Contribution of the Pittet's index, antigen assay, IgM, and total antibodies in the diagnosis of invasive candidiasis in intensive care unit

Abstract

Objective Nosocomial invasive candidiasis is about 15% of nosocomial infections in patients in intensive care units (ICUs). Clinical signs of severe infection lack specificity, and bloodstream lack of sensitivity. Suggested tools for improving the prognosis by providing an early diagnosis include the colonization index (CI), mannan antigenemia, and anti- Candida antibodies. Methods We evaluated these three tools in an ICU. Patients at risk for candidiasis were screened for colonization at ICU admission, and then once a week. The CI was determined at each timepoint. Serum was collected at the same timepoints for determination of mannan antigen (ELISA Platelia ®, Bio-Rad, France), anti- Candida IgM (ELISA, Candiquant-IgM ®, Biomerica distributed by Biotrin, Lyon, France), and total anti- Candida antibodies (immunofluorescence). Results During the 2-year study period, there were 75 eligible patients. In the 46 medical patients, antigenemia had the best sensitivity and specificity (75% and 57%) but failed to separate infected from non-infected patients (Fisher exact test, 0.240). In the 29 surgical patients, the CI allow us to differentiate infected patients (Fisher exact test, P = 0.052). Conclusion Serological tests failed to differentiate infected from non-infected patients. The Pittet's CI identified infected surgical patients (Fisher exact test, 0.052), which are in the population with CI > 0.5.