Ok, no idea where you trained so no offence intended here..
Your saying we can not tell our client they have infection but that they must go see a doctor??
Bacteria is the most common life form on the planet, and if we understand it then we can work with it, without having to escalate the problem and scare the client - I would be very worried if I went to a beautician and they didn't say why but said "quick, off to the doctor with you..."
A minor bacterial infection can very easily be dealt with by a nail technician that has the correct training, and this is something that schools should be teaching. There is great information regarding it in Doug Schoons product chemistry and nail anatomy (edition 2) and also take a read of Sam Sweets article...
http://www.salongeek.com/health-safety-unatural/2641-moldy-oldy-fun-guys.html