Non-toxigenic Corynebacterium diphtheriae in a boarding school.

A non-toxigenic strain of Corynebacterium diphtheriae var. gravis was isolated from 31 boys during an outbreak of sore throats at a boarding school of 15 staff and 134 pupils. Despite the non-toxigenicity of the strain involved, conventional isolation procedures were observed and all boys at the school were treated with antibiotics. Restrictions on the school were only relaxed when no further carriers were detected. The rationale of such management of an episode involving a non-toxigenic strain is discussed.