Can an adult get thrush from putting her infant's pacifier in her mouth?
Thrush is a fungal infection of the mouth caused by a fungus called candida albicans. Candida inhabitates almost all of us, living on the surfaces of our skin, but unable to penetrate deeper because of immunity that humans develop over time. What candida and related fungi love best are dark, wet places of the body, the creases of groins (jock itch), the vaginal area, between toes. Babies get candida in their mouths because mouths are also dark and wet and because babies' immune systems are not fully developed enough to ward off infections there. So, while you will expose yourself to a dose of candida in putting that pacifier in your mouth, your immunity will in all likelihood prevent the infection we call thrush.
P.S. It should now make sense if I remind you to sterilize the pacifier before it goes back in your baby's mouth and reinfects her!