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Summary: We present the case of a 57-year-old woman with a history of breast implants after augmentation mastopexy and persistent breast pain for six months. Despite a previous implant exchange with capsulectomy, the patient experienced a recurrence of symptoms for the last six months with a sudden worsening during the last night. Clinical examination revealed an asymmetry in favour of the left breast, but otherwise no clear evidence of implant-associated complication. The reported pain started retrosternally and radiated to the left scapula and arm. An acute myocardial infarction was suspected. Subsequent investigations confirmed a ST-elevation myocardial infarction. The patient received immediate cardiac catheterization, addressing an acute occlusion of the left anterior descending artery, followed by dual antiplatelet therapy.Despite successful treatment of the myocardial infarction, the patient continued to report pain in her left breast. In addition, inflammatory markers were significantly elevated. After excluding other possible sources of infection, sonography confirmed the suspicion of an implant infection. A multidisciplinary team approach guided therapeutic decision-making, balancing the high cardiovascular risk with the need to manage the implant-associated infection. Empirical antibiotic therapy and implant removal under sedoanalgesia facilitated resolution of symptoms and infection. This case highlights the importance of maintaining a broad differential diagnosis in patients presenting with breast implant-related concerns, particularly in those with concomitant cardiovascular risk factors.

Introduction. Deep infection after open osteosynthesis of tibial plateau fractures occurs in 9.9%. This rate is significantly higher than in surgical treatment of closed injuries of other localizations. Many authors consider it necessary to improve management protocols for patients with complex plateau fractures in order to minimize or prevent the development of infectious complications. Aims of the study: 1) to discuss the treatment tactics of a patient with an intraarticular fracture of the tibial plateau after osteosynthesis complicated by the development of early deep surgical site infection (SSI), using clinical case as an example; 2) to carry out the analysis of medical care defects. Case description. A 71-year-old patient with compromised somatic status underwent osteosynthesis with a buttress plate and allogeneic bone grafting of the metaphyseal defect on the 12th day after injury. In 7 days after the occurrence of signs of infection, a revision surgery was performed. Later, a number of consecutive revisions were performed due to recurrences of the infectious process. The complex of measures against SSI included the use of vacuum drainage systems and antibacterial spacers. As a result, the wounds had healed. Two years after the injury, the patient had a good functional result. Conclusion. The presented clinical case has shown that even if the treatment tactic for early peri-implant infection is chosen correctly, there are several defects in our routine practice. First of all, inaccurate sampling of material for bacteriological study and inadequate duration of antibacterial therapy are to be mentioned. To successfully treat infectious complications of osteosynthesis, a team of like-minded specialists including traumatologists as well as physicians, microbiologists and clinical pharmacologists is needed. Undoubtedly, surgical treatment of fractures might develop into infectious complications. Their diagnosis and treatment are often accompanied by a number of various mistakes. The most important points are early radical revision of the postoperative wound, etiotropic antibacterial therapy, maintaining stability of fixation after primary osteosynthesis. If these standards are complied with, the outcome of surgical treatment might be satisfying even with such a severe complication as peri-implant infection. At the same time, we are planning further researches aimed at improving algorithms and tactics for surgical treatment of infectious complications, reducing surgery trauma level and upgrading quality of primary osteosynthesis.

Bacterial biofilms on orthopedic implants are resistant to the host immune response and to traditional systemic antibiotics. Novel therapies are needed to improve patient outcomes. TRL1068 is a human monoclonal antibody (mAb) against a biofilm anchoring protein. For assessment of this agent in an orthopedic implant infection model, efficacy was measured by reduction in bacterial burden of Staphylococcus aureus, the most common pathogen for prosthetic joint infections (PJI). Systemic treatment with the biofilm disrupting mAb TRL1068 in conjunction with vancomycin eradicated S. aureus from steel pins implanted in the spine for 26 of 27 mice, significantly more than for vancomycin alone. The mechanism of action was elucidated by two microscopy studies. First, TRL1068 was localized to biofilm using a fluorescent antibody tag. Second, a qualitative effect on biofilm structure was observed using scanning electron microscopy (SEM) to examine steel pins that had been treated in vivo. SEM images of implants retrieved from control mice showed abundant three-dimensional biofilms, whereas those from mice treated with TRL1068 did not. Clinical Significance: TRL1068 binds at high affinity to S. aureus biofilms, thereby disrupting the three-dimensional structure and significantly reducing implant CFUs in a well-characterized orthopedic model for which prior tested agents have shown only partial efficacy. TRL1068 represents a promising systemic treatment for orthopedic implant infection.

