Dr. Patricia Stock’s particular area of study does not include the biochemical investigation of their composition to find their chemical usefulness or the cure for cancer or anything of that nature. Her aim is simply to research and study the mutuality between the bacteria and their nematode hosts in order to better understand their evolutionary biology and pathogenesis.
Unknown 10b is Staphylococcus epidermidis. According to Bergey’s Manual Staphylococcus bacteria are gram positive spherical cells that occur singly, in pairs or in irregular clusters. Unknown 10b was gram positive, spherical and occurred in clusters. Bergey’s Manual also says the bacteria grow well in high salt concentrations. Unknown 10b grew well on the mannitol salt agar. The optimum growing temperature is 30-37 degrees Celsius (Bergey’s Manual). Unknown 10b grew best at 37 degrees Celsius. The lab manual and past lab results confirmed all other test results. Unknown 10b was only able to use gamma lysis, it was unable to ferment mannitol and had no coagulase activity. When comparing to past labs it is confirmed that Unknown 10b is Staphylococcus epidermidis.
Mahon, C. R., Lehman, D. C., & Manuselis, G. (2011). Textbook of diagnostic microbiology (4th
Tortora G, Funke B, Case C. 2007. Microbiology: An Introduction, 9th Edition. Pearson Education, Inc.
Patterson, M. (2001, October). Streptococcus. The University of Texas Medical Branch. July 29, 2005: http://gsbs.utmb.edu/microbook/ch013.htm
The purpose of this study is to identify an unknown bacterium from a mixed culture, by conducting different biochemical tests. Bacteria are an integral part of our ecosystem. They can be found anywhere and identifying them becomes crucial to understanding their characteristics and their effects on other living things, especially humans. Biochemical testing helps us identify the microorganism present with great accuracy. The tests used in this experiment are rudimentary but are fundamental starting points for tests used in medical labs and helps students attain a better understanding of how tests are conducted in a real lab setting. The first step in this process is to use gram-staining technique to narrow down the unknown bacteria into one of the two big domains; gram-negative and gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species. These biochemical tests are process of elimination that relies on the bacteria’s ability to breakdown certain kinds of food sources, their respiratory abilities and other biochemical conditions found in nature.
Case, Christine L., Funke, Berdell R., Tortora, Gerard J. (2004). Microbiology: An Introduction (8th ed.). San Francisco: Benjamin Cummings.
It is important to know the identification of the E. aerogenes bacteria because it is pathogenic and it is known to cause infections.
The dichotomous keys show process of elimination taking place and several steps that were performed to the two unknown bacteria. Bacteria number one was concluded to be either S. aureus or E. faecals. As shown, a gram stain was performed to bacteria 1, because it helped in separating the bacteria into Gram negative or positive. Bacteria 1 was Gram positive bacteria, so the next step was to eliminate the bacteria that were bacilli, because under the microscope the bacteria was shown to be cocci. Then a lactose test was performed, because it helped me in determining the bacteria metabolism (if lactose was utilized as a sugar by the bacteria) (“Phenol Red Broth”, n.d). Lastly, with the help of process of elimination a MSA test was performed to
The identification of pathogens is critical in a clinical setting. Proper identification allows medical professionals to decide the appropriate course of treatment for infected individuals. Additionally, knowledge of characteristics of microbes that are present in everyday life is essential in protecting oneself from infection. A series of differential and biochemical tests was performed in order to identify an assigned unknown specimen. The bacterium to be identified was sample B from wounds.
To further determine the species of the unknown bacteria, an API 20E was used. API 20E system utilized a plastic strip with 20 separate compartments with each compartment consisting of cupule or a depression and a small tube containing a specific dehydrated medium (1). The ONPG tube consisted of an ingredient that functioned as an internal indicator. The ADH, LDC, ODC and URE tubes contain phenol red as the indicator. The CIT, GLU, MAN, INO, SOR, RHA, SAC, MEL, AMY and ARA tubes contain bromthymol blue as an indicator. The GEL tube contains charcoal and the H2S tube contains iron salts as indicators. The TDA, IND and VP tubes contain no indicator. All the tubes contain buffers and all the tubes with the exception of the CIT and URE contain
It is important in microbiology to be able to identify an unknown microorganism. Many tests that characterize functions of bacteria have been developed to accomplish this task. The unknown bacterium that was tested was discovered to be Escherichia coli. E. coli is a Gram-negative, bacillus bacterium. Gram-negative means there is an outer membrane surrounding the thin peptidoglycan layer of the cell. Bacillus means that the bacterium is rod-shaped. The E. coli was identified as Gram-negative and bacilli from performing a Gram stain. A Gram stain uses crystal violet for the primary dye and safranin as a counter stain (1). Gram-positive bacteria have a very thick peptidoglycan layer in their cell wall. This thick cell wall will stay stained purple by the crystal violet-iodine complex, and Gram-negative bacteria will be decolorized and stained pink from the safranin counter stain (1). The peptidoglycan layer’s thickness determines whether it is stained pink or purple.
The mother stated that the child complained of nausea at 10 o’clock the 2nd day of February, later, the child began vomiting and having multiple episodes of diarrhea, she was not able to eat or drink anything without vomiting. As it approached evening, the woman took the child to the local hospital where she was admitted at the emergency department, here they noted the child was dehydrated and had a lot of fever. The stool and blood specimen of the child was collected and the child was given intravenous fluids as a treatment and later she was released; the following day the mother made follow ups on the test results for the child and it turned out the stool culture displayed negative results for usual bacteria (Brehm-Stecher et al, 2009, p. 1774).