I don't know anything about mastic gum. Gums are fibers, right? Hmm.
You got the pylori beFore you started eating raw, I assume? Pylori I believe they say cause ulcers. Do you have ulcers? Is that how you found out?
I don't think I was tested for which bacteria, but close to twenty years ago I got stomach ulcers, and when they got out of control, I treated them with diet as I read in Balch's Prescription for Nutritional Healing. It worked fast. I was strict veg. Balch's remedy kind of had Bieler's soup as an integral part of it.
A couple of years earlier than that, I was teaching Ann Wigmore's program, and a student, an older woman had duodenal ulcers. With our help, on energy soup, her ulcers healed quickly. She came to us from cooked (Island food).
My son have had stomach trouble for about eight years (vegan that whole time). Acupunture helped him. Adding raw biodynamic butter and unheated honey to his diet and a few other dietary changes, and within a couple of months he finally got off stomach medication, and is still off, and happy about that.
I have heard raw kefir replenishes intestinal flora and overcomes the more hurtful bacterias. I have heard unheated honey can. I believe highmeats might be very beneficial for this. I do think raw meat will help you. Maybe it will take longer than you like, but I believe it will get your intestines functioning best.
Green juices clean the intestines in my experience, see how it goes.
To put on weight, it may help you to mix a raw egg in your green juice.
Have you tried raw eggs? I'm not sure specifically how they are with pylori, but they can be very easy and quick to digest and healing to weak intestines.