Bloodstream Infections Are an Improbable Cause of Positive Serum (1,3)-β-d-Glucan in Hematology Patients

Abstract

c Ninety-one serum samples from 51 hematology patients with bacteremia infections were tested for (1,3)-␤-D-glucan (BG). Eleven samples (15%) from 7 patients (14%) were positive for BG. Of these 7 patients with positive BG results, 4 (8%) had invasive aspergillosis and 3 (6%) had no invasive fungal disease. Bacteremia was an unlikely cause of the false-positive BG results.A major cell wall component of various clinically important fungi is (1,3)-␤-D-glucan (BG). Serum levels of BG are included in the updated European Organization for the Research and Treatment of Cancer-Mycoses Study Group (EORTC/MSG) diagnostic criteria for invasive fungal disease (IFD) in immunocompromised patients (1). One of the limitations reported for the BG assay is the high number of potential causes of false-positive results, including bacterial bloodstream infections (BSIs), particularly those due to Pseudomonas aeruginosa, Streptococcus pneumoniae, or Alcaligenes faecalis (2-5). However, existing data on the frequency of false-positive BG results during BSI with the aforementioned bacteria are inconsistent (6-12). While older studies reported up to 66% (10/15) of patients with a BSI due to Grampositive cocci having more than one sample positive for BG, a more recent analysis found only one positive BG result among 70 patients with BSI and no IFD (7, 12). The aim of this study was to investigate the rate of BG positivity in patients with hematological malignancies and BSI in whom the BG assay was used for IFD screening twice per week.All the patients who were admitted to the hematology units of San Martino University Hospital and who developed a BSI between January 2011 and December 2013 were retrospectively identified. In cases of common skin contaminants, two consecutive positive blood cultures were required to diagnose a BSI. Patients who had at least one BG measurement within 48 h after a positive blood culture were included in the study. The data on the concomitant IFD (diagnosed according to 2008 EORTC/MSG criteria), amoxicillin treatment, surgery, and immunoglobulin administration were recorded. BG testing was performed using the Fungitell assay (Associates of Cape Cod, Inc., Cape Cod, MA) according to the manufacturer's instructions. A BG value of Ͼ80 pg/ml was considered positive.Overall, 66 BSIs in 51 patients were included in the study (due to P. aeruginosa [26] A total of 91 serum samples were analyzed for BG (median number of samples per patient, 1 [range, 1 to 4]). The median time between the blood draws for culture and for the BG assay was 24 h. The BG measurement was performed at the same time as the blood culture in 27 BSI episodes, within 24 h after BSI in 30 episodes, and between 24 and 48 h in 9 episodes. In 21 BSI episodes, 2 consecutive samples were tested.BG results were positive in 11 samples (12%) from 7 patients (14%). Among these, 3 patients (6%) were diagnosed with probable invasive aspergillosis (IA) and 1 patient (2%) with possible IA. The median value of BG in these patients was 214 pg/ml. The other 3 pat...

β-d-Glucan and Candida albicans germ tube antibody in ICU patients with invasive candidiasis

“…Several factors that may increase BDG levels for reasons other than invasive fungal infection have been identified [12], including hemodialysis with cellulose membranes, thrombocyte infusion with leukocyte-removing filters, the administration of human blood products (immunoglobulins or albumins), the use of antibiotics such as amoxicillin-clavulanate or piperacillin-tazobactam [31,32], the presence of serious bacterial infections [12,33], the use of surgical gauzes containing glucan, and severe mucositis [11] and possibly enteral nutrition for their BDG content. Recent studies have also shown that BDG levels are not affected by the use of antibiotics, such as ampicillin-sulbactam and piperacillin-tazobactam [32,34] or the presence of Grampositive bacteremia (in hematology patients) [35,36]. colonization.…”

β- d -Glucan Screening for Detection of Invasive Fungal Disease in Children Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

“…There are a number of factors reported that may lead to false-positive results of the BDG assay, such as severe mucositis (19), the administration of albumin and immunoglobulins (20), thrombocyte infusion with leukocyte-removing filters, or the administration of antibiotics, such as amoxicillin-clavulanate or piperacillin-tazobactam (6). Although some authors argue that bacteremia is an improbable cause of a positive BDG assay (21), one recent study found a significant higher rate of false-positive BDG tests in bacteremic patients, independently of Gram-positive or Gram-negative bacteremia (6). Importantly, transient candidemia has been reported as a cause of persistent false-positive BDG levels (22), a True-positive (TP) and false-negative (FN) results refer to all BDG values assessed at the time of the potential onset of IFD (e.g., four, two, and zero weeks prior to the first pathological sign, such as blood culture results or biopsy, pathological imaging, or galactomannan positivity); all subsequent levels of BDG were considered a response control for therapy and were not included in the analysis.…”

Specificity Influences in (1→3)-β-d-Glucan-Supported Diagnosis of Invasive Fungal Disease

“…Another category of iatrogenic patient contamination, one that has had significant debate, is that of parenteral administration of potentially contaminated antibiotics. Multiple publications asserting the occurrence of patient false positives by this route as well as the opposite have been presented [ 67 , 68 , 69 ]. While this route of patient contamination is possible, the high level of dilution generated upon injection of relatively low volumes of antibiotic make this unlikely.…”