Can bacteria or other microorganisms be killed by applying pressure?
Yes, you can kill bacteria using pressure. The devised used is called a French press 

https://en.wikipedia.org/wiki/French_pressure_cell_press

http://www.glenmills.com/cell-disruption/high-pressure-homogenizer/french-press-gm/

However the pressure use is about 40k psi.... which is a lot higher pressure than anything a human body can generate.

Other methods to kill bacteria include, 
heat, gamma radiation, oxidative chemicals, antibiotics, dehydration, salt, oxygen exclusion, freezing.

However bacteria are a very diverse group, so it might take one or more methods in combination to kill all bacteria (and their spores) in a sample.