MRCP2-2813

MRCP2-2813

A 25-year-old man presents to the emergency department with fever, cough, and shortness of breath. He has been experiencing a non-productive cough for the past two weeks and has been feeling unwell with muscle aches and malaise before that. He visited his GP and was prescribed amoxicillin, but it did not help, and now he feels more breathless and unwell. He has not traveled outside of the UK in the last year and has no medical history or regular medications. His cough comes in paroxysms, which worries him.

During the examination, a few bilateral crepitations are present, but otherwise, the examination is normal. His vital signs indicate fever and mild hypoxia. Blood tests reveal mild anemia and elevated inflammatory markers. A chest X-ray shows bilateral consolidation, but he responds well to IV co-amoxiclav and clarithromycin over a few days.

What is the most probable causative organism?