Try cranberry juice capsules. One daily. It works well for some. There is also a formula with a dextrose molecule. Again one daily. It is well worth the trial. The rational for using it is to prevent E. coli from invading bladder wall.
A sensitivity report on your urine culture may show the bacteria are resistant to Keflex. Daily macrobid , from my experience resulted in a interesting overgrowth of bacteria that are often cultured out of Foley catheter bags, NO THANK YOU. The cranberry capsules have been remarkably beneficial and may work for others.

I'm in Barcelona, Spain, BTW. The nurse told me that there's always bacteria in the bladder, good and bad. It's about the p.h. balance. If renal function is off, or a culture is growing in a foley catheter bag, especially a reused one, and it back flows, it can enter the bladder and start a symptomatic infection. A normal urine p.h. is expressed as between 6.0-7.5. A high alkali p.h. can mean a UTI. Too acid, another condition such as diabetes. Renal function plays a role in maintaining p.h. Prolonged storage of urine, such as in a collection bag, or bladder retention can cause an overgrowth. Bacteria love that sugar! The concentrated cranberry has no sugar, I think it acidifies the bladder to keep it from being too alkali? I'm not sure which. When an infection happens and antibiotics are introduced, the antibiotics kill ALL the bacteria, but they don't stop an infection from a newer resistant bacteria, or another bacteria altogether, such as that from a collection bag. I use a new 2 liter collection bag at night and I'm on my second infection. I believe it has something to do with being a male, in my case, and having nocturnal erections that expose the urethra to the exposed portion of the catheter tube. That's my conclusion. It's a vicious cycle.
Regarding joint and ligament damage, CIPRO, has been long associated with joint and tendon injury, weakening and in some cases joint calcification, "frozen shoulder," etc. Most fluoroquinalones have this reputation; I believe the FDA put on a black-box warning. I tell them straight out no, on fluoroquinalones. Keflex, is a cephalosporin, broad-spectrum antibiotic and may not be strong enough, or be specific to address and pinpoint a specific bacteria. There is a second generation cephalosporin I'm on, it's called Ceftin (cefuroxime) and I'm on a second seven-day round of this. Cephalosporins also have a reputation for tendon damage, so does amoxicillin. These antibiotics are processed through the kidneys, so they have an affect on renal function in some people. If you are already predisposed with renal insufficiency, or chronic kidney damage (CKD) from urinary retention, this may influence how the antibiotics work, perhaps their efficacy- but take this with a grain of salt because I'm not a doctor. It's worth asking if kidney function plays a role in how an antibiotic can cause tendon injury / damage, because calcium and struvite crystals (stones and bladder crystals) also start from the kidneys, so I'm wondering if this tendon damage / injury, is really a calcification? All I know is that I don't want to deal with antibiotic treatment continuously.
I take 1 capsule CranActin daily and stay away from refined sugars, or sodas, high fructose anything. I sincerely hope you can achieve a beneficial state and an effective remedy.