Background and aim: Malassezia yeasts are normal flora of humans and warm-blooded animals. These lipophilic yeasts are associated with skin diseases in neonates such as pityriasis versicolor, neonatal postulitis and seborrheic or atopic dermatitis. Moreover in the recent years, these yeasts are increasingly isolated form fatal catheter-related fungemia in premature neonates. Concerning the role of Malassezia species in neonatal diseases and variation in their pathogenesis and sensitivity to antifungal drugs, we investigated the distribution of Malassezia species and related predisposing factors in neonates.
Materials and Methods: 261 skin samples from scalp, chest and ear were collected from neonates in both Children Medical Center and Vali-Asr Hospitals using cellotape method and sterile wet swab. All samples were also inoculated in plates containing Leeming-Notman medium and Malassezia colonies were then sub-cultured on modified-Dixon and SCC media. Malassezia species were identified accoding to their macroscopic and microscopic morphological features and their physiological properties including tween assimilation test, catalase reaction and splitting of sculine.
Results: In this study 36% of samples were collected from Vali-Asr Hospital and the rest from Children Medical Center. The average age of the examined individuals was 11.7 days. 58.7% of neonates were boys and 41.3% were girls. Based on culture results, 68.9% of examined neonates had Malassezia flora. Besides, significant differences in frequency of isolated Malassezia were not seen between either two examined hospitals nor NICU and neonatal wards. M. furfur was the most common isolated species followed in frequency by M. globosa. In addition, M. obtusa and M. slooffia were recovered only once from trunk and head samples, respectively.
Conclusion: In contrast to Malassezia flora in adults which is M.globosa, we isolated M. furfur as the dominant flora in neonates. This high prevalence of colonization may put hospitalized neonates in great danger of nosocomial Malassezia infections. Considering high mortality of Malassezia fungemia in neonates, skin should be cleaned effectively from Malassezia flora prior to administration of intra venous lipid or catheters.