Candida dubliniensis Sullivan et al., a new species in the human respiratory system

Abstract

Long-term observations of broadly defined mycological features of various human ontocoenoses show that the ontocoenosis of the resoiratory system is characterised by rapid changes of the dynamics and biodiversity of the fungi. The continuity of studies on the subject and a great biological diversification of the clinical material, collected mostly from individuals suffering from chronic diseases of the respiratory system and from oncological patients, contribute to the detection of many interesting and important species. In the last few years, the studies have been extended to include healthy individuals. Special attention is paid to the age and the place of residence of the subjects. The group analysed in this project comprised randomly chosen students from whom biological material was collected from primary infection routes. The material collected was treated in keeping with generally accepted recommendations for diagnostic mycological laboralories. Candida dubliniensis a species not recorded in Poland previously was found among the 7 fungi identified in the reconnaissance studies. The fungus is an opportunistic pathogen, strictly related to Candida albicans, however, different from it epidemiologically. Candida dubliniensis was isolated from the oral cavity and the throat. Its growth was poor or medium on Sabouraud agar; the colonies were creamy-coloured, soft and smooth. On Nickerson medium, it produced pseudomycelium with characteristic thick and inflated pseudohyphae on which grape-like blastoconidia, and big, darkly pigmented terminal chlamydosporcs, appearing characteristically between 1 and 3, formed. Chlamydospore formation under the inflated terminal cell is also characteristic of this species. The isolation of Candida dubliniensis from the respiratory system strictly corresponds to the studies by Dynowska (1993) on the blurring of physiological and ecological boundaries between trophic groups of potentially pathogenic fungi and corroborates her hypotheses on the continuous occurrence of new species in organ ontocoenoses.