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The human and animal pathogenic yeast genus Malassezia has received considerable attention in recent years from dermatologists, other clinicians, veterinarians and mycologists. Some points highlighted in this review include recent advances in the technological developments related to detection, identification, and classification of Malassezia species. The clinical association of Malassezia species with a number of mammalian dermatological diseases including dandruff, seborrhoeic dermatitis, pityriasis versicolor, psoriasis, folliculitis and otitis is also discussed.

An outbreak of nosocomial fungemia due to the unusual yeast, Pichia anomala occurred in the pediatric wards of our hospital over a period of 23 months (April 1996 to February 1998). A total of 379 neonates and children (4.2% admissions) were infected. The probable index case was admitted to the pediatric emergency ward, with subsequent transmission to the premature nursery, pediatric intensive care units, and other children wards. Carriage on the hands of health care personnel was likely to be responsible for dissemination of the fungus. The outbreak could only be controlled after a health education campaign to improve hand-washing practices was instituted and after nystatin-fluconazole prophylaxis to all premature neonates and high-risk infants was introduced. In a case-control study, we identified a lower gestational age, a very low birth weight (<1,500 g), and a longer duration of hospital stay as significant risk factors associated with P. anomala fungemia in premature neonates. We conducted a culture prevalence survey of 50 consecutive premature neonates and found that 28% were colonized with P. anomala at a skin or mucosal site on the date of delivery and that 20% of these neonates subsequently developed P. anomala fungemia. We performed multilocus enzyme electrophoresis on 40 P. anomala outbreak isolates (including patient and health care workers' hand isolates), and the results suggested that these isolates were identical. Our study highlights the importance of P. anomala as an emerging nosocomial fungal pathogen.Deep-seated fungal infections are important causes of morbidity and mortality in hospitalized patients (1, 2, 5, 13). Disseminated candidiasis is the most common nosocomial fungal infection, and Candida albicans has been reported to account for 50% to more than 70% cases of invasive candidiasis (2,5,6,8). However, recent reports have also suggested the emergence of infections caused by non-C. albicans candidas (3,14,21). In addition, less-common pathogenic yeasts (Malassezia, Trichosporon, Hansenula, and Rhodotorula spp.) have recently been reported, with increased frequency, as causes of nosocomial infections (7).Although a rare clinical isolate, the ascosporogenous yeast, Pichia anomala (formerly Hansenula anomala) has been implicated in causing fungemia in a neonatal intensive care unit (10), interstitial lung disease (19), endocarditis (12), and enteritis (9). In addition, there have been two reports of nosocomial outbreaks due to P. anomala: one in a Neonatal Intensive Care Unit in Liverpool, United Kingdom (10), and the other in an oncology hospital in Brazil (18). We describe here an outbreak of invasive P. anomala infection in the pediatric wards of our medical center that occurred during April 1996 to February 1998, with an attack rate of 4.2%. MATERIALS AND METHODSEpidemiologic investigation. The Nehru Hospital, affiliated with the Postgraduate Institute of Medical Education and Research, Chandigarh, India, is a 1,200-bed tertiary adult and pediatric referral center. The pediatric depa...

Seborrheic dermatitis (SD) is a common dermatological disorder that varies greatly in severity between individuals and with time. The etiology of this disease is poorly understood. Early investigators focused on the role of Malassezia (previously Pityrosporum) yeasts in the development of SD. Some researchers have hypothesized that there is an immunological component to SD and that this disease is caused by an altered immune response to Malassezia yeasts. However, other researchers view this condition as the result of hyperproliferation. Both antifungal and anti-inflammatory preparations have been used to treat SD effectively and safely. The wide range of antifungal formulations available (creams, shampoos, oral drugs) provides safe, effective and flexible treatment options for SD.

Malassezia yeasts are associated with several dermatological disorders. The conventional identification of Malassezia species by phenotypic methods is complicated and time-consuming, and the results based on culture methods are difficult to interpret. A comparative molecular approach based on the use of three molecular techniques, namely, amplified fragment length polymorphism (AFLP) analysis, sequencing of the internal transcribed spacer, and sequencing of the D1 and D2 domains of the large-subunit ribosomal DNA region, was applied for the identification of Malassezia species. All species could be correctly identified by means of these methods. The results of AFLP analysis and sequencing were in complete agreement with each other. However, some discrepancies were noted when the molecular methods were compared with the phenotypic method of identification. Specific genotypes were distinguished within a collection of Malassezia furfur isolates from Canadian sources. AFLP analysis revealed significant geographical differences between the North American and European M. furfur strains.The genus Malassezia has received considerable attention in recent years from dermatologists and other clinicians. This group of basidiomycetous yeasts, long known to be the causal agents of pityriasis (tinea) versicolor, is also increasingly being associated with the causation of folliculitis, papillomatosis, and invasive human infections, as well as potential immunogenic triggering of atopic dermatitis, seborrheic dermatitis, and dandruff (6,9,11,14,18,25,26,29). Malassezia species are listed among the new and emerging yeast pathogens (22,24).The genus Malassezia, until recently, was characterized on the basis of rRNA sequences as consisting of seven species, including the lipid-dependent species M. furfur, M. sympodialis, M. globosa, M. obtusa, M. restricta, and M. slooffiae and the lipophilic species M. pachydermatis (12, 13). Recently, two new species have been identified: M. dermatis (39), which was isolated from atopic dermatitis patients, and M. equi (unpublished), a species that was isolated from the skin of horses (32). The latter species has only tentatively been named and still awaits formal description; the present study deals only with the eight described species.Guillot et al. (17) introduced a physiological system based on lipid assimilation and other phenotypic characteristics for identifying the various Malassezia species. This phenotypic system has been used as the conventional method of identification, though in practice, the test results are not always easy to read. Therefore, several research groups have explored the use of molecular techniques, such as pulsed-field gel electrophoresis (3, 4, 36), randomly amplified polymorphic DNA analysis (1, 3), amplified fragment length polymorphism (AFLP) analysis (40), denaturing gradient gel electrophoresis (40), multilocus enzyme electrophoresis (30), sequencing analysis (37), restriction analysis of PCR amplicons of ribosomal sequences (8,15,16,20,28), and chitin synthase ...