Abstract A new hybrid ultrasound luminescent chemical imaging technique is described along with a pH sensor to image chemical concentrations at the surface of implanted medical devices. The purpose is to detect and study local biochemistry during infection. The sensor comprises a mechanoluminescent film (SrAl2O4:Eu, Dy microphosphors embedded in a biocompatible polymer film) and a pH indicator dye. A focused ultrasound beam generates green luminescence at the ultrasound focal point. By pulsing the ultrasound ON and OFF, the modulated luminescence can be distinguished from persistent luminescence, for high spatial resolution imaging. A red fluorescent dye and the pH indicator dye bromothymol blue are added to the coating to modulate the red‐light transmittance via pH dependent absorbance. Acidosis is observed as an increase in red luminescence intensity in spectroscopy and imaging. The films are sensitive to biologically relevant changes in pH (6.0–8.0) and can be imaged through optically scattering media to mimic tissue. The images have a knife edge spatial resolution of ≈3 mm through optically scattering phantoms, limited by the focused ultrasound spot size. This novel technique may permit the elucidation of implant infection at the implant surface and can be further developed for the measurement of other relevant chemical species in the future.

Abstract Background Orthopedic implant infection has become a common catastrophic complication after various orthopedic implants, which can lead to prolonged use of antibiotics and even surgical failure. The quality of care (QoC) of orthopedic implant infection is very important. Methods Titanium dioxide (TiO2) nanotube array with planar TiAg was prepared, and their antibacterial rates were tested. 400 patients hospitalized in the Department of Orthopedics of Wuhan Fourth Hospital from May 2019 to May 2020 were selected as controls (before QoC evaluation system of orthopedics), and 400 patients hospitalized from June 2020 to June 2021 were selected as observation group (after QoC evaluation system of orthopedics). Results Regardless of Staphylococcus aureus or Escherichia coli, the antibacterial rate of TiO2 nanotube array with planar TiAg was clearly higher than that of pure iron film on the 10th and 20th days (P

Abstract Host immune systems serving as crucial defense lines are vital resisting mechanisms against biofilm‐associated implant infections. Nevertheless, biofilms hinder the penetration of anti‐bacterial species, inhibit phagocytosis of immune cells, and frustrate host inflammatory responses, ultimately resulting in the weakness of the host immune system for biofilm elimination. Herein, a cell‐like construct is developed through encapsulation of erythrocyte membrane fragments on the surface of Fe3O4 nanoparticle‐fabricated microbubbles and then loaded with hydroxyurea (EMB‐Hu). Under ultrasound (US) stimulation, EMB‐Hu undergoes a stable oscillation manner to act in an “exocytosis” mechanism for disrupting biofilm, releasing agents, and enhancing penetration of catalytically generated anti‐bacterial species within biofilms. Additionally, the US‐stimulated “exocytosis” by EMB‐Hu can activate pro‐inflammatory macrophage polarization and enhance macrophage phagocytosis for clearance of disrupted biofilms. Collectively, this work has exhibited cell‐like microbubbles with US‐stimulated “exocytosis” mechanisms to overcome the biofilm barrier and signal macrophages for inflammatory activation, finally achieving favorable therapeutic effects against implant infections caused by methicillin‐resistant Staphylococcus aureus (MRSA) biofilms.

Spine implant infections portend poor outcomes as diagnosis is challenging and surgical eradication is at odds with mechanical spinal stability. The purpose of this method is to describe a novel mouse model of spinal implant infection (SII) that was created to provide an inexpensive, rapid, and accurate in vivo tool to test potential therapeutics and treatment strategies for spinal implant infections. In this method, we present a model of posterior-approach spinal surgery in which a stainless-steel k-wire is transfixed into the L4 spinous process of 12-week old C57BL/6J wild-type mice and inoculated with 1 x 103 CFU of a bioluminescent strain of Staphylococcus aureus Xen36 bacteria. Mice are then longitudinally imaged for bioluminescence in vivo on post-operative days 0, 1, 3, 5, 7, 10, 14, 18, 21, 25, 28, and 35. Bioluminescence imaging (BLI) signals from a standardized field of view are quantified to measure in vivo bacterial burden. To quantify bacteria adhering to implants and peri-implant tissue, mice are euthanized and the implant and surrounding soft tissue are harvested. Bacteria are detached from the implant by sonication, cultured overnight and then colony forming units (CFUs) are counted. The results acquired from this method include longitudinal bacterial counts as measured by in vivo S. aureus bioluminescence (mean maximum flux) and CFU counts following euthanasia. While prior animal models of instrumented spine infection have involved invasive, ex vivo tissue analysis, the mouse model of SII presented in this paper leverages noninvasive, real time in vivo optical imaging of bioluminescent bacteria to replace static tissue study. Applications of the model are broad and may include utilizing alternative bioluminescent bacterial strains, incorporating other types of genetically engineered mice to contemporaneously study host immune response, and evaluating current or investigating new diagnostic and therapeutic modalities such as antibiotics or implant coatings.

