Resposta adaptativa e efeitos das substâncias oxidantes - K2TeO3, H2O2 e paraquate - na produção de biofilme de amostras de Corynebacterium diphtheriae isolados de origens diversas

• Autor(a) principal: Teixeira, Aparecido Donizeti
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14404
• topic: Corynebacterium diphtheriae; ROS; Oxidative stress; Adaptive response; Biofilm; Corynebacterium diphtheriae; ERO; Estresse oxidativo; Resposta adaptativa; Biofilme; Espécies de oxigênio reativas; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA::MICROBIOLOGIA APLICADA::MICROBIOLOGIA MEDICA

Diphtheria is a disease it could be preventable by immunization although remains endemic in many regions of the world. Besides the classical cases of diphtheria, invasive diseases such as endocarditis, osteomyelitis, pneumonia and catheter-related infections, has affected adults partially immunized. The multifactorial nature of virulence factors that promote biofilm formation and survival in macrophages have been shown to Corynebacterium diphtheriae. However, few are the studies that investigated the influence of environmental conditions on the virulence of the pathogen. Since oxidants are capable of generating free radicals lead to oxidative stress and, consequently, may result in adaptive response and influence in biofilm formation and bacterial virulence, this study aimed to evaluate the effects of hydrogen peroxide (H2O2), paraquat and potassium tellurite (K2TeO3) in biological properties of strains of C. diphtheriae of different origins. The results show that the strains of C. diphtheriae showed levels of resistance K2TeO3, H2O2 and paraquat, but in varying intensities and independent production capacity of diphtheria toxin. Some samples, toxigenic or non-toxigenic, isolated respiratory tract demonstrated adaptive response to H2O2 passing thus expressing increased resistance after exposure prior to said oxidizing agent. C. diphtheriae seemed not display adaptive responses to K2TeO3 and paraquat. C. diphtheriae was able to produce biofilm on the surface of substrates abiotic hydrophilic in nature (glass) and hydrophobic (polystyrene) in the presence of oxidizing agents - K2TeO3, H2O2 and paraquat. The presence of oxidizing agents influence the biofilm formation of some samples.The paraquat inhibited the production of biofilm from all samples. The sample TR241 had inhibited the production of biofilm in the presence of oxidizing agents three analyzed. Moreover, the presence of H2O2 and K2TeO3 stimulated biofilm production of some samples. For all samples C. diphtheriae tested, independent of the origins and biotypes production capacity of diphtheria toxin, molecular assays indicated the presence of chromosomal gene sequences homologous to genes involved in tellurite resistance and protection against oxidative stress present in other bacterial species, genes encoding protein DIP 0906 (Ter) and protein DIP 1421 (oxyR). No correlation was observed susceptibility and adaptive response to oxidants with different biological activities bacterial: origin, isolation site, production of diphtheria toxin, sucrose metabolism and biofilm production. In conclusion, oxidative stress was able to influence virulence factors of C. diphtheriae, as the capacity of production of biofilm, which may be contributing to the pathogenesis of diphtheria classical as well as invasive disease caused by strains non-toxigenic.