RESEARCH ARTICLE Methicillin-Susceptible Staphylococcus aureus Biofilm Formation on Vascular Grafts: an In Vitro Study Cristina Tello-Díaz,a,b Marta Palau,c,d Estela Muñoz,c Xavier Gomis,c,d Joan Gavaldà,c,d Nuria Fernández-Hidalgo,d,e,f Sergi Bellmunt-Montoyab,c,d,g a Department of Vascular and Endovascular Surgery, Hospital de la Santa Creu i Sant Pau, Institute of Biomedical Research (II-B Sant Pau), CIBER CV, Barcelona, Spain b Universitat Autònoma de Barcelona (UAB), Departament de Cirurgia i Ciències Morfològiques, Barcelona, Spain c Antimicrobial Resistance Laboratory, Vall d'Hebron Research Institute (VHIR), Infectious Diseases Department, Hospital Universitari Vall d'Hebron, Barcelona, Spain d CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain e Infectious Diseases Department, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain Red Española de Investigación en Patología Infecciosa (REIPI RD16/0016/0003), Instituto de Salud Carlos III, Madrid, Spain f g Department of Angiology, Vascular and Endovascular Surgery, Hospital Universitari Vall d’Hebron, Barcelona, Spain Nuria Fernández-Hidalgo and Sergi Bellmunt-Montoya contributed equally to this work. Author order has been determined by seniority. ABSTRACT The aim of this study was to quantify in vitro biofilm formation by methicillin- susceptible Staphylococcus aureus (MSSA) on the surfaces of different types of commonly used vascular grafts. We performed an in vitro study with two clinical strains of MSSA (MSSA2 and MSSA6) and nine vascular grafts: Dacron (Hemagard), Dacron-heparin (Intergard heparin), Dacron-silver (Intergard Silver), Dacron-silver-triclosan (Intergard Synergy), Dacron- gelatin (Gelsoft Plus), Dacron plus polytetrafluoroethylene (Fusion), polytetrafluoroethylene (Propaten; Gore), Omniflow II, and bovine pericardium (XenoSure). Biofilm formation was induced in two phases: an initial 90-minute adherence phase and a 24-hour growth phase. Quantitative cultures were performed, and the results were expressed as log10 CFU per milliliter. The Dacron-silver-triclosan graft and Omniflow II were associated with the least biofilm formation by both MSSA2 and MSSA6. MSSA2 did not form a biofilm on the Dacron-silver-triclosan graft (0 CFU/mL), and the mean count on the Omniflow II graft was 3.89 CFU/mL (standard deviation [SD] 2.10). The mean count for the other grafts was 7.01 CFU/mL (SD 0.82). MSSA6 formed a biofilm on both grafts, with 2.42 CFU/mL (SD 2.44) on the Dacron-silver-triclosan graft and 3.62 CFU/mL (SD 2.21) on the Omniflow II. The mean biofilm growth on the remaining grafts was 7.33 CFU/mL (SD 0.28). The differ- ences in biofilm formation on the Dacron-silver-triclosan and Omniflow II grafts compared to the other tested grafts were statistically significant. Our findings suggest that of the vascular grafts we studied, the Dacron-silver-triclosan and Omniflow II grafts might pre- vent biofilm formation by MSSA. Although further studies are needed, these grafts seem to be good candidates for clinical use in vascular surgeries at high risk of infections due to this microorganism. Editor Aude A. Ferran, Innovations IMPORTANCE The Dacron silver-triclosan and Omniflow II vascular grafts showed the Therapeutiques et Resistances greatest resistance to in vitro methicillin-susceptible Staphylococcus aureus biofilm formation Copyright © 2023 Tello-Díaz et al. This is an compared to other vascular grafts. These findings could allow us to choose the most resist- open-access article distributed under the terms of the Creative Commons Attribution 4.0 ant to infection prosthetic graft. International license. KEYWORDS vascular graft, infection, biofilm, Staphylococcus aureus, in vitro, prosthesis Address correspondence to Cristina Tello-Díaz, cristina.tello11@gmail.com, or infections ctello@santpau.cat. The authors declare no conflict of interest. Received 27 September 2022 V ascular graft infection (VGI) is a feared complication that affects 2 to 4% of patients (1). It is associated with high morbidity and mortality rates of up to 75% (2, 3), and as many as 4 in 10 