Infection Of Orthopaedic Implants Research Articles

D-[5-11C]-Glutamine Positron Emission Tomography Imaging for Diagnosis and Therapeutic Monitoring of Orthopedic Implant Infections.

Orthopedic implant infections (OIIs) present diagnostic and therapeutic challenges, owing to the lack of methods to distinguish between active infection and sterile inflammation. To address this unmet need, d-amino-acid-based radiotracers with unique metabolic profiles in microorganisms have emerged as a novel class of infection-specific imaging agents. Given the pivotal role of d-glutamine in bacterial biofilm formation and virulence, herein, we explored the potential of positron emission tomography (PET) imaging with d-[5-11C]-Glutamine (d-[5-11C]-Gln) for early detection and treatment monitoring of OIIs. In vitro studies confirmed an active uptake of d-[5-11C]-Gln by Staphylococcus aureus (S. aureus) biofilm commonly associated with OIIs. In vivo evaluations included PET imaging comparisons with d-[5-11C]-Gln vs l-[5-11C]-Gln or 2-deoxy-2-[18F]-fluoroglucose ([18F]-FDG) in a rat OII model with tibial implantation of sterile or S. aureus-colonized stainless-steel screws before and after treatment. These studies demonstrated that the uptake of d-[5-11C]-Gln was significantly higher in the infected screws than that in sterile screws (∼3.4-fold, p = 0.008), which displayed significantly higher infection-to-background muscle uptake ratios (∼2-fold, p = 0.011) with d-[5-11C]-Gln as compared to l-[5-11C]-Gln. Following a 3 week vancomycin treatment, imaging with d-[5-11C]-Gln showed a significant reduction in uptake at the infected sites (∼3-fold, p = 0.0008). Further regression analyses revealed a superior correlation of residual infection-associated radiotracer uptake with the postimaging ex vivo bacterial counts for d-[5-11C]-Gln (k = 0.473, R2 = 0.796) vs [18F]-FDG (k = 0.212, R2 = 0.434), suggesting that d-[5-11C]-Gln PET had higher sensitivity for detecting residual bacterial burden than [18F]-FDG PET. Our results demonstrate the translational potential of d-[5-11C]-Gln PET imaging for noninvasive detection and treatment monitoring of OIIs.

Exploring Drug Resistance: Microbial Profiles, Antibiotic Sensitivity, and Biofilm Development in Orthopedic Implant Infections.

Background With the advent of and rise in antibiotic resistance globally, especially in postoperative patients, studying the antibiogram and associated factors is the need of the hour. The present study was undertaken to document the microbiological profile in postoperative orthopedic patients with the infected implant in situ and to observe the antibiotic susceptibility patterns of isolated organisms in such infections. Methods This study was conducted in the Department of Microbiology of a tertiary care hospital for six months after obtaining institutional ethical approval. A total of 236 samples from patients with orthopedic implant infections were received during the study period, out of which 53 samples with positive culture isolate were further analyzed for microbiological profile including biofilm production. All observations and demographics were recorded and analyzed using SPSS software version 21.0(IBM Corp., Armonk, NY, USA) and represented in the form of graphs, data, and tables. Results and conclusion The study showed a culture positivity rate of 53 (23%) out of 236 samples, in which gram-negative isolates 36 (68%)were more than gram-positive isolates 17 (32%). The most common isolate was staphylococcus aureus 17 (32%) of which the majority were MRSA 13 (76%), followed by Escherichia coli 9 (17%) and Klebsiella pneumoniae 9 (17%). Out of the 53 isolates, 20 were biofilm producers. Biofilm-producing isolates were more resistant to tested routine antibiotics compared to non-biofilm. This study could represent the initial interdisciplinary effort in an ongoing process to better understand and manage orthopedic implant infections at the hospital, specifically focusing on infections related to orthopedic devices.

Dosing and treatment duration of suppressive antimicrobial therapy in orthopedic implant infections: a cohort study.

