The genus Malassezia has been revised using morphology, ultrastructure, physiology and molecular biology. As a result the genus has been enlarged to include seven species comprising the three former taxa M. furfur, M. pachydermatis and M. sympodialis, and four new taxa M. globosa, M. obtusa, M. restricta and M. slooffiae. The descriptions of all the species include morphology of the colonies and of the cells, together with ultrastructural details. The physiological properties studied were the presence of catalase, the tolerance of 37 degrees C and the ability to utilize certain concentrations of Tween 20, 40, 60 and 80 as a source of lipid in a simple medium. Information is given for each of the taxa on mole% GC and also the rRNA sequence from the comparison previously described for the genus.

In this outbreak, it is likely that M. pachydermatis was introduced into the intensive care nursery on health care workers' hands after being colonized from pet dogs at home. The organism persisted in the nursery through patient-to-patient transmission.

Recent observations on tinea capitis cases in London suggest that there has been a change in the pattern of infection with a recent and significant rise in the incidence of infections due to anthropophilic fungi. The purpose of this study was to investigate the prevalence and identity of tinea capitis in schools in south-east London and factors which might affect the spread of infection. This was achieved by carrying out a survey of all children, with parental consent for scalp examination, in 14 nursery, infant or junior schools in Lambeth. In addition, the accuracy of clinical diagnosis was compared with mycological findings. There were 1057 children from 4 to 14 years of age in the study. The infection rate in different schools ranged from 0 to 12% with a mean of 2.5%. A further 4.9% of children were scalp carriers of dermatophytes (range in classes 0-47%). A striking feature was that all infections were caused by anthropophilic fungi, mainly Trichophyton tonsurans or Microsporum rivalieri, and there was a correlation between the presence of two or more carriers within a class and the infection in the other children. There was a poor correlation between ability of trained observers to predict infection on clinical grounds and mycological results. This investigation shows variable but significant levels of scalp ringworm in schools and that the dominant organisms are anthropophilic. It provides support for the observation that there has been a shift in the pattern of tinea capitis in London and, possibly, other U.K. centres, with a trend towards more infections transmissible among children, with T, tonsurans being the commonest organism. The implications for control, which involve screening in schools, where appropriate, and guidance to general practitioners on treatment, are discussed.

A survey of tinea capitis conducted under the auspices of the European Confederation of Medical Mycology showed that laboratories contributing to a voluntary scheme for reporting have recently been seeing a different pattern of scalp ringworm. The survey was conducted among 92 medical mycology laboratories across 19 European countries by postal questionnaire comparing the years 1987 with 1997. The survey shows an overall increase in the numbers of cases caused by anthropophilic infections, which, in 1997, were the dominant causes of scalp infection; the greatest increase was seen in laboratories covering urban populations and in African Caribbean children living in Europe. While the commonest infection remains Microsporum canis, the largest overall increase has been in Trichophyton tonsurans, which in 1997 was the second commonest cause of infection overall and the commonest in urban populations. The pattern of change is not uniform in Europe and while some cities have reported large increases in T. tonsurans others, e.g. in France, have seen more cases of infection due to T. soudanense and M. audouinii. While these figures do not necessarily reflect changes in the underlying prevalence of infection, the trends are important to recognize as the control measures for anthropophilic tinea capitis differ from those used in zoophilic infections. In particular there is a need for an increased level of surveillance and more advice on control given to primary care physicians, dermatologists and school health authorities.

Overall, the study showed that 4 weeks of treatment with oral terbinafine has similar efficacy to 8 weeks of treatment with griseofulvin for the management of tinea capitis in children.