Introduction Although some infections are unique enough to be identified clinically, usually microbiologic laboratory methods are needed to identify the etiologic agent and diagnose microbial infection (Washington, J.A., 1996). Although we have made significant progress in our ability to diagnose and treat infectious diseases, they still remain a strong challenge to human survival, for example the disease Tuberculosis caused by a microbial infection with Mycobacterium tuberculosis accounted for one third of the worlds bacterial infections in 2010 infecting a total of 8.8 million people worldwide (Dheda et al., 2010). Diagnosis is important not only for prescribing effective drugs but for preventing the evolution of resistant microorganisms (Mori and Notomi, 2009). Traditionally, the microbiology laboratory identified etiologic agents of infectious disease by the direct examination and culture of clinical specimens. Methods of identifying and differentiating microorganisms responsible for microbial infection mainly relied on microbial morphology, staining properties of the organism and its growth variables. However, a major restriction is that >99% of the microorganisms observed through a microscope are not cultivable by these direct techniques (Rastogi and Sani, 2011). Other disadvantages of these traditional methods include their lack of reproducibility and the difficulties they produce in typing as they are usually not sensitive enough for strain differentiation. These techniques are also restricted by the number of organisms present and the skill of the microbiologist in recognising different pathogens (Tang et al., 1997). Over the past few decades, the development and introduction of molecular-based techniques into the labora... ... middle of paper ... ...nd Notomi, T. (2009) 'Loop-mediated isothermal amplification (LAMP): a rapid, accurate, and cost-effective diagnostic method for infectious diseases.', J Infect Chemother, 15(2), pp. 62-69. Muldrew, K.L. (2009) 'Molecular diagnostics of infectious diseases',Curr Opin Pediatr, 21(1), pp. 102-111. Rastogi, G. and Sani, R.K. (2011) 'Chapter 2 :Molecular Techniques to Assess Microbial Community Structure, Function, and Dynamics in the Environment', in Ahmad, I., Ahmad, F. and Pichtel, J. (ed.)Microbes and Microbial Technology. California, USA: Springer Science, pp. 29-57. Tang, Y.W, Procop, G.W. and Persing, D.H. (1997) 'Molecular diagnostics of infectious diseases', Clin Chem, 43(11), pp. 2021-2038. Washington, J.A. (1996) 'Chapter 10 :Principles of Diagnosis', in Samuel Baron (ed.) Medical Microbiology 4th Edn. Galveston, Texas: University of Texas Medical Branch.
I identified the genus and species of an unknown bacterial culture, #16, and I applied the following knowledge of morphologic, cultural and metabolic characteristics of the unknown microorganism according to the laboratory manual as well as my class notes and power point print outs. I was given an incubated agar slant labeled #16 and a rack of different tests to either examine or perform myself; the tests are as follows: Gram Stain; Nutrient Gelatin Test; Carbohydrate Fermentation; Dextrose, Lactose and Sucrose; IMVIC tests; Citrate, Indole, Mythel-Red and Vogues Proskauer test; as well as a Urease and TSI Test.
After 48 hours of incubation the agar plates were viewed. Individual colonies were tested for successful isolation by gram staining and then viewing the stained bacteria under a microscope. Isolation was successful. One colony of each unknown bacteria was transferred to an agar slant for growth. The agar slants were stored at room temperature over the weekend so that they would not grow too much.
...uciana L. "Challenges to the Laboratory Diagnosis of Yersinia Pestis in the Clinical Laboratory." Lab Diagnosis of Y. Pestis. UPMC Center for Health Security, 29 Dec. 2005. Web. 07 Apr. 2014.
Trabelsi, H., Dendana, F., Sellami, A., Sellami, H., Cheikhrouhou, F., Neji, S., … Ayadi, A. (2012). Pathogenic
One thing that must be noted is that contrary to popular belief, infectious agents such as viruses, bacteria, parasites, etc. are not desig...
