You have a number of issues going on. You probably underwent a TLIF fusion of L4-S1 and had a dural leak that according to the MRI report (and your surgeon) is still leaking. To add to this, you have an infection with P. Acnes.
Your dural leak might stop with time but I cannot say for sure. You might develop a pseudomengiocele (a false pocket of CSF fluid) that might or might not give your trouble.
A big problem is the infection. Normally, you should be treated with IV antibiotics and if necessary, a debridement (opening of the incison and cleaning it out before closing it again.
There is a chance of meningitis if you have a hole in your dura (dural leak) where the bacterial can gain access to your central nervous system. This needs to be addressed by an infection disease specialist.
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.