...An outbreak investigation featuring a cohort study associated with food contamination with an unknown organism: Confirmed with a variety of biological identification techniques 2015 – Karl Olsen N0425691 During October 2015, an outbreak of 14 cases of symptoms related to gastroenteritis occurred at a bank staff party in Nottingham, it was confirmed via a cohort study that Salmonella was the infectious pathogen. A lack of significant association between specific food sources and illness suggests an attack rate distributed through multiple foods, including salad and chicken, which were considered to be contaminated through a food handler. Introduction A conventional outbreak investigation is when two or more people share identical or related diseases/symptoms or excrete the same pathogens. This is common when cases are shared between individuals that have circumstantial association. In this particular case, the number of confirmed symptoms exceeded that expected and illuminated the potential cause; a foodborne disease. Moreover, on the 11th of October 2015, the first incidence of 14 human cases of symptoms related to food poisoning occurred between bank staff colleagues in Nottingham; United Kingdom. Symptoms of diarrhoea and fever manifested themselves and were reported within a week of a party of which 36 of 42 staff members attended. Symptoms subsided by the 15th of October. The occurrence and proximity of these infections suggest a link which can be explained by the consumption...
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...IDENTIFICATION OF UNKNOWN BACTERIA It is virtually impossible to identify bacteria based on physical characteristics alone. This is due to the fact that there are only a few basic shapes and physical features commonly seen in the prokaryotic world. Instead, biochemical testing has been used to make bacterial identification down to the “species” level. These schemes are based on creating and matching biochemical profiles of the production of enzymes, acids and gases by isolated pure cultures of a given microorganism. Identification schemes and flow charts can be found in reference texts such as “Bergey’s Manual of Determinative Bacteriology” or “The Prokaryotes”. Each group of students will receive a TSA slant or broth containing a pure culture of an unknown bacterium belonging to the Family Enterobacteriaceae. It is the responsibility of the group to maintain stock cultures of the organism provided. Working stock cultures will be used to inoculate the various biochemical test media over the next several weeks and should be fresh and free from contaminants. A reserve stock culture should be made and after incubation and comparison with the original slant, kept with the original slant in the refrigerator. It is critically important that aseptic techniques are used during transfers and inoculations to prevent contamination of your cultures. If contamination is suspected, you will be able to fall back to your reserve stock. If you fail to maintain a reserve stock...
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...HOW TO WRITE AN UNKNOWN LAB REPORT IN MICROBIOLOGY GENERAL Unknown reports in microbiology are written in scientific format. Scientific writing is written differently from other types of writing. The results of the exercise or experiment are what are being showcased, not the writing. The purpose of scientific writing is not to entertain, but to inform. The writing should be simple and easy to understand. There is a specific style that must be followed when writing scientific reports. Scientific writing is typically written in the passive voice. The pronouns "I", "We" and "They" are not typically used.. For example, instead of writing "I used a TSA agar plate to isolate my unknown," it is customary to write, "A trypticase soy agar (TSA) plate was used to isolate the unknown." It is also customary to write in the past tense for most of the report. This includes the introduction, the summary, the description of the materials and methods and the results. The present tense is reserved for the conclusions about the results. See the examples given below. Some other general rules that should be followed are: Microbial nomenclature: The name of the bacterium should written and spelled correctly. The name should be italicized or underlined. Italicized is preferred. For example, Staphylococcus aureus. The genus is capitalized but the species is not. After the full genus name is given in the paper, it can be written as S. aureus, but still italicized. This is as long as there in no other...
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...Someone’s Name Bio 488C Lab A Re: Writing Assignment 2: Enterics Report 2/22/2016 Enterics Report The group received the Unknown sample of Patient #2 as well as a description of the illness. The method to identify this unknown organism was an Enteropluri tube. By using the inoculation needle in the Enteropluri tube to sample the organism and draw the sample through the set of agar compartments, multiple culture media are thereby inoculated. Given that this test is used on Enterobacteriaceae all organisms are assumed to be Gram negative and oxidase negative. However, each culture media provides a biochemical test that is used to differentiate and identify the microorganism such as glucose fermentation with or without gas production, lactose fermentation, urea hydrolysis, etc. Each feature is used to differentiate and identify the microorganism in question. While the Enteropluri tube is a useful device, I do not believe it is the most effective method of identification in a modern clinical setting. Possible drawbacks of this device is failing to get a uniform inoculation of each media – as the inoculation needle is drawn through each successive media less and less of the sample is present, meaning the first compartments inoculated may receive more cells which will result in quicker growth, compaired to the final compartments which may receive far fewer cells and result in slower growth and possible false negatives. There is also a concern that the media in each compartment...
