Introduction to biomaterials and medical device-associated infections
- History of biomaterials
- Overview of current medical devices and applications
- Overview of problems associated with medical devices
- Introduction to the structure of this book
The normal flora of the human body is diverse and most infections associated with medical devices. They are part of the normal skin flora and are frequently isolated from burn-related infections, particularly in intensive care units (Karlowski et al., 2003).
Introduction to biomaterials and medical device-associated infections Inhibition of complement activation on a model biomaterial surface by streptococcal M protein-derived peptides. Introduction to biomaterials and medical device-associated infections Polysaccharide intercellular adhesin or protein factors in biofilm accumulation of Staphylococcus epidermidis and Staphylococcus aureus isolated from hip and knee prostheses.
Biofilms and implant-associated infections
Introduction
Microbial profile of implant-associated infections
Bacteria associated with medical device infection are normally derived from the skin flora of the host (endogenous) and/or the physician (exogenous) and the environment (Rosenthal et al., 2011). Established chronic infections have a wider microbial profile with staphylococci joined by low-virulence strains of pathogens such as Propionibacterium species and other anaerobes (Zingg et al., 2008).
Relevance of biofilms in implant-associated infections
Together, they can act synergistically to form large microbial communities with increased antimicrobial resistance. Properties of increased antimicrobial resistance are attributed to the biofilm due to the presence of the extracellular polymeric matrix.
Structure and composition of biofilms
The major component of extracellular polymer can also vary between strains of the same microorganism. Therefore, both the type and amount of extracellular polymeric substances will influence the overall physicochemical properties of the biofilm ultrastructure (Celmer et al., 2008).
Pathogenesis of biofilm infection
The production of σ B also has a positive effect on the staphylococcal additional regulatory protein A (Rachid et al., 2000). Examples include L-rhamnosyl-3-hydroxydecanoyl-3-hydroxydecanoate and their production is associated with regulation of the rhaAB operon (Boles et al., 2005).
Future trends
Further information and advice
1990), 'Possible involvement of the division cycle in the spread of Escherichia coli from biofilms', Journal of Bacteriology, vol. 1973), 'Production and characterization of the mucus polysaccharide of Pseudomonas aeruginosa', Journal of Bacteriology, vol.
Introduction
Despite ongoing research, many aspects of antibiotic treatment for implant-related infections remain poorly understood. The most commonly used animals for implant-related infections are mice, rats, rabbits and guinea pigs.
Legitimacy of animal studies
Data are scarce on the most effective antimicrobials, optimal duration of administration, and best route of administration for all types of implant-related infections. In this chapter we provide an overview of the different animal models of implant-associated infections and their advantages and limitations.
Choosing the right animal model to study device- associated infections
They used implanted tissue cages (perforated Teflon cylinders) placed bilaterally in the flanks of guinea pigs (Zimmerli et al., 1982). This success in testing also translated into clinical success, albeit in clinical bone infections associated with implants (Zimmerli et al., 1998).
Repeatable data can be more easily obtained in animal studies compared to human studies due to a high variability and limited patient population in humans (Lazzarini et al., 2006). Therefore, serious side effects may go undetected in animal models and progress to human studies will fail after a successful animal study.
Correlation of outcome between animal and clinical studies
Therefore, results in animal models should be evaluated critically, but they will give a first idea about drug treatment or the efficacy of implants and are a necessary bridge between in vitro experiments and human clinical studies (Barza, 1978; Tunkel and Scheld, 1989). Animal studies also allow comparison between antimicrobial treatment regimens in a standardized experiment (Lazzarini et al., 2006).
Conclusion and future trends
Variability due to systemic or local patient factors influences immune surveillance and metabolism, and local vascularization can be avoided (Lazzarini et al., 2006). However, the relative scarcity of prospective, randomized studies with statistical power regarding treatment strategies in clinical cases of implant-associated infections makes it difficult to provide a general answer about the correlation with human studies.
