Abstract

BRISUELA RAYGOSA, Jennifer et al. Molecular identification and frequency of isolated pathogens from bovine mastitis in dairy herds from Baja California Peninsula, Mexico. Rev. mex. de cienc. pecuarias [online]. 2018, vol.9, n.4, pp.754-768. ISSN 2448-6698.  https://doi.org/10.22319/rmcp.v9i4.4365.

Bovine mastitis is a disease of high economic impact for the dairy industry and some of the etiological agents that cause it are also of interest in the field of public health. The purpose of study was to identify the bacterial causes of bovine mastitis from seven dairy farms located in the Baja California Peninsula. A total of 316 milk samples were collected from the same number of quarters belonging to 186 cows in production that tested positive for California Mastitis test. It was obtained 182 bacterial isolates from 163 quarters belonging to 106 cows and were identified by PCR, giving a total of 20 different species. Isolates were identified using specific oligonucleotides for the major mastitis pathogens and with universal oligonucleotides for the 16S ribosomal DNA gene with subsequent sequencing for those that did not amplify with the specific oligonucleotides and relative frequencies were obtained. The most frequent causal agents were: Staphylococcus aureus (58.8 %), Streptococcus agalactiae (13.2 %), Staphylococcus chromogenes (8.8 %), Escherichia coli (2.2 %) and Streptococcus uberis (2.2 %). A mixed infection was found in 6.13 % (10/163) of the quarters, being the most frequent combination S. aureus plus S. agalactiae 30 % (3/10). These results indicate a high frequency and diversity of contagious and environmental pathogens causing mastitis in dairy cattle in the region of study, being some of importance for public health. The results show that the causes of mastitis are diverse, so it is essential to improve control and prevention measures, but also to establish a routine diagnosis to control mastitis.

Keywords : Bovine mastitis; Molecular identification; Staphylococcus spp.; Streptococcus spp.