INVESTIGADORES
BUZZOLA Fernanda Roxana
artículos
Título:
Capsule expression and genotypic differences among Staphylococcus aureus isolates
Autor/es:
LATTAR SM, TUCHSCHERR LP, CACCURI RL, CENTRÓN D, BECKER K, ALONSO CA, BARBERIS C, MIRANDA G, BUZZOLA FR, VON EIFF C, SORDELLI DO.
Revista:
INFECTION AND IMMUNITY
Editorial:
AMER SOC MICROBIOLOGY
Referencias:
Año: 2009 vol. 77 p. 1968 - 1975
ISSN:
0019-9567
Resumen:
There is ample evidence that Staphylococcus aureus capsular polysaccharide (CP)promotes virulence. Loss of capsule expression, however, may lead to S. aureuspersistence in a chronically infected host. This study was conducted to determinethe relative prevalence of nonencapsulated S. aureus in patients with chronic andacute osteomyelitis. Only 76/118 (64%) S. aureus isolates from patients withosteomyelitis expressed CP, whereas all 50 isolates from blood cultures ofpatients with infections other than osteoarticular infections expressed CP (P =0.0001). A significantly higher prevalence of nonencapsulated S. aureus was foundin patients with chronic osteomyelitis (53%) than in those with acuteosteomyelitis (21%) (P = 0.0046). S. aureus isolates obtained from multiplespecimens from five of six patients with chronic osteomyelitis exhibitedphenotypic (expression of CP, alpha-hemolysin, beta-hemolysin, slime, and thesmall-colony variant phenotype) and/or genotypic (pulsed-field gelelectrophoresis and spa typing) differences. Nonencapsulated S. aureus wasrecovered from at least one specimen from each chronic osteomyelitis patient.Fourteen isolates obtained from two patients with acute osteomyelitis wereindistinguishable from each other within each group, and all produced CP5. Inconclusion, we demonstrated that nonencapsulated S. aureus is more frequentlyisolated from patients with chronic osteomyelitis than from those with acuteosteomyelitis, suggesting that loss of CP expression may be advantageous to S.aureus during chronic infection. Our findings on multiple S. aureus isolates fromindividual patients allow us to suggest that selection of nonencapsulated S.aureus is likely to have occurred in the patient during long-term bone infection.
