Introduction
The implementation of control measures for contagious mastitis pathogens has successfully reduced the prevalence of these organisms in U.S. dairy herds. However, dairy producers continue to struggle with the control of environmental pathogens. Serratia spp. are Gram-negative bacteria, similar in structure to Escherichia coli and Klebsiella spp. The most common mastitis-causing species is Serratia marcescens. However, the treatment and control of these organisms is similar across all species of Serratia.