Biochemical characteristics of typical and atypical Staphylococcus aureus in mastitic milk and environmental samples of Brazilian dairy farms

• Autor(a) principal: Silva,Wladimir Padilha da
• Data de Publicação: 2000
• Outros Autores: Destro,Maria Teresa, Landgraf,Mariza, Franco,Bernadette D.G.M.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Microbiology
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822000000200008
• topic: Staphylococcus aureus; atypical S.aureus; coagulase; thermonuclease; API-Staph; Baird-Parker agar; milk; mastitis; environmental samples

This study reports results on the biochemical characteristics of 274 Staphylococcus aureus strains isolated from mastitic milk, hands of milkmen and milking machines. Features included colony morphology on Baird Parker agar (BPA), catalase, coagulase and thermonuclease tests. API-Staph (bioMérieux, France) was used as reference identification system. 39.4% of the colonies on BPA identified as S.aureus were atypical. They were more frequent in milk samples (94.4%). All S.aureus strains were coagulase positive but intensity of the test varied according to the source: environmental strains were 3+ or 4+, while 17.1% of strains isolated from milk presented only 1+ or 2+ results. The majority of atypical S.aureus strains presented a 4+ coagulase result. 2.2% of S.aureus strains were thermonuclease negative. Sixteen thermonuclease positive and coagulase positive strains were identified as S.hyicus.