Molecular detection of Staphylococcus aureus mastitis in crossbred cows based on genus specific gap gene and species specific aroA gene PCR assay

Abstract

The present study aimed to diagnose Staphylococcus aureus from mastitic milk samples of crossbred cows using genus specific PCR assay based on gap gene (encoding glyceraldehyde –3–phosphate dehydrogenase) and species specific PCR assay based on aroA gene (encoding 5–enolpyruvylshikimate–3–phosphate synthase). For internal control, a set of universal primers were included. Out of 770 milk samples tested, 50.74 and 52.21% samples were diagnosed to be positive for Staphylococcus spp. by cultural examination and gap gene based genus specific PCR, whereas as many as 41.91% and 43.38% samples were found positive for Staphylococcus aureus by bacteriological examination and aroA gene based species specific PCR respectively. The assay could also detect the “no-growth” milk samples. Using this rapid, sensitive and specific method, staphylococcal isolates can be differentiated at the subspecies or strain level within 6–8 h and it can contribute to an increased understanding of mastitis epidemiology and control options for overall increase in lifetime productivity of crossbred cattle