Vascular prosthetic infection with Staphylococcus epidermidis: Experimental study of pathogenesis and therapy

Abstract

To determine whether a slime-producing strain of Staphylococcus epUlermUlis was capable of producing acute infection of a prosthetic vascular graft, 5 cm segments of knitted Dacron were implanted in the infrarenal aortic position ofdogs in three groups ofanimals. 'These included a control group (no graft contaminati~n), a contaminated group that received a graft soaked in an S. epidermidis solution (untreated group), and a contaminated group in which pe~operative antibiotics (three doses of ce(amandole, 100 mg/kg) were administered (prophylaxis group). In all the animals reexploration and graft removal were performed at 10 days, with replacement of the defect being achieved with a new uncontaminated graft. 'These animals underwent explorati~n a third time after an additional 10-day period.. S. epidermidis was not grown from the control animals (n = 7) but was cultured in 44% of the prophylaxis group (n = 9) and 88% of the untreated group (n = 16) during at least one of the• operative procedures (X 2 = 15.859; P < 0.001). 'The pathologic features ofacute S. epUlermidis. infectio~were best seen in the untreated animals and included anastomotic dismption (56%), periaortic hematoma, and lymphadenopathy (94%). Microscopic examination ofthe ,aortic tissues revealed extensive infiltrates ofleukoeytes, macrophages, and foreign body giant cells with aortic necrosis. These features were less prominent" in the prophylaxis animals. We conclude that S. epidermidis is capable of producing acute graft infection with perigraft inflammation and anastomotic dismption. 1he administration of perioperative antibiotics reduced but did not abolish these effects of bacterial con~ation of prosthetic vascular grafts. (J VAse SURG 1989;9:464-71.) Two percent to 5% of patients in w:hom a prosthetic vascwar graft is placed develop graft infection. 1 Since 1984 several reports have documented that coagulase-n~gativestaphylococci are now the most common organisms infecting vas~ular prosthetic grafts. 2 -4 Staphylococcus epidertnidis has also been identified as the most frequent cause of infection in ar-, tificial joints, prosthetic heart valves, and cerebral peritoneal shunt devices.~'Research concerping the pathogenesis of S. epiderm.idis infection and clinical recognition ofthe magnitude of the problem have been hampered by the lack of a reproducible animal model. We developed a model of S. epidertnidis prosthetic graft infections

Studies in thoracic aortic graft infections: The development of a porcine model and a comparison of collagen-impregnated dacron grafts and cryopreserved allografts

“…This is in contrast to the established infrarenal aortic graft infection preparation, which is relevant to abdominal aortic and peripheral vascular graft infections. [12][13][14] These findings may not be applicable to the thoracic aorta because of the intrinsically different properties between the thoracic and abdominal aorta.…”

Treatment of vascular graft infection by in situ replacement with cryopreserved aortic allografts: An experimental study

“…The model of infrarenal aortic S. epidermidis polyester graft infection that we used mimics the clinical situation of late graft infection, resulting in a perigraft inflammatory process and anastomotic false aneurysm formation. 23,25,26 This model proba-bly differs from the clinical setting only in regard of the degree of contamination and the required time before the infection is established. 23,26 The study strain was a clinical isolate of S. epidermidis, which now causes an increasing number of vascular prosthetic graft infections.…”

“…23,25,26 This model proba-bly differs from the clinical setting only in regard of the degree of contamination and the required time before the infection is established. 23,26 The study strain was a clinical isolate of S. epidermidis, which now causes an increasing number of vascular prosthetic graft infections. 8 These organisms produce an extracellular matrix of glycocalyx that facilitates bacterial adherence and colonization of the graft material and protects the bacteria from host defenses and antibiotic penetration.…”

DEVELOPMENT OF A STAPHYLOCOCCUS EPIDERMIDIS VASCULAR GRAFT INFECTION MODEL IN SHEEP

“…I-' Careful aseptic technique and pre-operative antibiotic prophylaxis minimizes the rate of infection but it still occurs up to a rate of 3.4%.3 Staphylococcus epidermidis is becoming an increasingly recognized problem in vascular surgery. Bandyk et al reported a 10 year series of 30 graft infections, 18 (60%) caused by Staph. epidermidis, though positive cultures were not obtained in three cases.4 They described Staph.…”