Orthopaedic implant material can get infected via haematogenous spread from a distant source at any point after implantation. The sources of haematogenous orthopaedic implant infections have been studied only for prosthetic joints. The most common source of infection has varied, but it can be, for example from the skin and soft tissues, cardiovascular system and dental infections. The risk for developing a periprosthetic joint infection (PJI) during bacteraemia is dependent on the pathogen: it is highest for Staphylococcus aureus and beta‐haemolytic streptococci, but low for gram‐negative bacteria. The risk for developing a (PJI) during Staphylococcus aureus bacteraemia (SAB) has varied between 12 and 41%; the risk for developing an infection in any orthopaedic implant in the extremities during SAB is probably almost the same as for prosthetic joints, but data are very limited. The risk of developing an infection in spinal implants during bacteraemia is not known, as it has not been studied. Especially in the case of SAB, infected orthopaedic implants are usually symptomatic, so asymptomatic implants do not routinely require further diagnostic work‐up, such as synovial fluid aspiration. [ABSTRACT FROM AUTHOR]

Study designA controlled, interventional animal study.ObjectiveSpinal implant infection (SII) is a devastating complication. The objective of this study was to evaluate the efficacy of a novel implant coating that has both a passive antibiotic elution and an active-release mechanism triggered in the presence of bacteria, using an in vivo mouse model of SII.Summary of background dataCurrent methods to minimize the frequency of SII include local antibiotic therapy (vancomycin powder), betadine irrigation, silver nanoparticles, and passive release from antibiotic-loaded poly(methyl methacrylate) cement beads, all of which have notable weaknesses. A novel implant coating has been developed to address some of these limitations but has not been tested in the environment of a SII.MethodsA biodegradable coating using branched poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS) polymer was designed to deliver antibiotics. The in vivo performance of this coating was tested in the delivery of either vancomycin or tigecycline in a previously established mouse model of SII. Noninvasive bioluminescence imaging was used to quantify the bacterial burden, and implant sonication was used to determine bacterial colony-forming units (CFUs) from the implant and surrounding bone and soft tissue.ResultsThe PEG-PPS-vancomycin coating significantly lowered the infection burden from postoperative day 3 onwards (P

Introduction Infections pose a significant challenge in orthopedics related to implant failure. In orthopedic surgeries, surgical site infections (SSIs) extend the patient's hospital stay by an average of two weeks and also increase morbidity, double hospitalization rates, and triple the financial burden on the patient. This study aims to determine the common organism in patients with postoperative implant infections presenting at a tertiary care hospital. Methods A cross-sectional study was conducted in the Department of Orthopedic Surgery at JPMC Karachi over a six-month period, from November 24, 2022, to May 25, 2023. All patients of both genders aged 18-65 years presenting with postoperative implant infection within six hours of the development of symptoms were enrolled. Baseline demographic details and clinical histories were recorded at the time of presentation. A swab for culture and sensitivity was taken from the implant site using a sterile swab stick in patients with confirmed or suspected infections. Results Of 196 patients, the mean age of the patients was 48.47±5.19 years. Gender distribution showed that 49% of patients were females and 51% were males. The mean duration of surgery was 1.71±0.49 hours (100 minutes approximately);  Klebsiella species 26% and Staphylococcus aureus  25.5% were the most common organisms isolated from infected surgical wounds, followed by Pseudomonas species in 32 patients (16.3%), Acinetobacter species in 27 patients (13.8%), Escherichia Coli  in 23 patients (11.7%), and coagulase-negative  Staphylococcus  in 13 patients (6.6%). Conclusion In our cohort, Staphylococcus species and Klebsiella species were the most common pathogens isolated from postoperative implant infections. The rise in Klebsiella species suggests that changes in prophylactic antibiotic practices may have contributed to this trend. Therefore, there is an urgent need to reassess current prophylactic strategies in light of the increasing incidence of infections caused by gram-negative bacteria., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. College of Physicians and Surgeons Pakistan issued approval OSG-2021-186-2504. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Mussab et al.)

