From the NMC Newsletter "Udder Topics", December 2001
Proteus species may reside in the cow's environment in bedding, feed and water.
Means of spread
Contact of Proteus spp. with teat ends occurs primarily between milkings.
Prevention and control measures
Little information is known regarding the pathogenesis of Proteus spp. Control procedures effective against other Gram-negative bacteria appear to be effective against Proteus spp. Effective environmental sanitation practices include the use of inorganic bedding; avoiding overcrowding of cows; frequent removal of manure and urine; and preventing access to muddy lots or corrals, wet areas under shades, marshy areas, and pools of standing water. The use of an effective germicidal predip and thoroughly drying teas prior to milking may reduce infections during lactation. Immunization of cows with rough mutants such as E. coli J5 can reduce incidence and severity of clinical cases caused by many Gram-negative mastitis-causing organisms.
Proteus spp. are not common mastitis pathogens in most herds. However, Proteus spp. can cause herd outbreaks. Infections tend to be chronic, and clinical cases are often severe. These infections respond poorly to antibiotic therapy.
Source: NMC publication "Laboratory Handbook on Bovine Mastitis" pg. 107 (1999)