Help - my pup's got campylobacter!

My puppy has had a very dodgy tum pretty much for the whole six months since I've had him. At first I thought it might be the food so have tried to find a diet that works for him and am now moving towards feeding raw.
The pattern has been a few days of runny poo followed by a couple of weeks of normal stools. I talk to the breeder regularly and she has been very supportive. The breed is known for their jippy tums.
I went to the vets recently as he was particularly poorly and they conducted a fecal test, the first result back showed something that sounded like coxydilla (which I'm told is normally present and nothing to worry about) and then after two weeks of growing the culture they found campylobacter. He's now just finished a 10 day course of antibiotics and fingers crossed he's okay - but we've had waves of good health before so aren't counting chickens just yet.
Can anyone tell me more about campylobacter, I've heard it described as a bacteria overgrowth? He is a terrible scavenger and is always eating poo on walks - from any species. He's also picked up the odd dead rabbit. Can this be the source and if so why don't all dogs have this problem as I'm sure my dog isn't the only one with nasty habits.
He's been thoroughly wormed at 12 weeks and also monthly due to the local risk of lungworm.
I've read on the Internet that camplyobacter can be passed to humans, how easily does this happen as he has lots of kids that love giving him pats and get lots of licks from him in return. Do I need to stop this? No one that has close conatct with him has had an upset tum.
Will he keep reinfecting himself if he's picking this up from eating poo?
Is camplyobacter present in all dogs - if so, why has my pup now developed a problem with it? The other dogs he mixes with all seem fine.
Could he have had it in his system since I got him? The breeder says his older brother had a similar problem until antibiotics sorted it out at six months.
I've no interest in trying to blame anyone, just want to sort my pup's tummy out and keep him healthy.
Julie Ashton, Bristol