Owing to the presence of microbial biofilm on the implant, the eradication of biofilm-associated infections poses a challenge for antibiotic therapies. The study aimed to investigate the efficacy and safety of the novel antibiotic agent TNP-2092 in the context of implant infections. In vivo, rats with periprosthetic joint infection (PJI) treated with antibiotics showed an increase in body weight and decrease in swelling, temperature, and width of knee, compared with the control group. Meanwhile, inflammatory markers in synovium and serum were decreased in the TNP-2092 group, consistent with the pathological results. Moreover, TNP-2092 was effective in eliminating bacteria and disruption biofilm formation, and further alleviated the abnormal bone absorption and reactive bone changes around the prosthesis. In conclusion, intra-articular injection of TNP-2092 is safe and effective in treating knee PJI in a rat model. The study provides a foundation for the future utilization of TNP-2092 in the management of implant-related infections. [ABSTRACT FROM AUTHOR]

Bacterial biofilms on orthopedic implants are resistant to the host immune response and to traditional systemic antibiotics. Novel therapies are needed to improve patient outcomes. TRL1068 is a human monoclonal antibody (mAb) against a biofilm anchoring protein. For assessment of this agent in an orthopedic implant infection model, efficacy was measured by reduction in bacterial burden of Staphylococcus aureus, the most common pathogen for prosthetic joint infections (PJI). Systemic treatment with the biofilm disrupting mAb TRL1068 in conjunction with vancomycin eradicated S. aureus from steel pins implanted in the spine for 26 of 27 mice, significantly more than for vancomycin alone. The mechanism of action was elucidated by two microscopy studies. First, TRL1068 was localized to biofilm using a fluorescent antibody tag. Second, a qualitative effect on biofilm structure was observed using scanning electron microscopy (SEM) to examine steel pins that had been treated in vivo. SEM images of implants retrieved from control mice showed abundant three-dimensional biofilms, whereas those from mice treated with TRL1068 did not. Clinical Significance: TRL1068 binds at high affinity to S. aureus biofilms, thereby disrupting the three-dimensional structure and significantly reducing implant CFUs in a well-characterized orthopedic model for which prior tested agents have shown only partial efficacy. TRL1068 represents a promising systemic treatment for orthopedic implant infection.

We present the case of a 57-year-old woman with a history of breast implants after augmentation mastopexy and persistent breast pain for six months. Despite a previous implant exchange with capsulectomy, the patient experienced a recurrence of symptoms for the last six months with a sudden worsening during the last night. Clinical examination revealed an asymmetry in favour of the left breast, but otherwise no clear evidence of implant-associated complication. The reported pain started retrosternally and radiated to the left scapula and arm. An acute myocardial infarction was suspected. Subsequent investigations confirmed a ST-elevation myocardial infarction. The patient received immediate cardiac catheterization, addressing an acute occlusion of the left anterior descending artery, followed by dual antiplatelet therapy. Despite successful treatment of the myocardial infarction, the patient continued to report pain in her left breast. In addition, inflammatory markers were significantly elevated. After excluding other possible sources of infection, sonography confirmed the suspicion of an implant infection. A multidisciplinary team approach guided therapeutic decision-making, balancing the high cardiovascular risk with the need to manage the implant-associated infection. Empirical antibiotic therapy and implant removal under sedoanalgesia facilitated resolution of symptoms and infection. This case highlights the importance of maintaining a broad differential diagnosis in patients presenting with breast implant-related concerns, particularly in those with concomitant cardiovascular risk factors., Competing Interests: The authors declare there is no conflict of interests., (© 2024 The Authors.)

We report the first published case of Prototheca wickerhamii breast implant infection. This occurred after mastectomy, chemotherapy, radiotherapy, breast reconstruction, implant revisions and breast seroma aspirations and was preceded by polymicrobial infection. Definitive treatment required implant removal and intravenous liposomal amphotericin B. The management of breast prosthesis infections is discussed.

Despite reductions in bacterial infection and enhanced success rate, the widespread use of systemic antibiotic prophylaxis in implant dentistry is controversial. This use has contributed to the growing problem of antimicrobial resistance, along with creating significant health and economic burdens. The basic mechanisms that cause implant infection can be targeted by new prevention and treatment methods which can also lead to the reduction of systemic antibiotic exposure and its associated adverse effects. This review aims to summarize advanced biomaterial strategies applied to implant components based on anti-pathogenic mechanisms and immune balance mechanisms. It emphasizes that modifying the dental implant surface and regulating the early immune response are promising strategies, which may further prevent or slow the development of peri-implant infection, and subsequent failure.

