The importance of washing your hands properly,
especially after touching a mobile phone..
This Bacteriology lecture, by Prof. Warren Levinson MD of the University of California San Francisco (UCSF) School of Medicine, might be movie-length, but it gives a good introduction to pathogenic bacteria. Infection via food preparation is well noted in last half – e.g. the infamous cook ‘Typhoid Mary’, the spinach that killed several people, and why e-coli bacteria has such different levels of disease causing virulence.
Aside from bad (pathogenic) bacteria, good bacteria are more than just our friends – bacteria are us!
Some interesting info from Canada