Current diagnostic approaches to invasive candidiasis in critical care settings

Abstract

For the specialist, the management of invasive candidiasis infections, from diagnosis to selection of the therapeutic protocol, is often a challenge. Although early diagnosis and treatment are associated with a better prognosis, apart from cases with positive blood cultures or fluid/tissue biopsy, diagnosis is neither sensitive nor specific, relying on many different factors, clinical and laboratory findings but there is certainly a need for the specific markers in this disease. Recently, new serodiagnostic assays as Candida albicans germ-tube antibodies or (1,3)-beta-D-glucan detection and molecular techniques for the detection of fungal-specific DNA have been developed with controversial results in critical care setting. One of the main features in diagnosis is the evaluation of risk factor for infection, which will identify patients in need of preemptive or empirical treatment. Clinical scores were built from those risk factors. For these reasons, an approach to the new diagnosis tools in the clinical mycology laboratory and an analysis of the new prediction rules and its application situations has been made. Currently, the combination of prediction rules and non-culture microbiological tools could be the clue for improving the diagnosis and prognosis of invasive fungal infections in critically ill patients.

Diagnostic performance and therapeutic impact of LightCycler SeptiFast assay in patients with suspected sepsis

“…The molecular methods are especially useful in detection of slow growing species such as fungi [27]. Our study also indicates the high potential of SF in the diagnosis of candidemia -we observed a signifi cantly higher detection rate of SF for C. albicans.…”

Non–Culture-Based Methods for the Diagnosis of Invasive Candidiasis

“…Recently, a commercial assay, the LightCycler SeptiFast test (Roche Molecular Systems, Basel, Switzerland), was launched in Europe [10][11][12][13]. This system is designed to detect 25 important bacterial and fungal species in whole blood in less than 6 h [14], and its sensitivity was superior to that of blood cultures [8•]. Similar data were obtained by Lehmann et al [12], who evaluated the technical and diagnostic accuracy of this commercial multiplex real-time PCR.…”

“…This test has been evaluated as a useful tool in the diagnosis of IC in bone marrow transplant recipients, hematologic or ICU patients, and users of intravenous heroin, with an overall sensitivity of 77% to 89% and a specificity of 91% to 100% [40]. It was observed that patients with positive CAGTA had a better outcome than those with negative antibodies [14]. Overall, the data are still limited, and more clinical studies are needed for sensitive evaluation.…”

“…However, BDG is ubiquitous in the environment, and false positive results may be caused by poor specimen handling (i.e., not using glucan-free and endotoxin-free glassware); also, hemodialysis using certain cellulose membranes, exposure to certain types of gauze, receipt of albumin or immunoglobulin products, or Gram-positive bacteremia have been associated with false positive results [14,32,[45][46][47]. In the study by Alexander et al [48•], it was demonstrated that the utility of the BGD test for the early diagnosis of invasive fungal disease is questionable in lung transplant recipients.…”

Invasive candidiasis: A review of nonculture-based laboratory diagnostic methods

“…[39,40] Conventional PCR with panfungal primers followed by species-specifi c detection of amplicons by enzyme immunoassay or uniplex/multiplex PCR with species-specifi c primers followed by gel electrophoresis is simple and cost-effective for identifying most frequently isolated Candida species. [16,27,29,[41][42][43] Panfungal real-time PCR assays, using species-specifi c probe primers, yield faster results in a single step. However, practical application of using distinct probe primers in a single reaction is limited.…”