|
KMID : 0984720040360010032
|
|
Infection and Chemotherapy
2004 Volume.36 No. 1 p.32 ~ p.39
|
|
|
Oxygen Stimulates the Expression of Iron-Repressible High-Affinity Iron-Uptake Systems of Staphylococcus aureus - Application of CAS agar diffusion assay -
|
|
Lim Yong
Cho Soo-Hyeong
Cho Nam-Soo
Lee Seung-Il
Chung Jae-Yong
Chung Choon-Hae
Shin Sung-Heui
|
|
|
Abstract
|
|
|
Background : Staphylococcus aureus is the major cause of nosocomial infections and causes infections at sites with various concentrations of iron and oxygen. High-affinity iron-uptake systems (IUS) of S. aureus consist of the two systems : Siderophore-mediated IUS and transferrin binding protein (SA-tbp)-mediated IUS. In the present study, we investigated the combined effect of iron concentration and oxygen tension on the expression of high-affinity IUS of S. aureus. ]
Materials & methods : The standard ATCC 6538 strain, which expresses simultaneously both IUS, was used. This strain was cultured in the iron-sufficient and iron- deficient BHI broth under the three different conditions : aerobic, microaerobic and anaerobic. The bacterial growth was measured by optical density at 600 nm of wavelength, the siderophore production by CAS agar diffusion assay, the expression of cell wall proteins by SDS-PAGE and Coomassie staining, and the expression of SA-tbp by Western blot using human transferrin conjugated with HRP as the probe.
Results : Bacterial growth was more active in the medium with high iron and high oxygen tension. Siderophore production was more stimulated in the medium with low iron and high oxygen tension. About 83, 75, 64, 55, 45, 38, 36, and 34 kDa of cell wall proteins were expressed more in the medium with low iron and high oxygen tension. SA-tbp was also expressed more in the medium with low iron and high oxygen tension.
Conclusion : We conclude that iron plays a more dominant role in the expression of S. aureus high- affinity IUS than oxygen, and oxygen stimulates the expression of iron-repressible IUS of S. aureus. These results suggest that iron and oxygen levels in the body fluid play an important role in pathogenesis of staphylococcal infections.
|
|
|
KEYWORD
|
|
|
Staphylococcus aureus, Iron, Siderophore
|
|
|
FullTexts / Linksout information
|
|
|
|
|
Listed journal information
|
|
  
|
|