RESUMO
Abstract Passeriformes and Psittaciformes birds and pigeons (Columba livia) are known to be reservoirs of microorganisms, and their stool allows fungi development. Since accumulated avian excreta can interfere with public health, this study aimed to perform a molecular screening of medically important Candida species in pigeon droppings in public places and birds raised in captivity. Excreta collected from captive birds (3 residences) and pigeons (4 districts) were inoculated on Sabouraud dextrose agar with chloramphenicol for Gram staining and subculture on Hicrome® Candida. Three DNA extraction methods were performed for comparison (commercial kit, in-house and by boiling) and PCR to screen 6 clinically important Candida species among the isolates. The correlation between phenotypic and molecular methods was calculated by kappa/K. Only 6 C. parapsilosis (20%) were identified from captive birds' feces among 30 isolates (80% not identified), while pigeons' feces harbored a greater diversity, with the 6 pathogenic species confirmed among 41 isolates: C. albicans (31.70%/13), C. krusei (14.63%/6), C. tropicalis (14.63%/6), C. parapsilosis (17.10%/7), C. glabrata (14.63%/6) and C. guilliermondii (7.31%/3); 100% correlation between tested methods (K = 1) for the first 3 species. Boiling DNA extraction method was fast and efficient to obtain viable DNA from Candida spp. for PCR. Our results indicate that pigeon droppings harbor more potentially pathogenic species than birds in residential captivity, which probably have non-albicans Candida less frequently isolated in infectious processes. The greater availability of nutrients may have contributed to a diversity of Candida spp. in feces from public environments.
RESUMO
As micoses cutâneas estão entre as infecções mais comuns em humanos e se tornaram um importante problema de saúde pública, principalmente por causarem infecções invasivas em pacientes imunodeprimidos. Durante a infecção, a interação dermatófito-hospedeiro desencadeia adaptações metabólicas específicas que permitem aos patógenos aderirem e penetrarem no tecido, remodelando seu metabolismo para captar nutrientes e superar os mecanismos de defesa do hospedeiro. Esse remodelamento metabólico e a inter-relação entre metabolismo, morfogênese e resposta ao estresse são importantes fatores que estão sendo intensamente avaliados em diversos patógenos. As células do hospedeiro também respondem aos estímulos do patógeno, ativando vias de sinalização intracelular que culminam no desencadeamento de uma resposta imune contra o agente infeccioso. O entendimento molecular dessas respostas metabólicas pode ajudar no estabelecimento de novas estratégias terapêuticas. Nesta revisão, são abordados diferentes aspectos da biologia dos dermatófitos, com ênfase na interação dermatófito-hospedeiro e nos mecanismos de resistência a antifúngicos.
Cutaneous mycoses are among the most common infections in humans and have become an important public health issue because they cause invasive infections in immunocompromised patients. During the infectious process, dermatophyte-host interactions trigger specific metabolic adaptations that allow the pathogen to adhere to and penetrate the host tissue, scavenge nutrients, and overcome the host defense mechanisms. This metabolic shift and the interplay between metabolism, morphogenesis and stress response are important factors that have been extensively studied in several pathogens. Host cells also respond to the pathogen stimuli by activating intracellular signaling pathways that trigger the immune response against the infectious agent. The comprehension of the molecular aspects of these responses may help to establish new therapeutical strategies. In this review, different aspects of the biology of dermatophytes are addressed, with emphasis on the dermatophyte-host interaction and the mechanisms of antifungal resistance.