Candida Bloodstream Infections

Over the last two decades, Candida has emerged as one of the most important pathogens causing bloodstream infections in both adults and children worldwide, representing up to 9% of all nosocomial bloodstream infections. Candida bloodstream infection (BSI), also called candidemia, is the most common form of Invasive Candidiasis (IC). (1) The spectrum of disease of IC ranges from minimally symptomatic candidemia to fulminant sepsis with associated mortality exceeding 70%. In addition, an invasive Candida infection increases the length of hospital stays by as much as 30 days, representing a burden not only for patients but also for the healthcare system.

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Risks factors for invasive Candida infections

Risk factors for the development of Candida BSI include hematologic or solid-organ malignancy, previous administration of antimicrobial agents, corticosteroids or chemotherapeutic agents, neutropenia, prior fungal colonisation, extensive intra-abdominal surgery or burns, central venous catheter, mechanical ventilation or admission to an intensive care unit (ICU). (2)

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Early diagnosis of invasive Candida infections

As a single species, C. albicans accounts for close to 50% of overall invasive Candida infection. However, there has been a proportionate increase in the isolation of nonalbicans species of Candida, some of which are resistant to commonly used antifungal drugs. (3) Therefore, an early diagnosis is of the utmost importance to initiate the appropriate treatment. However, despite the recognition of risk factors, the diagnosis and consequently treatment of invasive candidiasis is frequently delayed. The current gold standard for diagnosing IC is culture of blood and specimens from deep-seated sites of infection. This method has a sensitivity of approximately 50% and takes 24 to 48 h to become positive. It has been shown that the administration of appropriate treatment more than 12 h after the first positive blood sample for culture is drawn, is associated with higher hospital mortality. (4) In this context, non-culture-based methods for the identification of Candida, such as DNA detection by PCR, represent a promising approach to allow rapid diagnosis and initiation of species-oriented therapy as soon as possible after the onset of sepsis.

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OLM’s CandID? PCR Kit

OLM’s CandID? is a multiplex real-time PCR assay, which rapidly detects the six main causative species associated with IC, and differentiates those resistant to first-line treatment: C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, C. dubliniensis and C. krusei. Importantly, CandID? provides results within 1 hour of nucleic acid extraction, which can be done from blood fractions without the need for culture. CandID? is provided in a ready-to-use, wet-mix format, at working concentration and is designed to be compatible with existing laboratory equipment, minimising the need for dedicated bench space or additional training. A recent study showed that CandID? had a sensitivity of 0.67 (95% CI 0.45 – 0.83), a specificity of 0.97 (95% CI 0.84 – 0.99), a positive likelihood ratio of 20.7 (95%CI 2.94 – 145.50), and a negative likelihood ratio of 0.34 (95%CI 0.19 – 0.63) in clinical blood samples from confirmed candidemia vs bacteremia cases (manuscript in prep). In addition, species identification with CandID? kits agreed with those obtained through blood culture and MALDI-TOF identification. The rapid time-to-result guaranteed by CandID? is crucial to support clinical decision-making and avoid treatment delay, eventually reducing overall hospital mortality.?