Calcium Phosphate Cements as Carriers of Functional Substances for the Treatment of Bone Tissue

Interest in calcium phosphate cements as materials for the restoration and treatment of bone tissue defects is still high. Despite commercialization and use in the clinic, the calcium phosphate cements have great potential for development. Existing approaches to the production of calcium phosphate cements as drugs are analyzed. A description of the pathogenesis of the main diseases of bone tissue (trauma, osteomyelitis, osteoporosis and tumor) and effective common treatment strategies are presented in the review. An analysis of the modern understanding of the complex action of the cement matrix and the additives and drugs distributed in it in relation to the successful treatment of bone defects is given. The mechanisms of biological action of functional substances determine the effectiveness of use in certain clinical cases. An important direction of using calcium phosphate cements as a carrier of functional substances is the volumetric incorporation of anti-inflammatory, antitumor, antiresorptive and osteogenic functional substances. The main functionalization requirement for carrier materials is prolonged elution. Various release factors related to the matrix, functional substances and elution conditions are considered in the work. It is shown that cements are a complex system. Changing one of the many initial parameters in a wide range changes the final characteristics of the matrix and, accordingly, the kinetics. The main approaches to the effective functionalization of calcium phosphate cements are considered in the review.

A comparative 18F-FDG and an anti-PD-L1 probe PET/CT imaging of implant-associated Staphylococcus aureus osteomyelitis

Background

Early and accurate diagnosis of infection-induced osteomyelitis, which often involves increased PD-L1 expression, is crucial for better treatment outcomes. Radiolabeled anti-PD-L1 nuclear imaging allows for sensitive and non-invasive whole-body assessments of PD-L1 expression. This study aimed to compare the efficacy of 18F-FDG and an 18F-labeled PD-L1-binding peptide probe (18F-PD-L1P) in PET imaging of implant-associated Staphylococcus aureus osteomyelitis (IAOM).

Methods

In this study, we synthesized an anti-PD-L1 probe and compared its efficacy with 18F-FDG and 18F-PD-L1P in PET imaging of implant-associated Staphylococcus aureus osteomyelitis (IAOM). The %ID/g ratios (i.e., radioactivity ratios between the infected and non-infected sides) of both probes were evaluated for sensitivity and accuracy in post-infected 7-day tibias and post-infected 21 days, and the intensity of 18F-PD-L1P uptake was compared with pathological changes measured by PD-L1 immunohistochemistry (IHC).

Results

Compared with 18F-FDG, 18F-PDL1P demonstrated higher %ID/g ratios for both post-infected 7-day tibias (P=0.001) and post-infected 21 days (P=0.028). The intensity of 18F-PD-L1P uptake reflected the pathological changes of osteomyelitic bones. In comparison to 18F-FDG, 18F-PDL1P provides earlier and more sensitive detection of osteomyelitis caused by S. aureus.

Conclusion

Our findings suggest that the 18F-PDL1P probe is a promising tool for the early and accurate detection of osteomyelitis caused by S. aureus.

Chronic Suppressive Antibiotic Treatment for Staphylococcal Bone and Joint Implant-Related Infections

Prosthetic joint infection (PJI) and fracture-related infection (FRI) are difficult-to-treat conditions in patients with severe comorbidity or significant surgical risk. In cases not eligible for standard strategy, debridement procedures with the retention of prosthesis or internal fixation device, combined with long-term antibiotic treatment and subsequent indefinite chronic oral antimicrobial suppression (COAS), can be the only reasonable choice. The aim of this study was to investigate the role of COAS and its follow-up in the management of these cases. We retrospectively analyzed a cohort of 16 patients with a follow-up of at least 6 months (mean age 75 yo, 9F, 7M, 11 PJI, 5 FRI). All microbiological isolates were tetracycline-susceptible staphylococci and for this reason a minocycline-based COAS was adopted after debridement and 3 months of antibiogram-guided antibiotic treatment. Patient monitoring was carried out on a clinical basis, with bimonthly execution of the inflammation indices and serial radiolabeled leukocyte scintigraphy (LS). The overall median time of COAS follow-up was 15 months (min 6-max 30). Moreover, 62.5% of patients were still taking COAS with no relapse after cure at the last evaluation available. Clinical failure with a relapse of the infection was observed in 37.5% of patients; interestingly, 50% of them had previously stopped COAS due to side effects of the antibiotic used. In the COAS follow-up, a combination of clinical, laboratory and LS evaluation seems to monitor the infection properly. COAS can be considered as an interesting approach in patients not suitable for standard treatments of PJI or FRI but it requires careful monitoring.