Background: Orthopedic implant infection has become a common catastrophic complication after various orthopedic implants, which can lead to prolonged use of antibiotics and even surgical failure. The quality of care (QoC) of orthopedic implant infection is very important. Methods: Titanium dioxide (TiO2) nanotube array with planar TiAg was prepared, and their antibacterial rates were tested. 400 patients hospitalized in the Department of Orthopedics of Wuhan Fourth Hospital from May 2019 to May 2020 were selected as controls (before QoC evaluation system of orthopedics), and 400 patients hospitalized from June 2020 to June 2021 were selected as observation group (after QoC evaluation system of orthopedics). Results: Regardless of Staphylococcus aureus or Escherichia coli, the antibacterial rate of TiO2 nanotube array with planar TiAg was clearly higher than that of pure iron film on the 10th and 20th days (P < 0.05). The accuracy of hospitalization assessment, disease assessment, adverse event intervention, nursing record filing and nursing satisfaction in observation group were higher as against controls (P < 0.05). Conclusion: The TiO2 nanotube array with planar TiAg has good antibacterial property, which can effectively prevent orthopedic implant infection. The construction of QoC evaluation system for orthopedic specialists can effectively improve the QoC of orthopedic specialists. [ABSTRACT FROM AUTHOR]

BackgroundIntrawound vancomycin powder (VP) has been rapidly adopted in spine surgery with apparent benefit demonstrated in limited, retrospective studies. Randomized trials, basic science, and dose response studies are scarce.PurposeThis study aims to test the efficacy and dose effect of VP over an extended time course within a randomized, controlled in vivo animal experiment.Study design/settingRandomized controlled experiment utilizing a mouse model of spine implant infection with treatment groups receiving vancomycin powder following bacterial inoculation.MethodsUtilizing a mouse model of spine implant infection with bioluminescent Staphylococcus aureus, 24 mice were randomized into 3 groups: 10 infected mice with VP treatment (+VP), 10 infected mice without VP treatment (No-VP), and 4 sterile controls (SC). Four milligrams of VP (mouse equivalent of 1 g in a human) were administered before wound closure. Bioluminescence imaging was performed over 5 weeks to quantify bacterial burden. Electron microscopy (EM), bacterial colonization assays (Live/Dead) staining, and colony forming units (CFU) analyses were completed. A second dosing experiment was completed with 34 mice randomized into 4 groups: control, 2 mg, 4 mg, and 8 mg groups.ResultsThe (+VP) treatment group exhibited significantly lower bacterial loads compared to the control (No-VP) group, (p

Background: Evidence suggests the renin-angiotensin system (RAS) plays key immunomodulatory roles. In particular, angiotensin-converting enzyme (ACE) has been shown to play a role in antimicrobial host defense. ACE inhibitors (ACEi) and angiotensin receptor blockers (ARB) are some of the most commonly prescribed medications, especially in patients undergoing invasive surgery. Thus, the current study assessed the immunomodulatory effect of RAS-modulation in a preclinical model of implant infection. Methods: In vitro antimicrobial effects of ACEi and ARBs were first assessed. C57BL/6J mice subsequently received either an ACEi (lisinopril; 16 mg/kg/day), an ARB (losartan; 30 mg/kg/day), or no treatment. Conditioned mice blood was then utilized to quantify respiratory burst function as well as Staphylococcus aureus Xen36 burden ex vivo in each treatment group. S. aureus infectious burden for each treatment group was then assessed in vivo using a validated mouse model of implant infection. Real-time quantitation of infectious burden via bioluminescent imaging over the course of 28 days post-procedure was assessed. Host response via monocyte and neutrophil infiltration within paraspinal and spleen tissue was quantified by immunohistochemistry for F4/80 and myeloperoxidase, respectively. Results: Blood from mice treated with an ACEi demonstrated a decreased ability to eradicate bacteria when mixed with Xen36 as significantly higher levels of colony forming units (CFU) and biofilm formation was appreciated ex vivo (p < 0.05). Mice treated with an ACEi showed a higher infection burden in vivo at all times (p < 0.05) and significantly higher CFUs of bacteria on both implant and paraspinal tissue at the time of sacrifice (p < 0.05 for each comparison). There was also significantly decreased infiltration and respiratory burst function of immune effector cells in the ACEi group (p < 0.05). Conclusion: ACEi, but not ARB, treatment resulted in increased S. aureus burden and impaired immune response in a preclinical model of implant infection. These results suggest that perioperative ACEi use may represent a previously unappreciated risk factor for surgical site infection. Given the relative interchangeability of ACEi and ARB from a cardiovascular standpoint, this risk factor may be modifiable.

