Abstract
Malassezia furfur, an etiological agent of catheter-associated fungemia, requires long-chain fatty acids for in vitro growth. We examined the applicability of rDNA sequence analysis, autoaggregation testing in liquid culture, utilization of parenteral lipid emulsions, and phospholipase activity for discrimination of catheter-associated M. furfur strains. The rDNA sequence types of catheter-associated M. furfur strains were distinct from those of other isolates. All M. furfur isolates recovered from blood culture bottles and the tips of catheters from patients receiving fat emulsion therapy were type I-3. Only M. furfur isolate GIFU 01 from a blood culture bottle showed no autoaggregation in liquid culture. All strains of M. furfur examined grew well on Sabouraud's dextrose agar supplemented with Intralipid lipid emulsion as compared to individual Tweens (20, 40, 60, 80) and Cremophor EL. A high percentage of type I-3 M. furfur strains (80.0%) showed very high phospholipase activity compared to type I-1 and I-4 strains obtained from healthy skin of the same subjects or healthy control subjects (20.0% and 0.0%, respectively). The blood culture bottle isolate GIFU 01 showed very high lipolytic enzymes activity for Intralipid but no phospholipase activity. These results suggest that particular factors, such as non-autoaggregation and very high lipolytic enzyme activity for parenteral lipid emulsions, play important roles in the growth and pathogenicity of Malassezia-related sepsis.
Acknowledgements
This work was supported in part by Health and Labour Sciences Research Grants for Research on Emerging and Re-emerging Infectious Diseases from the Ministry of Health, Labor, and Welfare of Japan (K.M.).
Declaration of interest: Dr K. Makimura has received research grants from the following companies: Hisamitsu Pharmaceutical Co., Seikagaku Biobusiness Co., Kaken Pharmaceutical Co., Dai-nippon Sumitomo Pharmaceutical Co., Galderma Co., and Japan Space Forum. This study was financially supported by His amitsu Pharmaceutical Co. Inc.in part. The authors alone are responsible for the content and writing of the paper and declare no conflicts of interest.
This paper was first published online on Early Online on 27 May 2011.