Candida colonization and candiduria in critically ill patients in the intensive care unit

Clinical severity of invasive candidiasis in critically ill patients and existing difficulties in timely diagnosis mean that early empirical therapy, based upon a strict clinical and epidemiological judgement, is required in intensive care unit patients. One school of thought is that the clinical severity and epidemiological burden of this disease warrant prophylaxis in all critically ill patients. In reality, however, there are still many open-ended questions with regard to which variables are most apt for selection of patients requiring prophylactic or empirical treatment. As a consequence of a consistently significant correlation between colonization (one or more Candida-positive cultures from non-sterile sites) and subsequent infection, colonization remains the most universally accepted predictive variable with regard to invasive candidiasis. This is particularly true for high density colonization. It has not yet been clarified whether colonization can be used in isolation to identify high-risk patients or if it should be combined with other variables indicating high risk. Additionally, there is still a debate surrounding the question as to whether determination of multisite colonization is required, or whether detecting colonization at one or two specific sites is sufficient for the identification of high-risk patients. From a practical perspective, candiduria (a frequent finding in critically ill patients) appears one of the most promising parameters with regard to single-site assessment, owing to easy sampling procedures. Definitive evidence of a correlation between candiduria and invasive candidiasis is currently still lacking, as the few published studies thus far have yielded conflicting results. It is, however, apparent that candiduria can be reliably considered a surrogate marker of high density of colonization, thereby potentially representing a more practical, less resource-intensive screening marker of heavy colonization and high risk of infection than is currently possible using parameters such as the multiple-site colonization index.