Introduction: Limited data inform about the optimal dosing and duration of suppressive antimicrobial therapy (SAT) for orthopedic implant infection (OII). We aimed to compare the effectiveness of low-dosage with standard-dosage SAT and evaluate the safety of stopping SAT. Methods: All patients with OII treated with SAT from 2011 to 2022 were retrospectively included. Data were extracted from electronic patient files. Low-dosage SAT was defined as antimicrobial therapy dosed lower than the standard dosage recommended for OII. The association of dosing strategy and other factors with failure-free survival were assessed by Kaplan-Meier and Cox proportional hazard models. Results: One-hundred-and-eight patients were included. The median follow-up time after SAT initiation was 21months (interquartile range (IQR) 10-42 months). SAT was successful in 74 patients (69 %). Low-dosage SAT ( ) was not associated with failure in univariate (hazard ratio (HR) 1.23, 95 % confidence interval (CI) 0.53-2.83) and multivariate analyses (HR 1.24, 95 % CI 0.54-2.90). In 25 patients (23 %), SAT was stopped after a median treatment duration of 26 months. In this group, one patient (4 %) developed a relapse. Conclusions: In this study, low-dosage SAT was as effective as standard dosage SAT. Moreover, stopping SAT after 2 to 3years may be justified in patients with a good clinical course. These findings warrant further research on optimal dosing and duration of SAT and on the durability of in vivo biofilms.

Solid-State Dewetting of Thin Au Films for Surface Functionalization of Biomedical Implants.

Biomaterial-centered infections of orthopedic implants remain a significant burden in the healthcare system due to sedentary lifestyles and an aging population. One approach to combat infections and improve implant osteointegration is functionalizing the implant surface with anti-infective and osteoinductive agents. In this framework, Au nanoparticles are produced on the surface of Ti-6Al-4V medical alloy by solid-state dewetting of 5 nm Au film and used as the substrate for the conjugation of a model antibiotic vancomycin via a mono-thiolated poly(ethylene glycol) linker. Produced Au nanoparticles on Ti-6Al-4V surface are equiaxed with a mean diameter 19.8 ± 7.2 nm, which is shown by high-resolution scanning electron microscopy and atomic force microscopy. The conjugation of the antibiotic vancomycin, 18.8 ± 1.3 nm-thick film, is confirmed by high resolution-scanning transmission electron microscopy and X-ray photoelectron spectroscopy. Overall, showing a link between the solid-state dewetting process and surface functionalization, we demonstrate a novel, simple, and versatile method for functionalization of implant surfaces.

Synergistic effect of chlorhexidine and azoles on candida biofilm on titanium surface.

Candida infections of orthopedic implants are one of the most detrimental orthopedic implant-related complications with unsuccessful treatment and a poor prognosis. Most orthopedic Candida infections form biofilms and have resistance to the commonly used antifungal agents. This study aimed to develop a novel combination of normally prescribed drugs against Candida biofilm on orthopedic implants. We cultured 26 clinical isolates of Candida strains to form biofilm without titanium sheets or on titanium sheets, which are the most commonly used materials for permanent or orthopedic implants. The checkerboard method was used to evaluate the synergistic effects of chlorhexidine (CHL) and azoles on these Candida biofilms. For the evaluation of synergistic effects, we constructed the cell viability assay by fluorescence staining and CFU reduction hot map of Candida. Twenty-six clinical isolates of Candida strains formed biofilm in 96-well plates without titanium sheets, and we selected 9 of them to form biofilm on titanium sheets in 24-well plates. In Candida biofilm formed in 96-wells, the synergistic rates of CHL with fluconazole, itraconazole, and voriconazole were 61% (16/26), 65% (17/26), and 23% (6/26), respectively. When compared to the blank control group, CHL monotherapy significantly inhibited biofilm formation on titanium sheets (P < 0.05). We demonstrated 100% synergistic rates of the CHL and fluconazole combination against Candida biofilm formation on titanium sheets, and the minimum inhibitory concentration of CHL and FLU decreased four- to eight-fold. We concluded that CHL combined with azoles inhibited the Candida biofilm formation 96-wells or on titanium sheets and has the potential to control the infections of orthopedic implants.

Are Absorbable Plates More Resistant to Infection Than Titanium Implants? An Experimental Pre-Clinical Trial in Rabbits.

