Detection of different Staphylococcus aureus strains in bovine milk from subclinical mastitis using PCR and routine techniques

Abstract

Contamination of fresh milk with Staphylococcus aureus was assessed comparatively through routine phenotypic (coagulase tube test and coagulase slide test) and genotypic (PCR) screening of 128 S. aureus strains isolated from 555 milk samples. These samples were collected from 362 cows with subclinical mastitis, hosted in different dairy herds at various locations of the Northern and Northeastern rural areas of the State of Rio de Janeiro, 39.7% of which were CMT-positive. All S. aureus isolates tested positive for the presence of the coagulase gene by PCR and the isolates could be grouped into four distinct classes according to the size of the PCR product. The strains also yielded variable results when assayed with coagulase test. Taken together, these data indicate the existence of extensive polymorphism at the coagulase gene locus in the genus Staphylococcus and exemplifies the extent of molecular and phenotypic heterogeneity associated with the strains circulating in rural herds.

Species-level identification of staphylococci isolated from bovine mastitis in Brazil using partial 16S rRNA sequencing

“…Six S. aureus isolates did not clot rabbit plasma, but showed positive results in Voges-Proskauer and latex agglutination tests and amplified femA and coa genes. S. aureus strains isolated from bovine mastitis that failed to coagulate rabbit plasma have been previously described (Vieira-Da-Mota et al, 2001;Capurro et al, 2009;Akineden et al, 2011). Vieira-Da-Mota et al (2001) reported S. aureus strains isolated from bovine mastitis that were negative in the tube coagulase test, but showed a positive result in the PCR amplification of the coa gene.…”

Growth inhibition of Staphylococcus aureus and escherichia coli strains by neutralizing IgY antibodies from ostrich egg yolk

“…Anti-RAP antibodies inhibited in vivo infection caused by S. aureus in mouse (6, 11) and in vitro growth and secretion of enterotoxins by different strains of S. aureus were inhibited by specific antibodies developed against synthetic peptide RIP involved in agr activation (27, 28). S. aureus is also considered one of the main agents causing mastitis in cattle (1, 29). Diseases caused by Escherichia coli also pose as important losses for human and animals.…”

Characterization of Staphylococcus aureus Isolates from Buffalo, Bovine, Ovine, and Caprine Milk Samples Collected in Rio de Janeiro State, Brazil

“…In contrast to studies of bovine, caprine, and ovine infections, only a few studies of staphylococcal mastitis concerning buffalo intramammary infections have been published, and the importance of subclinical mastitis in this dairy species may not be enough to significantly influence milk production as in other domestic ruminants (22). In Brazil, in the rural areas of Rio de Janeiro State, bovine subclinical mastitis was reported to be higher than in other areas of the country and close to 40% (5,34), whereas S. aureus was identified in up to 37% of isolates from goats with subclinical mastitis (28).…”

“…Molecular studies of S. aureus isolates from dairy farms in Brazil are still limited and concentrate exclusively on cows (2,16,25,26,34) and goats (29). The aim of the present study was to characterize isolates from cases of bovine, caprine, ovine, and buffalo S. aureus mastitis by pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing (MLST) and contribute to the comprehension of the S. aureus genetic population in Brazilian dairy herds.…”