patients require amputation (4). Major complications include anastomotic Accepted 6 January 2023 Published 7 February 2023 March/April 2023 Volume 11 Issue 2 10.1128/spectrum.03931-22 1 S. aureus Biofilm Formation on Vascular Grafts Microbiology Spectrum TABLE 1 Bacterial counts of biofilm formation by MSSA2 and MSSA6 on the surfaces of nine vascular graftsa Data for strain: MSSA2 MSSA6 Material Mean (log10 CFU/mL) SD Mean (log10 CFU/mL) SD Dacron 7.30 0.34 7.51 0.25 Dacron-heparin 7.38 0.10 7.38 0.15 Dacron-silver 6.30 1.82 7.27 0.15 Dacron-silver-triclosan 0 0 2.42 2.44 Dacron-gelatin 7.55 0.24 7.47 0.15 Fusion 7.21 0.31 7.46 0.11 PTFE 6.40 0.39 6.88 0.31 Omniflow II 3.89 2.10 3.62 2.21 Bovine pericardium 6.98 0.30 7.35 0.26 aLog, logarithm; MSSA, methicillin-susceptible Staphylococcus aureus; PTFE, polytetrafluoroethylene. disruption with massive bleeding, aortoenteric fistulas, distal embolization of infected thrombi, sepsis, and death (3). Intraoperative contamination is considered the most common cause of VGI (3, 5), espe- cially when the groin is involved (4, 6). Risk factors for infection may be host related, such as diabetes mellitus, immunosuppression, and obesity (7), or surgery-related, such as emergent procedures and reinterventions. Active infections in lower extremity wounds at the time of surgery also increase the risk (3, 5). Up to 58% of VGIs are caused by Gram-positive bacteria, including Staphylococcus aureus, coagulase-negative staphylococci, and Enterococcus spp (8). Gram-negative bacteria are the next most common causative agents (38% of cases), followed by yeasts and anaerobic microorganisms (5). VGI is a complex condition that requires multidisciplinary management. The main treat- ments are antimicrobial therapy and aggressive surgery involving complete graft removal and in situ or extra-anatomic reconstruction (9). Complete graft removal, however, is not always feasible due to the high risk of morbidity and mortality (3, 5). Antimicrobial therapy, often long term, is the cornerstone treatment (5), but its effectiveness can be limited by biofilm formation on the surfaces of grafts that cannot be removed (10). Intraoperative measures to prevent graft infection are crucial and well established, but consideration must also be given to the type of graft used. Autologous material is preferable for vascular surgery (5), but it is often unavailable or unsuitable. Synthetic grafts are thus frequently used in peripheral artery interventions and aortic surgeries (5). They are designed to be as similar as possible to autologous graft material in terms of infection risk, patency, and user-friendliness. Conclusive evidence is lacking on which types of grafts are most susceptible to infection (5). The aim of this study was to quantify the in vitro formation of methicillin-susceptible Staphylococcus aureus (MSSA) biofilms on the surfaces of biosynthetic and biologic grafts used in routine vascular surgery. RESULTS The mean MSSA2 and MSSA6 counts (log10 CFU/mL), as well as standard deviation (SD) values, are shown in Table 1. Significant differences in biofilm formation were observed between the grafts (P , 0.001). The Dacron-silver-triclosan and Omniflow II grafts showed the least biofilm formation for both strains and were each compared with the other grafts. MSSA2 did not form biofilm on the Dacron-silver-triclosan graft (0 CFU/mL), and the mean count on the surface of the Omniflow II graft was 3.89 CFU/mL (SD 2.10). The mean growth of MSSA2 on the other seven grafts was 7.01 CFU/mL (SD 0.82). The differences in biofilm formation by MSSA2 were significant in both cases: 0 CFU/mL (P , 0.001) on the Dacron-silver-triclosan graft and 3.89 CFU/mL (P , 0.001) on the Omniflow II graft versus 7.01 CFU/mL on the other grafts. March/April 2023 Volume 11 Issue 2 10.1128/spectrum.03931-22 2 S. aureus Biofilm Formation on Vascular Grafts Microbiology Spectrum FIG 1 Biofilm quantification expressed as log10 CFU per milliliter and standard deviation (SD) of one strain of methicillin-susceptible Staphylococcus aureus (MSSA2) growing on