Contact Us
Sign In / Sign Up for FREE
Go to advanced search...

Molecular Microbiology - Case Study Example

Comments (0) Cite this document
Case 1: 1. A 67 year old leukaemic patient developed bacteriaemia in hospital. It was suspected that his plastic central line catheter was colonized as indicated by the swelling at the point of entry in his skin. Blood culture showed Gram-positive cocci in clusters.
Download full paperFile format: .doc, available for editing
GRAB THE BEST PAPER96.7% of users find it useful
Molecular Microbiology
Read TextPreview

Extract of sample "Molecular Microbiology"

Download file to see previous pages The commoner intravenous catheter-related infections are exit-site infections, as in this case, often with erythema around the area where the line penetrates the skin.
Bacterial blood stream infections are common in this given scenario, and Staphylococci are the second most prevalent bacteria. However, a smear suggesting the staphylococci or Gram-positive cocci in clusters in blood culture as in here, is not sufficient for the diagnosis of true bacterial blood stream infection before the species is identifiable, since the most frequent of this species, Coagulase-negative staphylococci or CoNS usually habituate in the skin, and there is always a chance of contamination of the culture bottles during the venipuncture. In contrast, such an infection due to Staphylococcus aureus is virulent by its intrinsic nature, and isolation in one blood culture bottle is clearly diagnostic and is an indication of initiation of antibiotic therapy. Thus the therapeutic decision making is based on identification of the organism (Beekmann, S. E., Diekema, D. J. and Doern, D. J., 2005).
The first test obviously would be to do a light microscopic examination. Direct microscopic examination may provide a rapid, presumptive report of Gram-positive cocci resembling staphylococci. Isolation of S. aureus should be performed using 5% blood agar following an incubation period of 18-24 h in air at 35-37 C. Staphylococcus aureus ferments mannitol, resulting in a change in the colour of the medium from pink to yellow. Colony morphology may be used by the experienced observer to define presumptive staphylococci. A Gram stain appearance of cocci in clusters and a positive catalase test provide rapid indicators of staphylococci. However, in order to be able to distinguish between Staphylococcus aureus and the remaining members of the staphylococcus species, other tests are necessary. For clinical microbiological purposes, two or three simple tests suffice. The coagulase test detects the production of coagulase by S. aureus. In this test, one colony is mixed with plasma, incubated at 37 C for 4 h and observed for clot formation. Samples that are negative at 4 h are incubated and observed again for clotting at 24 h. The slide agglutination test detects clumping factor (ClfA). This is performed by making a heavy homogenous suspension of cells in distilled water on a glass slide to which a drop of plasma is added. Within 10 s, the mixture is examined for presence of clumping (Chapin, K., and M. Musgnug, 2003).
How would you differentiate the cocci in clusters from those in chain
Cocci in clusters are named as staphylococci. All staphylococci have the ability to convert hydrogen peroxide into nontoxic H2O and O2. Both coagulase positive and negative staphylococci produce catalase. This test differentiates them from cocci in chain or streptococci, which cannot produce catalase and hence are catalase negative (Chapin, K., and M. Musgnug, 2003).
What is the principle of DNase test and what is the identity of this organism and why Support your answer with microbiological diagnostic facts.
DNase or deoxyribonuclease is an extracellular enzyme that can hydrolyze deoxyribonucleic acid to oligonucleotides. Several varieties of deoxyribonucleases are distinguished on the basis of antigenic properties, response to inhibitory substances, hydrolytic end products, and ...Download file to see next pagesRead More
Cite this document
  • APA
  • MLA
(“Molecular Microbiology Case Study Example | Topics and Well Written Essays - 1500 words”, n.d.)
Molecular Microbiology Case Study Example | Topics and Well Written Essays - 1500 words. Retrieved from
(Molecular Microbiology Case Study Example | Topics and Well Written Essays - 1500 Words)
Molecular Microbiology Case Study Example | Topics and Well Written Essays - 1500 Words.
“Molecular Microbiology Case Study Example | Topics and Well Written Essays - 1500 Words”, n.d.
  • Cited: 0 times
Comments (0)
Click to create a comment or rate a document

CHECK THESE SAMPLES OF Molecular Microbiology


...?Microbiology Essay In 1835 Bassi showed that a fungus caused silkworm disease, and in 1865 Pasteur discovered that a protozoan caused another silkworm disease. Why do we use Koch’s postulates instead of “Bassi’s” or “Pasteur’s” postulates? Bassi and Pasteur both worked on silkworm diseases. Bassi in the year 1835, established that a microscopic organism, a fungus, caused disease in the silk worm. Around 30 years later, in the year 1865, Pasteur established that another microbe, a protozoan, cause infection in silkworms. These findings established an association between the “questioning” microbes and disease. Indicating that disease is caused due to the attack by tiny micro-organisms. This formed the basis for further research. Whereas...
2 Pages(500 words)Essay


