Candida species are common causes of disease ranging from superficial cutaneous and mucocutaneous infections to invasive infections such as candidemia and disseminated candidiasis. There are more than 150 species of Candida, but only 9 are frequent human pathogens. The most common isolate is Candida albicans (Figure 170.1); other encountered pathogens include Candida tropicalis (Figure 170.2), Candida parapsilosis, Candida glabrata, Candida krusei (Figure 170.3), Candida kefyr, Candida lusitaniae, Candida dubliniensis, and Candida gulliermondii. Less commonly isolated species with medical significance include Candida lipolytica, Candida famata, Candida rugosa, Candida viswanathii, Candida haemulonii, Candida norvegensis, Candida catenulate, Candida ciferri, Candida intermedia, Candida utilis, Candida lambica, Candida pulcherrima, and Candida zeylanoides. Most species are commensal organisms, colonizing the skin, gastrointestinal tract, and vagina, and they become opportunistic pathogens only when the host has compromised immunologic or mechanical defenses or when there are changes in the host's normal flora, such as those triggered by broadspectrum antibiotic use.