the surfaces of nine different types of vascular grafts. The different grafts are indicated in different colors. The error bars in the graph indicate the standard deviation. log, logarithm; PTFE, polytetrafluoroethylene. The mean bacterial counts for the biofilms formed by MSSA6 were 2.42 CFU/mL (SD 2.44) on the Dacron-silver-triclosan graft and 3.62 CFU/mL (SD 2.21) on the Omniflow II. The mean growth on the other seven grafts was 7.33 CFU/mL (SD 0.28). The differences in the mean counts for the other grafts were significant: 2.42 CFU/mL (P , 0.001) for the Dacron-silver- triclosan graft and 3.62 CFU/mL (P , 0.001) for the Omniflow II versus 7.33 CFU/mL on the other grafts. The combined results of all the experiments and the standard deviation (SD) values are shown in Fig. 1 and 2. FIG 2 Biofilm quantification in log10 CFU per milliliter of one strain of methicillin-susceptible Staphylococcus aureus (MSSA6) growing on the surfaces of nine different types of vascular grafts. The different grafts are indicated in different colors. The error bars in the graph indicate the standard deviation (SD). log, logarithm; PTFE, polytetrafluoroethylene. March/April 2023 Volume 11 Issue 2 10.1128/spectrum.03931-22 3 S. aureus Biofilm Formation on Vascular Grafts Microbiology Spectrum DISCUSSION In this in vitro study, we studied biofilm formation by two clinical strains of MSSA on the surface of nine vascular grafts used in routine clinical practice in Spain. Overall, the grafts that were most resistant to biofilm formation were the Dacron-silver-triclosan graft and the Omniflow II. The performance of the Dacron-silver-triclosan graft was particularly no- table, as the bacterial count for one of the strains was zero in all experimental replicates. The antimicrobial properties of silver acetate-coated grafts are enhanced by the addition of triclosan [5-chloro-2-(2,4-dichlorophenoxy)phenol]. The excellent results observed for the Dacron-silver-triclosan graft in our in vitro study confirm this improved efficacy and are con- sistent with recent reports (11–13). Ricco et al. (11) were the first authors to demonstrate the bactericidal activity of silver-triclosan against methicillin-resistant S. aureus (MRSA). Their find- ings were later corroborated by Berard et al. (12), who showed that grafts combining triclosan and silver acetate had better short-term antimicrobial activity against Escherichia coli, MRSA, and Candida albicans than those containing silver only. In a later study, they also showed that Dacron-silver-triclosan grafts had superior bactericidal efficacy to rifampicin-soaked grafts (13). Omniflow II, a biosynthetic graft designed to minimize the risk of infection, has shown good patency rates (14). In our study, it was associated with significantly less biofilm forma- tion than the other grafts analyzed, although other in vitro studies have reported contrasting results (15, 16). Our findings are more in line with promising reports of low reinfection rates in clinical settings (17, 18). Staphylococcal infections are more common in peripheral vascular grafts, while Gram- negative infections are more common in intra-abdominal grafts; in the latter, an aortoenteric fistula should be suspected (19). Further work is needed to determine whether the results observed in this in vitro study would hold for different infection sites. Grafts are also impregnated with antimicrobial agents to reduce infection risk (20). While rifampicin-impregnated grafts and silver acetate grafts have shown good results in experimen- tal studies (21), considerable reinfection rates have been observed in clinical settings (5, 22). In our study, no differences in MSSA biofilm formation were observed between the silver acetate-coated graft and the other grafts analyzed, confirming previous findings by Hernández-Richter et al. (23). We also observed no differences between the Dacron and polytetrafluoroethylene (PTFE) grafts. Other studies, however, have reported greater bac- terial adherence to Dacron, possibly due to its porosity. Schmitt et al. (24), for example, described