K3-EDTA differentially inhibits the growth of Candida strains according to their azole resistance status.

The diagnosis of the life-threatening invasive Candida infections is mainly established using culture of specimens that might be collected on different devices including ethylene diamine tetraacetic acid (EDTA)-coated tubes. Despite the knowledge that EDTA inhibits bacterial cultures, and its use to treat oral fungal infections, its impact on Candida cultures has not been completely assessed. This study aimed at assessing it on azole-resistant and azole-susceptible strains. Clinical and American Type Culture Collection (ATCC) strains for Candida albicans (CA), C. glabrata (CGS), C. krusei (CK), azole-susceptible and azole-resistant strains of C. glabrata (CGS and CGR), C. lipolytica (CL), and C. inconspicua (CI) were characterized using MALDI-TOF MS and susceptibility testing and then incubated (1) with serial dilutions of tripotassic EDTA (0%-500% of the concentration in a sample tube) for 2 hours before plating onto ChromID Can2 agar; (2) for 0, 2, 4, 6, 7, or 8 hours at EDTA concentrations at 20% and 33% before seeding; and (3) with sodium citrate or lithium heparinate instead of EDTA for 2 hours before plating. After 48 hours at 35°C, colony-forming units were automatically quantified. An inhibitory effect of EDTA was observed, at different concentrations, for CA (20%), CGS (100%), and CGR (500%) (P < .05), but none was observed for CL, CI, and CK. The effect increased with incubation duration, at a faster rate for azole-susceptible strains. K3-EDTA inhibits Candida growth and EDTA-coated tubes should not be used for mycological culture-based analyses. The correlation between EDTA inhibition and Candida azole-resistance offers perspectives for the development of selective agar and new antifungal strategies.

Flagging performance of Sysmex XN-10 haematology analyser for malaria detection.

AIM: The aim was to assess the flagging performance of Sysmex XN-10 haematology analyser for malaria detection through the parasitic red blood cell ('pRBC') alarm. METHODS: We retrospectively studied 584 blood samples performed on the Sysmex XN-10 analyser that were tested for malaria. Sensitivity, specificity, positive and negative predictive values, and prevalence were established for the pRBC alarm. RESULTS: Sensitivity, specificity, and positive and negative predictive values for the pRBC flag were 7.8%, 100%, 100% and 87.7%, respectively. The prevalence of pRBC flag of 0.026% in the overall population was significantly different from the prevalence of 1.027% in the population tested for malaria. CONCLUSIONS: Considering the excellent specificity and the low prevalence of the flag in the overall population, we suggest, in case of the presence of pRBC flag, the implementation of a rapid review of the blood smear looking for Plasmodium, mostly if the patient had fever and had not been tested for malaria.