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...Lab Write Up Identifying an Unknown Microbe Gregory Howard 10E The isolation I was given two unknown microbes and asked to identify them. The first step was to isolate each microbe. I did this by using the streak method to apply each microbe to an enrichment culture. The enrichment culture provides conditions to enhance growth of a species. Obataining a pure culture makes it easier to identify and study a particular species. The macconkey agar plate which is used to isolate and differentiate members of the enterobacteriace based on its ability to ferment lactose. Macconkey agar w/o crystal violet or bile will only grow gn rods which inhibits the growth of gp cocci. Columbia can agar plate which is a medium that allows growth of gp orgs especiall staphylococci, streptococci, and enterococci and inhibits the growth of gn orgs. After both plates where streaked they where incubated at 35 degress celcius for 48 hours. The Gram Stain Next I performed a gram stain to detect differences between microbes or differences in structure of the same microbe. This being my first time I ever gram stained false results could be because of poor staining techniques. Usina a modern light microscope I observed each microbe that grew on its agar plate of interest. Through my gram staining and visual observation I came to the conclusion that the macconkey agar plate grew enterobacteriace , a GN rod shape org and the org that grew on the Columbia can plate resembled a cocci due to its cluster...
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...The positively best bacteria to receive when doing an unknown project The word bacteria receives a bad connotation in the everyday world but some may not realize the importance bacteria has on a person’s immunity and health. There can be both good and bad bacteria. Good bacteria, for example, helps to breakdown food enabling the digestion process to work smoothly and absorb nutrients like probiotics. These good bacteria are often found in foods like yogurt, cheese, and sauerkraut. Best of all, good bacteria can help treat infectious diseases. A study has shown that, when injected with a good predatory bacteria like Micavibrio aeruginosavorus and Bdellovibrio baceriovorus, an antibiotic resistant bacteria was defenseless (Nordqvist, 2013). The study was created for an eye infection to see whether good bacterial pathogens would be able to fight off bad bacterial pathogens without damaging the eye or causing further irritation. The term microbiology means the study of microscopic organisms. Within the specialized area, microbiologists help to identify new organisms and how they affect life on earth. There are new organisms being discovered every day, and there could be dangers or losses without proper identification of how they live, what they do, and can they be controlled. A study was done to show the process of categorizing and identifying an unknown organism. Throughout the semester, multiple tests were performed to distinguish between the different types of bacteria...
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...process was making the nutrient agar slants, smears, and then staining. Gram staining concluded that in fact plate B was a Gram negative organism. A. faecalis, P. fragi, and E. coli are all Gram negative bacteria.2 The Gram negative bacteria that was in plate B, had a cell shape of coccobacillus and a single cell arrangement. A. faecalis and P. fragi both are coccobacillus and singled celled while E. coli is bacillus and single celled.2 Because all three species are so close to cell shape and arrangement none of the options were yet eliminated. To narrow down the options with biochemical tests, the MOI test was done first. The results came back as positive, negative, negative. This eliminated E. coli as an option because E. coli’s MOI results are positive, negative/positive, and positive. During the 48 hours of incubation time for the MOI test, an oxidase test was also performed. However, the oxidase test came back as negative. Which, does not match up with the MOI results. Both A. Faecalis and P. fragi have positive oxidase result, but E. coli comes back as negative.2 A fresh sample was not used to perform the oxidase test, which is why the best results did not come out of the test. The oxidase test was then performed a second time with a fresh sample of the unknown Gram negative bacteria and came back positive. To be certain the unknown organism was not E. coli a fermentation test was performed. The results came back as neutral, which eliminated E. coli. When test under the fermentation...
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...causing products they produce. Overall, microorganisms play an important role in life. 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 bacteria based on specific biochemical characteristics. The differential tests used to identify the unknown cultures were Gram staining, oxidase, indole test, urea test, and casein test. MATERIALS AND METHODS: The unknown bacteria were given out by the lab instructor. Each student chose their own unknown bacteria according to the number. All methods have been practiced to ensure proper procedure identifying bacteria have been applied to this unknown. Procedures were followed as stated in the course laboratory manual provided by the instructor, unless otherwise noted. Each test performed identified was used to determine the specifics and identify the unknown bacterium. All of the following tests were performed on this unknown on February 09, 2008. Some of the tests required a follow-up right after the next lab. The first procedure that needed to be accomplished was to streak the unknown out on a Trypticase Soy Agar plate, using the T streak method described in the lab manual. The unknown culture was inoculated in the Tryptic Soy Broth tube, a TSA plate agar, and a TSA slant. This procedure is needed to be done in order...
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...Unknown Laboratory Report Sarah Mansfield Biology 203 Professor Lana November 19, 2014 INTRODUCTION Microorganisms are the earliest forms of life and most have thrived since the early birth of the planet. They have evolved into many different forms of life such as animals, humans, and plants. While some microorganisms impact life in a positive way by sustaining life, others cause disease and even death (Nester, et al. 2012). Prokaryotes are one of the earliest organisms to exist, and many of these organisms can thrive in conditions far worse than other living things. For example, they can tolerate extreme temperatures, acidic, or alkaline environments (Foster 1996). Prokaryotic cells do...
