Antibiotics may have different effects on the interaction of bacteria and leucocytes by interfering with one aspect of the immune or by directly affecting the bacterial cell. These interactions are important in the earyly stages of bacterial
pathogenesis and also during subsequent steps of the infectious process. Phagocytosis by neutrophils, adherence to HeLa cell, and bacterial morphology were studied on streptomycin treated bacteria in comparison with untreated controls.
1. MIC of streptomycin to SA157(which has high protein A content), SA14(which has low protein A content) and SA217(which has high protein A content) was 8,512, and 512(μg/ml), respectively, and the cultures of Staphylococcus aureus were exposed
for
12-15h tho streptomycin at 1/2 the MIC.
2. Phagocytosis of strains exposed to the streptomycin and untreated controls were investigated. The former had higher adherent capacity in PMNs and very much superior phagocytic uptake than the lator.
3. In accordance with the adherence assay of strains exposed to the streptomycin and untreated controls on HeLa cells, it was showed that strains exposed to the streptomycin had more excellent adherent capacity than untreated controls.
4. Cell sizes of S. aureus were analyzed by electron microscope after treatment of S. aureus with streptomycin. Sub-MICs of streptomycin produced larger forms with irregular cell walls.
|