Staphylococcus aureus is among the microorganisms more frequently associated with subclinical bovine mastitis. S. aureus may produce several virulence factors. This study aimed at determining the frequency of virulence factors such as enterotoxins, toxic shock syndrome toxin 1, and ica adhesion genes. In addition, we assessed antimicrobial drug resistance in S. aureus isolated from clinical and subclinical cases of mastitis. A total of 88 cows with clinical or subclinical mastitis were sampled, resulting in 38 S. aureus isolates, from which 25 (65.78%) carried toxin genes, including seb, sec, sed, tst, and icaD adhesion gene. These S. aureus isolates belong to 21 ribotypes and three S. aureus strains belonged to the same ribotype producing ica adhesion gene. Approximately 90% of S. aureus strains obtained in our study demonstrated multiple resistance to different antimicrobial agents. The most efficacious antimicrobial agents against the isolates were gentamicin, amoxicillin, and norfloxacin. Gentamicin was the most efficacious agent inhibiting 78.95% of the S. aureus isolates. The least efficacious were penicillin, streptomycin, and ampicillin. Our results can help in understanding the relationship between virulence factors and subclinical mastitis caused by S. aureus. Further research about diversity of S. aureus isolates and genes responsible for the pathogenicity of subclinical mastitis is essential.

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Staphylococcus aureus is commonly involved in food poisoning due to production of toxins responsible for causing animal and human diseases. In this study, 60 strains of presumptive S. aureus isolates from raw milk and cheese were biochemically identified in four dairies: 54 (90%) from refrigerated raw milk (RRM) with counts exceeding 10 6 CFU/mL, and six (10%) from cheese with similar concentrations of CFU/mL. Out of the 60 strains of presumptive S. aureus, 46 (76.7%) amplified the femA gene and then they were investigated regarding the presence of the Toxic Shock Syndrome Toxin-1 (TSST-1) gene and the classical enterotoxin genes (SEs) types A, B, C, D and E: 31 (67.4%) carried one or more encoding toxin genes, and 13 different genotypes were identified. Twenty-one strains (61.8%) carried one gene; three (8.8%), two genes; seven (20.6%), three genes; two (5.8%), four genes; and one (3%), five genes. The sec gene was the most frequent one, followed by seb and tst. The sed gene was expressed by 10 strains (29.4%), sea by five (14.7%) and see by three (8.8%). The S. aureus isolates showed genetic potential for producing toxins of importance for public health that presented a danger of food poisoning.

Introdução: O mel é um produto de excelente qualidade nutricional e muito utilizado também por suas propriedades medicamentosas. É produzido por abelhas a partir do néctar das flores ou exsudatos sacarínicos das partes vivas das plantas, que elas coletam, transformam, combinam com substâncias específicas e estocam nas colmeias. Objetivos: Avaliar a qualidade higiênico-sanitária de 30 amostras de méis de Apis mellifera produzidos no Estado do Maranhão no período de novembro de 2005 a fevereiro de 2006. Metodologia: Realizou-se pesquisa de coliformes totais, termotolerantes, bolores, leveduras e bactérias aeróbias mesófilas no Laboratório de Microbiologia de Alimentos e Água da Universidade Estadual do Maranhão (UEMA). Resultados: Do total de amostras analisadas, nenhuma apresentou contaminação por coliformes totais, termotolerantes, bolores e leveduras. Referente às bactérias aeróbias mesófilas, suas contagens foram baixas de modo que a qualidade do produto foi considerada boa, portanto recomendado para o consumo.Palavras-chave: Mel, Apis mellífera, Qualidade higiênico-sanitária.