title: Genotypic and phenotypic detection of capsular polysaccharide and biofilm formation in Staphylococcus aureus isolated from bovine milk collected from Brazilian dairy farms.
abstract: Staphylococcus aureus is a pathogen that frequently causes mastitis in bovine herds worldwide. This pathogen produces several virulence factors, including cell-associated adhesins, toxic and cytolytic exoproteins, and capsular polysaccharides. The aim of the present study was to test for the presence of genes involved in capsular polysaccharide production and biofilm formation in S. aureus isolated from bovine mastitis samples collected from 119 dairy herds located in three different Brazilian regions, as well as to assay the production of capsular polysaccharides and biofilm, in vitro. The detection of the cap, icaAD, and bap genes was performed using PCR. The detection and quantification of capsular polysaccharide production was performed using ELISA assays. The ability of the isolates to form a biofilm was examined using the polystyrene surface of microtiter plates. All 159 S. aureus isolates investigated harboured the cap gene: 80 % carried the cap5 gene and 20 % carried the cap8 gene. Sixty-nine percent of the isolates expressed capsular polysaccharide (CP) in vitro, 58 % expressed CP5 and 11 % expressed CP8. All of the isolates harboured the icaA and icaD genes, and 95.6 % of the isolates carried the bap gene. Of the 159 isolates analysed, 97.5 % were biofilm producers. A significant association between the capsular genotype and phenotype and the amount of biofilm formation was detected: cap5/CP5 isolates tended to form more biofilm and to produce a thinner CP layer than cap8/CP8 isolates. The results indicate a high potential for pathogenicity among S. aureus isolated from bovine milk collected from three different regions in Brazil.
authors.affiliation: Embrapa Dairy Cattle Research Center, Rua Eugênio do Nascimento 610, 36038-330, Juiz de Fora, Minas Gerais, Brazil.|Food Science Department, Federal University of Lavras, PO Box 3037, 37200-000, Lavras, Minas Gerais, Brazil.
authors.forename: Alessandra P S
authors.initials: AP
authors.lastname: Salimena
authors.affiliation: Embrapa Dairy Cattle Research Center, Rua Eugênio do Nascimento 610, 36038-330, Juiz de Fora, Minas Gerais, Brazil. carla.lange@embrapa.br.
authors.forename: Carla C
authors.initials: CC
authors.lastname: Lange
authors.affiliation: Rafaela Agricultural Experimental Station, INTA, Ruta 34, Km 227, (2300) Rafaela, Santa Fe, Argentina.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Camussone
authors.affiliation: Rafaela Agricultural Experimental Station, INTA, Ruta 34, Km 227, (2300) Rafaela, Santa Fe, Argentina.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Signorini
authors.affiliation: Rafaela Agricultural Experimental Station, INTA, Ruta 34, Km 227, (2300) Rafaela, Santa Fe, Argentina.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Calvinho
authors.affiliation: Embrapa Dairy Cattle Research Center, Rua Eugênio do Nascimento 610, 36038-330, Juiz de Fora, Minas Gerais, Brazil.
authors.forename: Maria A V P
authors.initials: MA
authors.lastname: Brito
authors.affiliation: Embrapa Dairy Cattle Research Center, Rua Eugênio do Nascimento 610, 36038-330, Juiz de Fora, Minas Gerais, Brazil.
authors.forename: Cristiano A V
authors.initials: CA
authors.lastname: Borges
authors.affiliation: Embrapa Dairy Cattle Research Center, Rua Eugênio do Nascimento 610, 36038-330, Juiz de Fora, Minas Gerais, Brazil.
authors.forename: Alessandro S
authors.initials: AS
authors.lastname: Guimarães
authors.affiliation: Embrapa Dairy Cattle Research Center, Rua Eugênio do Nascimento 610, 36038-330, Juiz de Fora, Minas Gerais, Brazil.
authors.forename: João B
authors.initials: JB
authors.lastname: Ribeiro
authors.affiliation: Embrapa Dairy Cattle Research Center, Rua Eugênio do Nascimento 610, 36038-330, Juiz de Fora, Minas Gerais, Brazil.
authors.forename: Letícia C
authors.initials: LC
authors.lastname: Mendonça
authors.affiliation: Food Science Department, Federal University of Lavras, PO Box 3037, 37200-000, Lavras, Minas Gerais, Brazil.
authors.forename: Roberta H
authors.initials: RH
authors.lastname: Piccoli
mesh_terms: D000818:Animals; D018441:Biofilms; D001938:Brazil; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay; D005798:Genes, Bacterial / Q000235:genetics; D005838:Genotype; D008414:Mastitis, Bovine / Q000382:microbiology; D008892:Milk / Q000382:microbiology*; D010641:Phenotype; D011135:Polysaccharides, Bacterial / Q000235:genetics*; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*
chemical_list: D011135:Polysaccharides, Bacterial
keywords: Adhesin; Capsule; bap; cap; icaAD