greater adherence to woven polyester (Dacron) than expanded PTFE for S. aureus, Staphylococcus epidermidis, and E. coli, and their findings were confirmed by in vitro assays by Herten et al. (2). Heparin did not modify biofilm formation, and the findings for the Intergard heparin graft were very similar to those observed for the Hemagard graft fea- turing Dacron only. We also observed no differences for the gelatin-sealed graft (Gelsoft), supporting previous findings by Yasim et al. (25). Similar to our results, Lumsden et al. (26) found no differences in biofilm growth between the Fusion graft combining Dacron and PTFE and the grafts featuring these components in isolation. Bovine pericardium, which is widely used in cardiac surgery, is also used for peripheral artery surgery and, more recently, for in situ prosthetic reconstruction in patients with aortic graft infections (27–29). The use of bovine pericardium for reconstruction has been associ- ated with low reinfection rates in a number of studies, although it should be noted that these studies had short follow-ups (27, 28, 30, 31). The MSSA strains in our study showed similar levels of biofilm formation on the bovine pericardium and synthetic grafts. Lorenz et al. (32), using bioluminescence imaging for the in vivo detection of S. aureus biofilms on vascular grafts in mice, showed that bovine pericardium was significantly less resistant to S. aureus infection than the other grafts studied. A biofilm is defined as a community of microorganisms surrounded by a hydrated, extrac- ellular matrix of polymeric substances (polysaccharides, proteins, lipids, and nucleic acids) formed by these microorganisms (2). The matrix allows the microbes to adhere to surfaces (biologic or synthetic), resulting in the immobilization of cells within the biofilm and provid- ing mechanical stability and a barrier against the penetration of antimicrobials (33). In such cases, infections are difficult to resolve with medical treatment only. March/April 2023 Volume 11 Issue 2 10.1128/spectrum.03931-22 4 S. aureus Biofilm Formation on Vascular Grafts Microbiology Spectrum FIG 3 Graft preparation. (A) Graft piece attached to the loop by three stitches. (B) Samples were suspended in the tubes by perforating the caps. Because biofilms confer increased protection against the immune system and anti- biotics, the use of antimicrobial grafts could prevent these films from forming and limit colo- nization (11). This study has some limitations. As an in vitro study, its findings cannot be simply extrapolated to clinical settings, since in vivo bacterial adherence is influenced by other factors, such as graft endothelialization, contact with plasma proteins, and cellular immune responses (34). We also analyzed just two strains of MSSA, although these are preliminary results from a broader line of research that includes new experiments with other species of Staphylococcus and Gram-negative bacteria. Conclusions. The findings of this in vitro study suggest that Dacron-silver-triclosan and Omniflow II grafts have the greatest ability to prevent biofilm formation by MSSA. Further studies are needed to confirm our results and guide graft choice in patients at high risk of infection. MATERIALS AND METHODS Vascular grafts used for biofilm formation. We studied all prosthetic vascular grafts available for use in clinical practice. There were nine grafts: seven synthetic and two biologic. These were comprised of (i) Dacron (Hemagard; Maquet, Baden-Württemberg, Germany), (ii) Dacron heparin (Intergard heparin; Maquet), (iii) Dacron with silver acetate (Intergard Silver; Maquet), (iv) Dacron with silver acetate and tri- closan (Intergard Synergy; Maquet), (v) gelatin-sealed Dacron (Gelsoft Plus; Vascutek-Terumo, Inchinnan, Scotland, UK), (vi) expanded polytetrafluoroethylene (ePTFE) (Propaten with CBAS heparin surface; W.L. Gore Associates, Putzbrunn, Germany), (vii) ePTFE merged with Dacron (Fusion; Maquet), (viii) polyester with denatured sheep collagen (Omniflow II; LeMaitre Vascular, Inc., Burlington, MA, USA), and (ix) bo- vine