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CaracterizaĆ§Ć£o cultural e molecular de Staphylococcus coagulase-positiva de origem alimentar e humana

2025Master thesis Restricted access
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dc.contributor.advisorPintado, Cristina Maria Baptista Santos
dc.contributor.authorMartinho, Mara Isabel Branca
dc.date.accessioned2025-07-28T15:36:11Z
dc.date.available2025-07-28T15:36:11Z
dc.date.issued2025
dc.descriptionDissertaĆ§Ć£o apresentada Ć  Escola Superior AgrĆ”ria do Instituto PolitĆ©cnico de Castelo Branco para cumprimento dos requisitos necessĆ”rios Ć  obtenĆ§Ć£o do grau de Mestre em InovaĆ§Ć£o e Qualidade na ProduĆ§Ć£o Alimentar.
dc.description.abstractStaphylococcus aureus Ć© a principal espĆ©cie do grupo Staphylococcus coagulase positiva. Ɖ tambĆ©m a espĆ©cie mais frequentemente relacionada com casos e surtos de intoxicaĆ§Ć£o alimentar, os quais tĆŖm origem na produĆ§Ć£o de enterotoxinas estafilocĆ³cicas (SE), principalmente em alimentos de origem animal. Atualmente, o recurso aos dados obtidos pela sequenciaĆ§Ć£o completa do genoma (Whole Sequencing Genome, WSG) constitui uma ferramenta essencial para o estudo da epidemiologia das doenƧas provocadas por S. aureus, assim como das suas caracterĆ­sticas de virulĆŖncia e resistĆŖncia aos antibiĆ³ticos. Alternadamente, pode ser usado o PCR Multiplex tendo como alvo a deteĆ§Ć£o de genes de interesse em saĆŗde pĆŗblica. Tendo em conta o que foi referido anteriormente, o objetivo principal deste trabalho foi fazer a caracterizaĆ§Ć£o fenotĆ­pica e genotĆ­pica de um conjunto de 98 isolados de Staphylococcus coagulase-positiva de origem alimentar e humana. Foi usada a tĆ©cnica de PCR Multiplex para avaliar a presenƧa de fragmentos do gene femA e de genes que codificam para as enterotoxinas estafilococias SEA, SEB, SEC, SED E SEE, bem como para avaliar a presenƧa de genes associados Ć  toxina da sĆ­ndrome do choque tĆ³xico (tst), Ć s toxinas exfoliativas A e B (etaA e etaB) e Ć  resistĆŖncia Ć  meticilina (mecA). Verificou-se que todos os isolados caracterizados por PCR Multiplex tinham o gene femA, marcador de S. aureus. Cerca de 24% dos isolados apresentaram um dos 5 genes que codificam a produĆ§Ć£o de enterotoxinas, sendo o mais predominante o gene sec. Nenhum dos isolados apresentou o gene sed nem o gene eta e etb. Quatro dos isolados apresentaram o gene tsst-1 que codifica para a sĆ­ndrome do choque tĆ³xico. Do ponto de vista de saĆŗde pĆŗblica, destaca-se ainda a presenƧa do gene mecA em trĆŖs isolados, resultado este concordante com o comportamento caracterĆ­stico das culturas meticilino-resistentes no meio de cultura MRSA Agar.por
dc.description.abstractAbstract: Staphylococcus aureus is the main species of the coagulase-positive Staphylococcus group. It is also the species most frequently associated with cases and outbreaks of food poisoning, which originate from the production of staphylococcal enterotoxins (SE), mainly in foods of animal origin. Currently, the use of data obtained by whole genome sequencing (WSG) constitutes an essential tool for studying the epidemiology of diseases caused by S. aureus, as well as its virulence and antibiotic resistance characteristics. Alternatively, Multiplex PCR can be used to target the detection of genes of interest to public health. Taking into account the above, the main objective of this work was to perform the phenotypic and genotypic characterization of a set of 98 isolates of coagulase positive Staphylococcus of food and human origin. The Multiplex PCR technique was used to evaluate the presence of fragments of the femA gene and genes encoding the staphylococcal enterotoxins SEA, SEB, SEC, SED and SEE, as well as to evaluate the presence of genes associated with toxic shock syndrome toxin (tst), exfoliative toxins A and B (etaA and etaB) and methicillin resistance (mecA). It was found that all isolates characterized by Multiplex PCR had the femA gene, a marker for S. aureus. Approximately 24% of the isolates presented one of the 5 genes that encode the production of enterotoxins, the most predominant being the sec gene. None of the isolates presented the sed gene or the eta and etb genes. Four of the isolates presented the tsst-1 gene that encodes for toxic shock syndrome. From a public health perspective, the presence of the mecA gene in three isolates is also noteworthy, a result that is consistent with the characteristic behavior of methicillin-resistant cultures in the MRSA Agar culture medium.eng
dc.identifier.tid203975901
dc.identifier.urihttp://hdl.handle.net/10400.11/10266
dc.language.isopor
dc.rights.uriN/A
dc.subjectStaphylococcus coagulase positiva
dc.subjectPCR Multiplex
dc.subjectSaĆŗde pĆŗblica
dc.subjectSeguranƧa alimentar
dc.subjectCoagulase positive Staphylococcus
dc.subjectMultiplex PCR
dc.subjectPublic heath
dc.subjectFood safety
dc.titleCaracterizaĆ§Ć£o cultural e molecular de Staphylococcus coagulase-positiva de origem alimentar e humanapor
dc.typemaster thesis
dspace.entity.typePublication
thesis.degree.nameMestrado em InovaĆ§Ć£o e Qualidade na ProduĆ§Ć£o Alimentar

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