Clinical significance of non‐Candida fungal blood isolation in patients undergoing high‐risk allogeneic hematopoietic stem cell transplantation (1993–2001)

Abstract

BACKGROUNDThe clinical relevance of mold isolated from blood cultures, even in severely immunosuppressed allogeneic hematopoietic stem cell transplantation (HSCT) recipients, remains uncertain. The authors hypothesized that isolation of non‐Candida fungi from blood cultures in patients undergoing high‐risk HSCT would have clinical significance.METHODSThe authors reviewed the records of 73 allogeneic HSCT recipients between January 1, 1993 and January 1, 2001 in whom fungal species were isolated from blood cultures.RESULTSFifty‐two episodes of non‐Candida fungemia occurred in 48 patients (66%) after a median of 10 days (range, 2–341) after transplantation. All 48 patients had indwelling intravascular catheters, and 23 patients (48%) had profound neutropenia. Thirty‐five of 48 patients had received partially matched, related donor stem cell grafts (19 patients had 3‐antigen‐mismatched grafts); 35 patients had undergone T‐cell depleted transplantation and 9 patients were receiving treatment for acute graft‐versus‐host disease. In 5 of 48 patients (10%), death was attributed to fungemia that occurred 8–11 days after the initial fungal blood culture was obtained; all 5 patients were age > 30 years. No deaths occurred in the younger age group (n = 22 patients; P = 0.05). In the 24 patients who did not receive systemic antifungal therapy, 4 deaths (17%) were attributed to infections with Penicillium (n = 2 patients), Epicoccum (n = 1 patient), or Penicillium plus Cladosporium species (n = 1 patient). Of the 24 patients who received amphotericin B, only 1 patient (4%) died as a result of a probable hematogenous Aspergillus species infection; this difference in outcome, however, was not significant (P = 0.2).CONCLUSIONSMost of the non‐Candida fungal blood culture isolates in recipients of high‐risk, mismatched donor transplantation were clinically nonsignificant. However, because these low‐virulence saprophytes occasionally may cause life‐threatening disease, a reevaluation of the existing diagnostic paradigm is needed so that clinically significant fungemia may be differentiated from pseudofungemia. Cancer 2004. © 2004 American Cancer Society.

High-dose caspofungin combination antifungal therapy in patients with hematologic malignancies and hematopoietic stem cell transplantation

“…Isolation of Aspergillus and Penicillium species in blood cultures alone in patients with no evidence of deep-tissue infection was regarded as pseudofungemia. 18 Isolation of Fusarium and Scedosporium species from sterile blood culture isolates obtained from separate body sites and/or more than 24 h apart even in the absence of known deep-tissue infection was also considered definite infection. [17][18][19][20] Disseminated fungal infection was defined as infection involving two noncontiguous body sites; the presence of fungemia was not required to establish a diagnosis of disseminated fungal infection.…”

“…18 Isolation of Fusarium and Scedosporium species from sterile blood culture isolates obtained from separate body sites and/or more than 24 h apart even in the absence of known deep-tissue infection was also considered definite infection. [17][18][19][20] Disseminated fungal infection was defined as infection involving two noncontiguous body sites; the presence of fungemia was not required to establish a diagnosis of disseminated fungal infection. [17][18][19][20] Combination antifungal therapy was defined as concomitant administration of two antifungal agents given for at least 7 days and started within 24 h of each other.…”

“…[17][18][19][20] Disseminated fungal infection was defined as infection involving two noncontiguous body sites; the presence of fungemia was not required to establish a diagnosis of disseminated fungal infection. [17][18][19][20] Combination antifungal therapy was defined as concomitant administration of two antifungal agents given for at least 7 days and started within 24 h of each other. CAP was given as a single 70-mg dose followed by 50 mg daily (SD) or a single 100-mg dose daily (high dose).…”

Low Utility of Pediatric Isolator Blood Culture System for Detection of Fungemia in Children: a 10-Year Review

“…Much less commonly isolated from automated systems are non-Candida fungi, including yeast-like fungi such as Geotrichum spp. and Trichosporon spp., or certain filamentous fungi such as Fusarium spp., Scedosporium spp., or Exophiala spp., which may represent up to 10% of all fungemias (7).…”

“…Determining the clinical significance of the isolation of a saprophytic filamentous fungus, such as Aspergillus or a zygomycete species, is important since these fungi can cause either severe infection or contamination of specimens and/or media (7,10). Furthermore, it is very uncommon to isolate Aspergillus spp.…”