INVESTIGADORES
ALVAREZ Lucia Paula
artículos
Título:
Capsule-Negative Staphylococcus aureus Induces Chronic Experimental Mastitis in Mice
Autor/es:
TUCHSCHERR L; BUZZOLA F; ALVAREZ L; LEE J; SORDELLI D
Revista:
INFECTION AND IMMUNITY
Editorial:
ASM Press
Referencias:
Año: 2005 vol. 73 p. 7932 - 7937
ISSN:
0019-9567
Resumen:
Staphylococcus aureus capsular polysaccharides (CP) have been shown to enhance staphylococcal virulence
in numerous animal models of infection. Although serotype 5 CP (CP5) and CP8 predominate among S. aureus
capsular polysaccharides (CP) have been shown to enhance staphylococcal virulence
in numerous animal models of infection. Although serotype 5 CP (CP5) and CP8 predominate among S. aureusS. aureus
isolates from humans, most staphylococcal isolates from bovines with mastitis in Argentina are capsule
negative. This study was designed to evaluate the effects of CP5 and CP8 expression on the pathogenesis of
experimental murine mastitis. Lactating mice were challenged by the intramammary route with one of three
isogenic S. aureus strains producing CP5, CP8, or no capsule. Significantly greater numbers of acapsular
mutant cells were recovered from the infected glands 12 days after bacterial challenge compared with the
encapsulated strains. Histopathological analyses revealed greater polymorphonuclear and mononuclear leukocyte
infiltration and congestion in the mammary glands of mice infected with the encapsulated strains
compared with the acapsular mutant, and the serotype 5 strain elicited more inflammation than the serotype
8 strain. In vitro experiments revealed that the acapsular S. aureus strain was internalized by MAC-T bovine
epithelial cells in significantly greater numbers than the CP5- or CP8-producing strain. Taken together, the
results suggest that S. aureus lacking a capsule was able to persist in the murine mammary gland, whereas
encapsulated strains elicited more inflammation and were eliminated faster. Loss of CP5 or CP8 expression
may enhance the persistence of staphylococci in the mammary glands of chronically infected hosts.
S. aureus strains producing CP5, CP8, or no capsule. Significantly greater numbers of acapsular
mutant cells were recovered from the infected glands 12 days after bacterial challenge compared with the
encapsulated strains. Histopathological analyses revealed greater polymorphonuclear and mononuclear leukocyte
infiltration and congestion in the mammary glands of mice infected with the encapsulated strains
compared with the acapsular mutant, and the serotype 5 strain elicited more inflammation than the serotype
8 strain. In vitro experiments revealed that the acapsular S. aureus strain was internalized by MAC-T bovine
epithelial cells in significantly greater numbers than the CP5- or CP8-producing strain. Taken together, the
results suggest that S. aureus lacking a capsule was able to persist in the murine mammary gland, whereas
encapsulated strains elicited more inflammation and were eliminated faster. Loss of CP5 or CP8 expression
may enhance the persistence of staphylococci in the mammary glands of chronically infected hosts.
S. aureus strain was internalized by MAC-T bovine
epithelial cells in significantly greater numbers than the CP5- or CP8-producing strain. Taken together, the
results suggest that S. aureus lacking a capsule was able to persist in the murine mammary gland, whereas
encapsulated strains elicited more inflammation and were eliminated faster. Loss of CP5 or CP8 expression
may enhance the persistence of staphylococci in the mammary glands of chronically infected hosts.
S. aureus lacking a capsule was able to persist in the murine mammary gland, whereas
encapsulated strains elicited more inflammation and were eliminated faster. Loss of CP5 or CP8 expression
may enhance the persistence of staphylococci in the mammary glands of chronically infected hosts.