Campylobacter culturing with Medlab's advice

I followed Chris' (Microbiology Manager of Medlab) advise to incubate the Campylobacter species in CO2 incubater (10% CO2 at 42C) last Friday. However, when I observed those Campys this morning (which have elapsed more than 48 hr), those colonies were much smaller than what they showed me before. I even doubt if those spots I saw are exactly the Campy colonies or merely the fiber of swabs. My incubating environment is as follow: 10% CO2 42C Campylobacter Selective Agar (Charcoal agar) with supplement (cefoperazone, amphotericin) added I have decided to give them another two days to go, but I really wonder what makes them grow so slow. Could it because I streaked the swabs too much? (but there is no problem with Salmonella spp.) What else could go wrong???