Of course there are myelopathy cases that do not involve spinal cord compression but those cases are rare. Most cases of myelopathy are caused by canal compression resulting in direct injury to the cord. I am unaware of myelopathy symptoms being caused or aggravated by antibiotics. Of course Cipro and some other floxacins can cause ligament damage, typically extremity problems but I would imagine that the spine would not be immune to that condition. Nonetheless, I have never seen spinal involvement with antibiotics.
I did do a simple Google search and found no relation between myelopathy and antibiotics.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.