or Enterobacter aerogenes because they both are facultative anaerobes that are able to ferment Glucose, Sucrose, and Lactose.

For the indole production test, we inoculated a SIM deep tube with a loop of stock broth culture that was hours old and incubated it for 24 hours. For the Citrate Utilization Test, we inoculated a Simmons citrate agar slant using a stab-and-streak method and incubated the tube for 24 hours.North Dakota Morbidity Report.

North Dakota Department of Health Division of Disease Control Confidentiality Protected by North Dakota Century Codes and *North Dakota Department of Health . May 18,  · Apple cider vinegar, made from apples, and garlic kills caninariojana.com Other spices/herbs kill bacteria as well.

I use apple cider vinegar 50% with water to spray my cutting board, sink, counters instead. In lab, we have to identify two unknown organisms in a sample of jump to content. my subreddits. edit subscriptions. popular I need help identifying an unknown organism.

(caninariojana.comiology) but E. coli strains are sometimes motile and sometimes not (Cocci are RARELY ever motile). When a lactose-positive colony such as E.

Coli is inoculated on the agar, the decrease in pH yields a change in color on the agar and the presence of a noticeable border surrounding the bacterial colonies. Microbiology Unknown Project - Instructions. General. For the next several weeks, your sole responsibility will be to identify the two microbes in the test tubes you have been handed.

report for each of your unknown bacteria. The template can be found linked to the online class syllabus. Escherichia coli. Haemophilus. The unknown #3 was thus identified as E. coli. Conclusion The identity of the unknown bacterium #3, E. coli, was supported by all of the tests that were performed for this experiment.

The search began with the identification of the bacteria as being rod shaped under the light microscope.

How to Identify an Unknown Bacteria in Microbiology | Sciencing