A young, previously fit man presents with a one week history of a influenza-like illness which has worsened over the past 24 hours. His temperature is 39.5 °C with a heart rate of 100 and increased respiratory rate. His chest X-ray shows diffuse mottled shadowing in both lung fields. A diagnosis of community-acquired pneumonia is made, and he is started on co-amoxiclav and clarithromycin. After 24 hours his condition has not improved, his temperature is 39 °C and a repeat chest X-ray reveals multiple nodular shadows with the possibility of a fluid level.

Q1-What organisms are the most likely to cause community-acquired pneumonia in a young patient? Describe them.

Q2-What investigations should you carry out and why?

Q3-What element in the history makes one of the organisms more likely? Explain

Q4-What sympoms are particularly alarming in this history? What might this be due to? Explain. Q5- Describe the laboratory techniques that will help identify this organism.