Comparative performance of BD-BACTEC® Mycosis IC/F versus standard aerobic and anaerobic bottles in simulated fungemia and mixed bloodstream infections

Candidemia is a leading cause of bloodstream infection-associated morbidity and mortality, particularly among critically ill patients. Time to detection (TTD) is crucial, but standard blood culture systems often fail to recover yeasts, filamentous fungi, or identify fungi in polymicrobial infections. The BD BACTEC™ Mycosis IC/F bottle was designed to improve fungal detection, yet comparative performance data are limited. This study aimed to compare the detection rate and TTD of BD BACTEC™ Mycosis IC/F with those of standard BD BACTEC™ Plus Aerobic/F and BD BACTEC™ Plus Anaerobic/F bottles using simulated models of fungemia and mixed fungal-bacterial bloodstream infections. This in vitro study included 333 blood culture bottles inoculated with Candida spp., Cryptococcus neoformans, Trichosporon asahii, Fusarium spp., and Aspergillus terreus, as well as bottles simulating coinfections with multidrug-resistant Gram-negative bacteria. All bottles were incubated in the BD BACTEC™ FX system for up to 14 days. BD BACTEC™ Mycosis IC/F achieved 100% detection for Candida spp., outperforming BD BACTEC™ Plus Anaerobic/F (58.5%) and matching BD BACTEC™ Plus Aerobic/F. It showed shorter TTDs for Nakaseomyces glabratus, Candidozyma haemuli, Meyerozyma guilliermondii, and molds. In mixed infections, BD BACTEC™ Mycosis IC/F provided better fungal recovery, especially at low inocula, although recovery was impaired when coinoculated with carbapenemase-producing bacteria. In conclusion, BD BACTEC™ Mycosis IC/F improved fungal detection and recovery compared with standard bottles, including in polymicrobial settings. Its use may enhance diagnostic yield in suspected fungemia, though cost and limited availability may limit widespread adoption.