Genomic investigation of coagulase-negative staphylococci isolated from mastitis cows

Abstract

Mastitis causes economic losses due to reduced milk production, milk discard, premature slaughter, veterinary costs, and antibiotic usage. The genus Staphylococcus is divided in coagulase positive and coagulase negative groups and both are considered etiological agents that cause bovine mastitis. Nowadays, besides Staphylococcus aureus, coagulase-negative Staphylococci has special attention as causative of mastitis, but they are not studied as S. aureus. The objectives of this study are to obtain a phylogenetic tree of strains of CoNS isolated from mastitis cows and to identify virulence factors and resistance antimicrobial genes of coagulase -negative staphylococci based on whole genome sequencing. A collection of CoNS isolates from dairy cows with clinical mastitis isolated in the Department of population medicine and diagnostic sciences in Cornell University will be used. The DNA of strains will be extracted and will be prepared libraries which will be paired-end sequenced applying Illumina's NextSeq platform with a read length of 2×151bp. Clonality and relatedness of the isolates will be investigated using single nucleotide polymorphism (SNP) analysis and appriate software tools, such as CSI Phylogeny. The isolates also will be investigated for all resistance and virulence genes in de novo assembled contigs using ResFinder v2.1 and Virulence Finder v1.5 , respectively.