Yes, amoxicillin is a good broad spectrum antibiotic, but if the bacteria is a particular type and is one of the more stubborn ones, a more targeted antibiotic would probably work better. That's why, after struggling with these sores for so long, it would be extremely helpful to know more about the bacteria you are dealing with.
Different bacteria have cell walls or none, and some antibiotics are better at penetrating strong cell walls or getting around the evasive tactics of a bacterium without cell walls, which can sometimes be more of a challenge.
Ask your vet if you can take a swab at home and bring the sample in so they can send it to a lab for a gram stain test. That will go a long way toward knowing if it's a gram positive bacterium or gram negative. That has to do with the existence or absence of cell walls. Further tests could possibly tell us the name of the bacterium, but just knowing if it has cell walls or not can help us choose the best antibiotic to kill it.
Different bacteria have cell walls or none, and some antibiotics are better at penetrating strong cell walls or getting around the evasive tactics of a bacterium without cell walls, which can sometimes be more of a challenge.
Ask your vet if you can take a swab at home and bring the sample in so they can send it to a lab for a gram stain test. That will go a long way toward knowing if it's a gram positive bacterium or gram negative. That has to do with the existence or absence of cell walls. Further tests could possibly tell us the name of the bacterium, but just knowing if it has cell walls or not can help us choose the best antibiotic to kill it.