﻿ Antibiotic Resistance (Drug Resistance, Antimicrobial
Resistance) Symptoms, Causes, Treatment - Causes of
antimicrobial drug resistance - MedicineNet  Antibiotic
Resistance (cont.)  Causes of antimicrobial drug resistance
Microbes, such as bacteria, viruses, fungi, and parasites, are
living organisms that evolve over time. Their primary function
is to reproduce, thrive, and spread quickly and efficiently.
Therefore, microbes adapt to their environments and change in
ways that ensure their survival. If something stops their
ability to grow, such as an antimicrobial, genetic changes can
occur that enable the microbe to survive. There are several ways
this happens.  Natural (Biological) Causes  Selective Pressure
In the presence of an antimicrobial, microbes are either killed
or, if they carry resistance genes, survive. These survivors
will replicate, and their progeny will quickly become the
dominant type throughout the microbial population.   Most
microbes reproduce by dividing every few hours, allowing th