Showing papers by "Frank Møller Aarestrup published in 1994"
TL;DR: One of the reasons for the variation in prevalence of different genotypes of S. aureus in the mammary gland is due to the superior ability of some types to resist phagocytosis and/or killing by bovine neutrophils.
Abstract: This study investigated the functional capabilities of neutrophils against different Staphylococcus aureus genotypes isolated from cows with mastitis. Six strains of S. aureus were chosen for use in the study, two with a common genotype, two with an intermediate genotype, and two with a rare genotype. The interaction between bacteria and neutrophils was measured by phagocytosis and bactericidal effect. The average percent killing of bacteria was lowest (40.0%) with strains belonging to the most common genotype, medium (50%) with strains belonging to the intermediate type, and highest (64.2%) with strains belonging to the rare type (P < or = 0.001). Statistically significant differences (P < or = 0.001) in the numbers of phagocytized bacteria were also found between the most prevalent type (6.27 bacteria per cell) and the other two types (intermediate type, 9.26/cell; rare type, 10.5/cell). These findings suggest that one of the reasons for the variation in prevalence of different genotypes of S. aureus in the mammary gland is due to the superior ability of some types to resist phagocytosis and/or killing by bovine neutrophils.
52 citations
01 Jan 1994
TL;DR: ReduceMTTtopurpleformazan wasquantitated by measuring opticaldensity at 595 nm by determined by comparison to a standard formazan curved by adding MTT to known concentrations of bacteria.
Abstract: reduceMTTtopurpleformazanwasquantitatedbymeasuringopticaldensity at 595 nm. Percent killing ofS. aureus byneutrophilswas determined by comparison to a standard formazan curvederived by adding MTTto knownconcentrations ofbacteria.The percentages of bacteria killed were calculated by thefollowing equation: percent killed =90