Ocorrência de fungos em sistema de distribuição de água e sua correlação com isolados do ar em uma unidade pediátrica de transplante de células tronco hematopoiéticas

• Ano de defesa: 2009
• Autor(a) principal: Rocha, Sabrina Mesquita [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Aspergillus; Fungos na água de sistema hidráulico hospitalar; Fusarium; Genotipagem; Fungos no ar de ambiente hospitalar; Fungos
• Link de acesso: http://repositorio.unifesp.br/handle/11600/9881

Introduction: The expansion of the immunocompromised patient population in the last two decades has led to an increased incidence of invasive fungal infections, especially by filamentous fungi. Although external sources of contamination are well known related to airconditioning in units of risk, recent investigations have shown that water distribution systems or linked to tanks of hospitals have been also identified as an important source of infection when it is colonized by pathogenic fungi. Objectives: Quantify and identify samples of fungi isolated from water and air of a unit of HSCT, and evaluate them by using molecular techniques looking for their genetic relationship among strains of A. fumigatus, A. flavus and F. solani. Material and Methods: The current study was performed in a unit of HSCT, collecting samples monthly over 12-month period. Air samples were recovered from outdoor air, bathrooms, and rooms in hospital unit, the air sample was collected with six-faced Andersen collector, with Petri dishes containing Sabouraud-dextrose agar. All water samples were collected in sterile polystyrene bottles and passed through sterile 0.45um filters using a filtration apparatus. Using sterile forceps, the filters were place directly on Sabouraud-dextrose agar plates. The phenotypic identification was made using keys for identification of Hoog (2000). In the genotypic analysis, the isolates of A. fumigatus, A. flavus and F. solani were typing using oligonucleotide and microsatellite minisatellite. Results: A total of 164 samples of water where collected. We observed higher amount of conidia in the months corresponding to the autumn and summer. The average conidia were 6.07 CFU / l. The most prevalent genera were Paecilomyces, Penicillium and Cladosporium. Fusarium was more frequent in the water of the unit. The unique parameter correlated to the increasing isolation of fungi was the water temperature. In the microbiological analysis of air from the hospital unit, a total of 264 samples were collected recovering larger quantities of conidia during the fall. The individual average of conidia was 11.09 CFU/m3. The most prevalent genera were Cladosporium and Penicillium. The genus Aspergillus was isolated in the air mostly indoor. In the molecular analysis, it was observed poor similarity among F. solani strains from air and water, however, we reported that two isolates remained in the hydraulic system of the unit for a period over 30 days. Two samples of air, showed 2 distinct environment strains of A. fumigatus showing high similarity through molecular analysis. In our molecular analysis, conflicting profiles of A. flavus strains were obtained with different oligonucleotide, it was not possible to establish any direct relationship between samples of air and water. Conclusions: environmental surveillance in the units of risk is the highest importance not only applying to outbreaks, as well as to evaluate potential sources of nosocomial infection. Pathogenic fungi to humans can be often isolated, and persist in the water for months in the hydraulic system as a reservoir of infection. We did not identified genetic relationship among samples from air and water, propagules of A. fumigatus, A. flavus and F. solani.