Comparison of Anti-Bacterial Prophylactic Properties of Two Different Vascular Grafts: Action of Anti-Bacterial Graft Coating and Systemic Antibiotic Treatment

Abstract

M.A. and G.L.S. contributed equally to this researchThe main problem associated with artificial vascular devices is the risk of bacterial infections, mostly sustained by coagulase negative staphylococci or Staphylococcus aureus. Many efforts have been made to identify materials refractory to bacterial adhesion. The aim of our study is to verify the antimicrobial properties of two kinds of vascular prosthesis to prevent early onset infections and the efficacy of the concomitant action of a systemic antibiotic treatment. Adult male Wistar rats were used. We subcutaneously implanted in four groups a silver-coated prosthesis fragment, and a rifampicin-soaked prosthesis fragment in the remaining four groups. We inoculated in the site of implant a high bacterial burden of S. aureus in four groups and a low burden in the remaining groups. Systemic levofloxacin was administered for seven days in four groups representing the two kinds of prosthesis; after 21 days the rats were sacrificed, prosthesis fragments were sonicated and the corresponding supernatants were plated for bacterial counts. The rifampicin-soaked prostheses explanted from rats treated with levofloxacin were sterile, regardless of the bacterial inoculum. In other groups some prostheses were colonized. In the experimental rat model used, the action of local and systemic antibiotic treatment was able to reduce colonisation of artificial prostheses.Vascular grafts are made with highly biocompatible polymeric materials. The main problem associated with their use is related to infections due to colonization of the graft by biofilm forming bacteria, even in the very early phases after graft implant. The consequence is graft failure and removal (1-2).Gram-positive bacteria, especially staphylococci, are the prevalentpathogens involved in approximately 80% of all cases (3-5). In arterial graft infections S.aureus is the most common organism isolated from infected synthetic grafts, accounting for 24% to 36% of isolates, but coagulase-negative staphylococci are isolated in 4% to 21% of infections. In recent years research efforts in the field of new biomaterials have aimed at the discovery of new devices refractory to the microbial adhesion (6-7).The aim of our study is to verify the susceptibility

A systematic review of preclinical data regarding commercial silver-coated vascular grafts

“…Different results were obtained. In the study of Artini et al (24), IGS could prevent infection at 21 days if a low bacterial load (10 5 CFU/ml) was used, but not when a high bacterial load was applied (10 8 CFU/ml). This effect disappeared when no systemic antibiotics (levofloxacin intraperitoneally for seven days) were given.…”

“…Seven articles studied a commercially available silver coated graft in an animal model. (8,15,17,(24)(25)(26)(27) In this group, two studies added rifampicin soaking onto the silver coated graft. This combination resulted in an augmented antibacterial activity and a prolonged release of antibiotic and silver in the perigraft site.…”

“…(7) In a study of a subcutaneous implantation model in rats, a positive effect was observed only with a low inoculum (10 5 CFU/ml) and in the presence of systemic antibiotics. (24) Possible reasons for these conflicting in vivo results are the fact that different animal species were studiedall with their inherent different immune systemsand the extent to which the graft is exposed to bacteria and physiological conditions such as shear stress and serum components (i.e. bloodstream).…”

Rifampicin-soaked Silver Polyester versus Expanded Polytetrafluoro-ethylene Grafts for In Situ Replacement of Infected Grafts in a Porcine Randomised Controlled Trial

“…Several studies have shown that the use of antibiotic-bound grafts or systemic antibiotic treatment alone cannot prevent PVGI. 9,19,25 Furthermore, the systemic administration of rifampicin and ciprofloxacin in combination can avert the development of rifampicin resistance and achieve a higher cure rate. 26,27 In the present study, the bacteria spread into the perigraft and the aortic tissues 14 days after inoculation, and the infected tissues were not completely cleared even after performing intensive debridement.…”

What You Should Know about Escherichia Coli Infection

“…In physiological conditions, humans can hold 8-9 litres of liquid in the intestinal tract, and only about 10% of this is reabsorbed. Enteric E. coli can alter this balance, causing strong discharges of diarrhoea (26)(27)(28)(29). Enteric attacks are better controlled if the infection is controlled.…”