Performance of fungal blood cultures by using the Isolator collection system: is it cost-effective?

Abstract

Enhanced recovery of fungal isolates from blood by using the Isolator system has been reported previously. We examined bacterial and fungal blood cultures during a 14-month period to determine if this enhanced recovery required a separate fungal culture and to determine the differential utility between a fungal blood culture and a routine bacterial culture. During this period, 84 of 5,196 (1.6%) fungal blood cultures and 170 of 25,702 (0.6%) bacterial blood cultures were positive for yeast or filamentous fungi. Thirty-seven positive fungal cultures, simultaneously collected, had correspondingly positive bacterial cultures. An additional 15 positive fungal cultures yielded isolates that had either been previously recovered from a bacterial culture or were recovered from a bacterial culture collected within 48 h. Of the 32 unpaired fungal cultures remaining, 5 were Candida albicans whose unique isolation was believed to be the result of specimen sampling variance rather than any enhanced recovery characteristics of fungal culture methods. Examination of patient data relating to the 27 remaining isolates (24 patient episodes) showed that only five fungal blood cultures (0.096% of all collected) had any impact on patient therapy decisions, and one of these was judged to be the cause of unnecessary therapy. Our data suggest that separate fungal cultures of blood are not cost-effective for those laboratories using the Isolator for routine blood cultures and furthermore may not be cost-effective for laboratories using automated broth systems that are comparable to the Isolator in recovery of fungi.

Potential Pathogens among Fungi Identified as Nonsporulating Molds from Blood Cultures

“…Despite method such as PCR may lead to the identification of the NSM, the significance of isolation of the NSM need to be confirmed. Rate of isolation of filamentous molds in commercial blood culture systems that represented true fungemia has been very low and involved fungi mostly in the genera of Fusarium and Aspergillus [12]. Molds other than Fusarium and Aspergillus spp.…”

Performance of Five Agar Media for Recovery of Fungi from Isolator Blood Cultures

“…The clinical laboratorian must allocate resources judiciously and establish diagnoses in the most cost-effective manner, without compromising the quality of the tests performed. The Isolator system is a proven method of diagnosing fungemia, but its cost-effectiveness has been questioned (19). Our study suggests that, with the exception of H. capsulatum, clinically relevant fungi that cause bloodstream infections will be adequately recovered on CA within 3 days of incubation using the Isolator system.…”

ECIL-3 classical diagnostic procedures for the diagnosis of invasive fungal diseases in patients with leukaemia

“…A lysis centrifugation blood culture technique has been explored in order to improve the detection of fungi, but is time-consuming, more prone to contamination and does not appear more sensitive than current automated blood culture systems in recent studies for the majority of invasive fungi. 53,96 The diagnosis of catheter-related fungaemia is established when the same organism has been detected both in blood cultures and in catheter cultures. 65 For bacteria, study results suggest that the differential time to positivity of catheter blood vs peripheral blood culture taken simultaneously might be an important diagnostic indicator, but this has not been validated for candidaemia.…”