Another aspect may be that vaccines are used before any infection has occurred, so the organism may never come in contact or is destroyed early and never has a chance to reproduce and so evolve into a more resistant form. Also, vaccines are changed if that is needed, such as the flu vaccine.
It is a whole different process. Bacteria develop resistance to antibiotics after their repeated exposure to them. They mutate slightly and once some survive they reproduce others with the same resistance. With vaccines our bodies develop antibodies after exposure to a specific antigen (a killed bacteria or portion of) which will prevent that same bacteria from getting a foothold in our system.