Definitely fireblight, but I don’t think that’s a Kieffer pear. Kieffer pears don’t have highly symmetric shape in their fruits. And one thing nice about the real Kieffer Pear, is that even if they get infected with fireblight, they can tolerate it and still produce. The fireblight don’t spread way down into the branches. So if it isn’t a Kieffer pear and it has fireblight spreading, you’ll have to get ahead and cut at least 1 ft down from the visible bottom spot of the infection. Check out the cut wood if there’s some staining in the cambium, and if there is, then cut further another foot.