Candida refers to a type of yeast that is part of the normal flora of human mucosal surfaces. However, when conditions allow, such as during antibiotic treatment, immune suppression, or hormonal changes, Candida can proliferate and cause infections like candidiasis. The most common species responsible for these infections is Candida albicans, but other species like Candida glabrata and Candida krusei can also be problematic.