pericardium (XenoSure; LeMaitre Vascular, Inc.). The synthetic grafts were sterilized with gas at a low temperature, while the biologic grafts were pre- pared with 70% alcohol under sterile conditions. The grafts were attached to a loop, as a modification of the protocol developed by Chandra et al., in order to submerge the samples in the inoculum and to keep them from floating. Using a standardized method, each graft was cut into circular pieces adjusted to the diameter of a 10-m L calibrated loop (Deltalab SL, Barcelona, Spain). Each graft piece was attached to a loop using 3 stitches of nonabsorb- able monofilament polypropylene (Prolene 6-0; Ethicon Inc.; Johnson & Johnson, Somerville, NJ, USA) (Fig. 3A). The cap of a 10-mL tube was then pierced and the handle fitted so that the graft was sus- pended within the tube, 1.5 cm from the bottom (Fig. 3B). Three replicates of each graft and MSSA strain were studied, and the experiment was performed in triplicate. Strains. Two clinical strains of MSSA isolated from catheter infections were used for this in vitro study. Quantification of biofilm formation was performed to ensure subsequent standardization. To this end, three MSSA strains (MSSA2, MSSA6, and MSSA7) were seeded on the surface of silicone and polyvi- nyl chloride discs using a slightly modified version of the protocol described by Chandra et al. (35). The biofilm formation steps involved a 90-min adherence phase, followed by a 24-h growth phase. Crystal violet staining according to the protocol described by Stepanovic et al. (36) was used to assess the bio- film-forming ability. MSSA2 and MSSA6 were the strongest biofilm producers and were therefore selected for this study. Biofilm formation on the surface of vascular grafts. A slightly modified version of the protocol described by Chandra et al. (35) was used to characterize biofilm formation on the surface of the vascular grafts. The MSSA strains were grown overnight in tryptic soy broth (TSB; Becton, Dickinson and Company, Le Pont-de-Claix, France) at 37°C and 60 rpm. After centrifuging and washing the bacterial suspension three times with sterile phosphate-buffered saline (PBS), pH 7.2 (Merck, Germany), an inoculum of 1  107 CFU/mL was prepared with PBS, pH 7.2. Next, tubes containing 6 mL of the inoculum were prepared, and the vascular graft March/April 2023 Volume 11 Issue 2 10.1128/spectrum.03931-22 5 S. aureus Biofilm Formation on Vascular Grafts Microbiology Spectrum preparations were submerged in them. The tubes were incubated for 90 min at 37°C (adherence phase). Then, the vascular graft was gently and carefully moved from the adhesion step tube to the new tube containing 6 mL of TSB, avoiding adding any drops containing unattached microorganisms. The grafts were incubated for 24 h at 37°C and 60 rpm (growth phase). Following the protocol of Chandra et al. (35), there were no washing steps between phases, in order to avoid underestimating the number of bacterial cells attached to the graft and therefore the biofilm formation. Quantification of biofilm formation. The suture binding the graft to the loop handle was cut out- side the tube on a sterile field, being careful not to transfer bacterial cells from the loop. Then, the graft was gently transferred to a sterile 12-well plate containing 1 mL of TSB using a sterile needle, avoiding adding any drops of liquid. Finally, both surfaces of the graft samples were gently scraped into the 12-well plate using the blunt edge of a no. 11 scalpel (Swann-Morton Ltd., Sheffield, UK). The suspension was transferred to new tubes, vortexed for 1 min, and sonicated for 10 min at 59 MHz. The tubes were centrifuged at 3,500 rpm for 10 min at room temperature and then resuspended with 1 mL of TSB; after that, the samples were serially diluted in physiological serum, and 50 m L was plated in tryptic soy agar (TSA; bioMérieux SA, Marcy l’Etoile, France) for quantitative culture. Finally, the bacterial cells were quantified and expressed as log10 CFU per milliliter. Statistical analysis. Continuous variables are reported as the