Análise de aspectos da virulência e resistência à antifúngicos de isolados clínicos e ambientais de Candida albicans

Abstract

The incidence of fungal infections has increased in recent decades. Fungal infections mainly affect immunosuppressed individuals and the few therapeutic options available on the market make treatment difficult, especially with the emergence of Candida spp isolates. resistant to one or more classes of antifungals. Besides being etiological agents of infections, microorganisms of the Candida genus can be isolated in different environments. C. albicans is an example of a species that can be found living as a commensal in the human body, as an etiologic agent of infections, and in nature. Knowing the characteristics of environmental isolates of these microorganisms is extremely important, especially if they show some sign of virulence and/or resistance, placing them as potential human pathogens. Considering these issues, the work aims to analyze aspects of virulence and resistance of environmental and clinical C. albicans isolates, seeking to better understand how these variables are expressed in nature, and finally to make a comparison with what is found in the clinical environment. Thermotolerance at different temperatures, adhesion in oral epithelial cells, production of hydrolytic enzymes, biofilm formation, virulence in an invertebrate model and susceptibility to fluconazole, itraconazole and amphotericin B were the factors analyzed in clinical isolates, anthropized and non-anthropic environmental in the present work. The environmental isolates, mainly those isolated from places with anthropogenic influence, presented results of the analyzed variables similar to those obtained with the clinical isolates. Most of the evaluated isolates grew up to 45°C. In the morphogenesis tests, the isolates, in general, showed greater filamentation in the SPIDER medium. Most environmental and clinical isolates were producers of the phospholipase enzyme and just over 50% of them were able to produce the proteinase enzyme. All isolates, clinical and environmental, were biofilm producers. Antifungal resistance was variable in the groups evaluated, with clinical isolates and environmental isolates with high anthropogenic influence showing a greater number of resistant isolates. Virulence tests in invertebrate models showed that most isolates, both clinical and environmental, are lethal to more than 50% of the animals. These results show that environmental isolates have characteristics that qualify them as opportunistic pathogens. Our results also support that the environments in which these isolates were obtained may be an alternative source of contact with these microorganisms whose pathogenic potential can lead to the emergence of resistance and virulence factors with a direct influence on clinical treatment.