Candida is a genus of yeasts and is the most common cause of fungal infections worldwide. Many species are harmless commensals or endosymbionts of hosts including humans; however, when mucosal barriers are disrupted or the immune system is compromised they can invade and cause disease, known as an opportunistic infection. Candida is located on most of mucosal surfaces and mainly the gastrointestinal tract, along with the skin. "Candida albicans" is the most commonly isolated species and can cause infections (candidiasis or thrush) in humans and other animals. In winemaking, some species of "Candida" can potentially spoil wines.