mean (standard deviation [SD]). Grafts were compared using analysis of variance, and differences were examined using post hoc multiple-com- parison tests with Bonferroni correction. Since none of the grafts could be considered controls, we decided to compare the two grafts with the weakest biofilm formation by both strains with the rest of the grafts. Differences were compared using the t test. A P value of ,0.05 was considered statistically significant. The results are presented using descriptive statistics, and comparisons were made using SPSS version 26.0 (IBM Corporation). ACKNOWLEDGMENTS This study was conducted as part of the “Doctorat en Cirurgia i Ciències Morfològiques” doctoral program at Universitat Autònoma de Barcelona (UAB). We thank Manuel Quintana for providing statistical and technical support. We have no conflicts of interest to declare. REFERENCES 1. Riambau V, Böckler D, Brunkwall J, Cao P, Chiesa R, Coppi G, Czerny M, Inadequate perioperative prophylaxis and postsurgical complications after Fraedrich G, Haulon S, Jacobs MJ, Lachat ML, Moll FL, Setacci C, Taylor PR, graft implantation are important risk factors for subsequent vascular graft Thompson M, Trimarchi S, Verhagen HJ, Verhoeven EL, Kolh P, de Borst GJ, infections: prospective results from the Vascular Graft Infection Cohort Study. Chakfé N, Debus ES, Hinchliffe RJ, Kakkos S, Koncar I, Lindholt JS, Vega de Clin Infect Dis 69:621–630. https://doi.org/10.1093/cid/ciy956. Ceniga M, Vermassen F, Verzini F, Kolh P, Black JH, III, Busund R, Björck M, 8. Bandyk DF, Bergamini TM, Kinney EV, Seabrook GR, Towne JB. 1991. In Dake M, Dick F, Eggebrecht H, Evangelista A, Grabenwöger M, Milner R, situ replacement of vascular prostheses infected by bacterial biofilms. J Naylor AR, Ricco J-B, Rousseau H, Schmidli J. 2017. Editor’s choice—manage- Vasc Surg 13:575–583. https://doi.org/10.1016/0741-5214(91)90339-V. ment of descending thoracic aorta diseases: clinical practice guidelines of 9. Post ICJH, Vos CG. 2019. Systematic review and meta-analysis on the man- the European Society for Vascular Surgery (ESVS). Eur J Vasc Endovasc Surg agement of open abdominal aortic graft infections. Eur J Vasc Endovasc 53:4–52. https://doi.org/10.1016/j.ejvs.2016.06.005. Surg 58:258–281. https://doi.org/10.1016/j.ejvs.2019.03.013. 2. Herten M, Bisdas T, Knaack D, Becker K, Osada N, Torsello GB, Idelevich EA. 10. Chiesa R, Astore D, Frigerio S, Garriboli L, Piccolo G, Castellano R, Scalamogna 2017. Rapid in vitro quantification of S. aureus biofilms on vascular graft surfa- M, Odero A, Pirrelli S, Biasi G, Mingazzini P, Biglioli P, Polvani G, Guarino A, ces. Front Microbiol 8:2333. https://doi.org/10.3389/fmicb.2017.02333. Agrifoglio G, Tori A, Spina G. 2002. Vascular prosthetic graft infection: epidemi- 3. Wilson WR, Bower TC, Creager MA, Amin-Hanjani S, O’Gara PT, Lockhart ology, bacteriology, pathogenesis and treatment. Acta Chir Belg 102:238–247. PB, Darouiche RO, Ramlawi B, Derdeyn CP, Bolger AF, Levison ME, Taubert https://doi.org/10.1080/00015458.2002.11679305. KA, Baltimore RS, Baddour LM, American Heart Association Committee on 11. Ricco JB, Assadian A, Schneider F, Assadian O. 2012. In vitro evaluation of Rheumatic Fever, Endocarditis, and Kawasaki Disease of the Council on Cardio- the antimicrobial efficacy of a new silver-triclosan vs a silver collagen-coated vascular Disease in the Young, Council on Cardiovascular and Stroke Nursing, polyester vascular graft against methicillin-resistant Staphylococcus aureus. J Council on Cardiovascular Radiology and Intervention, Council on Cardiovas- Vasc Surg 55:823–829. https://doi.org/10.1016/j.jvs.2011.08.015. cular Surgery and Anesthesia, Council on Peripheral Vascular Disease, Stroke 12. Berard X, Stecken L, Pinaquy J-B, Cazanave C, Puges M, Pereyre S, Bordenave Council. 2016. Vascular graft infections, mycotic aneurysms, and endovascular L, M'Zali F. 2016. Comparison of the antimicrobial properties of silver impreg- infections: a scientific statement from the American Heart Association. Circu- nated vascular grafts with and without triclosan. Eur J Vasc Endovasc Surg 51: lation 134:e412–e460. https://doi.org/10.1161/CIR.0000000000000457. 