How Antimicrobial Resistance Happens Antimicrobial resistance happens when germs like bacteria and fungi develop the ability to defeat the drugs designed to kill them.However, increases in antimicrobial resistance are driven by a combination of germs exposed to antibiotics and antifungals, and the spread of those germs and their resistance mechanisms.Definition of Germs & Antimicrobials Antimicrobial resistance does not mean our body is resistant to antibiotics .The content on this webpage does not include resistance to antivirals or antiparasitics.Bacteria cause infections such as strep throat, foodborne illnesses, and other serious infections.Antimicrobials is a term used to describe drugs that treat many types of infections by killing or slowing the growth of pathogens causing the infection.Antimicrobial resistance is a naturally occurring process.It means the bacteria causing the infection are resistant to the antibiotic treatment.Antibiotics treat bacterial infections.Resistant infections can be difficult, and sometimes impossible, to treat.