MRCP2-3005

A 43-year-old man presents with a fever. He reports that it started a few days ago and he has developed a frontal, dull headache. He usually stays healthy but had a fever and joint pain a few weeks ago. During the examination, nuchal rigidity and sensory loss in the right ulnar nerve distribution were noted. Blood tests showed elevated WBC and CRP levels, while CSF analysis revealed lymphocytic pleocytosis and elevated protein levels. An ECG showed first-degree heart block. What is the most likely causative agent for this patient’s symptoms?