We used antibiotics to fight against bacterial (and fungal) infection. However, bacteria fight back by finding ways to survive in the presence of antibiotics. These defense strategies are called resistance mechanisms, including the creation of antibiotic resistance genes. Only bacteria and fungi (not people) become resistant to antibiotics. Additionally, one bacteria can easily pass these antibiotic resistance genes to their offspring (from generation to generation). They can also share their antibiotic resistance genes with other bacteria (or fungi!).
Learn more by checking out the attached CDC handouts.