Objective: Lipophilic Malassezia species may induce catheter-associated sepsis in newborns and immunocompromised patients receiving parenteral lipids. Therefore, we tested whether M. furfur and six other Malassezia species can use commercially available infusions as a lipid source.
Design: Prospective in vitro study.
Setting: Research laboratory in a university hospital.
Measurements and main results: With the exception of M. restricta, all Malassezia species grow on lipid infusions. There are no substantial differences among the different brands. The most rapid growth is shown by M. furfur, which grows better on agar containing a 20% rather than a 10% lipid infusion. Growth of M. furdur and M. sympodialis can be reduced by infusions containing medium-chain triglycerides. Incubated in triglycerides, M. furfur is strongly suppressed by 50% medium-chain triglycerides and M. sympodialis by 8% medium-chain triglycerides. When medium-chain free fatty acids are added to triglycerides, both species can be suppressed by about 1% free fatty acids.
Conclusion: Medium-chain triglycerides and medium-chain free fatty acids are toxic for Malassezia species. Commercially available infusions containing medium-chain triglycerides might be used to prevent systemic Malassezia infections.