Antibiotics suppositories?

It is well documented that Antibiotics cause massive and sometimes permanent damage to the intestinal microbiome. But as most of us know, in some cases Antibiotics are the only option. IV Antibiotics are far more effective while also being less damaging to the gut. I did some research and saw several studies showing antibiotics in rectal suppository form enter the blood as well if not better than oral.

It is very easy to dissolve a Antibiotic capsule in a coffee enema or other suppository. I wonder how safe and effective this is in the long run? The lower colon has some bacteria but nothing like the 2 to 6 lbs of normal intestinal flora in a healthy gut.