Background: Infection of orthopaedic implants after internal fixation of bone fractures remains a major complication with occasionally devastating consequences. Recent studies have reported that the use of absorbable materials, instead of metallic ones, may lead to a lower incidence of postoperative infection. In this experimental pre-clinical animal study, we compared the infection rate between absorbable implants consisting of copolymers composed from trimethylene carbonate, L-polylactic acid, and D, L-polylactic acid monomers, and titanium implants after the inoculation of a pathogenic microorganism. Material and Methods: We used an experimental implant-related infection model in rabbits. Sixty animals were randomly and equally divided into two groups. In all animals, the right femur was exposed via a lateral approach and a 2.5 mm two-hole titanium plate with screws (Group A), or a two-hole absorbable plate and screws (Group B), were applied in the femoral shaft. Afterwards, the implant surface was inoculated with Pseudomonas Aeruginosa at a concentration of 2 × 108 CFU/mL. The primary outcome was the comparison of the incidence of developed infection between the two groups. The wound condition was monitored on a daily basis and radiographies were obtained at 12 weeks postoperatively. Infection-related laboratory markers (white blood cell count, erythrocyte sedimentation rate, and C-reactive protein values) were assessed at 3, 6, and 16 weeks postoperatively. Histologic analysis and cultures of tissue samples were also performed to evaluate the presence of infection. Results: Clinical and laboratory signs of infection were evident in 11 rabbits in Group A (36.7%), and 4 in Group B (13.3%). The difference between the groups was statistically significant (p = 0.04). Five animals in Group B (16.7%) had clinical and histologic signs of a foreign-body reaction with significantly elevated CRP and ESR values but no simultaneous presence of infection was identified (p = 0.04). Bone remodelling with thickening of the periosteum and surrounding sclerosis was demonstrated radiologically in animals developing infection or foreign-body reactions. Conclusions: Absorbable plates and screws show lower susceptibility to infection compared to titanium ones. However, their application is associated with foreign-body reaction and the potential need for a second surgical intervention.

Antifouling Behavior of Copper-Modified Titania Nanotube Surfaces.

Titanium and its alloys are commonly used to fabricate orthopedic implants due to their excellent mechanical properties, corrosion resistance, and biocompatibility. In recent years, orthopedic implant surgeries have considerably increased. This has also resulted in an increase in infection-associated revision surgeries for these implants. To combat this, various approaches are being investigated in the literature. One of the approaches is modifying the surface topography of implants and creating surfaces that are not only antifouling but also encourage osteointegration. Titania nanotube surfaces have demonstrated a moderate decrease in bacterial adhesion while encouraging mesenchymal stem cell adhesion, proliferation, and differentiation, and hence were used in this study. In this work, titania nanotube surfaces were fabricated using a simple anodization technique. These surfaces were further modified with copper using a physical vapor deposition technique, since copper is known to be potent against bacteria once in contact. In this study, scanning electron microscopy was used to evaluate surface topography; energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were used to evaluate surface chemistry; contact angle goniometry was used to evaluate surface wettability; and X-ray diffraction was used to evaluate surface crystallinity. Antifouling behavior against a gram-positive and a gram-negative bacterium was also investigated. The results indicate that copper-modified titania nanotube surfaces display enhanced antifouling behavior when compared to other surfaces, and this may be a potential way to prevent infection in orthopedic implants.

BACTERIOLOGICAL PROFILE AND THEIR SENSITIVITY PATTERN OF ANTIBIOTICS TO POST-OPERATIVE ORTHOPAEDIC IMPLANT INFECTIONS IN TERTIARY CARE HOSPITAL

Background: A correct information about most common causative organism and it sensitivity pattern in that clinical setup is essential for designing empirical therapy. Present study has been designed to study the microbiological prole and antibiotic sensitivity pattern of post-operative orthopaedic Implant infections in tertiary care teaching hospital. Material and Method: This prospective observational study. Patients who presented with the signs and symptoms of infections, conrmed by laboratory and other routine investigations, were included in present study. The demography, microbiological data sensitivity to antimicrobial agent of organism was recorded. Result: The most common pathogen isolated was pseudomonas aeruginosa that is 37 (41.1%), followed by staphylococcus aureus that is 36 (40%). Pseudomonas aeruginosa was sensitive to Piperacillin tazobactam 28(77.7%), Imipenem 26(72.2%), Imipenem+cilastatin 28(77.7%) and Meropenem 30(83.3%). Methicillin resistant staph aureus were sensitive to Cotrimoxazole 4(44.4%), Clindamycine 6(66.6%), Vancomycin 8(88.8%) and Linazolid 7(77.7%). Conclusion: Implant of femur was most commonly infected. Staphylococcus Aureus (MSSA) was commonly associated with biolm formation followed by Staphylococcus Aureus (MRSA). Pseudomonas aeruginosa isolated from implant infections were sensitive to Piperacillin+ tazobactam, Imipenem, Imipenem+cilastatin and Meropenem

