Implant-associated infection

An important characteristic of microbial biofilms is their innate resistance to immune system and antibiotic killing (89, 90). This has made microbial biofilms a common and difficult-to-treat cause of medical infections (87,91,92). It has recently been estimated that over 60% of the bacterial infections currently treated in hospitals are caused by bacterial biofilms (91). Several ehronic infections (e.g. respiratory infections caused by Pseudomonas aeruginosa in the cystic fibrosis lung. Staphylococcal lesions in endocarditis, and bacterial prostatitis, primarily caused by Escherichia coli) have been shown to be mediated by biofilms (93). More notably, biofilms (particularly of Staphylococcus aureus, P. aeruginosa, and E. coli) are also a major cause of infections associated with medical implants (94, 95). The number of implant-associated infections approaches 1 million per year in the United States alone, and their direct medical costs exceed 3 billion annually (96). Thus, there is an urgent need to find novel approaches to eradicate biofilms. 

Saginur R, StDenis M, Ferris W, Aaron SD, Chan F, Lee C, et al. Multiple combination bactericidal testing of staphylococcal biofilms fiom implant-associated infections. Antimicrob Agents Chemother 2006 50 55-61. http //dx.doi.0rg/lO.l 128/aac.50.1.55-61.2006. 

These global findings suggest that electrospim fiber-based devices could be suitable to prevent and treat implant-associated infections. 

Kazemzadeh-Narbat, M., Lai, B.F.L., Ding, C., Kizhakkedathu, J.N., Hancock, R.E.W, Wang, R., 2013. Multilayered coating on titanium for controlled release of antimicrobial peptides for the prevention of implant-associated infections. Biomaterials 34,5969-5977. http //dx.doi. org/10.1016/j.biomaterials.2013.04.036. 

ZimmerU, W., SendL P., 2011. Pathogenesis of implant-associated infection the role of the host Semin. Immunopathol. 33, 295-306. http //dx.doi.org/10.1007/s00281-011-0275-7. 

Gilchrist SE, Lange D, Letchford K, Bach H, Fazli L, Burt HM (2013) Fusidic acid and rifampicin co-loaded PLGA nanofibers for the prevention of orthopedic implant associated infections. J Control Release 170 64—73... 

In addition to blood-material interaction, fibrous encapsulation, and microbial infection, implantable prostheses are associated with a multitude of other interrelated biological phenomena including specific immunologic reactions, complement activation, systemic toxicity, hypersensitivity, and implant-associated tumor formation [9]. For more detailed discussion on these biological processes, the readers are referred to specialized textbooks [9,17] and reviews [12,30,40],... 

After implantation, the surface of the prosthesis is the first component to come into contact with the surrounding biological milieu. Therefore, surface characteristics play an important role in controlling the course of subsequent biological reactions. Antifouling materials are materials that can resist protein adsorption or microbial adhesion [205,206]. Hence, they have potential applications as surface coatings on implantable devices such as heart valves and hip joint prostheses to minimize biofihn formation and subsequent device-associated infections. 

A. Trampuz, W. Zimmerli, Diagnosis and treatment of implant-associated septic arthritis and osteomyelitis, Curr. Infect. Dis. Rep. 10 (2008) 394-403. 

Infection, loosening, and patellar complications have been identified as prevalent reasons of TKA revision (Figure 8.10). In a study of 440 revision surgeries performed between 1982 and 1999, Fehring and colleagues reported that infection was the single largest cause of knee arthroplasty revision within the first 5 years of implantation (2001). In a more recent study of 212 knee revisions performed between 1997 and 2000 by Sharkey and associates, infection was responsible for 25% of revisions within the first 2 years of implantation, but only 7.8% of components implanted over 2 years were infected (2002). 

Because of the high resistance against antibiotics and chemotherapy, biofilm-associated infections usually lead to recurrent inflammation. Reoperation may be necessary, but inflammation could also result in osteomyelitis, amputation, or even death. The development of longer-term performing synthetic implants, showing reduced infectious complications, requires full understanding of bacterial adhesion. 

Ambrose, C.G., Clyburn, T.A., Mika, J., et al. Evaluation of emtibiotic-impregnated microspheres for the prevention of implant-associated orthopaedic infections. J. Bone Joint Surg. Am. 96, 128-134 (2014)... 

From what has been said it is obvious that the environmental conditions within the human body are quite hostile and vary according to the degree of interaction with the body and the implant and the degree of trauma and infection associated with the implantation procedure. 

SSIs are classified as either incisional (such as cellulitis of the incision site) or involving an organ or space (such as with meningitis). Incisional SSIs may be superficial (skin or subcutaneous tissue) or deep (fascial and muscle layers). Both types, by definition, occur by postoperative day 30. This period extends to 1 year in the case of deep infection associated with prosthesis implantation. 

High-risk procedures include implantation of prosthetic materials and other procedures in which surgical-site infection is associated with high morbidity. 

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