Anti-fungal potential of ozone against some dermatophytes

ABSTRACT Dermatophytes are classified in three genera, Epidermophyton, Microsporum and Trichophyton. They have the capacity to invade keratinized tissue to produce a cutaneous infection known as dermatophytoses. This investigation was performed to study the effect of gaseous ozone and ozonized oil on three specific properties of six different dermatophytes. These properties included sporulation, mycelia leakage of sugar and nutrients and the activity of their hydrolytic enzymes. Generally, ozonized oil was found to be more efficacious than gaseous ozone. Microsporum gypseum and Microsporum canis were the most susceptible, while Trichophyton interdigitale and T. mentagrophytes were relatively resistant. The study revealed a steady decline in spore production of M. gypseum and M. canis on application of ozonated oil. An increase in leakage of electrolytes and sugar was noticed after treatment with ozonized oil in the case of M. gypseum, M. canis, T. interdigitale, T. mentagrophytes and T. rubrum. The results also revealed loss in urease, amylase, alkaline phosphatase, lipase and keratinase enzyme producing capacity of the investigated fungi.

Dermatófitos: interação patógeno-hospedeiro e resistência a antifúngicos / Dermatophytes: host-pathogen interaction and antifungal resistance

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.

Dermatofitoses humanas no interior do Rio Grande do Sul no periodo 1988-1992 / Human dermatophytoses in Rio Grande do Sul (Brazil): in 1988 - 1992 period

O espectro dos dermatofitos na regiao central do Rio Grande do Sul demonstrou importante variacao na frequencia das especies no periodo 1998-1992. As especies antropofilicas Trichophyton rubrum, T. mentagrophytes var. interdigital e Epidermophyton floccosum diminuiram em frequencia, enquanto as especies zoofilicas Microsporum canis e T. mentagrophytes var. mentagrophytes apresentaram sensivel aumento. Sao comentadas as alteracoes na relacao perasita/hospedeiro em funcao das alteracoes na morfologia dos agentes e a dificuldade do isolamento destes agentes em cultivo.