Gram Positive Bacteria

There are many types of bacteria that can be found in your bathroom. They might also be found on your toothbrush! I have been researching about what bacteria are lurking in my bathroom. I placed 6 petri dishes filled with agar in my bathroom. I left them there for 24 hours to collect bacteria samples.

This test is used to detect the hemolytic activity in the bacteria. A darkish green color on the media around the bacteria would represent incomplete hemolysis. A transparent media around the bacteria colony represents complete lysis of the red blood cells. If no change is observed around the bacteria colony then the bacteria is non-hemolytic. For my

This is important in the medical field because identification of unknown bacteria can help treat a patient by knowing the contributing source of a disease. Also knowledge of different bacteria helped others make antibiotics used today. This lab was completed by using the methods learned thus far in identification of bacteria.

Bacteria are ubiquitous; they can be found on the skin, in the soil, and inside the body. Because of the very nature of this ubiquity, it is important to be able to determine between different strains of bacteria. An example of this is determining the causative agent for a disease so that the patient will be treated with the appropriate antibiotics. It may be important to determine the bacteria in a certain region, because like with enteric bacteria, it is normal to find them in the digestive tract as they are in a symbiotic relationship with our bodies in this area; however, they also cause opportunistic infections in places outside of the digestive tract to our detriment, such as with a urinary tract infection. Some strains of bacteria are common to nosocomial infections, and identifying these bacteria as such helps create the guidelines for healthcare workers in antiseptic technique. All of the morphology and characteristics of each strain of bacteria help us to better understand the role of bacteria in the body as well as helps us understand how they can cause illness, and what treatment regimen to set in place. In lab this semester, a sample of unknown

I inoculated a T-Soy agar with bacteria number 118, for this I used a streak isolation method. Next, in order to distinguish between Gram positive and Gram negative I used a streak isolation technique on a CNA plate, then performed the same exact procedure on a MacConkey plate. The results from the CNA plate showed the Gram Positive bacteria was an Alpha hemolyzer. Next, I used a P Disc on a T-Soy agar inoculated with bacteria 118 and determined the Gram Positive bacteria was not sensitive to P Disc antibiotics. This revealed the Gram Positive bacteria to be Streptococcus Mitis. The results from the MacConkey plate proved the Gram Negative bacteria to be a lactose fermenter. With the Gram Negative bacteria I performed a lysine test with positive results. Next, I performed an ornithine test on the Gram Negative bacteria, with negative results, therefore I concluded the Gram Negative bacteria was Klebsiella pneumoniae.

Clostridium difficile is a Gram-positive, spore-forming, rod-shaped bacillus that is renowned for being the leading cause of hospital-acquired diarrhea in adult patients. C. difficile is present as normal intestinal flora within 3% to 5% of healthy people2, while its spores are ubiquitous in the environment, especially in hospital settings. It grows at an optimal temperature and pH of 37ºC and 6.5–7.5 respectively.1 It is an obligate anaerobic as it thrives in the absence of oxygen. It is highly motile with the presence of peritrichous flagella, which are evenly spread out along its surface. As briefly mentioned above, this evolving pathogen produces endospores. The bacterium produces dormant spores, which are extremely hardy and resistant to antibiotics, the host’s innate immune system, and once shed into the environment through the host’s feces, they are resistant to unfavorable aerobic conditions3 as well as several types of bleach-free disinfectants, which are commonly used in hospitals.3 The spores will germinate under the favorable conditions of the intestinal tract, resulting in the multiplication of vegetative cells, colonizing in the gastrointestinal tract. The vegetative cells release two powerful exotoxins upon adherence to the epithelial cells of the GI tract. Pathogenic strains of C. difficile produce two exotoxins: toxin A and toxin B. Toxin A is an enterotoxin that causes fluid excretion, resulting in fluid accumulation and watery diarrhea. Toxin B is a potent

In the Voges-Proskauer test, I inoculated the tube with bacteria from my TSA plate and incubated the tube at 37 degrees Celsius for 3 days. After three days I placed some Barrits Reagent A and Barrits Reagent B in the test tube. The color change of red or pink indicates a positive reaction for acetoin which tells you that the organism is a butanediol fermentor.

The purpose of this lab was to identify an unknown microorganism using lab techniques. The importance of identifying microorganisms is essential to the survival of humans, expansion of modern day medicine and improvement of quality of life. In 1884, Hans Christian Gram designed a differential staining technique to identify bacteria that would change the future of microbiology. He give rise to a staining process, known as the Gram stain to differentiate microorganisms into two groups between positive and negative gram staining microorganisms. The Gram stain is essential in a lab technique as it distinguishes the cells based on the physical properties of the individual cell walls, and is almost always the first test preformed to differentiate a microorganism. The identification of weather a microorganism is gram positive or negative can revel the bacteria’s virulence, cell wall structure, resistance to antibiotics, resistance to physical disruptions and so much more. In order to identify the unknown provided, unknown #27, the Gram stain was the first test preformed. After discovering that the unknown bacterium was indefinitely a gram positive microorganism, the vast possibilities were narrowed down. However, In order to more definitively identify the unknown, the next step was to preform biochemical tests. A biochemical test identifies metabolic

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.

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.

The oxidation fermentation test was used to differentiate if the organism utilizes lactose, mannitol, glucose and citrate aerobically (oxidation) or anaerobically (fermentation). A methyl red test was performed to determine if the organism carried out mixed-acid fermentation when supplied glucose. A Voges-Proskauer test was performed to evaluate if the unknown was able to ferment glucose into butanediol. A citrate test was performed to determine if the unknown organism was able to break down citrate into ammonia. An oxidase test was then performed to determine if the unknown culture was oxidase positive or negate.

In conclusion, after conducting previously mentioned biochemical tests in order to identify the unknown bacteria, became obvious that unknown gram negative was Proteus Vulgaris. Having eliminated all the bacteria that didn’t show expected results and confirming with such tests as catalase, glucose, indole, citrate, urea, and SIM, it was accurate to name the unknown gram negative. Furthermore, gram positive became obvious it was Streptococcus Pneumoniae. Having eliminated all the bacteria that didn’t show expected results and confirming with such tests as blood agar, catalase, and optochin and bacitracin tests, it was accurate to name the unknown gram positive. I have learned that it is extremely important to be to able to identify what kind

Sample number 32 displayed beta hemolysis on the blood agar plate it was cultured on. I proceeded to gram stain the sample on a slide, and observed it at 1000x magnification. The organism is rod shaped, with no particular arrangement, and is gram negative. The appropriate identifying tests for this type of bacteria were performed, including the use of SIM agar, Urease, Citrate and OF Glucose tests. Once inoculated, these tests are incubated at 37 degrees Celsius for 24-48 hours. The findings of these tests revealed that the organism is motile, positive for indole production, negative for sulfur, negative for urease, negative for citrate and is a fermenter. The characteristics displayed are indicative of Escherichia coli.

Isolation, Examination, and Identification of Gram Negative Pathogenic Bacteria Present in Urine Used to Discover and Diagnose a Urinary Tract Infection

In the natural environment, organisms form a complexity of relationships, these interactions aid the composition and maintenance of genetic variation within ecosystems. The interaction of a predator with its prey offers one such example. To become a successful predator an organism is likely to be subject to trade-offs. This project aimed to begin identification of phenotypic trade-offs, and the genes that control them, during the predation of multiple bacterial species by the social amoeba Dictyostelium discoideum. The study looked to increase tractability of previously used bacterial virulence assays by completing multiple experiments on a single 24-well plate. The assay displayed the Gram-negative bacterium, Klebsiella aerogenes to be