Potentially pathogenic yeasts from soil of children’s recreational areas in the city of Łódź (Poland)

Objectives: Yeasts may become potential human and animal pathogens, particularly for individuals with a depressed immune system. Their presence in the environment, especially in soil, may favour their spread into human ontocenoses. Materials and Methods: Eighty-four soil samples obtained from 21 children's recreational sites in Łódź in autumn 2010 and spring 2011 were evaluated. The yeasts were isolated by classical microbiological methods and identified on the basis of morphological and biochemical features. Results: The fungi were found in 73.8% and in 69.0% of the examined samples collected in autumn and spring, respectively. Among 97 isolates of yeasts, the species potentially pathogenic to humans and animals were Candida colliculosa, C. guilliermondii, C. humicola, C. inconspicua, C. lambica, C. lusitaniae, C. pelliculosa, C. tropicalis, Cryptococcus albidus, C. laurentii, C. neoformans, C. terreus, Kloeckera japonica, Geotrichum candidum, G. penicillatum, Rhodotorula mucilaginosa, R. glutinis, Saccharomyces cerevisiae, Sporobolomyces salmonicolor and Trichosporon cutaneum. The most frequently isolated fungi included the genus Cryptococcus (38 isolates) and two species: Rhodotorula glutinis (15), Trichosporon cutaneum (14). C. neoformans, an etiological factor of cryptococcal meningitis, was present in the sandpits of 3 kindergartens. The Candida species were identified from park playgrounds and school sports fields mainly in autumn 2010 (14 isolates), in spring 2011 - only 1 isolate. The concentration of fungal species in particular samples varied considerably, but in the majority of samples, fungi were present at concentration of up to 1×102 CFU/1 g of soil. Conclusions: Yeasts were present in the soil of parks, schools and kindergarten recreational areas; the fact may pose a health risk to humans, especially to children, and this type of biological pollution should be regarded as a potential public health concern

Some aspects of multifocal and disseminated mycosis.

Some aspects of multifocal and disseminated mycosis are discussed. Special attention is devoted to factors, which play a significant role in the development of fungal infections. Host criteria and microbiological as well as a clinical criteria are discussed. A special attention is given to nosocomial invasions and post-transplantation mycosis

The immune response to fungal infections

In mycoses congenital – nonspecific innate as well as acquired immunity (involving neutrophiles, monocytes, macrophages, dendritic cells and lymphocytes) both play important roles in host defence. Th1 lymphocytes release cytokines (IL-2, IL-12, IFNg) and stimulate cytotoxic cells and neutrophiles to destroy fungal cells. Th2 lymphocytes, on the other hand, suppress cellular immunity by releasing the cytokines IL-4, IL-6 and IL-10 which counter regulate the secretion of IL-2, IL-12, IFNg and depress the activity of macrophages. Cellular mechanisms play essential roles in host responses to fungal infections. Dysfunction of T lymphocytes and a reduction in their number are typically observed in patients with mycotic diseases. There occurs a reduction of both T lymphocyte populations and the T-helper to T-suppressor cell number ratio, and these are of critical importance in explaining the diminished IgA production and enhanced adhesion of fungal cells to the surface of host cells as well as in facilitating the intrusion of fungi throughout the skin and mucous membranes. The specific immunological reaction, associated with the synthesis of antibodies against fungal cell wall or cytoplasmic antigens, is of little significance in protective immunity, but nevertheless has a rather important role to play in diagnosis as well as in supporting phagocytosis by inhibition of fungal cell adherence. In patients with mycoses, typically low blood serum level of the immunoglobulin class G and A and low sIgA in saliva are observed. A detailed understanding the nature and function of the immune system in mycoses is necessary to enable improvements in pharmacotherapy with antifungal antibiotics and chemotherapeutics, as well as to treatments based on immunotherapy and vaccination

Biofilm caused by fungi - structure, quorum sensing, morphogenetic changes, resistance to drugs

Formation of fungal biofilms in patients with implanted biomedical prosthesis constitutes very serious clinical problems. The biofilm can lead to dysfunction of implanted material and can be a reservoir for chronic and systemic infections. Numerous investigations demonstrated differences in quantity and structure of biofilms that had been formed by various species of fungi belonged to Candida genus. Stages of biofilm formations had been examined carefully in in vitro conditions. Biofilm formation begin with adhesion of fungi to the surface, microcolonies are formed subsequently. At the end of the process, extracellular material is excreted, and its formula, that is various in different fungi Candida species, contribute to its resistance to antifungal drugs. Farnesol and tyrosol are two quorum-sensing molecules. They are acting inversely, regulating formation of „germ tubes” and influencing morphogenetic conversion between yeast and filamentous forms, which plays a very important role in pathogenicity and formation of biofilm. Drug resistance of fungi from Candida has been shown to create a very important clinical problem. Many experiments in vitro confirm significantly lower activity of antifungal drugs toward Candida biofilm than toward Candida, in the form of planctonic cells. Surprisingly, some non-steroidal anti-inflammatory drugs can inhibit biofilm formation