Influence of nutrient availability on <i>in vitro</i> growth of major bovine mastitis pathogens

Abstract The aim of the present study was to investigate effects milk composition changes on in vitro growth bovine mastitis pathogens. Nutritional requirements three major pathogens Escherichia coli ( E. ), Staphylococcus aureus S. and Streptococcus uberis ) were investigated . We used ultra-high temperature (UHT) treated with different contents fat, protein, carbohydrates test influence availability various constituents pathogen characteristics. Additionally, bacterial under experimentally modified nutrient by dilution subsequent supplementation individual nutrients (carbohydrates, nitrogen sources, minerals, types B vitamins) either or a conventional medium (thioglycolate broth, TB). Varying protein lactose did not affect exception being promoted protein-enriched milk. addition diluted whole TB partly revealed effects, indicating that there are media-specific limiting factors after dilution. Supplementation minerals rates all studied bacteria. Bacterial decreased high concentrations amino acids , urea additional vitamins rate increased results demonstrate growth-limiting differ among types. Because reduced only shown TB, it is unlikely alterations occurring as consequence physiological cow's udder would directly susceptibility course mastitis.