I don't believe there's any info on this site about apple cider vinegar as it relates to people after having C-Diff. I would surmise that it would depend on whether your stomach can handle the acidity.
There's a wealth of info on the web if you Google it as it is recommended for so many problems, like heatburn, etc. I do know it must be the raw, unfiltered organic Apple Cider Vinegar with the "Mother." Common brand is made by Bragg and readily available in most grocery stores or health food stores. Believe most web sites say to mix it with honey. I've even seen it recommended on some major hospital web sites.
I have a 72 year old diabetic neighbor that swears by it for everything. Takes a couple tablespoons a day. He's never sick, goes to doctor once a year, bowls 5 days a week, and has so much energy and is always on the go, and helping other people.
"Life is not measured by the number of breaths you take, but by the moments that take your breath away".