Prevalence of Streptococcus agalactiae in milk samples from cows suspected of sub-clinical mastitis.
Board Location: #45
Discipline: Biological Sciences
Subcategory: Microbiology/Immunology/Virology
Session: 1
Stephanie M. González-Avilés - University of Puerto Rico-Aguadilla
Co-Author(s): Javier O. Galarza-Avilés, University of Puerto Rico-Aguadilla; Wilgeyshka S. Acevedo-Acevedo, University of Puerto Rico-Aguadilla, Yavier Nazario-Caceres, University of Puerto Rico-Aguadilla.
Bovine mastitis is an inflammation of the mammary gland. It is the most common disease of dairy cattle and the costliest disease on dairy farms. A dairy farm can lose profit through decreased milk yield, treatment costs, discarded milk, premature culling and death, decreased genetic potential and decreased reproductive performance. Sub-clinical mastitis caused by S. agalactiae can only be diagnosed in the laboratory because the animal shows no common symptoms of infection in the mammary gland. Scientific literature suggests that sub-clinical mastitis can be caused by S. agalactiae. However, in Puerto Rico, other bacteria are considered to be responsible for this disease. Correct identification of the bacteria present in milk of cows with suspected sub-clinical mastitis is necessary for optimal treatment and recovery of the lactating cow. Thus, the specific aim of this study is to investigate the prevalence of S. agalactiae in milk samples from dairy cows with suspected sub-clinical mastitis in farms at the southwest of Puerto Rico using microbiology and molecular biology techniques. Milk samples are collected from cows suspected of sub-clinical mastitis, transported to the laboratory, and enriched in selective media for gram-positive bacteria and incubated at 37 C for 48 hours. Colony count and morphological analysis is then performed to select suspected S. agalactiae colonies based on known characteristics. Biochemical tests and PCR amplification of target gene 16s rRNA are performed for the identification of S. agalactiae in milk samples. The control in this investigation is the milk from healthy cows. The prevalence of S. agalactiae in milk samples is calculated and correlated to the sub-clinical mastitis status of each cow. There are no results yet in this investigation. However, the expectation is to find a higher prevalence of S. agalactiae in milk samples from cows with sub-clinical mastitis compared to cows with clinical mastitis.
Funder Acknowledgement(s): PR-LSAMPRUTAS
Faculty Advisor: Dr. Juliana Pérez-Laspiur, Ph.D., juliana.perez-laspiur@upr.edu
Role: I had the opportunity to do milk collection, non-selective and selective agar preparations, biochemical tests, genomic DNA isolation, primer design for target gene, DNA bioinformatics, PCR, Real-time PCR, electrophoresis of nucleic acids. I also prepared reagents and materials for this study, followed research protocols, worked individually and in groups, learned to collect data and do basic statistical analysis, among other skills.