MRCP2-3131

A 32-year-old intravenous drug user presents with a 3-day history of double vision, difficulty swallowing, slurred speech, and overall weakness. During the examination, the patient displays numerous skin lesions and an infected wound on their right thigh. They exhibit ophthalmoplegia with limited gaze in all directions, bilateral facial nerve weakness, and dysphonia. The patient’s limb examination reveals global flaccid weakness, which is worse proximally. Reflexes are diminished. The general medical examination is unremarkable except for shallow breathing.

Spirometry results are as follows:
– FVC: 50% of predicted
– FEV1: 50% of predicted
– FEV1/FVC: 0.84
– TLCO: low
– KCO: high

Cerebrospinal fluid (CSF) examination shows:
– Glucose: 3.5 mmol/l (serum 6.0)
– Protein: 0.45 g/l (normal 0.3-0.5)
– White cell count (WCC): 1 cell/mm3 (normal < 5)
– Red cell count (RCC): none seen
– Gram stain: negative
– Culture and PCR: pending

What is the most likely causative agent?