Host immune systems serving as crucial defense lines are vital resisting mechanisms against biofilm-associated implant infections. Nevertheless, biofilms hinder the penetration of anti-bacterial species, inhibit phagocytosis of immune cells, and frustrate host inflammatory responses, ultimately resulting in the weakness of the host immune system for biofilm elimination. Herein, a cell-like construct is developed through encapsulation of erythrocyte membrane fragments on the surface of Fe 3 O 4 nanoparticle-fabricated microbubbles and then loaded with hydroxyurea (EMB-Hu). Under ultrasound (US) stimulation, EMB-Hu undergoes a stable oscillation manner to act in an "exocytosis" mechanism for disrupting biofilm, releasing agents, and enhancing penetration of catalytically generated anti-bacterial species within biofilms. Additionally, the US-stimulated "exocytosis" by EMB-Hu can activate pro-inflammatory macrophage polarization and enhance macrophage phagocytosis for clearance of disrupted biofilms. Collectively, this work has exhibited cell-like microbubbles with US-stimulated "exocytosis" mechanisms to overcome the biofilm barrier and signal macrophages for inflammatory activation, finally achieving favorable therapeutic effects against implant infections caused by methicillin-resistant Staphylococcus aureus (MRSA) biofilms., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

BackgroundAnimal models are used to guide management of periprosthetic implant infections. No adequate model exists for periprosthetic shoulder infections, and clinicians thus have no preclinical tools to assess potential therapeutics. We hypothesize that it is possible to establish a mouse model of shoulder implant infection (SII) that allows noninvasive, longitudinal tracking of biofilm and host response through in vivo optical imaging. The model may then be employed to validate a targeting probe (1D9-680) with clinical translation potential for diagnosing infection and image-guided débridement.MethodsA surgical implant was press-fit into the proximal humerus of c57BL/6J mice and inoculated with 2 μL of 1 × 103 (e3), or 1 × 104 (e4), colony-forming units (CFUs) of bioluminescent Staphylococcus aureus Xen-36. The control group received 2 μL sterile saline. Bacterial activity was monitored in vivo over 42 days, directly (bioluminescence) and indirectly (targeting probe). Weekly radiographs assessed implant loosening. CFU harvests, confocal microscopy, and histology were performed.ResultsBoth inoculated groups established chronic infections. CFUs on postoperative day (POD) 42 were increased in the infected groups compared with the sterile group (P < .001). By POD 14, osteolysis was visualized in both infected groups. The e4 group developed catastrophic bone destruction by POD 42. The e3 group maintained a congruent shoulder joint. Targeting probes helped to visualize low-grade infections via fluorescence.DiscussionGiven bone destruction in the e4 group, a longitudinal, noninvasive mouse model of SII and chronic osteolysis was produced using e3 of S aureus Xen-36, mimicking clinical presentations of chronic SII.ConclusionThe development of this model provides a foundation to study new therapeutics, interventions, and host modifications.

Spine implant infections portend poor outcomes as diagnosis is challenging and surgical eradication is at odds with mechanical spinal stability. The purpose of this method is to describe a novel mouse model of spinal implant infection (SII) that was created to provide an inexpensive, rapid, and accurate in vivo tool to test potential therapeutics and treatment strategies for spinal implant infections. In this method, we present a model of posterior-approach spinal surgery in which a stainless-steel k-wire is transfixed into the L4 spinous process of 12-week old C57BL/6J wild-type mice and inoculated with 1 x 103 CFU of a bioluminescent strain of Staphylococcus aureus Xen36 bacteria. Mice are then longitudinally imaged for bioluminescence in vivo on post-operative days 0, 1, 3, 5, 7, 10, 14, 18, 21, 25, 28, and 35. Bioluminescence imaging (BLI) signals from a standardized field of view are quantified to measure in vivo bacterial burden. To quantify bacteria adhering to implants and peri-implant tissue, mice are euthanized and the implant and surrounding soft tissue are harvested. Bacteria are detached from the implant by sonication, cultured overnight and then colony forming units (CFUs) are counted. The results acquired from this method include longitudinal bacterial counts as measured by in vivo S. aureus bioluminescence (mean maximum flux) and CFU counts following euthanasia. While prior animal models of instrumented spine infection have involved invasive, ex vivo tissue analysis, the mouse model of SII presented in this paper leverages noninvasive, real time in vivo optical imaging of bioluminescent bacteria to replace static tissue study. Applications of the model are broad and may include utilizing alternative bioluminescent bacterial strains, incorporating other types of genetically engineered mice to contemporaneously study host immune response, and evaluating current or investigating new diagnostic and therapeutic modalities such as antibiotics or implant coatings.

