Phagocytosis and killing of slime-producing Staphylococcus epidermidis bypolymorphonuclear leukocytes. Effects of sparfloxacin.
The interaction of slime-producing Staphylococcus epidermidis (S+ strain) with human polymorphonuclear leukocytes (PMNs) was analyzed. The phagocytosis index (PI) and the killing index (KI) were evaluated, and the effect of subinhibitory concentrations (sub-MICs) of sparfloxacin in this interaction was determined. The study was carried out in parallel with a non-slime-producing strain (S- strain). The MIC values of sparfloxacin against both strains was 0. 06 mg/ml. In the S- strain the mean values of PI and KI were 82% and 31%, respectively, whereas in the S+ strain these values diminished to 49% and 8%, respectively (p <0.05) when the inocula were prepared in aerobiosis. In a constant flow atmosphere of 5% CO2, the results were similar to the previous ones in the S- strain (PI = 79% and KI = 27%), whereas in the S+ strain a increase in the PI (59%) and a similar value to the KI (9%) were observed. Significant increases (p <0.05) in the PI were noted when PMNs were preincubated with 1/4 and 1/16 MIC of sparfloxacin, and S. epidermidis S+ grown in aerobiosis were used. In the other assays the variations in PI and KI were not statistically significant (p >0.05). Our results confirm that slime protects against phagocytosis and killing by PMNs, although they also suggest that the S+ strains possess additional properties which make them resistant to the action of the PMNs.
Morán
F J
FJ
Department of Microbiology, Faculty of Medicine, University of Extremadura, Badajoz, Spain.
García
C
C
Pérez-Giraldo
C
C
Hurtado
C
C
Blanco
M T
MT
Gómez-García
A C
AC
D000332:Aerobiosis; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development; D024841:Fluoroquinolones; D006801:Humans; D008826:Microbial Sensitivity Tests; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology / Q000382:microbiology*; D010587:Phagocytosis; D015363:Quinolones / Q000494:pharmacology*; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000276:immunology / Q000502:physiology
D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D015363:Quinolones; C061363:sparfloxacin