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Advisor(s)
Abstract(s)
A resistência aos antimicrobianos é uma das causas de centenas de mortes todos os anos, no mundo. As estirpes de Staphylococcus aureus resistentes à meticilina (MRSA) são patógenos nosocomiais sérios, sendo, portanto, um desafio encontrar um tratamento eficaz. O objetivo principal deste estudo foi caracterizar isolados de Staphylococcus (coagulase positiva – SCP e coagulase negativa – SCN), com origem em alimentos comercializados nas ruas em Moçambique, relativamente à sua capacidade de formação de biofilme e suscetibilidade à meticilina. Foram utilizadas três superfícies diferentes (aço inoxidável, vidro e polistireno). Todas as estirpes apresentaram capacidade de formação de biofilme, sendo o poliestireno a superfície onde o biofilme apresentou um número significativamente maior de células viáveis (UFC/cm2). Relativamente ao valor de MIC da meticilina, 56,7% dos isolados apresentaram valores inferiores a 4 μg/ml, podendo ser considerados suscetíveis à meticilina. Os mais suscetíveis pertenceram à espécie S. warini e os mais resistentes a S. aureus e a S. saprophyticus. As espécies S. pasteuri e S. saprophyticus foram as espécies que apresentaram maior produtividade de biofilme (cerca de 8 log UFC/cm2. Relativamente à avaliação da suscetibilidade do biofilme à meticilina, constatou-se uma elevada resistência em todas as doses testadas (concentração máxima 32 g/ml). Não foi detetada associação entre a capacidade de formação de biofilme e a resistência à meticilina (correlação entre a formação de biofilme e o MIC foi de -0,331, e entre a formação de biofilme e o MBC foi de -0,329). A presença destes isolados de Staphylococcus em alimentos pode representar uma ameaça para a saúde pública. Reforça-se, assim, com este trabalho a necessidade de implementação de boas práticas de produção e comercialização dos alimentos vendidos nas ruas, o que passa pela melhoria da higiene dos produtores e do ambiente de produção.
Antibiotic resistance is one of the causes of hundreds of deaths every year around the world. Methicillin-resistant Staphylococcus aureus (MRSA) strains are serious nosocomial pathogens, making it a challenge to find effective treatment. The main objective of this study was to characterize isolates of Staphylococcus (coagulase-positive - SCP and coagulase-negative - SCN) from food sold on the streets in Mozambique, with respect to their biofilm formation capacity and susceptibility to methicillin. Three different surfaces (stainless steel, glass, and polystyrene) were used. All strains showed biofilm formation capacity, with polystyrene being the surface where the biofilm had a significantly higher number of viable cells (CFU/cm2). Regarding the MIC value of methicillin, 56.7% of the isolates had values lower than 4 μg/ml, which could be considered susceptible to methicillin. The most susceptible belonged to the S. warini species, and the most resistant were S. aureus and S. saprophyticus. The S. pasteuri and S. saprophyticus species showed the highest biofilm productivity (about 8 log CFU/cm2). Regarding the evaluation of biofilm susceptibility to methicillin, a high resistance was observed at all doses tested (maximum concentration 32 μg/ml). No association was found between biofilm formation capacity and methicillin resistance (correlation between biofilm formation and MIC was -0.331, and between biofilm formation and MBC was -0.329). The presence of these Staphylococcus isolates in food can represent a threat to public health. Therefore, this study reinforces the need to implement good production and commercialization practices for street foods, which involves improving the hygiene of producers and the production environment.
Antibiotic resistance is one of the causes of hundreds of deaths every year around the world. Methicillin-resistant Staphylococcus aureus (MRSA) strains are serious nosocomial pathogens, making it a challenge to find effective treatment. The main objective of this study was to characterize isolates of Staphylococcus (coagulase-positive - SCP and coagulase-negative - SCN) from food sold on the streets in Mozambique, with respect to their biofilm formation capacity and susceptibility to methicillin. Three different surfaces (stainless steel, glass, and polystyrene) were used. All strains showed biofilm formation capacity, with polystyrene being the surface where the biofilm had a significantly higher number of viable cells (CFU/cm2). Regarding the MIC value of methicillin, 56.7% of the isolates had values lower than 4 μg/ml, which could be considered susceptible to methicillin. The most susceptible belonged to the S. warini species, and the most resistant were S. aureus and S. saprophyticus. The S. pasteuri and S. saprophyticus species showed the highest biofilm productivity (about 8 log CFU/cm2). Regarding the evaluation of biofilm susceptibility to methicillin, a high resistance was observed at all doses tested (maximum concentration 32 μg/ml). No association was found between biofilm formation capacity and methicillin resistance (correlation between biofilm formation and MIC was -0.331, and between biofilm formation and MBC was -0.329). The presence of these Staphylococcus isolates in food can represent a threat to public health. Therefore, this study reinforces the need to implement good production and commercialization practices for street foods, which involves improving the hygiene of producers and the production environment.
Description
Mestrado em Engenharia Alimentar. Universidade de Lisboa, Instituto Superior de Agronomia
Keywords
Staphylococcus resistente à meticilina biofilmes Boas Práticas de Higiene (BPH) Boas Práticas de Fabrico (BPF) Methicillin resistant Staphylococcus biofilms Good Hygiene Practices (GHP) Good Manufacturing Practices (GMP)
Pedagogical Context
Citation
Correia, J.P.P. Avaliação da capacidade de formação de biofilme e resistência à meticilina de isolados de Staphylococcus de origem alimentar. Lisboa: ISA-Universidade de Lisboa, 2023. Dissertação de Mestrado
Publisher
Instituto Superior de Agronomia, Universidade de Lisboa