Coliform mastitis is usually considered as an acute disease although some milder forms and even chronic cases do occur. It is caused by the bacterial organism Escherichia coli, hence the name, coliform. Other, related organisms, Enterobacter aerogenes and Klebsiella pneumoniae, are also often called “coliforms.”
Bagley, Clell, "Controlling Coliform Mastitis" (1997). All Current Publications. Paper 421.