Skin Colonization by Malassezia in Neonates and Infants

Objective: To identify the timing, pattern, and determinants of colonization of neonates by Malassezia. Design: Prospective observational study. Setting: A neonatal medical and surgical unit consisting of 10 special care, 10 high-dependency, 10 intensive care, and 10 surgical cots. Participants: All neonates (≤ 28 days of age) or infants (> 28 days of age) admitted to the unit during the 20-week period from October 1995 to March 1996. Methods: All infants or neonates were swabbed on the day of admission and every third day thereafter and risk factors were collected for every day on the unit. Results: During the study period, 245 neonates and 42 infants were sampled for their entire duration of stay on the unit. Of these, 41 infants (97.6%) were colonized with Malassezia on admission to the unit and thereafter, as assessed by subsequent samples. Within the neonate population, 78 (31.8%) became colonized, but none were colonized immediately after birth. Univariate analysis showed that many factors appeared to be significantly associated with colonization in the neonates, including use of ventilation, presence of central venous catheters, use of parenteral nutrition, and use of antibacterial or antifungal drugs. However, when the data were analyzed by multivariate logistic regression to control for confounding variables, only gestational age and length of stay on the unit were found to be significantly associated with colonization. Conclusion: Colonization of infants is not as unusual as previously thought and many infants have established a cutaneous Malassezia commensal flora by the age of 3 to 6 months. Factors that predispose to colonization in neonates may not be the same as those that predispose to infection.