Despite reductions in bacterial infection and enhanced success rate, the widespread use of systemic antibiotic prophylaxis in implant dentistry is controversial. This use has contributed to the growing problem of antimicrobial resistance, along with creating significant health and economic burdens. The basic mechanisms that cause implant infection can be targeted by new prevention and treatment methods which can also lead to the reduction of systemic antibiotic exposure and its associated adverse effects. This review aims to summarize advanced biomaterial strategies applied to implant components based on anti-pathogenic mechanisms and immune balance mechanisms. It emphasizes that modifying the dental implant surface and regulating the early immune response are promising strategies, which may further prevent or slow the development of peri-implant infection, and subsequent failure.

Introduction: Implant infections caused by Staphylococcus aureus are responsible for high mortality and morbidity worldwide. Treatment of these infections can be difficult especially when bacterial biofilms are involved. In this study we investigate the potential of infrared photoimmunotherapy to eradicate staphylococcal infection in a mouse model., Methods: A monoclonal antibody that targets Wall Teichoic Acid surface components of both S. aureus and its biofilm (4497-IgG1) was conjugated to a photosensitizer (IRDye700DX) and used as photoimmunotherapy in vitro and in vivo in mice with a subcutaneous implant pre-colonized with biofilm of Staphylococcus aureus. A dose of 400 μg and 200 μg of antibody-photosensitizer conjugate 4497-IgG-IRDye700DXwas administered intravenously to two groups of 5 mice. In addition, multiple control groups (vancomycin treated, unconjugated IRDye700DX and IRDye700DX conjugated to a non-specific antibody) were used to verify anti-microbial effects., Results: In vitro results of 4497-IgG-IRDye700DX on pre-colonized (biofilm) implants showed significant (p<0.01) colony-forming units (CFU) reduction at a concentration of 5 μg of the antibody-photosensitizer conjugate. In vivo, treatment with 4497-IgG-IRDye700DX showed no significant CFU reduction at the implant infection. However, tissue around the implant did show a significant CFU reduction with 400 μg 4497-IgG-IRDye700DX compared to control groups (p = 0.037)., Conclusion: This study demonstrated the antimicrobial potential of photoimmunotherapy for selectively eliminating S. aureus in vivo. However, using a solid implant instead of a catheter could result in an increased bactericidal effect of 4497-IgG-IRDye700DX and administration locally around an implant (per operative) could become valuable applications in patients that are difficult to treat with conventional methods. We conclude that photoimmunotherapy could be a potential additional therapy in the treatment of implant related infections, but requires further improvement., Competing Interests: The authors have no conflicts of interest to declare, (Copyright: © 2024 Dijk et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Spine implant infections portend disastrous outcomes, as diagnosis is challenging and surgical eradication is at odds with mechanical spinal stability. Current imaging modalities can detect anatomical alterations and anomalies but cannot differentiate between infection and aseptic loosening, diagnose specific pathogens, or delineate the extent of an infection. Herein, a fully human monoclonal antibody 1D9, recognizing the immunodominant staphylococcal antigen A on the surface of Staphylococcus aureus, was assessed as a nuclear and fluorescent imaging probe in a preclinical model of S. aureus spinal implant infection, utilizing bioluminescently labeled bacteria to confirm the specificity and sensitivity of this targeting. Postoperative mice were administered 1D9 probe dual labeled with 89-zirconium (89Zr) and a near infrared dye (NIR680) (89Zr-NIR680-1D9), and PET-CT and in vivo fluorescence and bioluminescence imaging were performed. The 89Zr-NIR680-1D9 probe accurately diagnosed both acute and subacute implant infection and permitted fluorescent image-guided surgery for selective debridement of infected tissue. Therefore, a single probe could noninvasively diagnose an infection and facilitate image-guided surgery to improve the clinical management of implant infections.