Sources of further information and advice
1992 a) 'Effect of subinhibitory concentrations of cefamandole and cefuroxime on adherence of Staphylococcus aureus and Staphylococcus epidermidis to polystyrene culture plates', Eur J Clin Microbiol Infect Dis b) 'Effectiveness of subinhibitory concentrations of pefloxacin in preventing experimental Staphylococcus aureus foreign body infection in mice', Drugs Exp Clin Res. 2011) "Monoclonal anti-glucosaminidase antibodies as passive immunization for methicillin-resistant Staphylococcus aureus (MRSA) orthopedic infections", Bonekey Osteovision.
Diagnosis of biofilm- associated infections in medical devices
- Introduction
- Importance of detection of biofilm
- Sites of biofilm formation
- Collection of samples for biofilm detection
- Examples of methods for the detection of biofilms associated with infections
- Future trends
- Conclusion
Early detection of biofilm at an infected site can aid in successful treatment and save the patient from an expensive, long hospital stay (Chowdhary et al. To confirm CAUTI, urine is collected from the sampling port of the urinary catheter using a sterile syringe and needle (Singh et al al., 2010).
Acknowledgement
2009 ) Biofilm formation potential of Staphylococci on polymer surface and its correlation with Methicillin susceptibility. 2006 ) Detection of three different screening methods for biofilm formation among clinical isolates of Staphylococci: an evaluation.
Diagnosis and treatment of implant-associated infections
- Introduction
- Risk factors and prevention
- Diagnosis
- Treatment
- Future trends
However, adverse effects, such as myalgias, arthralgias and nausea limit its use (Uçkay et al., 2009a). Improved knowledge of metabolic properties of biofilm-grown bacteria is still needed (Uçkay et al., 2009c).
Surface modification of
Introduction
Principles of bacterial cell–biomaterial surface interactions
In addition to being passively moved by flow, bacteria can exhibit directed motility, including swimming, swarming, and twitching, in response to chemical and physical cues (Berdakin et al., 2013). Recently, the tortuous motility-mediated biofilm expansion of Pseudomonas aeruginosa was visualized (Gloag et al., 2013).
Substrate specific biological response
Host cells will also respond differently to such surfaces, given the significantly higher interfacial shear strength in the case of the high-peaked surface. The scale at which the surfaces are examined also affects the values of the roughness parameters.
Looking at nature for inspiration
The self-cleaning (dynamic) component of wettability is also influenced by the specific surface morphology, where the arrangement of triple contact lines can modify the adhesive/repellent affinity of the surface (Sun et al., 2011). Even more interesting are examples where architecture alone, independent of chemistry, is responsible for the bactericidal activity of the surface.
Modifications to prevent initial stages of bacterial adhesion
Recently, naturally nanopatterned surfaces of the wings of the cicada Psaltoda claripennis were demonstrated to kill bacteria on contact based solely on their physical surface structure (Pogodin et al., 2013). In fact, cicada wings were able to repel or even resist adhesion by Pseudomonas aeruginosa cells (Ivanova et al., 2012).
Methods to prevent irreversible attachment of microorganisms
Exposure to fetal bovine serum prior to bacterial challenge did not reduce coating activity against the tested strains. The spacer helped preserve penicillin's mobility, allowing the molecules to disrupt S.
Mitigation of biofilm formation by attached organisms
A poly(ethylene glycol) spacer separated by maleic anhydride (PEG-MA) was used to immobilize penicillin on expanded poly(tetrafluoroethylene) surfaces in the form PEN – PEG – MA – ePTFE ( Aumsuwan et al., 2007 ). A material-independent NO immobilization and release is based on poly(noradrenaline) surface chemistry (Hong et al., 2013).
Future trends
Production and antibacterial activity of hybrid materials containing quaternary ammonium salts via sol-gel process. Antibacterial activity of plastic coated with silver-doped organic-inorganic hybrid coating produced by sol-gel processes.
Surface nanoengineering for
Introduction
Modification of surface nano topography to inhibit bacterial adhesion
Nanoscale topography has been shown to influence the morphology, genomics and proteomics of adherent Escherichia coli (Rizzello et al., 2011). On the other hand, albumin has shown inhibitory effects on bacterial adhesion (An et al., 1995;.
Surface functionalization with eluting antibacterial agent
Another method of incorporating silver onto surfaces is through the use of polyelectrolyte multilayers (PEMs) (Lichter et al., 2009). The thickness of the coating typically ranges from tens to hundreds of nanometers (Croll et al., 2006).
