The Effect Of Standard Curve Developed Using A Concentration Gradient Of Titration

Three ways to assess water are positive/negative, membrane filtration and IDEXX Colilert and Enterolert assays. For membrane filtration, petri dishes and an incubator are used. For IDEXX coliert powdered medium is used for total coliform and E. Coli, while Enterolert media is used for enterococci. Also an incubator, colilert trays are used. IDEXX is more expensive than membrane filtration.

Proper collection of blood cultures are necessary and the most direct method of determining whether or not a patient is septic. The purpose of obtaining blood cultures is to identify and isolate the bacteria that are causing an illness and then determine the best course of treatment based on the sensitivity of the bacteria to particular antibiotics. One of the most frustrating problems plaguing hospitals is the increased rate at which blood culture results are being returned as contaminated specimens. These results can lead to a significant increase in cost to the hospital and patient as well as an increased length in hospital

Spectrophotometer; the finding of protein concentration of an unknown sample of BSA, and by using the standard curve.

The first result of importance was the result of the Gram stain. The observations of the unknown bacteria from the slant culture after Gram staining showed that the unknown bacteria were Gram negative bacilli (Image 1). After determining the unknown bacteria was Gram negative, an oxidase test was conducted on a sample from the slant culture. The cotton swap with the sample of bacteria did not change color when the oxidase reagent was applied, thus providing a negative result. With a negative oxidase test, further tests were conducted to determine various characteristics of the unknown bacteria. A MR-VP broth was inoculated with a sample from a slant culture of unknown bacteria. After incubation, the methyl red reagent was added to the broth, and the broth turned red, providing a positive result (Image 2). An EMB agar streak plate was inoculated with a sample from a slant culture of the unknown bacteria, and after incubation, growth was found on the plate, providing a positive result (Image 3). A Citrate agar slant was inoculated, and after incubation, growth was found on the media, providing a positive result (Image 4). A Urea agar slant was inoculated, and after incubation, the agar had changed from a peach color to a bright pink color, providing a positive result (Image 5). Using the flowchart (Figure 1) developed from the Table of Expected Results, the lab partners started at the oxidase test. Given the negative result of the oxidase test, the flowchart is

Using the information found in the Gram Negative Enteric Baccilli and Gram Positive Cocci Reference books,

Most pathogens prefer to grow in pH neutral conditions; many of the cavities in the body are protected from an invasion by a high pH. An example of this is the stomach, which is very acidic and kills ingested pathogens.

The purpose of this lab was to identify two unknown bacteria cultures using various differential tests. The identification of these unknown cultures was accomplished by separating and differentiating possible

|MSA Agar |For organisms that are |Isolates for mannitol fermentation |Yellow color change in |Staphylococcus aureus |

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.

An unknown bacterium was handed out by the lab instructor. The methods that have been learned so far in identifying bacteria were applied to this unknown. Procedures were followed as stated in the lab manual and biochemical test handouts. The first procedure that was done was a gram stain followed by a streak of the unknown on a TSA plate in order to determine the gram reaction and observe the colony morphology. After that, specific biochemical tests were performed for gram positive, since unknown number five was determined to be gram positive rod. The other tests were performed in this order: Mannitol Salt (MSA) streak, Blood Agar streak, Catalase test, Nitrate Reduction test, and Phenyl

The IMViC test is a series of different tests that differentiate between enterics. One is the Indole test. This test tells whether the bacterium possesses tryptophanase which is the enzyme that breaks down tryptophan into indole. The agar contains tryptic soy broth so if the bacterium contains tryptophanase, indole is produced. This production of indole is seen by adding Kovac’s reagent which causes a red ring to be seen at the top of the tube. The citrate test is also used to see which kind of products the bacteria make. It uses a green agar slant that contains sodium and ammonium phosphate. Bromythymol blue dye is late added as an indicator. Inoculation of the slant with a needle using a zig-zag then stab technique was used with the gram positive bacterium. Conversion of the medium to blue is a positive citrate result. All plates, slants, and broths were incubated at 37°C for 24‐48 hours.

Seven test tubes were labeled numerically with 2 mL of VO3- and H2SO42- added to each tube. A small pea size portion of solid Na2SO3 was added to the first test tube. Then, 20 drops of distilled water were added to the second test tube. In the third test tube, 20 drops of (.2 M) NaBr were added. Then, to drops of (.2 M) NaNO2 were added into the fourth test tube. A small portion of Fe(NH4)2(SO4)2 * 6H2O was added into the fifth test tube. The sixth test tube had 20 drops of (.2 M) H2Cr2O4 added, where the seventh test tube was the control tube with no additional chemicals added. All the test tubes were left to react for 3 minutes and then heated in a heated bath for approximately 20 minutes.

A great deal of cultural tests and physiological procedures were performed on the unknown before the conclusion of P. aeruginosa was made. The first test preformed was Gram’s staining which involves the use of crystal violet, Gram’s Iodine, Ethyl Alcohol, and Safranin. Gram staining is known as a differentiating stain, since it can determine the presence or absence of peptidoglycan in the cell wall. The unknown bacteria were Gram stain negative. After that the motility of the cell was tested using a hanging drop slide. The slide was examined, but the results were inconclusive due to the inability to make a clear distinction between motility and Brownian motion. This test was not

5. Equivalence Point: 24% error, Gravimetric determination: 17% error. The gravimetric determination was more accurate because an exact amount of precipitate was formed.

2. Introduction: Each student was given unknown bacteria and was instructed to perform a variety of experimental tests that would help to identify their bacteria. During the process of identification, the unknown bacteria was added to many different testing medias using aseptic technique. They are as follows: lactose fermentation on eosin methylene blue (EMB), TSI (Triple Sugar Iron agar), Phenol red sucrose, the SIM test, H2S by SIM, IMViC (indole, motility, voges-proskauer, and citrate), Urease (urea broth), PDase (Phenylalanine Deaminase), Lysine Decarboxylase, and Ornithine Decarboxylase. Colonial morphology on EMB was used to