285–292. https://doi.org/10.1016/j.ejvs.2015.10.016. 4. Gharamti A, Kanafani ZA. 2018. Vascular graft infections: an update. Infect 13. Berard X, Puges M, Pinaquy J-B, Cazanave C, Stecken L, Bordenave L, Pereyre S, Dis Clin North Am 32:789–809. https://doi.org/10.1016/j.idc.2018.06.003. M'Zali F. 2019. In vitro evidence of improved antimicrobial efficacy of silver and 5. Chakfé N, Diener H, Lejay A, Assadian O, Berard X, Caillon J, Fourneau I, triclosan containing vascular grafts compared with rifampicin soaked grafts. Eur Glaudemans AWJM, Koncar I, Lindholt J, Melissano G, Saleem BR, Senneville E, J Vasc Endovasc Surg 57:424–432. https://doi.org/10.1016/j.ejvs.2018.08.053. Slart RHJA, Szeberin Z, Venermo M, Vermassen F, Wyss TR, de Borst GJ, Bastos 14. Neufang A, Duenschede F, Espinola-Klein C, Weisser G, Savvidis S, Poplawski Gonçalves F, Kakkos SK, Kolh P, Tulamo R, Vega de Ceniga M, von Allmen RS, A, Vahl CF, Dorweiler B. 2020. Contemporary results with the biosynthetic glu- van den Berg JC, Debus ES, Koelemay MJW, Linares-Palomino JP, Moneta GL, taraldehyde denatured ovine collagen graft (Omniflow II) in femoropopliteal Ricco J-B, Wanhainen A. 2020. Editor’s choice—European Society for Vascular position. J Vasc Surg 71:1630–1643. https://doi.org/10.1016/j.jvs.2019.08.234. Surgery (ESVS) 2020 clinical practice guidelines on the management of vascular 15. Bozoglan O, Mese B, Eroglu E, Elveren S, Gul M, Celik A, Yildirimdemir HI, graft and endograft infections. Eur J Vasc Endovasc Surg 59:339–384. https://doi Ciralik H, Yasim A. 2016. Which prosthesis is more resistant to vascular graft .org/10.1016/j.ejvs.2019.10.016. infection: polytetrafluoroethylene or Omniflow II biosynthetic grafts? Surg 6. Antonios VS, Noel AA, Steckelberg JM, Wilson WR, Mandrekar JN, Harmsen WS, Today 46:363–370. https://doi.org/10.1007/s00595-015-1141-3. Baddour LM. 2006. Prosthetic vascular graft infection: a risk factor analysis using 16. Wozniak W, Kozi nska A, Ciostek P, Sitkiewicz I. 2017. Susceptibility of vascular a case-control study. J Infect 53:49–55. https://doi.org/10.1016/j.jinf.2005.10.004. implants to colonization in vitro by Staphylococcus aureus, Staphylococcus 7. Anagnostopoulos A, Ledergerber B, Kuster SP, Scherrer AU, Näf B, Greiner epidermidis, Enterococcus faecalis and Pseudomonas aeruginosa. Pol J Micro- MA, Rancic Z, Kobe A, Bettex D, Hasse B, VASGRA Cohort Study. 2019. biol 66:125–129. https://doi.org/10.5604/17331331.1235001. March/April 2023 Volume 11 Issue 2 10.1128/spectrum.03931-22 6 S. aureus Biofilm Formation on Vascular Grafts Microbiology Spectrum 17. Krasznai AG, Snoeijs MGJ, Siroen MP, Sigterman T, Korsten A, Moll FL, graft for femoropopliteal bypass. J Vasc Surg 61:703–712.e1. https://doi.org/10 Bouwman LH. 2016. Treatment of aortic graft infection by in situ recon- .1016/j.jvs.2014.10.008. struction with Omniflow II biosynthetic prosthesis. Vascular 24:561–566. 27. Almási-Sperling V, Heger D, Meyer A, Lang W, Rother U. 2020. Treatment https://doi.org/10.1177/1708538115621195. of aortic and peripheral prosthetic graft infections with bovine pericar- 18. Töpel I, Stigler T, Ayx I, Betz T, Uhl C, Steinbauer M. 2017. Biosynthetic grafts to dium. J Vasc Surg 71:592–598. https://doi.org/10.1016/j.jvs.2019.04.485. replace infected prosthetic vascular bypasses: a single-center experience. Surg 28. Keschenau PR, Gombert A, Barbati ME, Jalaie H, Kalder J, Jacobs MJ, Infect (Larchmt) 18:202–205. https://doi.org/10.1089/sur.2016.203. Kotelis D. 2021. Xenogeneic materials for the surgical treatment of aortic infec- 19. Antonello RM, D'Oria M, Cavallaro M, Dore F, Cova MA, Ricciardi MC, tions. J Thorac Dis 13:3021–3032. https://doi.org/10.21037/jtd-20-3481. Comar M, Campisciano G, Lepidi S, De Martino RR, Chiarandini S, Luzzati R, Di 29. Alonso W, Ozdemir B, Chassin-Trubert L, Ziza V, Alric P, Canaud L. 2021. Bella S. 2019. Management of abdominal aortic prosthetic graft and endograft Early outcomes of native and graft-related abdominal aortic infection man- infections. A multidisciplinary update. J Infect Chemother 25:669–680. https:// aged with orthotopic xenopericardial grafts. J Vasc Surg 73:222–231. https:// doi.org/10.1016/j.jiac.2019.05.013. doi.org/10.1016/j.jvs.2020.04.513. 