I recently went to a lecture on viruses and germs. An interesting piece of information about health care workers, especially in the hospitals, that wear laced tennis shoes: they are spreading MRSA ( a bad staph infection). How you say? Because those laces of the tennis shoes drag on the floor and the person wearing them will continue to retie them also. Germs on the laces and the hands. You can only wash tennis shoes so many times before they either fall apart or become deformed. The suggestion by the lecturer is to wear plastic shoes like clogs that can be wiped down.