...?Microbiology Compare and contrast photophosphorylation and oxidative phosphorylation. Both photophosphorylation and oxidative phosphorylation result in production of ATP. Photophosphorylation is a process by which ATP is produced using energy of the sunlight. In oxidative phosphorylation, ATP is produced by energy released by the oxidation of nutrients (Boyer, 1977). In photophosphorylation, light energy is used to create a high-energy electron donor and a lower-energy electron acceptor. In oxidative phosphorylation, electrons are transferred from electron donors to electron acceptors such as oxygen, in various redox reactions which are carried out by a series of protein complexes within mitochondria among eukaryotes and in the cells...
2 Pages(500 words)Essay


...?Microbiology Microbiology is the science that studies microorganism. They can be pathogenic or non-pathogenic; they can be beneficial for human environment or be hazardous for human health. This research comprises similarities and differences between Variola viruses or Poxvirus and Staphylococcus epidermis. Moreover, benefits of non-pathogenic microorganisms in human environment are discussed further on. Variola virus and Staphylococcus epidermis: comparing and contrasting Variola virus infects human beings. It can be transmitted to other humans via face-to-face contact or contact with other objects, or through the air. Nevertheless, not all the ways of the virus transmission have been fully defined and studied by the scientists... Microbiolo...
2 Pages(500 words)Essay


...? Microbiology Practical Describe the full theory behind the catalase test. Why must plain agar be used? Catalase is an enzyme that converts hydrogen peroxide to water and oxygen. Aerobic and facultative organisms have developed various protective mechanisms against the toxic forms of oxygen (especially superoxide radicals as they can potentially inactivate vital cell components). Enzyme known as superoxide dismutase, eliminates superoxide radicals by enhancing the rate of reaction. During the process toxic substance hydrogen peroxide (H2O2) and hydroxyl radical (OH-) are produced, which in turn is dissipated by catalase and peroxide enzymes respectively. Catalase test is used to identify organisms that are capable of producing catalase...
10 Pages(2500 words)Coursework


.... The Composition of Camembert Cheese-ripening Cultures modulates both Mycelia Growth and Appearance, Applied and Environmental Microbiology, Vol.78, No.6, pp: 1813- 1819. Neidhardt, FC, Ingraham, JL, and Schaechter, M., 1990. Physiology of the Bacterial Cell: a Molecular Approach, Sinauer Associates. Reed, R, Holmes, D, Weyers, J and Jones, A., 2007. Practical skills in Biomolecular Sciences, Pearson Education. Saxena, NP and Awasthi, DK., 2003. Krishna’s Microbiology, Krishna Prakashan Media P Ltd. Sharma, K., 2007. Manual of Microbiology, 2nd edition, Ane books Pvt ltd. Waites, MJ, Morgan, NL, Rockey, JS and Highton, G., 2009. Industrial Microbiology, John Wiley and Sons....
6 Pages(1500 words)Lab Report


We went through intricate aseptic techniques for preparing microbial cultures from the commensal population of microbes in the GI tract isolated from the diabetic and normal rats for recording their count from the extent of lactate, acetate, and glucose production based on four kinds of bacteria, Staphylococcus aureus, Enterobacteriaceae sp, Lactobacillus sp, and Enterococcus sp. The basic kinds of agar displays that were used included, Mannitol Salt Agar for Staphylococcus aureus, MacConkey Agar for Enterobacteriaceae sp, Slanetz & Bartley agar for Enterococcus sp and MRS Agar for Lactobacillus sp. Subsequently we observed the commensal microbial growth in 4 and 8 week diabetic rats along with that in normal rats for obtaining c...
30 Pages(7500 words)Lab Report


...1. a. Substances capable of inducing specific immune responses are referred to as antigens. The properties of a good antigen are – 1. Induction of an immune response(immunogenecity) 2. Specific reaction with antibodies or sensitized cells( immunological reactivity) b. 2. a b. Immunoglobulin are of 5 classes namely IgG, IgA, IgM, IgD & IgE. IgG: - This is the major serum immunologlobulin constitutes about 80% of total serum immunoglobulin. It has a molecular weight of 1,50,000. There are four IGg sub classes in humans, IgG1, IgG2, IgG3, IgG4 IgA: - This is the 2nd most abundant class, constituting about 10-15% of serum immunoglobulin. It is a major immunoglobulin...
2 Pages(500 words)Essay