Surface functionalization with anti- adhesive polymers
In high ionic strength media, reduced electrical double-layer interactions will also compromise the stability of the PLL-g-PEG layer (Blättler et al., 2006). The functionalized surfaces are highly hydrophilic (contact angle of 8°) and bacterial adhesion is inhibited (Zhang et al., 2008).
Immobilization of bactericidal moieties on surfaces
Examples of strategies that can be used for the controlled immobilization of AMP are given in Figure 7.5 (Costa et al., 2011). CMCS has also been grafted onto polydopamine-pretreated medical grade silicone surfaces (Wang et al., 2012).
Conclusion and future trends
By chemically cross-linking the PEMs using carbodiimide, the structural stability was improved and the antibacterial properties were maintained even after prolonged immersion in PBS. Further advances in this field will require collaborative interdisciplinary efforts among physicians, scientists, and engineers in designing and testing innovative surfaces to combat biomaterial-related infections.
Sources of further information and advice
Chua PH, Neoh KG, Kang ET and Wang W (2008 b), 'Surface functionalization of titanium with hyaluronic acid/chitosan polyelectrolyte multilayers and RGD for promoting osteoblast functions and inhibiting bacterial adhesion', Biomaterials. Hu XF, Neoh KG, Shi ZL, Kang ET, Poh CK and Wang W An in vitro assessment of titanium functionalized with polysaccharides conjugated with vascular endothelial growth factor for enhanced osseointegration and inhibition of bacterial adhesion', Biomaterials.
Bioactive biomaterials for controlling biofilms
Introduction
As such, high-value combination products (drug and device combinations) have been the subject of significant global growth. By 2014, global sales of drug-device combination products are expected to reach $27 billion annually.
Definition of medical device
Biomaterials
The concept of bioactivity was thus defined as "a bioactive material is one that elicits a specific biological response at the material interface, resulting in the formation of a bond between the tissue and the material" (Hench et al., 1972; Hench, 1994). Bioresorption provides a means by which drug release from biomaterials can be altered by altering the rate of resorption and surface modification (Simpson et al., 2014).
Biomaterial applications in medical devices
There is also evidence of a localized immunosuppressive environment in the immediate vicinity of the material. Successful prevention of medical device-related infection requires a deep understanding of interfacial mechanisms leading to bacterial attachment and biofilm formation, but it is also necessary to develop an understanding of the host responses to the implanted biomaterial, especially the processes involved in the FBR, if indeed .
Post- implantation device- associated infections
Synergy within mixed cultures may occur due to increased access of extracellular enzymes and the absorption of molecules facilitated by this. The transfer of substrates from the medium can be increased up to threefold by any increase in turbulence at the interface between the biofilm surface and the surrounding medium.
Development of conventional antimicrobial biomaterials
Recently, pH-activated release of antifungal (miconazole) and microbicidal agents (chlorhexidine digluconate) from polymethacrylic acid (PMAA)/diurethane dimethacrylate-based dental biomaterials for the control of Candida-associated denture stomatitis has been described (Cao et al., 2010). A number of studies have validated the use of enzymatic triggers as stimuli for release of antimicrobial agents to control adhesion and biofilm formation at hydrogel surfaces.
Conclusion
Recently, Gilmore and colleagues described the development of hydrogel-based coatings for medical devices containing PEGylated peptidyl prodrugs of conventional antibiotics, which are substrates for staphylococcus. 1999) Microbial biofilms: their development and significance for infections associated with medical devices. of these microbial communities is leading to a revolution that could transform the science of microbiology.
Antibiotics and cements for the prevention of biofilm-associated
- Introduction
- Biomaterials, infections and orthopedics
- History of antibiotic- loaded bone cement (ALBC)
- Indication of ALBC
- Method of mixing the ALBC
- The choice of antibiotic, its dosage and associations of different drugs
- The antibiotic release
- Mechanical properties of ALBC
- Toxicity
- Conclusion
This could lead to a decrease in the diffusion rate of antibiotics (Neut, 2001), but this difference is not considered significant by most surgeons (Neut, 2003). There is also a linear relationship between the porosity of the cement and the release of antibiotics after one week.
Antibacterial composite restorative materials for
Introduction
Current direct aesthetic restorative materials