Current treatment and prevention of orthopaedic infections in the horse

SummaryOrthopaedic infections, including synovial sepsis, osteomyelitis and infection of orthopaedic implants are common in equine medicine. Infections can be caused by haematogenous spread of pathogens, trauma or penetrating injuries, extension of local infections and iatrogenic causes such as surgery and synovial injections. Horses with orthopaedic infections are generally markedly lame and often require aggressive and prolonged therapy. Early diagnosis can greatly impact treatment outcomes and can be facilitated by careful physical examinations, haematology, diagnostic imaging and timely synovial fluid sampling. Concerted efforts should always be made to obtain a positive bacterial culture and sensitivity. Treatment is focused on antimicrobial therapy with local therapy, including intravenous regional limb perfusion and intrasynovial injections, being employed whenever possible; lavage and debridement; and analgesia and supportive care. Responsible use of antimicrobials and antimicrobial stewardship are critical when treating orthopaedic infections. Prognosis will depend on the source and severity of the infection, the causative agent and the time to intervention. Foals and horses can respond well to treatment and return to soundness with early, aggressive and targeted treatment.

Strontium doped electrospinning fiber membrane with antibacterial and osteogenic properties prepared by pulse electrochemical method

• Composite fibers were prepared by electrostatic spinning and pulse electrochemical deposition. • PPy controls the slow release of Sr 2+ and Cu 2+ for a long time. • Good physiological stability and long-term antibacterial effect. • Fiber has good osteogenic and angiogenic properties. The osteogenic differentiation and new bone formation are commonly delayed by bacterial infection of orthopedic implants, which is urgent to be resolved quickly in the clinic. The current paper prepared a strontium-doped electrospinning fiber membrane with antibacterial and osteogenic properties by pulse electrochemical method. Polylactic acid/hydroxyapatite (PLLA/HA) composite fiber substrate was fabricated by electrospinning technology, and strontium doped SrHA/Cu/Polypyrrole (PPy) composite coating was constructed with pulse electrodeposition method on its surface. The strontium doping technique, degradation of Sr 2+ and Cu 2+ , cellular compatibility, and the antibacterial activity of the fiber membrane were examined. The results revealed that the deposition of phosphorus and calcium on composite fiber was the highest, indicating good biological activity. The release of Sr 2+ and Cu 2+ was stable and gradual due to the modulation of PPy. The composite fiber presented excellent antibacterial performance and the antibacterial rate was close to 100% against Staphylococcus aureus and Escherichia coli. Furthermore, it is conducive to the adhesion, spread, and proliferation of vascular endothelial cells and osteoblasts, namely outstanding osteogenesis and angiogenesis abilities. In conclusion, the multifunctional PLLA/HA@SrHA/Cu/PPy composite fiber membrane with good antibacterial and osteogenic activity by electrospinning technology and pulsed electrochemical deposition method provides an effective strategy for the poor bone healing of infected bone defects. Strontium doped antibacterial osteogenic PLLA/HA@SrHA/Cu/PPy composite fiber was constructed by electrostatic spinning and pulsed electrochemical deposition technology, which showed good antibacterial properties and had the ability to promote bone induction and angiogenesis.

Research progress of antibacterial modification of orthopaedic implants surface

To summarize the related research progress of antibacterial modification of orthopaedic implants surface in recent years. The domestic and foreign related literature in recent years was extensively consulted, the research progress on antibacterial modification of orthopaedic implants surface was discussed from two aspects of characteristics of infection in orthopedic implants and surface anti-infection modification. The orthopaedic implants infections are mainly related to aspects of bacterial adhesion, decreased host immunity, and surface biofilm formation. At present, the main antimicrobial coating methods of orthopaedic implants are antibacterial adhesion coating, antibiotic coating, inorganic antimicrobial coating, composite antimicrobial coating, nitric oxide coating, immunomodulation, three-dimensional printing, polymer antimicrobial coating, and "smart" coating. The above-mentioned antibacterial coating methods of orthopedic implants can not only inhibit bacterial adhesion, but also solve the problems of low immunity and biofilm formation. However, its mechanism of action and modification are still controversial and require further research.