Mycobacterium tuberculosis (M. tuberculosis) is the bacterium that causes the disease tuberculosis (TB). A distinctive characteristic of the genus Mycobacteria is the presence of a thick lipid-rich cell wall and resistance to the decolourization step of the gram stain (being acid-fast). The acid-fast characteristic of the M. tuberculosis is the result of a waxy, lipid-rich cell wall. The cell envelope of the tubercle bacilli contains a layer beyond the peptidoglycan which is exceptionally rich in lipids, glycolipids and polysaccharides. The bacterium is gram positive bacillus which is an obligate aerobe, is non-motile, a non-endospore forming and is non-capsulated. The microscopic appearance of M. tuberculosis is seen as straight, slightly curved rods approximately 3 x 0.3µm in size. In liquid culture media, the bacteria usually grow as twisted rope-like pellets known as ‘serpentine cords’. M. tuberculosis is capable of growing on a wide range of enriched culture media such as Lowenstein-Jensen medium or Middlebrook medium. The optimum growth temperature of the pathogenic organsim is 35-37°C and unlike most other mycobacteria, it cannot grow at a temperature of 25°C or 41°C. M. tuberculosis is an airborne pathogen that is transmitted from person to person, usually infecting the respiratory tract through inhalation (Greenwood, et al., 2012).
Morse, Stephen A., et al. "Detecting biothreat agents: the laboratory response network." ASM News-American Society for Microbiology 69.9 (2003): 433-437.
wards. Clinical Microbiology And Infection: The Official Publication Of The European Society Of Clinical Microbiology And Infectious Diseases, 18(12), 1215-1217. doi:10.1111/j.1469-0691.2011.03735.x
Observing under 1000X magnification, the gram stain depicts purple bacilli, as seen in Figure 1. Figure 2 depicts growth of a light brown, opaque bacteria on a Phenylethyl Alcohol Agar (PEA) plate. As seen in Figure 3, the blood agar plate shows brown growth surrounded by a very thin clear area. Figure 4 shows an endospore stain of the gram-positive unknown. It depicts green endospores surrounded by pink bacilli. Figure 5 depicts a slant of gram-positive isolate, which appears as an opaque, white film. As seen in Figure 6, the catalase test resulted in vigorous bubbling. The lactose test resulted in a color change from pink to yellow, as seen in Figure 7.
The purpose of this project was to identify unknown bacteria species from a mixed culture. The two unknown species were initially plated onto Tryptic Soy Agar (TSA), Eosin Methylene Blue (EMB), Mannitol Salt Agar (MSA), and blood agar plates to distinguish between the two different bacteria using colony size, color, shape, and growth characteristics. By identifying and inoculating the differing types of colonies, the two unknown bacteria were purified and able to be tested
"Tuberculosis." Tests and diagnosis. Mayo Foundation for Medical Education and Research, n.d. Web. 13 May 2014. .
Polymerase chain reaction (PCR) is a technique used “to amplify the number of copies a specific region of DNA (Brown)”, in order to produce enough DNA to be adequately tested. This technique can be used to identify with a very high-probability, disease-causing viruses, bacteria, a deceased person, a criminal suspect, and also in the event of an outbreak, “Real-Time PCR can effectively monitor the success of clean-up efforts (RAL,Inc)”.
Rouphael, N.G. & Stephens, S.S. (2012). Neisseria meningitidis: Biology, Microbiology, and Epidemiology. Neisseria meningitidis: Advanced Methods and Protocols, Methods in Molecular Biology. 799: 1-20. Retrieved from: http://download.springer.com/static/pdf/954/chp%253A10.1007%252F978-1-61779-346-2_1.pdf?auth66=1385454607_76421ed179b1332c8755d5ca9118b502&ext=.pdf
Greenwood, D., Slack, R., Peutherer, J. and Barer, M. (2007) Medical Microbiology, the United States: Elsevier.
Its history is long and successful. Additionally, its sensitivity and simplicity, spatial and temporal resolution have all played a part in its importance that has led to its persistence as the gold standard in disease detection (Kiernan, 1999; Boekelheide, K. & Schuppe-Koistinen, I. 2012)