Can Blood Culture Contaminaton Cloud Fungal Positivity?

Abstract

Objective: Blood culture (BC) is gold standard for diagnosis of fungemia. Contamination of BC is a major problem worldwide, since it may delay actual diagnosis. The aim of this study was to evaluate “contaminant” vials with a prolonged incubation (max 30 days) with antimicrobial supplemented media to observe any mycological growth. Materials and Methods: Routine BCs optained patients of XXX Hospital for a year period were included. Render BC System BC12-8 (Render Biotech Co. Ltd., Shenzhen, China) were used. Contaminated vials were reincubated and conventionally-inoculated weekly for four weeks total. In case of any growth, identifications were done by PhoenixTM 100 system (Becton Dickinson, MA, USA) with cornmeal tween 80 agar (RTA Laboratories, Kocaeli, Turkey). Antifungal susceptibility testing were applied with CLSI disk diffusion method. Results: 3.9% (235 sets and additional 138 vials) of total 6047 BC sets were contaminated. Only one vial from central venous catheter showed fungal growth within the first week of conventional inoculation (>8th day of total incubation). The isolate was identified as Candida guilliermondii complex and susceptible to caspofungin. Latter set of this patient were positive in the 3rd day of incubation. Conclusion: International guidelines recommend