Caracterização fenotípica e genotípica de staphylococcus aureus isolados de queijo minas frescal industrial e artesanal

• Ano de defesa: 2015
• Autor(a) principal: Ferreira, Mariana de Andrade
• Orientador(a): André, Maria Cláudia Dantas Porfirio Borges
• Banca de defesa: Campos, Maria Raquel Hidalgo, Borges, Liana Jayme, André, Maria Cláudia Dantas Porfírio Borges
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Nutrição e Saúde (FANUT)
• Departamento: Faculdade de Nutrição - FANUT (RG)
• País: Brasil
• Palavras-chave em Português: Staphylococcus aureus; Resistência microbiana a medicamentos; Enterotoxinas; Microbiologia de alimentos
• Palavras-chave em Inglês: Staphylococcus aureus; Cheese; Antimicrobial resistance; Staphylococcal enterotoxin
• Área do conhecimento CNPq: CIENCIAS DA SAUDE::NUTRICAO
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/5564

Staphylococcus aureus is an important foodborne pathogen, able to produce extracellular toxins and to express antimicrobial resistance. Among the foods involved in staphylococcal food poisoning, stands out the cheese, especially when manufactured under improper hygienic and sanitary conditions. The objectives of this study were to characterize Staphylococcus aureus isolated from artisanal and industrialized Minas frescal cheeses, to determine their antimicrobial susceptibility profile as well as the genetic similarity among the isolates. The isolates were also tested for staphylococcal enterotoxins (SE) genes and other virulence factors. Fifty-six artisanal raw milk cheeses sold at street fairs and 10 industrialized cheeses commercialized in supermarkets of Goiânia, Goiás were analyzed between June and August 2014. S. aureus was confirmed in 19 samples (33.9%) of artisanal cheese by detection of femA gene, in which 29 isolates were obtained. These isolates were submitted to the antimicrobial susceptibility test and classified into nine different profiles (A - I). Thirteen isolates (44.8%) were resistant to penicillin and three (10.3%) to tetracycline, with two (7.4%) resistant to both. The Multiplex PCR technique was performed to detect virulence genes that code for the production of hemolysins (Hla and Hlb), toxic shock syndrome toxin (TSST-1), exfoliative toxins (ETa and ETb) and enterotoxins (SEA - SEE, SEG - SEJ, SEM - SEO). Genes encoding TSST-1 and exfoliative toxins were not detected. All the isolates amplified for the hla gene and 14 (48.3%) for the hbl gene. The seh gene was the most frequently detected (n=11, 37.9%) followed by seo gene (n = 3; 10.3%), seg, sem and sen genes (n = 2, 6.9%) and sec and sei genes (n = 1, 3.4%). In one isolate (3.4%), four enterotoxins genes were detected, and in another, six (3.4%). The comparison performed by Pulsed Field Gel Electrophoresis technique revealed 18 different DNA banding patterns which were grouped into five clusters. The genotyping found high genetic similarity among the isolates. Identical isolates were obtained from different samples and one sample showed more than one genetically different isolate. It was identified up to four different isolates from the same sample. The high prevalence of S. aureus in a widely consumed product like Minas fresh cheese, as well as the detection of toxin encoding genes identified in this study, warns of the necessity to reduce the contamination levels in this type of cheese through monitoring and controling the production and trade of the product.