The main purpose of spinal fixation is to provide conditions for vertebral fusion at the level of injury. Bone fusion is associated with many factors including stability of injured segment, restoration of the anterior support column, condition of the bone tissue and other aspects. The timing of bone formation can be affected by soft tissue inflammation at the site of the rods of the external fixation system. Peri-implant infection is reported to occur in 0.7-20 % of cases with external transpedicular fixation. The timing of the complication and the dependence of the frequency of the occurrence on the patient's treatment strategy are debatable. Another topical issue is the study of the consequences of peri-implant infection with the need to establish the validity of the assumption about the effect of peri-implant infection on the rate of bone formation using a clinical model. This would allow the findings to be used for new methods of treatment considering the risk of possible complications, giving preference to low-traumatic semi-closed methods of spine fixation. Nevertheless, external transpedicular fixation is practical for open spinal injury or significant vertebral displacement with the need of significant reduction efforts to be applied. The purpose was to explore the effect of soft tissue inflammation on the timing of bone formation with spinal fusion surgery using different surgical methods of treatment of uncomplicated spinal fractures. Material and methods The review included 111 patients with uncomplicated fractures of the lower thoracic and lumbar spine. Based on a retrospective analysis the participants were assigned to three groups depending on the presence/absence of peri-implant infection and the timing of the occurrence: 81 patients experienced no complications, 16 had serous-purulent inflammation of soft tissues at the site of the rods of the external fixation device that developed on average after 20 days with 14 patients seen with pin tract infection after 2 months of anterior fusion surgery and failed bone formation. Results Peri-implant infection rate was found to be higher with external fixation (14.4 %) than that with anterior fusion surgery (12.6 %). The complication rate was 1.85 times less with one-stage surgical treatment as compared to two-stage treatment. Peri-implant infection developed later (after 21‑63 days) with one-stage treatment as compared with two-stage procedure (after 12-24 days). Infection associated with the external fixation led to increase in timing of bone formation by 6-7 %, by 2-4 weeks on average. Bone formation failed in 35 % of cases (p < 0.0002) due to peri-implant inflammation caused by Staphylococcus aureus, as the common pathogen and the bacteria detected resulted in ineffective antibacterial therapy. Immunological parameters (IgM and haptoglobin) were quantified to assess the risk of peri-implant infection. Discussion Peri-implant infection rate associated with external transpedicular fixation was shown to be comparable with the previously obtained data. Sharply defined notions were reported earlier to differentiate between infectious peri-implant osteolysis and mechanical loosening. We compared the data on the duration of bone formation and the timing of peri-implant infection and developed a model that with high sensitivity (73 %) and specificity (100 %) allowed description of cases with impaired osteogenesis. Changes in some immunological parameters (immunoglobulins, acute-phase proteins) were shown to affect both bone formation and stability of bone fixation.

An 11-year-old male neutered Yorkshire Terrier was presented with a cervical mass that developed a draining tract. Aside from the dysphagia reported by the owner, his neurologic exam was normal. Three years prior, the patient was diagnosed with an atlantoaxial subluxation that was ventrally stabilized with polymethylmethacrylate (PMMA) and self-tapping titanium screws. There were no postoperative complications until presenting with the cervical mass and dysphagia. Computerized tomography (CT) of the cervical spine confirmed caudal migration of the PMMA and screws with an abscess surrounding the implant. A surgical explant of the PMMA and screws was performed without complication. The atlantoaxial joint remained normally aligned on postoperative radiographs. Cultures of the implant grew Streptococcus bovis. He was treated with cephalexin (22 mg/kg PO BID) for 30 days. At the time of his one-month recheck, he was swallowing normally with no neurologic deficits. He remains normal at the time of this report (17 months later). This case reports a successful explant of a chronic atlantoaxial implant infection.

Recently, dental implants have had the most important role in oral rehabilitation. Peri-implantitis is considered a common complication of dental implants. Adjacent natural teeth with untreated endodontic pathology may be a potential risk for implant placement. Retrograde/periapical peri-implantitis (RPI), the inverting of the progress direction of peri-implantitis. Radiographically, it is characterized by signs of periapical bone loss and normal coronal osteointegration of the implant; and its prevalence is closely associated with endodontic lesions of adjacent teeth. Another novel separate disease entity is known as the endodontic peri-implant defects (endo-implant defects), manifesting as the peri-implant marginal bone loss due to endodontic pathology of adjacent teeth, to which endodontists and implantologists are supposed to attach great importance. This current study presented two cases of different types of peri-implant infection in which conducting proper intervention to the endodontic lesions of adjacent teeth resulted in full radiographic and clinical resolution of peri-implant defects.