Phase variation in the genus Serratia

Abstract
During an investigation of the serotypes of S. marcescens present in a cancer center, 8.7% of 241 strains had more than 1 H antigen. There were 19 diphasic and 2 triphasic strains. Antigen H1 was a component of the phases in approximately half of the strains with multiple phases. This is the 1st report of such phases in the genus Serratia.