Mastitis caused by the bacterium Escherichia coli usually occurs as an acute, sometimes even peracute (very severe) disease with a fever and general symptoms of impairment of health occur. The udder is enlarged, stiff, warm and very painful. The supramammary lymph nodes are strongly enlarged and painful to the touch. The dairy cow has a fever, a fast pulse, fast breathing, stops eating and chewing, toxins from bacterial cells can release to the bloodstream, and process culminates in the fatal end - dairy cow is laying, is in the shock and dies.
Escherichia coli is a bacterium that grows very actively in a favorable environment, and thus the mammary gland is very active (division of the bacterium even more often than every 20 minutes), the pathological process develops rapidly in the mammary gland. Already 4 hours after the infection, the inflammatory reaction is fully developed and in the next 2 hours, fever and general symptoms of disruption appear.
Escherichia coli is found in large amounts in the digestive tract of cattle, other animals and humans. So far, no strains have been found that have a greater affinity for the mammary gland, so we can expect virtually any strain of the bacterium to penetrate the udder and cause colimastitis. Mastitis can be preceeded by diarrhea, eg in the event of a sudden change in feeding, worsened zoohygienic conditions, metabolic disorders, etc. Mastitis caused by E. coli is particularly risky for dairy cows and dairy cows with reduced teat canal closure - E. coli can adhere very well to weaving thanks to the short protrusions protruding from the surface of the bacterial cell (so-called fimbriae) and then to form a biofilm and spread ascending to the udder. Interestingly, this way a bladder infection often occurs in humans.
On the PM test, Escherichia coli grows in large, pink colonies. It grows very well within 24 hours and it is necessary to test the sensitivity to antibiotics as soon as possible - to control the already started treatment, because E. coli is one of the bacteria in which antibiotic resistance often occurs.
In the photo (above) from the examination of milk from dairy cows with mastitis we see that the bacteria Escherichia coli and eg Streptococcus uberis can be clearly distinguished by color and growth in one of the sectors of the bowl, so we can have the first information about the mastitis causative agents on the farm within 24 hours.