A study on the microbial profile at surgical site with orthopedic implant in traumatic injuries and its associated risk factors at tertiary care hospital

Introduction: Study was conducted to identify the etiological agents of orthopedic implant infections in posttraumatic postoperative period. To identify the risk factors for orthopedic implant infection. To study the Antimicrobial susceptibility patterns of the isolates with a view to formulate an empiric antibiotic regimen.Material and Methods: The study period was prospective study conducted January 2020 to December 2021. One hundred and fifty patients were investigated for early, intermediate and late post-operative infections of orthopedic bone implants using conventional microbiological procedures. Antimicrobial susceptibility testing was then performed for the isolated bacteria according to the standard guidelines.Results: Out of 150 orthopedic post traumatic, postoperative implant infections, a total of 140 isolates had positive culture (138 aerobes and 2 anaerobes). Of the total 150 cases 80.66 % was mono microbial infection whereas 12.6% had poly microbial. Staphylococcus aureus is the most common organism isolated followed by Pseudomonas and E.coli. 60.2 % of Staphylococcus aureus and 73.52% of Staphylococcus epidermidis were found to be methicillin resistant. 85 % Proteus and 67.2% of Escherichia coli were found to be Extended Spectrum Beta-Lactamases (ESBL) producers. 60% of staphylococcus showed sensitivity to Vancomycin and Rifampin, 76.78 %, 66.96%, 49.10%, 42.84%, 46.42% to Linid, Tiecoplanin, Clindamycin, Meropenum and to Imipenum respectively. Whereas 68.7% of Pseudomonas showed sensitivity to collistin, 56.25% and 53.12 to Piptaz/Tazobactum and tobramycin respectively. 70.2% of staphylococcus, 40% of Pseudomonas was sensitive to cephalosporins. Diabetes mellitus, compound injuries and longer duration of surgery were the important risk factors noted in our study. Diabetes was associated more with methicillin resistant Staphylococcus aureus. There was no difference found in sensitivity pattern in stainless steel and titanium implant.Conclusion: Prophylactic antibiotics should be started as per locally commonly observed organism and their sensitivity pattern to prevent infection.

2D materials for bone therapy.

Due to their prominent physicochemical properties, 2D materials are broadly applied in biomedicine. Currently, 2D materials have achieved great success in treating many diseases such as cancer and tissue engineering as well as bone therapy. Based on their different characteristics, 2D materials could function in various ways in different bone diseases. Herein, the application of 2D materials in bone tissue engineering, joint lubrication, infection of orthopedic implants, bone tumors, and osteoarthritis are firstly reviewed comprehensively together. Meanwhile, different mechanisms by which 2D materials function in each disease reviewed below are also reviewed in detail, which in turn reveals the versatile functions and application of 2D materials. At last, the outlook on how to further broaden applications of 2D materials in bone therapies based on their excellent properties is also discussed.

English

BACKGROUND Orthopaedic implant site infection is one of the major problems of surgical site infection associated with high morbidity and mortality. As implants are commonly used in orthopaedic procedures and especially when preceded by trauma, orthopaedic procedures are more prone for surgical site infections. We wanted to study the aerobic bacterial aetiology of infected orthopaedic implants. METHODS This was a cross sectional study carried out over a period of one and half years. The study group comprised of 100 patients who had undergone orthopaedic prosthetic implant surgeries and presented with signs and symptoms of infections. The demographic data were recorded, type of surgery, the time of infection during postoperative period and risk factors were noted. Serous / purulent discharge adjacent to infected implants were processed in the laboratory as per the standard protocol. RESULTS Among the 100 samples studied, 79 % were culture positive and 21 % culture sterile. 55.7 % were Gram-positive cocci isolated in pure, 29.1 % were Gramnegative bacilli (GNB) isolated in pure and 15.2 % were a mixture of Gram-positive cocci and Gram-negative bacilli. Staphylococcus aureus 45 (80.4 %) was the predominant isolate followed by Coagulase Negative staphylococci 11(19.6 %). Among the GNB (35), the predominant isolate was Pseudomonas aeruginosa 10 (28.6 %) followed by Klebsiella pneumoniae 8 (22.9 %). Infections occurred during the early post-operative period in 63 % cases. Methicillin resistant Staphylococcus aureus were 53.4 % and 35 % were extended spectrum beta lactamases (ESBL) among Enterobacteriaceae strains. CONCLUSIONS Orthopaedic implant site infections are common during early post-operative period. Methicillin resistant staphylococcus and ESBL strains were high. This study of aerobic bacterial analysis and their current antibiogram of orthopaedic implant infections would greatly help the orthopaedic surgeons in selecting appropriate antibiotics for prophylaxis as well as better management of patients. KEYWORDS Orthopaedic Implants, MRSA, ESBL, Orthopaedic Implant Infections, Biofilm

