and Streptococcus spp. After the initial tests were conducted, five more tests were done to narrow down the genera and species. From the provided list of possible unknown genera, the only genus left was Staphylococcus. However Staphylococcus has many species, so test focused on differentiating the many species of Staphylococcus were conducted.…
The purpose of this experiment was to isolate two unknown bacteria and perform a series of selective and differential tests to correctly identify each. After the bacteria was isolated a series of differential and selective tests following the dichotomous key attached were used to identify each bacteria. The Gram-positive bacteria were identified as Staphylococcus aureus with a positive confirmatory test, mannitol salt agar, showing consistent results as well for S. aureus. The Gram-negative bacteria were Pseudomonas aeruginosa with a positive confirmatory…
Cited: Tortora, G., J. Funke, B.R., Case, C.C. (2010) Microbiology: An Introduction. Tenth Edition. San Francisco, Pearson Benjamin Cummings.…
The purpose of this lab was to determine the identity of an unknown bacteria slant culture. The unknown was identified using differential tests to determine its metabolic and morphology characteristics. Results from the differential tests indicated that unknown culture 5 is Staphylococcus aureus.…
For my dirty results, I saw a combination of gram negative staphylococci, gram positive cocci, and gram positive staphylococci.…
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.…
The unknown bacteria A and bacteria B have to be identified by its genus and species. First both bacteria had to be inoculated into a TSA agar media using the streak plate method. Four quadrants were drawn, so that the bacteria could be isolated as much as possible. Each bacteria was inoculated into two different plates, so that one could be incubated at 37 degrees Celsius and the other at 25 degrees Celsius. Bacteria B, which was incubated at room temperature showed red colonies throughout its media. This identified it as the gram-negative bacteria Serratia marcescens, but further tests had to be conducted to fully confirm. Bacteria A showed a white opaque growth in both of its plates.…
The possible identity of the unknown organisms in the mixed culture was limited to bacteria that we had worked with previously in lab. Initially a Gram stain was conducted in order to distinguish the unknown bacterium as a Gram-positive and/or a Gram-negative organism (Lancaster and Bennett, 2012; Kellenberger, 2001). Based upon the results, both Gram-negative and Gram-positive bacteria were observed in the unknown mixed culture (Table 1 and Table 2; Kellenberger, 2001). In order to isolate the two different bacteria, colonies that grew on the MSA were used to inoculate Gram-positive tests, where as MacConkey Agar colonies were used to inoculate Gram-negative tests.…
After the gram stain test I carried out a catalase test. This test was carried out to investigate if my unknown was streptococci (negative) or staphylococci (positive) and or micrococci (positive). The catalase test result indicated that my unknown was negative because no bubbles formed when I placed a loop of the organism into hydrogen peroxide.…
We have a patient that may be infected with an unknown bacterial infection; we’ve collected a sputum sample and will be testing for one of the following genera: Bacillus, Escherichia and Mycoplasma. In order to determine which one of the three may be the source of the infection we have to recognize the characteristics of each one and the staining protocol needed to identify them.…
Although bacteria is microscopic in size, it is largely important in the healthcare field, environmental work, food preparation, as well as many other industries. In particular, it is essential that healthcare workers be able to identify the species of bacteria invading a human reservoir in order to prescribe the correct antibiotic that will kill that species. For the purpose of bacteria identification, numerous tests have been devised to find out the exact species in question. However, because new strains continue to emerge, it is of the utmost importance that microbiologists and microbiology students understand the nature of each bacterial species and how that species creates and maintains its complex communities. Of equal…
In this laboratory exercise explore the differences of microorganism and continue our use of specialized media and use some biochemical testing.This report discloses the basic laboratory instruments will be used in each of our practices .It is of great importance to recognize and identify the different instruments and laboratory tools, because in this way will we be able to use them properly and also to call them by name and know why.…
You are working as an emergency room nurse in Topeka when a mother brings in her 8 year old son because of severe, bloody diarrhea. When questioned, the boy said that it hurts when he goes to the bathroom and his mother said he had vomited in the previous two days. When asked about their previous movements, the mother and son both mentioned a backyard barbeque that had taken place 6 days earlier. The boy complained that his mother made him eat a “pink” hamburger that was not thoroughly cooked. A physical examination of the boy revealed nothing out of the ordinary except dehydration from the diarrhea. Lab tests showed that he had 13,000 white blood cells/microliter of blood, and a methylene blue stain of his feces showed abundant neutrophils. His stool specimen was plated on MacConkey agar and several colonies on the plate turned bright pink after 24 hours. Based on symptoms and the lab results, he was treated with trimethoprim-sulfamethoxadole and intravenous fluid therapy. He improved quickly and was released after 24 hours.…
Having the ability to collect and identify unknown microorganisms is vital in health and medicine. This capability is important for a variety of reasons, such as knowing the causative agent of disease, knowing if the microorganism obtains any beneficial properties and knowing the correct microorganism to use to create a successful antibiotic. Implementing the experimental methods learned thus far in the microbiology laboratory allowed an unknown bacterium to be identified as a result of this study. This study allows the student to exercise their ability to use and understand sterile techniques, transmission, and prevention of microorganisms.…
Staph infections are caused by a staphylococcus bacterium, Staphylococcus aureus. S. aureus is a purple, cocci shaped cell with its morphological arrangements in grape-like clusters, it is determined by a bacteriological stain, known as the Gram stain. This determines it to be a gram positive bacterium. When grown on bacteriological media, S. aureus appears as a large white to golden colony. It is not very fastidious but it grows well, either aerobically or under anaerobic conditions and produces good growth within 24 hours (2). They grow in a pH of 4.2 to 9.3 and in salt concentrations of up to 15%, they belong to the Staphylococcaceae family (3). The host for this microorganism are humans, many animals both wild and domestic acts as reservoirs also. It is a type of bacteria commonly found in the intestinal, genitourinary and upper respiratory tracts; such as nose and skin, sometimes hair as well as…