Final answer:
Vaginal yeast infections are primarily caused by the yeast Candida albicans. Antibiotics do not kill Candida because they target bacteria, not fungi, and can disrupt normal bacterial flora, leading to yeast overgrowth.
Step-by-step explanation:
The micro-organism responsible for vaginal yeast infections is the yeast Candida albicans. This yeast is a common member of the normal microbiota found in the urogenital system of healthy individuals but can cause infections if an overgrowth occurs. The condition known as vaginal candidiasis typically happens when there is a disruption in the balance of the normal vaginal microbiota. Such disruptions can be caused by antibiotics used to treat other infections, hormonal changes during pregnancy, or conditions like diabetes that affect the immune system.
Candida was not eliminated by antibiotics for a urinary tract infection (UTI) because those medications specifically target bacteria and do not affect fungi like Candida. Instead, they may disrupt the balance of normal bacterial flora that helps control the growth of yeast, potentially leading to an overgrown Candida population and resulting in a yeast infection.
The treatment of vaginal candidiasis would involve antifungal medications that target the yeast directly, helping to restore the natural balance of microorganisms in the vagina.