10-Fold Dilution Series Process: Necessary To Equilibrium

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.

9. After the 48 hour time period the inhibition of the Escherichia coli bacteria around the disinfectant disks was measured. A ruler was used to measure the clearing from the edge of the disk to the perimeter of the clearing. Irregularities in the clearing were not included in the area of clearing.

In the beginning of lab, we were advised to obtain a nutrient agar petri plate, which is used for the cultivation of microbes supporting growth of non-fastidious organisms. Since it contains many nutrients, a wide variety of bacteria and fungi can grow. Taking the plate,

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

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.

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

Two smears of the unknown bacterium #5 were inoculated while the second smear was used for a back up. The unknown bacterium dried for at least forty minutes. After the smears dried, the slides were heat fixed two times to ensure the stability of the organism. The slide was placed on top of the staining rack then over the small sink.

There are many reasons for identifying an unknown bacterium. The purpose of this exercise was to identify an unknown bacterium from a liquid culture. We chose our unknown bacteria from a rack of test tubes with several different species of bacteria inside. I wanted to pick an unknown bacteria with a number easy to remember so I pick the test tube labeled “745”. Procedures were followed as stated in the lab manual written by Dr. Pedro J.A. Gutierrez.

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 purpose of this project was to identify the identities of two unknown bacteria in a mixed broth culture by using several separation methods. To separate the organisms, a four-way streak plate technique was used to isolate the two unknown bacteria into separate visible colonies. Then after each colony were clearly isolated; the two unknowns were processed through Gram staining test to determine the Gram stain and morphology. After Gram staining, a carbohydrate test was performed on each unknown to determine if it had glucose, sucrose, or lactose fermentation. The results of the sugar test help determining which biochemical test should be performed next. The Gram positive organism was tested through a carbohydrate fermentation test, then further tested to confirm its identity through an indole and catalase test. The Gram negative organism was tested through carbohydrate fermentation test, then further tested to confirmed its identity through an indole, and TSIA test. After running four biochemical tests, the results conclude that the Gram positive unknown was Staphylococcus aureus. S. aureus was identified based on the fermentation results of the glucose test, negative indole test, and a positive catalase production. S. aureus is a Gram positive circular shaped bacterium that is very common in the U.S and is normally found in the nose, respiratory tract, and on the skin. This bacterium is usually the most common cause of infections after injury or surgery.

The bases of this experiment was to discover the identify of the unknown from three possible specimens: Klebsiella pneumonia, Escherichia coli, and Enterobacter aerogenes. Utilizaing the T streak technique, the bacteria was isolated into pure colonies for further study. The Gram Stain method was used to identity the morhphology of the bacteria such as the shape and whether the bacteria was Gram positive or Gram negative. Biochemical test were also used to help identify the unknown bacteria. The biochemical test used was the Triple Sugar Iron Agar, Sulfur Indole Motility test, Methyl Red test, Voges-Proskauer test, Citrate test, Urease test, and the Gelatin test. After observing the morphology of the bacteria using the Gram Stain method and utilizing all the possible biochemical test, the bacteria was identified to be Enterobacter aerogenes.

The best and most accurate way of identifying an unknown microorganism is by sequencing its DNA, but this is very expensive and only used in highly qualified labs. So, the identification of unknown bacteria number 63 was be done by putting the bacteria through numerous laboratory tests. Microorganisms are different among each other by their macroscopic morphology, microscopic morphology, and the unique metabolic processes they use to survive and reproduce. Identifying an unknown microorganism in the laboratory is important because knowledge is gained on the appropriate way to cultivate an organism, how to correctly read the result of a test, and learning about the different characteristics of the bacteria. All of the following tests were done using the best sterile technique and the most new turbid bacterial growth subculture.

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).

The aim of this experiment was to observe the effect different concentrations of Dettol had on the growth of S. albus. The highest concentration of Dettol (100% - D) was predicted to be the most effective solution to kill and stop the growth of this particular bacteria. This can be justified as S. albus is gram-positive; easier bacteria to kill, developing resistance slower than a gram-negative. Therefore, the highest concentration of antibiotic should be – and was – the most successful in changing the pH levels, and killing S. albus. Through discussion and analysis of the results collected through the experiment, it can be concluded that there is higher chance of killing and the growth of this particular bacteria if 100% Dettol is used.

Nutrient Broth and Nutrient Agar were used to inoculate bacteria taken from different surfaces. Nutrient agar plate was inoculated with a sample taken from skin surface. A sterile cotton swab was first immersed on sterile water, then, rubbed against the skin with swirling motion and transferred to an agar plate by rubbing