How does one get a yeast infection?

how do people get them? can they be caused by tampons? can a women give it to a man?

Candida albicans, and other forms of yeast, grow in the vagina, rectum, and mouth. In a healthy vagina, the presence of some yeast may not be a problem. When a woman's system is out of balance, yeast-like organisms can grow profusely and cause a thick, white discharge. A yeast infection is not necessarily an STI; however, treating a woman and her sexual partner may help prevent recurrent yeast infections.

Factors that can disturb the vagina's balance include:
Antibiotic treatments
Oral contraceptives
Hot weather or non-ventilating clothing, which increase moisture and warmth, fostering fungal growth
Repeated intercourse over a short period of time
Stress
Suppressed immune system (including HIV)
High carbohydrate intake, especially refined sugars and alcohol
Pregnancy
Diabetes
Other causes can be irritants such as soaps, powders, new detergents and other products

You can help prevent a vaginal yeast infection by doing the following:
Eat a balanced diet.
Get enough sleep.
Don't use deodorant tampons.
Avoid feminine deodorant sprays and douches. They irritate the vulva and vaginal areas.
Wipe from front to back after using the toilet.
Antibiotics can also cause a yeast infection, since they kill or decrease normal flora. If you need to take antibiotics, you can ask for an anti-yeast prescription, or you can buy over-the-counter creams or suppositories.
Avoid tight-fitting clothing and wear cotton, rather than synthetic, underwear.