Pneumonia Case Study
Pneumonia is a respiratory infection that impacts millions of Americans each year, and results in thousands of deaths across the country. Pneumonia can be caused by different types of microbes including fungi, viruses, or bacteria.
Case Background: A 76-year old male is admitted to the hospital complaining of shortness of breath, high fever, coughing, and chest pain. X-rays and a medical exam indicate that the patient has pneumonia, but the causative microbe is unknown.
Imagine that you work in the microbiology lab and you have been asked to help identify the cause of the patient’s pneumonia. A sputum sample is obtained and a slide is prepared for microscopic examination to identify the cause of the illness. At this stage, microscopic examination will only determine if the causative microbe is a fungus, a virus, or a bacterium.
You have been asked to create an experimental plan to identify the type of microbe causing the patient’s pneumonia. Please complete Parts 1 and 2 below to help identify the causative agent of the pneumoni. Then, provide additional information about the impact of pneumonia on human health.
- Create a hypothesis to guide your experiment in determining if the patient’s pneumonia has been caused by a fungus, a virus, or a bacterium. You may only choose one of the three. Your hypothesis should be in an ‘if-then’ format, and should make a logical prediction of the type of microbe that caused the disease. For information on Hypothesis design, review the Designing a Hypothesis video, and/or visit the PG Science Center.
- Lab protocol requires examination of a sputum sample from an uninfected person to be used as a control. What is the purpose of a control sample in an experiment?
- In the first question you constructed a hypothesis with an independent variable that can be controlled by the experimenter such as the staining or fixation process to prepare the sample slides. Now you need to discuss the observable results or the dependent variable. What would you expect to see on the slide based on your prediction? What would the causative microbe cells look like under a microscope? For example, would you see a nucleus in the microbial cell? Would it be larger or smaller than the human cells?