Macro-restriction Analysis of Staphylococcus Aureus Isolated from Subclinical Bovine Mastitis in Nigeria

Abstract

Different pathogens cause both clinical and subclinical mastitis and Staphylococcus aureus is the most common. One hundred and thirty six apparently healthy cows from six Local Government Areas of Plateau state, Nigeria were sampled for the isolation of this pathogen. Three hundred and thirty nine quarter milk samples from the cows were collected, out of which 102 S. aureus were isolated. Twenty isolates were further analysed at molecular level. The species of the 20 strains were confirmed by PCR amplification using S. aureus specie-specific primers derived from the 23S rDNA and by amplification of nuc, coa and spa genes. Epidemiological relationships of the strains were studied by macro-restriction analysis of their chromosomal DNA using pulse field gel electrophoresis (PFGE). Among the 20 S. aureus strains identified, PFGE revealed an identical DNA pattern for 18 strains while two strains differed in two bands. These differences were revealed by the amplification of the spa gene. The relationship between the S. aureus isolated from nomadic raised cows discovered in the study areas remains unclear as only two pulse types were observed.