Tissue Oximetry Changes during Postoperative Dangling in Lower Extremity Free Flap Reconstruction: A Pilot Study

Background: Lower extremity free flap dangling protocols are still widely practiced, despite a paucity of evidence for their use. This pilot study investigates the use of tissue oximetry to provide further insight into the physiological effect of postoperative dangling in lower limb free flap transfer. Methods: Ten patients undergoing lower extremity free flap reconstruction were included in this study. Free flap tissue oxygen saturation (StO₂) was continuously measured using non-invasive near-infrared spectroscopy. Measurements were performed on the free flap and contralateral limb during dangling from postoperative day (POD) 7 until 11, according to the local dangling protocol. Results: StO₂ values measured in the free flap diminished to 70 ± 13.7% during dangling. This minimum StO₂ was reached significantly later, and correspondingly the area under the curve (AUC) was significantly larger on POD 11 compared to the start of the dangling protocol on POD 7, reflecting an improving free flap microvascular reactivity. The dangling slope was equal between the free flap and contralateral leg. The reperfusion slope was significantly flatter on POD 7 compared to the other PODs (p < 0.001). Thereafter, no significant differences between PODs were observed. Patients with a history of smoking had significantly lower tissue oximetry values compared to non-smokers. Conclusions: The application of tissue oximetry during dangling provides further insight into the physiological effect (i.e., changes in microcirculatory function) of the free flap of the reconstructed lower extremity. This information could potentially be useful to either revise or disrupt the use of such dangling protocols.

aureus Infection with Osseointegration in Murine Models of Implant-Associated Osteomyelitis

Eradication of MRSA osteomyelitis requires elimination of distinct biofilms. To overcome this, we developed bisphosphonate-conjugated sitafloxacin (BCS, BV600072) and hydroxybisphosphonate-conjugate sitafloxacin (HBCS, BV63072), which achieve "target-and-release" drug delivery proximal to the bone infection and have prophylactic efficacy against MRSA static biofilm in vitro and in vivo. Here we evaluated their therapeutic efficacy in a murine 1-stage exchange femoral plate model with bioluminescent MRSA (USA300LAC::lux). Osteomyelitis was confirmed by CFU on the explants and longitudinal bioluminescent imaging (BLI) after debridement and implant exchange surgery on day 7, and mice were randomized into seven groups: 1) Baseline (harvested at day 7, no treatment); 2) HPBP (bisphosphonate control for BCS) + vancomycin; 3) HPHBP (bisphosphonate control for HBCS) + vancomycin; 4) vancomycin; 5) sitafloxacin; 6) BCS + vancomycin; and 7) HBCS + vancomycin. BLI confirmed infection persisted in all groups except for mice treated with BCS or HBCS + vancomycin. Radiology revealed catastrophic femur fractures in all groups except mice treated with BCS or HBCS + vancomycin, which also displayed decreases in peri-implant bone loss, osteoclast numbers, and biofilm. To confirm this, we assessed the efficacy of vancomycin, sitafloxacin, and HBCS monotherapy in a transtibial implant model. The results showed complete lack of vancomycin efficacy, while all mice treated with HBCS had evidence of infection control, and some had evidence of osseous integrated septic implants, suggestive of biofilm eradication. Taken together these studies demonstrate that HBCS adjuvant with standard of care debridement and vancomycin therapy has the potential to eradicate MRSA osteomyelitis.