... the concentration of salt outside the cell in the environment so at greater concentrations it busted the cells. Thus it is concluded that the bacterial load is present in both the sponge and chicken isolates and the most predominant ones are Escherichia Coli and Staphylococcus epidermis. References: Butler, DA., Lobregat, CM and Gavan, TL 1975, “Reproducibility of the Analytab (API 20E) System”, Journal of Clinical Microbiology, vol. 2, no. 4, pp. 322-326. Chelikani, P., Fita, I. and Loewen, PC 2004, “Diversity of structures and properties among catalases,” Cellular and Molecular Life Sciences, vol. 61, no. 2, pp.192– 208. Farmer, JJ., Fanning, GR., Huntley-Carter, GP., Holmes, B., Hickman, FW., Richard, C and Brenner DJ 1981...
6 Pages(1500 words)Essay


...2nd October Problems for Chapter 3 C.3.6 Dice Suppose that you roll three fair dice. What is the probability of getting a five on at least one of the dice? Total outcomes in a dice {1 2 3 4 5 6} Probability of getting a five on one dice {event X) = 3 No. of possible outcomes in one dice = 3{1 2 3 4 5 6} = 18 P (X) = = In 3 dices the probability of getting at least a 5 = 3/18 = 1/6 C. Forensic DNA testing DNA found at a crime scene can be compared with DNA from suspected criminal to estimate the likelihood that both samples came from the same person. An enzyme is used to cut each DNA into short fragments; the enzyme always cuts at the same DNA sequence, and the positions of such sequences differ among individuals... October...
5 Pages(1250 words)Speech or Presentation

Molecular Biology and Molecular Diagnostics

..., molecular microbiology aims at analyzing how the DNA can be manipulated in order to mutate or sequence it. A mutat3d DNA is usually inserted into the genome of a living being to offer some mutation effects caused by the phenomenon. Of late, there has been an increase in the study of molecules (Carson, Miller, and Witherow, 2012, p. 59). The studies have either been direct or indirect in their approach to the study of molecules. Direct studies have focused on the interactions of molecules (cell biology and developmental biology). Other indirect studies have focused on inferring historical attributes of species/masses (populations). Molecular Diagnostics Molecular diagnostics is a method that is employed to assess biological markers...
2 Pages(500 words)Essay

Microbiology of Milk

...INTRODUCTION Milk has been used since time immemorial, across all cultures, as an integral part of the food pyramid. It has been used right from the raw fluid form to various forms of processed milk like butter, cream and milk desserts, milk powder, cheese etc. Milk is a nutritious medium, right from meeting complete food requirements of an infant in the form of colostrum, to normal milk which is a rich source of sugars esp. lactose, fat and proteins. Milk is a highly perishable commodity and one of the critical factors determining the keeping quality of milk is its microbiological status. In a healthy animal, milk is sterile in the udder, however microbiological contamination may happen depending on the milking methods and the hygiene...
14 Pages(3500 words)Research Proposal

Microbiology: Green Burials

By avoiding many modern burial practices, green cemeteries avoid environmentally destructive practices. Green cemeteries avoid the use of large amounts of water, herbicides, and pesticides used to maintain conventional cemetery grounds. Cremation, which uses energy and pollutes the air, is also usually avoided. Although cremation is sometimes used in burials that are referred to as green burials, such as in space burials and some underwater burials that mix a deceased person ashes with concrete in a new artificial memorial reef. Although there is some discrepancy about what practices exactly can be included within a green burial, the idea is to leave the environment just as it was, or for one's body to become one with the surround...
7 Pages(1750 words)Term Paper

Current Molecular Techniques in Genetic Disease Diagnostics

...Current Molecular Techniques in Genetic Disease Diagnostics Introduction The discovery of the main principles behind genetics, heredity, and DNA in the twentieth century has led to many advances in the field of science, specifically medicine. The important personages in the century are Gregor Mendel (the ‘Father of Genetics”), Avery (DNA as the genetic material; Avery, McLeod and McCarty 1944); Watson and Crick ((Watson and Crick 1953; the double helix structure of the DNA which is made up of only four nucleotides) and Nirenberg (genetic code is made up of simple three letter codes). The human genome is made up of approximately 30,000 genes. In each gene, there are exons and introns which are involved in forming mature messenger RNA...
7 Pages(1750 words)Coursework

Molecular Genetic Diagnostics in the 21st Century

...Molecular Genetic Diagnostics in the 21st century: The advent of molecular genetic diagnostics has opened up new opportunities in the field of preventative and restorative healthcare. The newly available genetic diagnostic technologies have given rise to legal and moral conundrums that have not been sufficiently resolved. Just as the debate on the broader implications of genetic technology continues, the number of patients willing to avail of the technology is also on the rise. Such trends are witnessed here in the United Kingdom, as elsewhere in the industrialized world. This essay will discuss the molecular genetic diagnostic techniques that are currently being employed for various medical conditions. Even as the civil society waits...
8 Pages(2000 words)Term Paper

