Procalcitonin as a marker of Candida species detection by blood culture and polymerase chain reaction in septic patients

Abstract

BackgroundThe aim of our study is to test procalcitonin (PCT) as surrogate marker of identification of Candida spp. by blood culture (BC) and real-time-polymerase chain reaction (PCR), whether alone or in association with bacteria, in septic patients.MethodsWe performed a single-centre retrospective study. We reviewed the clinical charts of patients with a diagnosis of severe sepsis or septic shock treated at our general intensive care unit from March 2009 to March 2013. We analysed all diagnostic episodes consisting of BC, real-time PCR assay and dosage of PCT. We registered age, sex, white blood count, sequential organ failure assessment score and type of admission between medical or surgical. When inclusion criteria were met more than once, we registered the new diagnostic episode as subsequent diagnostic episode. The diagnostic performance of PCT to predict Candida spp. identification alone or in mixed infections by either BC or PCR was tested using the receiver-operative characteristic curve. Logistic regression was constructed using presence of Candida spp. as the dependent variable.ResultsA total of 260 diagnostic episodes met the inclusion criteria. According to BC results classification, a significantly lower value of PCT was observed in Candida spp. BSI (0.99 ng/ml, 0.86 - 1.34) than in BSI caused by bacteria (16.7 ng/ml, 7.65 - 50.2) or in mixed infections (4.76 ng/ml, 2.98 - 6.08). Similar findings were observed considering PCR results. A cut-off of ≤ 6.08 ng/ml for PCT yielded a sensitivity of 86.8%, a specificity of 87.4%, a positive predictive value of 63.9%, a negative predictive value (NPV) of 96.3% and an area under the curve of 0.93 for Candida spp. identification by BC. A similar high NPV for a cut-off ≤ 6.78 ng/ml was observed considering the classification of diagnostic episodes according to PCR results, with an AUC of 0.85. A subsequent diagnostic episode was independently associated with Candida spp. detection either by BC or PCR.ConclusionPCT could represent a useful diagnostic tool to exclude the detection of Candida spp. by BC and PCR in septic patients.

Combined use of serum (1,3)-β-d-glucan and procalcitonin for the early differential diagnosis between candidaemia and bacteraemia in intensive care units

“…This result is not surprising since patients with candidaemia might have slightly increased PCT values [11–13]. In this regard, the median PCT concentration of 0.73 ng/ml we found in patients with candidaemia is in line with values suggested by other authors for possibly indicating candidaemia [11–13]. However, it should be noted that in our population the discriminatory performance of PCT was overall inferior to that of BDG (sensitivity 84% and specificity 67% for PCT <2 ng/ml vs. sensitivity 92% and specificity 81% for BDG ≥80 pg/ml).…”

Intra-abdominal Candida spp infection in acute abdomen in a quality assurance (QA)-certified academic setting

“…Our enrolled surgical patients showed at least one of the following specimens positive for Candida spp—peritoneal fluid, peritoneal fluid cultures, drainage fluid/blood or bile or tissue—during surgical procedures according to the Infectious Diseases Society of America and the American Society for Microbiology 10. In our institution, the BACTEC 9050 system (Becton Dickinson Diagnostic Instrument System, Paramus, New Jersey, USA) is used as the first step in the culture procedure 24 . Candida spp were also identified by conventional morphological and biochemical methods as previously reported 24–26.…”

Should we Administer Antifungal Drugs Before the Diagnosis of Invasive Fungal Infection in Non-Neutropenic Critically Ill Patients?

“…fungal colonization, central venous catheter, parenteral nutrition, dialysis, abdominal surgery, broad spectrum antibiotics); 2) 'empiric treatment' defined as antifungals administration triggered by signs and symptoms of infection in patients at risk for IFI; 3) 'pre-emptive treatment' defined as treatment triggered by microbiological evidence of fungal infection, without definitive microbiological identification (e.g. positive biomarkers such as 1-3-beta-D-glucan, mannan-antimannan antibodies, procalcitonin); (10,11). The common point of these strategies is that they are 'untargeted treatments' since they are not driven by an established diagnosis of IFI.…”