Detection Of Invasive Candidiasis Research Articles

Controversies in Candida management

Invasive candidiasis (IC) is associated with increased morbidity and mortality. Although advances in diagnosis and management of this infection have been reached, there remain several controversies. The aim of this review is to tackle some of these controversies and shed light on studies that support the different sides of the arguments. Regarding central line-associated candidaemia, the current evidence appears to be more in favour of early central line removal whenever possible. Otherwise, antifungal agents such as echinocandins or polyenes should be the preferred agents. In the setting of infection with Candida parapsilosis and in light of the high minimum inhibitory concentrations (MICs) to echinocandins, azoles have been considered the preferred treatment agents. However, a recent study appears to indicate that empirical echinocandin use was not associated with a worse outcome when the isolated species was C. parapsilosis. Different strategies of antifungal treatment have been considered, namely prophylactic, empirical, pre-emptive or directed therapies. Whilst there is consensus on the need for prophylaxis in high-risk cancer patients, especially haematological malignancy and stem cell transplant populations, it remains debatable whether prophylaxis is of benefit in very low birthweight infants and in intensive care unit (ICU) patients. In the era of antifungal resistance and where antifungal stewardship has been advocated, pre-emptive therapy based on predictive models with various Candida risk scores and sensitive non-culture-based biomarkers such as β-d-glucan appears to be a more cost-effective approach. Future efforts should be directed to optimise clinical predictive models and reliable biomarkers for early detection of IC.

Utilizing Rapid Diagnostics for Detection of Candida Species

Rapid diagnostic tests are now available to aid in the detection of invasive candidiasis (IC) and promise significant advantages to conventional detection and identification methods. The most progress has been made on rapid species identification when blood culture bottles turn positive and/or when isolated pure colonies are available, while the diagnosis of IC directly from a clinical specimen (e.g., the patient’s blood) remains problematic. For the latter, nucleic acid-based tests (PCR, PCR/electrospray ionization-mass spectrometry (PCR/ESI-MS), and T2 magnetic resonance) and immunologic tests [1,3-β-D-glucan (BG) and Candida antigen and antibody tests] are promising but each contains certain limitations which have restricted their impact on clinical practice. In-house PCR assays are not standardized, and commercially available PCR tests are limited by minimal clinical data and a long turnaround time. The PCR/ESI-MS and T2 magnetic resonance platforms both require substantial up-front resources, and further clinical experience is required to understand their role in the clinical laboratory. Also, the BG and Candida antigen and antibody tests may be useful in certain scenarios (e.g., a negative BG may help rule out IC) but require significant clinical correlation and interpretation of results. On the other hand, PNA FISH and FilmArray Blood Culture ID Panel can substantially reduce the time-to-identification from a positive blood culture, impact clinical practice, and are quite reasonable to implement in the clinical laboratory. While the clear advantages for MALDI-TOF MS are speed, versatility, and excellent accuracy for identification of organisms from culture plates (which is its primary use in the clinical laboratory), further optimization is required before it can reliably be used for organism identification directly from blood culture bottles and its cost is currently prohibitively expensive for a small clinical laboratory. MALDI-TOF MS is very appealing, however, for rapid identification of organisms in a large clinical laboratory. All of these rapid diagnostic methods complement but do not replace the culture, however, as having the organism itself is still critical for susceptibility testing and strain typing

Clinical experience of urine D-arabinitol/L-arabinitol ratio in the early diagnosis of invasive candidiasis in paediatric high risk populations

In 2 prospective studies, we previously reported on the early and accurate diagnosis of invasive candidiasis by determining the D-arabinitol/L-arabinitol (DA/LA) ratio in urine in neutropenic children with cancer at the paediatric oncology unit (POU) and in premature infants at the neonatal intensive care unit (NICU) at our hospital. In this retrospective study at the same units, we report how the DA/LA assay was implemented in clinical practice immediately after the prospective study periods. We found that, in the POU, the recommendation of regularly monitoring urine DA/LA ratios in patients at risk and considering antifungal therapy in the case of elevated ratios had been followed. A significant decrease in the incidence of culture positive invasive candidiasis may have been attributed to the introduction of the DA/LA assay. At the NICU, where the DA/LA assay was recommended only as an adjunct to other diagnostic tools, morbidity in invasive candidiasis remained unchanged. While regular monitoring of the urine DA/LA ratio probably facilitates the early detection of invasive candidiasis in paediatric oncology, it remains to be determined if the test can be used in a similar way in neonatal intensive care.

Serum levels of arabinitol in the detection of invasive candidiasis in animals and humans.

Arabinitol is a pentitol generated in large quantitites by several species of Candida, including Candida albicans. The level of arabinitol in the sera of infected animals and humans was determined by gas-liquid chromatography of an acetone extract of the serum. Experimentally infected mice with pyelonephritis due to C. albicans had elevated levels of arabinitol; rabbits with pyelonephritis did not have elevated levels, nor did rabbits with catheter-induce cystitis, but rabbits with endocarditis developed elevated levels of arabinitol shortly before death. A prospective study in patients clinically suspected of having invasive candidiasis failed to show elevated levels of arabinitol in most. Mice and patients not colonized or infected with yeasts but with renal failure had high serum levels of arabinitol. The data indicate that an elevated level of arabinitol in the serum of a patient without renal disease is suggestive of invasive candidiasis, but normal serum levels do not contradict the diagnosis.