ABSTRACT
Fungal nail infection [onychomycosis] is a common disease in all communities consisting about 50 percent of nail disorders. Yeasts are one of the important causative agents of onychomycosis. Identification of the yeast species is important in the epidemiological and therapeutical point of views. The aim of the present study is the precise species identification of the pathogenic yeast isolated from fungal nail infections, using the DNA-based methods. The isolates were preliminary studied according to study of morphological characteristics. For species identification, the genomic DNA of each sample was extracted by boiling method and the ITS region of ribosomal DNA was amplified by polymerase chain reaction [PCR]. The amplified DNA was digested by the restriction enzyme MspI and each isolate was identified according to the electrophoretic patterns. A new enzymatic profile was used for final differentiation of Candida albicans and C. dubliniensis. A few of yeast isolates were identified by using ITS-sequensin. C. albicans with the prevalence of 45.6% was the most common isolate, followed by C. parapsilosis with 22.5% and C. tropicalis with 21.8%. The less common species were C. glabrata, C. krusei, C. kefyr, C. lusitaniae, C. guilliermondii and C. pulcherrima that consisted 2.72%, 2%, 1.36%, 0.68% and 0.68% of the isolates, respectively. No C. dubliniensis was found among C. albicans isolates. Two isolates [1.36%] were identified as Trichosporon spp. The most common group of the patients was in the age range of 40-70 years old and the majority [83.2%] of the patients were women with finger nail infections. Although C. albicans is still the most prevalent isolates of nail candidiasis, the increasing number of non-albicans species is notable. The study showed that for identification of some rare species, the routine phenotypical approaches are not efficient and application of the ITS-PCR-RFLP can improve the level of differentiation up to 98%. The remaining isolates can be identified by more expensive methods such as sequencing
ABSTRACT
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. 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 according to their macroscopic and microscopic morphological features and their physiological properties including tween assimilation test, catalase reaction and splitting of sculine. 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. 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