Characterization and scanning electron microscopy of Malassezia species isolated from central line tips of neonates on total parenteral nutrition

Abstract

Background: Aim of this study was to demonstrate colonization by Malassezia species in the central lines of very low birth weight newborns on total parental nutrition (TPN). We also aimed to perform scanning electron microscopy (SEM) of central line tip cut sections to document the quality of the biofilm, cell structure, micro-colony characteristics, and the presence of extracellular matrix. Methods: We collected central line tips of very low birth weight newborns (<1.5 kg) over a one-year period. We included a total of 63 samples, which were cultured on slants along with controls purchased from CBS Netherlands. We incubated the cultures at 32°C and observed them every two days for three weeks. Once growth occurred, we phenotypically identified the cultures and observed the central line tip cut sections with SEM. Results: Among the 63 central line tips, two (3.1%) were colonized by Malassezia. We observed a visible biofilm on the tips. We confirmed the phenotypic identification of the isolates as M. furfur and M. restricta by gene sequencing. Conclusions: Our study revealed Malassezia colonization in the central line used for total parenteral nutrition. Hence, it is important to have a high index of suspicion towards Malassezia catheter-related blood stream infection in newborns on TPN with a clinical picture of fever (in spite of antibiotic therapy), leukocytosis, thrombocytopenia with cardiac disease, and pulmonary infiltrates. The outbreak potential of Malassezia warrants preventive steps, and early identification and treatment.