20. Ricco JB, Assadian O. 2011. Antimicrobial silver grafts for prevention and 30. Allon M, Imrey PB, Cheung AK, Radeva M, Alpers CE, Beck GJ, Dember LM, Farber treatment of vascular graft infection. Semin Vasc Surg 24:234–241. https://doi A, Greene T, Himmelfarb J, Huber TS, Kaufman JS, Kusek JW, Roy-Chaudhury P, .org/10.1053/j.semvascsurg.2011.10.006. Robbin ML, Vazquez MA, Feldman HI, Hemodialysis Fistula Maturation (HFM) 21. Schneider F, O’Connor S, Becquemin JP. 2008. Efficacy of collagen silver- Study Group. 2018. Relationships between clinical processes and arteriovenous coated polyester and rifampin-soaked vascular grafts to resist infection fistula cannulation and maturation: a multicenter prospective cohort study. Am J from MRSA and escherichia coli in a dog model. Ann Vasc Surg 22:815–821. Kidney Dis 71:677–689. https://doi.org/10.1053/j.ajkd.2017.10.027. https://doi.org/10.1016/j.avsg.2008.06.011. 31. Belkorissat RA, Sadoul C, Bouziane Z, Saba C, Salomon C, Malikov S, 22. Batt M, Jean-Baptiste E, O'Connor S, Bouillanne P-J, Haudebourg P, Settembre N. 2020. Tubular reconstruction with bovine pericardium xen- Hassen-Khodja R, Declemy S, Farhad R. 2008. In-situ revascularisation for ografts to treat native aortic infections. Ann Vasc Surg 64:27–32. https:// patients with aortic graft infection: a single centre experience with silver doi.org/10.1016/j.avsg.2019.10.104. coated polyester grafts. Eur J Vasc Endovasc Surg 36:182–188. https://doi 32. Lorenz U, Schäfer T, Ohlsen K, Tiurbe GC, Bühler C, Germer C-T, Kellersmann R. .org/10.1016/j.ejvs.2008.02.013. 2011. In vivo detection of Staphylococcus aureus in biofilm on vascular pros- 23. Hernández-Richter T, Schardey HM, Wittmann F, Mayr S, Schmitt-Sody M, theses using non-invasive biophotonic imaging. Eur J Vasc Endovasc Surg 41: Blasenbreu S, Heiss MM, Gabka C, Angele MK. 2003. Rifampin and triclo- 68–75. https://doi.org/10.1016/j.ejvs.2010.09.007. san but not silver is effective in preventing bacterial infection of vascular 33. Olsen I. 2015. Biofilm-specific antibiotic tolerance and resistance. Eur J Clin Dacron graft material. Eur J Vasc Endovasc Surg 26:550–557. https://doi Microbiol Infect Dis 34:877–886. https://doi.org/10.1007/s10096-015-2323-z. .org/10.1016/S1078-5884(03)00344-7. 34. Camiade C, Goldschmidt P, Koskas F, Ricco JB, Jarraya M, Gerota J, Kieffer 24. Schmitt DD, Bandyk DF, Pequet AJ, Towne JB. 1986. Bacterial adherence E. 2001. Optimization of the resistance of arterial allografts to infection: to vascular prostheses. J Vasc Surg 3:732–740. https://doi.org/10.1016/ comparative study with synthetic prostheses. Ann Vasc Surg 15:186–196. 0741-5214(86)90037-6. https://doi.org/10.1007/s100160010051. 25. Yasim A, Gul M, Ciralik H, Ergun Y. 2006. Gelatin-sealed Dacron graft is not 35. Chandra J, Mukherjee PK, Ghannoum MA. 2008. In vitro growth and anal- more susceptible to MRSA infection than PTFE graft. Eur J Vasc Endovasc ysis of Candida biofilms. Nat Protoc 3:1909–1924. https://doi.org/10.1038/ Surg 32:425–430. https://doi.org/10.1016/j.ejvs.2006.03.014. nprot.2008.192. 26. Lumsden AB, Morrissey NJ, Comparison of Safety and Primary Patency 36. Stepanovic S, Vukovic D, Hola V, Di Bonaventura G, Djukic S, Cirkovic I, between the Fusion Bioline Heparin-Coated Vascular Graft and Exxcel Ruzicka F. 2007. Quantification of biofilm in microtiter plates: overview of Soft ePTFE (FINEST) Trial Co-investigators. 2015. Randomized controlled testing conditions and practical recommendations for assessment of bio- trial comparing the safety and efficacy between the Fusion Bioline heparin- film production by staphylococci. APMIS 115:891–899. https://doi.org/10.1111/j coated vascular graft and the standard expanded polytetrafluoroethylene .1600-0463.2007.apm_630.x. March/April 2023 Volume 11 Issue 2 10.1128/spectrum.03931-22 7