Experimental colonization of a polyester vascular graft with Staphylococcus aureus: a quantitative and morphologic study.
Colonization of a polyester (Dacron) vascular graft by Staphylococcus aureus 209P-R was studied. Twenty-five dogs had thoracoabdominal aortic bypass. After intervals of 2 hours (three dogs), 8 days (five dogs), 1 month (six dogs), 2 months (six dogs), or 6 months (five dogs), a bacteremic challenge was produced by intravenous injection of 6 x 10(8) colony-forming units of S. aureus. Two hours later grafts were removed and cut into 10 fragments, each submitted to bacterial counts and scanning electron microscopic studies. Results of bacterial counts were expressed in colony-forming units (CFU) per square centimeter of graft segment (median [lower to upper quartiles]). Normal canine aortas (n = 2) used as controls trapped no bacteria. Colonization of Dacron grafts varied according to the duration of graft function (p less than 0.01): after 2 hours, 4416.5 CFU (1158 to 9073 CFU); after 8 days, 1515 CFU (963 to 2893 CFU); after 1 month, 199 CFU (86 to 538 CFU); after 2 months, 615 CFU (243 to 1407 CFU); and after 6 months, 1 CFU (1 to 5 CFU). Heavily colonized fragments were observed for duration of graft function of 2 months or less, whereas at 6 months all the fragments trapped fewer than 50 CFU/cm2 of graft segment. Scanning electron microscopy showed that colonization was closely associated with healing. Staphylococcal entrapment was related to the amount of fibrin deposits, which were especially abundant where the thrombotic matrix was unorganized and on bare polyester filaments. Graft colonization is especially to be feared in the first weeks after graft implantation, an observation which may help to define guidelines for preventing hematogenous vascular graft infection.
Leport
C
C
Department of Infectious and Tropical Diseases, Claude Bernard Hospital, Paris, France.
Goéau-Brissonnière
O
O
Lebrault
C
C
Guidoin
R
R
Vildé
J L
JL
Bacourt
F
F
Péchère
J C
JC
D000818:Animals; D001012:Aorta, Abdominal / Q000648:ultrastructure; D001013:Aorta, Thoracic / Q000648:ultrastructure; D001807:Blood Vessel Prosthesis; D004285:Dogs; D008855:Microscopy, Electron, Scanning; D011093:Polyethylene Terephthalates; D011183:Postoperative Complications / Q000473:pathology*; D018805:Sepsis / Q000473:pathology*; D013203:Staphylococcal Infections / Q000473:pathology*; D013997:Time Factors; D014945:Wound Healing
D011093:Polyethylene Terephthalates