Important Biofilms in Clinical Microbiology

...Important Biofilms in Clinical Microbiology Biofilms are now present in all the environmental systems such as aquatic and industrial water systems, these biofilms were first described by Anton Von Leuwenhook but were not discovered until 1978. These biofilms are complex polymer matrix containing water channels through which the surface cells communicate among themselves. The physical structure and the characteristics of the cells were found by using the scanning electron microscope and confocal laser scanning microscope. Further studies have found that these biofilms are formed by certain genes in the micro organisms. The micro organisms growing in these biofilms have become resistant to the antimicrobial agents. These biofilms are now...
6 Pages(1500 words)Research Paper

Diagnostic Microbiology and the Microflora Inhabiting the Human Body

...Diagnostic Microbiology and the Microflora Inhabiting the Human Body Introduction: The human body is home to approximately 200 species of microflora, the maximum population inhabiting the GIT, next skin and then mouth. Most of these are commensals or mutualistic, however, some of these become pathogenic in cases of previous trauma or injury; or when immune system is weakened because of some reason; i.e. when normal defenses of the body are down. Body can also be infected by other pathogenic microbes from the environment, upon exposure to these microbes e.g. Salmonella sp. Such infections invoke responses from the body which are more or less specific to the microbe involved and so are their response to different antibiomicrobial agents...
7 Pages(1750 words)Lab Report

Medical Microbiology

... an advantage when competing with our immune system, as they have a shorter generation time, and are able to frequently mutate into new stains. However, our immune systems continue to battle them, and both bacteriologists and virologists continue to work on new techniques and vaccines to deal with bacteria and viruses respectively. Bibliography Levinson, W. 2006. Review of medical microbiology and immunology, McGraw-Hill Medical, 1-7. Martinez Medina, M., Aldeguer, X., Lopez Siles, M., González Huix, F., López Oliu, C., Dahbi, G., Blanco, J. E., Blanco, J., Garcia Gil, L. J. & Darfeuille Michaud, A. 2009. Molecular diversity of Escherichia coli in the human gut: New ecological evidence supporting the role of adherent invasive E. coli...
6 Pages(1500 words)Essay

Applied Microbiology: Predictive Microbiological Models

... foods. Future models include dynamic modelling in which interaction between bacteria and environmental factors and structure of the food. Lag modelling which models will take into account the effect of history and physiological state of the bacteria. Modelling including probability growth will address the probability of the prediction. Modelling single cell kinetics will account for variability at a single cell level. Relating predictive microbiology and molecular microbiology which will utilise knowledge about responses at molecular level for instance gene expression under certain conditions. Predictive models are used in a two-step approach for growth curves and death. In the first step, the growth or death model is established...
8 Pages(2000 words)Literature review

Microbiology and Chemistry, Bacterial and Fungal Infections

...INSTRUCTIONS In this Word document, you are asked to submit some of the data generated during the B31BFI chemistry and microbiology practical and to answer a series of questions about your data. Complete the following sections as instructed; the marks for each section are clearly indicated. Note that not all sections carry marks. You must complete the proforma in Arial font 11pt and adhere to the page limit for each section. Frequently asked questions (FAQs) will be added to Moodle so keep up to date with these. When you have completed theproforma, convert the document to a PDF and save using your student ID number only as the filename. This is so that we can mark your work anonymously. Submit the document through Turnitin before 17...
6 Pages(1500 words)Assignment

Medical Microbiology

Another difference is that gram-negative bacteria have an outer membrane while gram-positive bacteria do not. Gram-positive bacteria have 2 rings in a basal body while gram-negative bacteria have 4 rings in the basal body (Harvey, Champe, & Fisher 2007, p. 110).
Despite the fact that gram-positive bacteria have a thick Peptidoglycan layer, the lack of an outer membrane makes it easier for there to be easy penetration of stains that’s why they take the initial stain and turns purple. On the other hand, the presence of an outer membrane of gram-negative bacteria has the outer membrane that makes it impossible for the initial stain to penetrate (Murray, Rosenthal & Pfaller 2013, p. 189). The gram-negative bacteria th...
8 Pages(2000 words)Research Paper
sponsored ads
We use cookies to create the best experience for you. Keep on browsing if you are OK with that, or find out how to manage cookies.

Let us find you another Case Study on topic Molecular Microbiology for FREE!

Contact Us