Performance of Candida real-time polymerase chain reaction, β-D-glucan assay, and blood cultures in the diagnosis of invasive candidiasis.
ABSTRACT The sensitivity of blood cultures for diagnosing invasive candidiasis (IC) is poor.
We performed a validated Candida real-time polymerase chain reaction (PCR) and the Fungitell 1,3-β-D-glucan (BDG) assay on blood samples collected from prospectively identified patients with IC (n = 55) and hospitalized controls (n = 73). Patients with IC had candidemia (n = 17), deep-seated candidiasis (n = 33), or both (n = 5). Controls had mucosal candidiasis (n = 5), Candida colonization (n = 48), or no known Candida colonization (n = 20).
PCR using plasma or sera was more sensitive than whole blood for diagnosing IC (P = .008). Plasma or sera PCR was more sensitive than BDG in diagnosing IC (80% vs 56%; P = .03), with comparable specificity (70% vs 73%; P = .31). The tests were similar in diagnosing candidemia (59% vs 68%; P = .77), but PCR was more sensitive for deep-seated candidiasis (89% vs 53%; P = .004). PCR and BDG were more sensitive than blood cultures among patients with deep-seated candidiasis (88% and 62% vs 17%; P = .0005 and .003, respectively). PCR and culture identified the same Candida species in 82% of patients. The sensitivity of blood cultures combined with PCR or BDG among patients with IC was 98% and 79%, respectively.
Candida PCR and, to a lesser extent, BDG testing significantly enhanced the ability of blood cultures to diagnose IC.
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ABSTRACT: Purpose: To assess the value of (1?3)-b-D-glucan (BDG), Candida albicans germ tube antibody (CAGTA), C-reactive protein (CRP), and procalcitonin (PCT) levels for the diagnosis of invasive candidiasis (IC) and for differentiating Candida spp. colonization from infection in ICU patients with severe abdominal conditions (SAC). Methods: Pro-spective study of 176 non-neutropenic patients, with SAC at ICU admission, and expected to stay at least 7 days. Surveillance cultures and BDG, CAGTA, CRP, and PCT levels were performed on the third day of ICU stay and twice a week for four consecutive weeks. Patients were grouped into invasive candidiasis (IC), Candida colonization, and nei-ther colonized/nor infected. The classification and regression tree (CART) analysis was used to predict IC in colonized patients. The dis-criminatory ability of the obtained prediction rule was assessed by the area under the ROC curve (AUC). Results: The probabilities of IC were 59.3 % for the terminal node of BDG greater than 259 pg/mL and 30.8 % for BDG less than 259 pg/mL and CAGTA positivity, whereas there was a 93.9 % probability in predict-ing the absence of IC for BDG less than 259 pg/mL and negative CAG-TA. Using a cutoff of 30 % for IC probability, the prediction rule showed 90.3 % sensitivity, 54.8 % Intensive Care Med (2012) 38:1315–1325 DOI 10.1007/s00134-012-2616-y ORIGINAL specificity, 42.4 % positive predictive value, and 93.9 % negative predictive value with an AUC of 0.78 (95 % confidence interval 0.76–0.81). Significant differences in CRP (p = 0.411) and PCT (p = 0.179) among the studied groups were not found. Conclusions: BDG with a positive test for CAGTA accurately differentiated Candida colonization from IC in patients with SAC, whereas CRP and PCT did not.Intensive Care Medicine 01/2012; · 5.40 Impact Factor