Styr på transportkvaliteten

Gennem 2 projekter for henholdsvis Energiforskningsprogrammet og Assurandør-Societetet har DTI Emballage- & Transportinstituttet udviklet en transportkvalitets deklaration, der er under europæisk standardisering. Standarden ventes indført i hele Europa om 3-4 år. Projekterne indikerer et besparelses potientiale på ca. 1.000 mia.kr/år i EU og ca. 15 mia. kr/år i Danmark. Langt hovedparten af disse besparelser kommer fra reduktion af det volumet, som emballagen optager under transporten. Projekterne viser, at grunden til dette emballageforbrug er transportbranchens manglende kvalitetsløfter. Derfor skal en kvalitetsdeklaration gensidigt forpligte transportør og transportkøber

Fibrinolytic and antibiotic treatment of prosthetic vascular graft infections in a novel rat model.

ObjectivesWe developed a rat model of prosthetic vascular graft infection to assess, whether the fibrinolytic tissue plasminogen activator (tPA) could increase the efficacy of antibiotic therapy.Materials and methodsRats were implanted a polyethylene graft in the common carotid artery, pre-inoculated with approx. 6 log10 colony forming units (CFU) of methicillin resistant Staphylococcus aureus. Ten days after surgery, rats were randomized to either: 0.9% NaCl (n = 8), vancomycin (n = 8), vancomycin + tPA (n = 8), vancomycin + rifampicin (n = 18) or vancomycin + rifampicin + tPA (n = 18). Treatment duration was seven days. Approximately 36 hours after the end of treatment, the rats were euthanized, and grafts and organs were harvested for CFU enumeration.ResultsAll animals in the control group had significantly higher CFU at the time of euthanization compared to bacterial load found on the grafts prior to inoculation (6.45 vs. 4.36 mean log10 CFU/mL, p = 0.0011), and both the procedure and infection were well tolerated. Vancomycin and rifampicin treatment were superior to monotherapy with vancomycin, as it lead to a marked decrease in median bacterial load on the grafts (3.50 vs. 6.56 log10 CFU/mL, p = 0.0016). The addition of tPA to vancomycin and rifampicin combination treatment did not show a further decrease in bacterial load (4.078 vs. 3.50 log10 CFU/mL, p = 0.26). The cure rate was 16% in the vancomycin + rifampicin group vs. 37.5% cure rate in the vancomycin + rifampicin + tPA group. Whilst interesting, this trend was not significant at our sample size (p = 0.24).ConclusionWe developed the first functional model of an arterial prosthetic vascular graft infection in rats. Antibiotic combination therapy with vancomycin and rifampicin was superior to vancomycin monotherapy, and the addition of tPA did not significantly reduce bacterial load, nor significantly increase cure rate

Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines checklist.

Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines checklist.</p

Mean relative weight changes post-infection compared to starting weight.

NaCl (n = 8), Vanco (n = 8), Vanco+rif (n = 18), Vanco+tPA (n = 8), Vanco+Rif+tPA (n = 16). Vanco: Vancomycin, Rif: Rifampicin, tPA: tissue plasminogen activator. Symbols are mean values whereas error bars show one standard deviation.</p

Dissemination of infection.

(A) Percentage of animals in each treatment group with infections in the liver, kidney or spleen. The animals could have infection in more than one organ. (B): Percentage of animals in each treatment group with systemic infection (infection in either liver, kidney or spleen). NaCl (n = 8), Vanco (n = 8), Vanco+tPA (n = 8), Vanco+Rif (n = 18), Vanco+Rif+tPA (n = 16). Vanco = Vancomycin, Rif = Rifampicin.</p

Qualitative results on bacterial growth from explanted grafts.

Qualitative results on bacterial growth from explanted grafts.</p

Effect of antibiotics and tPA on biofilms formed on grafts <i>in vivo</i> after a 7-day treatment period.

Each data point represents median Log10 CFU/mL of three replicates from one graft. Error bars represent median with IQR. Pairwise comparison of treatment groups (Mann-Whitney test, *p≤0.05 **p≤0.005).</p

Histological and immunohistochemic images of infected and sterile graft, artery and sorrounding tissue from rats 19 days after insertion.

A: Normal left a. carotis (HE), bar = 250 μm. B: Right a. carotis 19 days after insertion of a vascular graft. Neointima (ni) formation, tunica media atrophy (arrow) and fibrosis of tunica adventitia (HE), bar = 100 μm. C-F: Right a. carotis 19 days after insertion of a vascular graft and inoculation with Staphylococcus aureus. C: Pink fibrin (f) is present within graft lumen. Neutrophil granulocyte (ng) infiltration, broken elastic bands (arrow) and surrounding macrophages and collagen producing fibroblasts (HE), bar = 200 μm. D: Masson trichrome staining to identify collagen in blue, bar = 200 μm. E: Red S. aureus positive bacteria located on fibrin within graft lumen (IHC), bar = 100 μm. F: Red S. aureus positive bacteria located on the vessel surface towards the graft. Insert shows red positive bacteria within a macrophage (IHC), bar = 80 μm.</p

Surgical procedure of rat PVGI model.

(a) Anesthetized rat with shaved and exposed chest prior to surgery. (b) Incision with view to the space created between the right sternocleidomastoid and the omohyoid muscle. (c) Common carotid artery exposed and ligated. (d) Blue arrow shows exposed common carotid artery, prior to insertion of graft. (e) Graft inserted in common carotid artery and secured with ligatures. (f) Green arrow shows graft with blood flow inserted in to common carotid artery. (g) Rat post-surgery, with wound closed with sutures.</p