What's the antibiotic that we must not use in Gillian barre syndrome?

This could be a trick question, because GBS is a post-viral condition, not caused by a specific bacteria I am aware of. It is a de-myelination of the myelin sheaths on the nervous system. Not treated with antibiotics. It is systemic, starting distally, and moving proximally. It does not always move to the stage where ventilation is required. Treatment is of a supportive nature. ie. ventilation if required, SCD's and full nursing care, and steroids.