A 42-year-old woman from Mumbai with a history of myasthenia gravis presents with acute exacerbation of symptoms: ptosis, diplopia, and generalized muscle weakness. She was empirically started on ciprofloxacin 500 mg twice daily 2 days ago for a suspected respiratory tract infection. Her symptoms have worsened significantly since starting the antibiotic. Neurological examination confirms worsening of ocular and bulbar signs. What is the mechanism by which this fluoroquinolone is likely exacerbating her myasthenia gravis?