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...Madeline M. Westrick Unknown 2 Unknown Lab Report INTRODUCTION In this study, each student was assigned a different unknown bacterium, with the task of identifying it correctly. Unknown 2 was Streptococcus pyogenes. S. pyogenes is gram-positive cocci that can result in human ailments that are classified as Streptococcal A infections, such as impetigo, cellulitis, erysipelas, and scarlet fever. The allotted testing time given was a total of four laboratory periods, or two weeks total. MATERIALS AND METHODS The unknown bacterial pathogen was presented via a liquid broth suspension in a double-walled glass test tube and on two nutrient agar (NA) plates. Its appearance was creamy yellow in color with sparse growth of medium-sized colonies...
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...Unknown Identification Introduction to Microbiology Lab Professor M Biology Lab 1913 11/11/2014 I. Introduction A series of tests was completed in order to identify an unknown microorganism. A gram stain reaction test was done. A gram stain reaction test is used to differentiate between two bacterial species. The two species; gram positive and gram negative bacteria have varying properties of their cell wall structural composition. The gram positive bacteria contain a thick peptidoglycan layer in their cell wall which retains the primary crystal violet stain. The crystal violet is washed from the fixed stain and gram-negative bacteria appear red after the decolorizer washes the primary stain due to their more porous higher lipid content walls and the safranin counter stain adheres to their thinner cell wall. The microscopic examination of the bacteria after staining allows for the morphology of the organism to be determined because as the cell is killed during the staining process it retains its rigid structure allowing for morphology determination. A fermentation test was done. Three different carbohydrates are used to determine whether the organism can ferment a sugar as well as if a gas is produced during heterofermentation. A phenol red broth is used which retains a red color at a pH of 7.4 indicating no fermentation of a sugar. When an acid is produced during fermentation, the pH of the broth will lower and the broth will turn yellow. The sugars...
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...Bio 15 – Microbiology Final Unknown Report Sheet Unknown # ___90___ Genus and species of unknown _______Escherichia coli_________ Gram reaction and morphology ____Gram Negative reaction/Translucent and Shiny___ Other stains performed and results: Results: Please list the test results for all tests that were performed on the unknown. For tests not performed, write ND. |Carbohydrates: |IMViC Tests: | |Glucose |AG |Indole |+ | |Lactose |+ |Methyl Red |+ | |Mannitol |AG |Voges Proskauer |_ | | | |Citrate |ND | | | |Additional Biochemical Tests: | |Oxidase |_ |Lysine decarboxylase |+ | |Catalase |ND |Ornithine decarboxylase |ND...
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...Based on the results of my unknown A, I concluded that the bacteria was Escherichia Coli. After I had collected the results and compared them with my dichotomous key, I was convinced that Escherichia coli was the only organism with a bacillus morphology gram negative that was able to survive under this conditions. The result for the lactose fermentation clarified that the bacteria carrie the enzyme lactase in the DNA, therefore can ferment lactose and produce acid and gasses. This type of bacteria contain also the enzyme indole which can use tryptophan as a way for growth and survival. the result from the tryptophanase came out positive, eliminating the identification of the other organisms with a morphology bacillus and with a gram negative...
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...Introduction: Biological organisms are classified uniformly in order to easily categorize and identify organisms. This classification, or taxonomy, uses the genus name followed by the species name, in Latin. By having a universal method of identifying bacteria allows for all scientists from any part of the world to identify the same species in an identical manner allowing for a precise of classification. Bacteria are distributed throughout the world in almost every conceivable habit. Bacteria are unicellular microorganisms, with variable shapes and nutritional needs. They lack a distinct nucleus and occur singly or in chains or clusters and form distinct colonies. Bacteria are classified on the basis of many characteristics. Morphological and physiological features such as cell shape, motility, formation of spores and other distinguishable structures, and reaction to Gram stain is a good start in identifying bacteria. Other staining techniques such as Acid Fast stain are also useful in determining species. More important in identification of a genus and species of bacteria are biological tests, including the determination of the types of nutrients a cell can use, the products of its metabolism, and the response to specific chemicals. Other factors that can assist in identification of bacteria are their ecological habitats and more advanced methods such as genetic and molecular composition. Using various techniques one is able to distinguish and ultimately assign...
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...Introduction Bacteria are microscopic unicellular prokaryotic organisms characterized by the lack of a membrane-bound nucleus and membrane-bound organelles. They are remarkably adaptable to diverse environmental conditions and are found in bodies of all living organisms and on all parts of the earth. The purpose of microbial biochemical tests is to identify the unique traits it yields and with that knowledge we can then categorize them in groups and specify them by scientific name. These experiments included the Triple-sugar iron agar (TSIA), Sulfur Indole Motility (SIM), Methyl Red (MR), Voges-Proskauer (VP), Citrate, Urease, Gelatin, and Oxidase Test. In order for these tests to produce reliable and credible results, the bacterium organism must be grown using strict and meticulous procedure to produce viable colonies of pure culture. Having pure culture is significant to ensure that a single type of bacteria is used for identification without contamination so tests can be run without complications or confusion. Once all these tests are performed, the unknown bacteria in this lab will be one of the following: Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, Klebsiella pneumoniae, or Salmonella typhimurium. This report included the results and details to these experiments which are discussed further on. Abstract Gram negative bacteria Unknown #12 was run through an array of tests which produced positive and negative results. The results obtained from the various...
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