Rapid colorimetric test for <em>Candida albicans</em>

Recent trends in the incidence of invasive Candida infection have highlighted a need for the rapid differentiation of C. albicans from non-albicans Candida species. In addition to a worldwide increase in systemic Candida infection, some countries have found that an increasing proportion of these infections are due to non-albicans Candida species. Although C. albicans is sensitive to azoles, which are the most widely used antifungal agents, some non-albicans Candida species are resistant to this group of drugs. Therefore, it is important to obtain rapid, species-level identifications in order to direct appropriate antifungal treatment. O.B.I.S. albicans is easy to use and quickly indicates whether or not a suspect colony is C. albicans. The two-stage test detects the presence of two enzymes, β-galactosaminidase and L-proline aminopeptidase. Both are produced by C. albicans; however, one or other (or both) enzyme is absent in other yeast species. If both stages of the test produce a colour reaction, the result is presumptive positive for C. albicans. The absence of a colour reaction in either or both stages of the test indicates that the suspect colonies are not C. albicans. Unlike some biochemical tests, O.B.I.S. albicans uses safe, non-carcinogenic substrates. In addition, it is a much faster alternative to time-consuming and subjective physiological methods.