Open AccessVirulence of Salmonella enteritidis phage type 4 is related to the possession of a 38 MDa plasmid
Author(s) -
Chart Henrik,
Threlfall E.John,
Rowe Bernard
Publication year - 1989
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1989.tb03063.x
Subject(s) - virulence , plasmid , microbiology and biotechnology , salmonella enteritidis , biology , aerobactin , bacteria , salmonella , enterobacteriaceae , virology , hemolysin , vero cell , escherichia coli , virus , gene , genetics
Nine strains of Salmonella enteritidis phage type 4 were examined for virulence in BALB/c mice. The possession of a 38 MDa plasmid was necessary for full virulence. Strains carrying this plasmid had LD 50 values of <20 bacteria whilst plasmid‐free strains had LD 50 values of >10 6 bacteria when challenged intraperitoneally. Pathogenesis of disease involved the widespread distribution of bacteria throughout the tissues. Possession of the 38 MDa plasmid could not be linked with the ability of strains to express novel outer membrane proteins, to produce toxins affecting Vero, Y1, HeLa, Henle or HEp‐2 cells, or to invade HEp‐2 cells. Furthermore, the 38 MDa plasmid did not encode an aerobactin‐mediated iron uptake system or the production of a haemolysin. Strains of S. enteritidis PT4 isolated in 1967, 1978 or 1979 and possessing the 38 MDa plasmid showed the same virulence properties as the current plasmid‐carrying strains. This suggests that the enhanced virulence of the current strains for poultry is unlikely to be the result of changes in the 38 MDa plasmid.