Abstract
During an investigation of the serotypes of Serratia marcescens present in a cancer centre, it was found that 8.7% of 241 strains had more than one H antigen. There were 19 diphasic and two triphasic strains. Antigen H1 was a component of the phases in the approximately half of the strains with multiple phases. This is the first report of such phases in the genus Serratia.