Direct Blood Culturing of Candida spp. on Solid Medium by a Rapid Enrichment Method with Magnetic Beads Coated with Recombinant Human Mannan-Binding Lectin.

ABSTRACT

A rapid and accurate method to identify the species and antibiotic resistance of Candida spp. in blood is vital to increase the survival rates of patients with bloodstream infections. However, the extremely low levels of Candida spp. in blood make rapid diagnosis by standard blood culture difficult. In this study, we constructed a direct blood culturing method (i.e., the M1 method) by a rapid enrichment method with magnetic beads coated with a recombined human mannan-binding lectin (rhMBL; i.e., M1 protein), which demonstrated much higher Candida sp.-binding capacity than that of full-length MBL expressed in vitro (i.e., M2). With the M1 method, individual colonies were obtained before the standard blood culture method for each species of Candida spp. tested at <1 CFU/ml (an average of 29 h earlier). Additionally, the clinical sensitivity of the M1 method was 90.5% compared with that of the standard blood culture method when detecting frozen plasma from patients. More significantly, the turnaround time of the M1 method for blood culture could be reduced by approximately 37 to 43 h compared with that of the standard blood culture method in clinical sample identification.