Protocatechualdehyde inhibits receptor activator of nuclear factor kappa-B ligand-induced osteoclastogenesis and attenuates lipopolysaccharide-induced inflammatory osteolysis.

Inflammatory osteolysis as a consequence of chronic bacterial infection underlies several lytic bone conditions, such as otitis media, osteomyelitis, septic arthritis, periodontitis, periprosthetic infection, and aseptic loosening of orthopedic implants. In consideration of the lack of effective preventive or treatments options against infectious osteolysis, the exploitation of novel pharmacological compounds/agents is critically required. The present study assessed the effect of protocatechualdehyde (PCA), a natural occurring polyphenolic compound with diverse biological activities including but not limited to antibacterial and antiinflammatory properties, on nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis in vitro and lipopolysaccharide (LPS)-induced bone loss in vivo. In the present study, it was found that PCA potently inhibited RANKL-induced osteoclast formation, fusion, and activation toward bone resorption in a dose-dependent manner via the suppression of the ERK/c-Fos/nuclear factor of activated T-cells, cytoplasmic 1 signaling axis. It was further demonstrated that the in vivo administration of PCA could effectively protect mice against the deleterious effects of LPS-induced calvarial bone destruction by attenuating osteoclast formation and activity in a dose-dependent manner. Collectively, these findings provided evidence for the potential therapeutic application of PCA in the prevention and treatment of infectious osteolytic conditions, and potentially other osteoclast-mediated bone diseases.

Microbiological profile and antibiotic sensitivity pattern of post-operative orthopaedic Implant infections in tertiary care hospital

Background: A correct information about most common causative organism and it sensitivity pattern in that clinical setup is essential for designing empirical therapy. Present study has been designed to study the microbiological profile and antibiotic sensitivity pattern of post-operative orthopaedic Implant infections in tertiary care teaching hospital.Material and Method: This prospective observational study. Patients who presented with the signs and symptoms of infections, confirmed by laboratory and other routine investigations, were included in present study. The demography, microbiological data sensitivity to antimicrobial agent of organism was recorded.Result: The most common pathogen isolated was pseudomonas aeruginosa that is 52(43.3 %), followed by staphylococcus aureus that is 50(41.66%). Pseudomonas aeruginosa was sensitive to Piperacillin tazobactam 42(80.7%), Imipenem 40(76.9%), Imipenem+cilastatin 42(80.7%) and Meropenem 43(82.7%). Methicillin resistant staph aureus were sensitive to Cotrimoxazole 6(50%), Clindamycine 9(75%), Vancomycin 11(91.7%) and Linazolid10 (83.4%).Conclusion: Implant of femur was most commonly infected. Staphylococcus Aureus (MSSA) was commonly associated with biofilm formation followed by Staphylococcus Aureus (MRSA). Pseudomonas aeruginosa isolated from implant infections were sensitive to Piperacillin+ tazobactam, Imipenem, Imipenem+cilastatin and Meropenem.

A trilogy antimicrobial strategy for multiple infections of orthopedic implants throughout their life cycle

Bacteria-associated infection represents one of the major threats for orthopedic implants failure during their life cycles. However, ordinary antimicrobial treatments usually failed to combat multiple waves of infections during arthroplasty and prosthesis revisions etc. As these incidents could easily introduce new microbial pathogens in/onto the implants. Herein, we demonstrate that an antimicrobial trilogy strategy incorporating a sophisticated multilayered coating system leveraging multiple ion exchange mechanisms and fine nanotopography tuning, could effectively eradicate bacterial infection at various stages of implantation. Early stage bacteriostatic effect was realized via nano-topological structure of top mineral coating. Antibacterial effect at intermediate stage was mediated by sustained release of zinc ions from doped CaP coating. Strong antibacterial potency was validated at 4 weeks post implantation via an implanted model in vivo. Finally, the underlying zinc titanate fiber network enabled a long-term contact and release effect of residual zinc, which maintained a strong antibacterial ability against both Staphylococcus aureus and Escherichia coli even after the removal of top layer coating. Moreover, sustained release of Sr2+ and Zn2+ during CaP coating degradation substantially promoted implant osseointegration even under an infectious environment by showing more peri-implant new bone formation and substantially improved bone-implant bonding strength.

