Virulence factors in Serratia marcescens: cell-bound hemolysin and aerobactin

ABSTRACT

A total of 60 nosocomial isolates of Serratia marcescens were screened for the presence of markers related to virulence, i. e., cell-bound hemolysin and production of siderophore aerobactin. No aerobactin-producing strains were found, and the incidence of cell-bound hemolysin was 97%. Hemolysin-positive (58 strains) and hemolysin-negative (2 strains) Serratia marcescens showed the same LD50 (3 x 107) bacteria) in a test of virulence for mice. These results indicate that cell-bound hemolysin is not a main factor of virulence for mice in Serratia marcescens