Esculin-blood agar as a diagnostic tool in acute mastitis for the practitioner

Culturing of milk samples from cases of acute mastitis will give useful information on the causal agent. It requires very few technical installations, is based on simple characteristic reactions, and can be implemented by every interested veterinarian in a private laboratory. Drops of milk are spread on esculin blood agar without and with 0.1 IU penicillin. The plates are incubated overnight at 37 degrees C in a ''candle jar''. After this incubation relevant bacteriological growth is seen in eighty per cent of the cases. The bacterial growth is read by the naked eye. Basic characteristics such as presence or absence of haemolysis, growth or no growth on the 0.1 IU penicillin blood agar plate are registered. Few simple supplementary tests such as, catalase activity and KOH-reaction can be used to reach a reliable identification on the species level. The interpretation of the results is based on a simple diagnostic key. The veterinarian can use the obtained knowledge to establish a correct treatment and give a probable prognosis for the case. Together with the farmer the veterinarian can make use of the result in an attempt to prevent new cases of acute mastitis in the herd.