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DDI - Dissertações de mestrado

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http://hdl.handle.net/10400.18/25

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Browsing DDI - Dissertações de mestrado by Author "Bandeira, Maria"

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  • Hospital acquired infections: Biofilm assembly and increased antibiotic resistance of microorganisms
    Publication . Bandeira, Maria; Martins, Raúl Daniel Carneiro Lavado; Jordão, Luísa
    [ENG] Healthcare-associated infections (HAI) are a public health threat. The etiological agents responsible for these infections are diverse and, in the case of bacteria, often resistant to antibiotics. Bacteria are able to assemble biofilm persisting in healthcare units, becoming more resistant to antibiotic and being responsible for HAIs onset and spread. Bacteria isolated from samples collected in hospitals fulfilling the criteria of HAI were used. The selected bacteria comprise classical (Klebsiella pneumoniae) and emergent agents of HAI (Nontuberculous mycobacteria: NTM). The bacterial ability to assemble biofilm on cell culture plates was evaluated by the microtiter plate test. The structural features of bacteria (planktonic and biofilms)were accessed using scanning electron microscopy (SEM). Biofilms assembled on the model surface(cell culture plate) and on abiotic surfaces present in healthcare units (e.g. silicon) were characterized. For K. pneumoniae strains the ability to assemble biofilms on biotic surfaces (HeLa cells) was also evaluated. The SEM analysis allowed the identification of differences between planktonic and sessile bacteria that can be related to increased virulence. The results showed that biofilm assembly depends on bacteria and abiotic surface. On biotic surfaces, the biofilm assembly is dependent on tropism relations between bacteria and the host. For NTM biofilm was possible to identify factors involved in biofilm assembly: sliding and membrane charges. In the case of K.pneumoniae this relation was not establish. Nevertheless, it was possible to establish a link between the ability to assemble biofilm and increased antibiotic resistance. Altogether these data revealed a relation between biofilm assembly,antibiotic resistance and spread of HAIs.
    2014-04Master thesis Restricted access Show more