However, by limiting an examination to four tests a positive identification can be achieved in
most cases. These reactions are the production of acid from inulin (I) and raffinose (R), the
hydrolysis of arginine to release ammonia (A) and the ability to grow and produce gas in
acid citrate broth (C). Over 99.0% of isolates showing the IRAC pattern+-+-are Strep. uberis.
About 1.6% of Strep. uberis are atypical, usually because they also ferment raffinose (lO%),
do not ferment inulin (0.4%) or fail to hydrolyse arginine (0.1%). Serologically Strep. uberis is …