MOLECULAR STUDY OF SOME VIRULENCE GENES DETERMINATE IN STAPHYLOCOCCUS AUREUS ISOLATED FROM MILK BOVINE MASTITIS.
Zeyad SH. Abbas*, Mohammad I. Nader and Ilham A. Khalaf
ABSTRACT
Mastitis is one of the common diseases of dairy cattle and an
inflammatory response of the mammary glands tissue. Staphylococcus
aureus is probably the most lethal agent Staphylococcus aureus is the
main etiological agent of contagious clinical/subclinical mastitis in
dairy herds. The aim of this study aims at the genotypic
characterization of S. aureus strains isolated from dairy cows suffering
from mastitis in the different regions (Abu Ghraib, Taji, Latifiya,
Yousofia, Al-futailia) in Iraqi-Baghdad farms. A total of 60 S. aureus
strains, obtained from 120 dairy cows, were phenotypically
characterized and identified. Amplification of genes encoding
clumping factor (clfA), coagulase (coa), thermonuclease (nuc), enterotoxin A (entA),
and the gene segments encoding the immunoglobulin G binding region and the X region of
protein A gene (spa) by Polymerase Chain Reaction was used for the genotypic
characterization of isolated S. aureus strains. There was a statistical difference between
isolates obtained from samples collected from cows infected in mastitis (P <0.01). All of the
isolates are posative for nuc and spa genes, 36 out of 60 isolates are posative of the
polymorphic ClfA gene and X-region binding was detected in 55 isolates. Amplification of
the coa gene yielded five different products in 4, 12, 23, 9 and 12 isolates. The amplification
of the entA gene, was observed in 41 out of 60 isolates.
Keywords: Bovine mastitis, Staphylococcus aureus, virulence factors, polymerase chain reaction (PCR), Iraq.
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