Changes

An organism which lives on another organism whereby the host organism is neither helped (which would be [[symbiosis]]) nor harmed (which would be [[parasitism]]). Examples may include organisms in the human gut flora such as ''Escherichia coli''.  There has been some debate as to whether true commensalism exists; for instance, there is some evidence that the gut flora benefits the human by aiding digestion.   

An organism which lives on another organism whereby the host organism is neither helped (which would be [[mutualism]]) nor harmed (which would be [[parasitism]]). Examples may include organisms in the human gut flora such as ''Escherichia coli''.  There has been some debate as to whether true commensalism exists; for instance, there is some evidence that the gut flora benefits the human by aiding digestion.   

Some commensal microorganisms can, under certain conditions, become pathogenic.  Examples include ''Candida albicans'' and ''Staphylococcus aureus''.

Some commensal microorganisms can, under certain conditions, become pathogenic.  Examples include ''Candida albicans'' and ''Staphylococcus aureus''.