Identify or not?

Peter thinks that Campylobacter is a kind of "difficult cultures" and wouldn't like me to spend too much effort (and budget) on isolation and identification of Campylobacter species. After all, isolation and identification of Campylobacter is not the point of my research work. (and also many medical papers just notify "Campylobacter spp" rather than specifically notify the species' name like "Campylobacter coli""Campylobacter jejuni" such and such) On the other hand, Ray - my another supervisor - thinks that to identify the species of Campylobacter is very important from medical point of view and suggested me to use PCR method rather than traditional biochemical methods to identify them (to his mind, PCR is cheaper than traditional biochemical tests). However, Peter thinks identify the species of Campylobacter with PCR would cost hundreds of thousands of dollars and take months of time to do, which is unaffordable and also unfavorable. Indeed, those molecular methods are normally expensive than traditional tests; and also Campylobacters are growing much slower than other bacteria (such Salmonella spp, E.coli etc.) and in most case they don't survive in -70C storage. Identify or not?...Mmm...it's really a dillema.