Nadjia Benhamed1,2, Gautier Philippe3, Mezouar Ismahene1,
Donnio Pièrre Yves3 and Kihal Mebrouk2

1Department of Applied Molecular Genetics, Faculty of Nature and Life Sciences, University of Sciences Technologies of Oran –Mohammed Boudiaf (USTO-MB), BP 1505 El M’naouar Bir Eldjir Oran 31000, Oran, Algeria.
2Laboratory of Applied Microbiology, Department of Biology, Faculty of Nature and Life Sciences, University Oran 1, Ahmed Ben Bella, BP 16, ES-senia 31000,Oran, Algeria.
3Unit of Microbiology, University of Rennes 1, 35043, Rennes, France.


Staphylococcus aureus causes one of the most common types of chronic mastitis.
Mastitis is an inflammation of the mammary gland with local and symptoms that
occasionally result in a systemic infection. This disease has profound impact on animal
welfare and milk quality. This study allowed us to determine the MLST and spa typing
diversity of Staphylococcus aureus isolated from cases of bovine mastitis in the west
Algeria. The first purpose of this work was to investigate the phylogenetic profile of
Staphylococcus aureus by spa typing and Multilocus sequence typing (MLST) isolated
from Mastitis subcliniques and clinical cases which were previously investigated by
Mass Spectrometry Maldi-Tof and spa typing. The second purpose was to determinate the
complex clonal of strains. In total, 213 quarters milk samples were collected from 56
dairy cows at 6 farms in the region of Oran, from 2011 to 2012. The quarter milk samples
were bacteriological analyzed and scored using California Mastitis Test. The prevalenceisolated bacteria were Staphylococci (38.9%).

Keywords: Mastitis, Staphylococcus aureus, identification, MLST, spa, phylogeny.