W. Mamo et al., OPSONIZATION OF STAPHYLOCOCCUS-AUREUS WITH A FIBRONECTIN-BINDING PROTEIN ANTISERUM INDUCES PROTECTION IN MICE, Microbial pathogenesis, 19(1), 1995, pp. 49-55
The virulence of Staphylococcus aureus opsonized with an antiserum rai
sed against a recombinant fibronectin-binding protein (FnBP) was compa
red with homologous, non-opsonized bacteria (treated with pre-immune s
erum) in a mouse mastitis model. Virulence was evaluated comparing the
number of bacteria recovered from the infected mammary glands and acc
ording to the type of lesions produced. The average number of bacteria
recovered from the mammary glands inoculated with S, aureus opsonized
with FnBP-antiserum was significantly lower (up to 10(7) cfu/ml) than
the average number of bacteria recovered after inoculation with non-o
psonized bacteria (up to 10(10) cfu/ml). Gross examination of infected
mammary glands showed that 65% of glands infected with opsonized bact
eria developed low grade/or had no pathological changes, and 35% devel
oped severe mastitis whereas, 75% of glands inoculated with non-opsoni
zed bacteria developed severe mastitis and 25% low grade mastitis or h
ad no pathological changes. According to the histopathological examina
tion eight out of 10 glands inoculated with opsonized bacteria produce
d disseminated focal necrosis or had no pathological changes and two g
lands produced non reactive necrotic lesions. In contrast, only three
out of 10 glands inoculated with non-opsonized homologous bacteria dev
eloped disseminated focal necrosis and had no pathological changes whi
le seven glands developed total necrosis. (C) 1995 Academic Press Limi
ted