Think about that bacteria...Staph something or other. It's on all of our skin. It provides a lot of protection against harmful bacteria therefore according to my high school level of biology, we can call the relationship between that bacteria and humans mutualistic. However, under certain circumstances this staph can act as a factor in illness as it's benefits can also provide benefits to actual pathogens.
Is culture the same way? Does it inject itself like a virus? Or, does it grow and spread like bacterium? In which way does it spread? When is the transmission of culture a disease, and when is it beneficial?
Interesting questions. I think I have Dr. Piboon Puriveth to thank for this line of thinking.