These terms refer to antibiotic sensitivities; antibiotic resistant organisms versus antibiotic susceptible organisms.

Also known as "superbugs", antibiotic resistant bacteria have evolved to a point that our usual antibiotics won't kill them. VRE and MRSA are common forms of antibiotic resistant bacteria.

Why is the human body resistant to antibiotics?

Because synthetic medicines tend to be quite simple, the bacteria that should be affected by the antibiotic are able to build a defense against it.

survive the presence of an antibiotic

superbug.