Efficacy of Antibiotic Treatment for Patients With Chronic Low Back Pain and Modic Type I Changes - Randomized Placebo-controlled Trial

The goal of this clinical trial is to learn if antibiotics (amoxicillin) work to treat chronic low back pain in adults. In some patients, this type of back pain may be caused by bacteria in the vertebrae, resulting in a condition known as "Modic type I change." The main questions the trial aims to answer are: * What is the efficacy (primary objective) of antibiotic treatment for patients with chronic low back pain and Modic type I changes? * What is the cost-effectiveness (secondary objective) of antibiotic treatment for patients with chronic low back pain and Modic type I changes? Researchers will compare amoxicillin to a placebo (a look-alike substance that contains no active drug) to see if amoxicillin works to treat chronic low back pain. Participants in the trial will: * Be invited for an MRI scan to determine if they have a Modic type I change; those who do will be included in the study. * Take either amoxicillin or a placebo daily for 100 days. * Take probiotics daily for 100 days to reduce the occurrence and impact of any side effects from the antibiotics. * Attend clinic visits at baseline (the start), 4 weeks, 3 months, and 12 months for checkups and tests. * Complete questionnaires at baseline, 3 months, 6 months, and 12 months.