Identification and Morphological Characterization of Biofilms Formed by Strains Causing Infection in Orthopedic Implants.

Objectives: For a better understanding of the mechanisms involved in biofilm formation, we performed a broad identification and characterization of the strains affecting implants by evaluating the morphology of biofilms formed in vitro in correlation with tests of the strains’ antibiotic susceptibility in planktonic form. The ability of the strains to form biofilms in vitro was evaluated by means of colony forming units counting, metabolic activity tests of biofilm cells, and scanning electron microscopy. Methods: A total of 140 strains were isolated from patients with orthopedic implant-related infections during the period of 2015 to 2018. The identification of the isolates was carried out through microbiological cultures and confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic susceptibility rates of the isolates were accessed according to EUCAST (European Committee on Antimicrobial Susceptibility Testing). The ability of all isolates to form biofilms in vitro was evaluated by counting the colony forming units, by measuring the metabolic activity of biofilm cells, and by analyzing the morphology of the formed biofilms using scanning electron microscopy. Results: From all the isolates, 41.84% (62 strains) were Staphylococcus epidermidis and 15.60% (22 strains) were Staphylococcus aureus. A significant difference in the capacity of biofilm formation was observed among the isolates. When correlating the biofilm forming capacity of the isolates to their antibiotic susceptibility rates, we observed that not all strains that were classified as resistant were biofilm producers in vitro. In other words, bacteria that are not good biofilm formers can show increased tolerance to multiple antibiotic substances. Conclusion: From 2015 until 2018, Staphylococcus epidermidis was the strain that caused most of the orthopedic implant-related infections in our hospital. Not all strains causing infection in orthopedic implants are able to form biofilms under in vitro conditions. Differences were observed in the number of cells and morphology of the biofilms. In addition, antibiotic resistance is not directly related to the capacity of the strains to form biofilms in vitro. Further studies should consider the use of in vitro culture conditions that better reproduce the joint environment and the growth of biofilms in humans.

Complete Genome Sequences and Methylome Analyses of Cutibacterium acnes subsp. acnes Strains DSM 16379 and DSM 1897T.

Cutibacterium acnes is a member of the normal human skin microbiome. However, it is also associated with skin disorders and persistent infections of orthopedic implants. Here, we announce complete genome sequences and methylomes of the C. acnes subsp. acnes strains DSM 1897T and DSM 16379 together with their active restriction-modification systems.

Plasma d-Dimer Levels in Non-prosthetic Orthopaedic Implant Infection: Can it Aid Diagnosis?

d-Dimer estimation has been proposed as a reliable biomarker in prosthetic joint infections. Its role in non-prosthetic orthopaedic implant infections has, however, not been studied. The objectives of this study were to assess the levels of plasma d-Dimer in non-prosthetic orthopaedic implant infection. The diagnostic efficiency of d-dimer on orthopaedic implant-related infection was evaluated. The study was designed as a cross-sectional comparative study. Patients who presented with orthopaedic implant-related infection as diagnosed by modified MSIS criteria were allocated to case group (n = 49) and patients who underwent surgical procedures with orthopaedic implants with no evidence of infection at 6weeks postoperatively were allocated to the control group (n = 48). Serum d-Dimer levels were assessed quantitatively using immunoturbidimetric assays in both groups and compared between both groups. The mean (± SD) value of serum d-Dimer in case group was 0.64 (± 0.45) μg/ml and control group was 0.77 (± 0.47) μg/ml. No significant difference was found in serum d-Dimer levels between cases and control groups (p value = 0.183). The diagnostic accuracy of d-dimer in orthopaedic implant-related infection also could not be demonstrated. The findings of d-dimer as a marker for the diagnosis of prosthetic joint infections cannot be extrapolated to non-prosthetic orthopaedic implant infection.