Pilar Cyst From a Maxillofacial Surgeon's Perspective: A Case Report and Review of Literature

Pilar cysts/trichilemmal cysts are benign lesions that arise from the hair follicle epithelium. The commonest area of occurrence is the scalp but it can also occur in the head and neck region. The pilar cyst grows at a prolonged rate. They are relatively rare and occur in about 10% of the population. They appear in the region of high concentrations of hair follicles. A 75-year-old male patient came to the Department of Oral and Maxillofacial Surgery with a chief complaint of swelling on the left side of the face for the past one year. Cytological examination revealed an infected cystic lesion. Computed tomography (CT) showed a well-defined lesion in the left temporal region. After surgical excision of the lesion, it was sent for histopathological examination. Excisional biopsy revealed a pilar cyst. We report a rare case of pilar cyst in the left temporal region in a patient who was previously operated on for osteomyelitis of the left side of the mandible up to the coronoid process. These cysts may mimic temporal space infection and lead to an incorrect treatment plan.

A Case of Pediatric Garré's Osteomyelitis Caused by Germ Infection in the Lower Impacted Wisdom Tooth

Garré's osteomyelitis, first described by Carl Garré in 1893, is a type of chronic osteomyelitis accompanied by hyperplastic periostitis. This condition affects relatively young patients and occurs in the fibula, femur, and other long bones as chronic non-purulent sclerosing osteomyelitis. Further, reactive periosteal bone formation develops due to chronic irritation or infection. In the maxillofacial region, it often occurs in the first molar region of the mandible due to caries and other similar causes, and it is rarely associated with impacted teeth. Herein, we present a 12-year-old female patient who primarily complained of swelling on the right side of the mandible. Despite taking antibiotics prescribed at local otolaryngologist, the swelling did not completely resolve. Thus, the patient was referred to the Department of Otorhinolaryngology at our hospital, where a dental-related disease was suspected. On a computed tomography scan, radiolucent findings were observed around the germ of the impacted wisdom tooth as well as hyperostosis in the lower jaw. Thus, Garré's osteomyelitis was suspected. The patient received oral anti-inflammatory treatment by the incision prior to surgery. Thereafter, the tooth germ was enucleated and newly-formed bone, which was laterally located to the cortical bone of the mandible, was removed under the effect of general anesthesia. On computed tomography scan 9 months after the surgery, hyperostosis in the angle of the mandible disappeared. Thereafter, pain and swelling did not recur, and the patient was doing well.

Non-typeable Haemophilus influenzae Osteomyelitis and Discitis of the Cervical Vertebrae in an Elderly Adult: A Case Report and Literature Review

While Haemophilus influenzae type B (Hib) is well described in the literature to cause osteomyelitis, non-typeable H. influenzae has not. In areas where vaccination is routine, the prevalence of Hib has declined, whereas, in contrast, the prevalence of non-typeable H. influenza has increased. Generally, the non-typeable strains are less invasive but can access the vascular system by transmural migration through epithelial tight junctions or by an independent intercellular mechanism. Herein, we described a case of a 79-year-old man with the first case of non-typeable H. influenzae causing cervical osteomyelitis with associated bacteremia in an elderly adult.

Orthognathic surgery associated with reconstruction of the temporomandibular joint with a customized prosthesis: a case report

The objective of this case report is to describe the treatment of a dentofacial and temporomandibular joint (TMJ) deformity by means of reconstruction with a customized TMJ prosthesis and orthognathic surgery. The article discusses the therapeutic approach and the importance of functional and esthetic rehabilitation of the patient. A 22-year-old man displayed sequelae of osteomyelitis diagnosed at 6 years of age, including facial asymmetry, laterognathism, unsatisfactory occlusion, and mandibular retrognathism. Computed tomography revealed a deformity of the left mandibular condyle, ramus, and fossa. The patient underwent 1-stage surgery that involved bimaxillary orthognathic surgery and mentoplasty in conjunction with reconstruction of the left TMJ with a customized prosthesis. Postoperatively, substantial improvement was observed in the patient's facial pattern and masticatory function, and the beneficial changes have been maintained through 2 years of follow-up. The positive outcome in this patient suggests that TMJ reconstruction using a customized prosthesis in combination with computer-guided orthognathic surgery can be a satisfactory approach to correct a mandibular defect. The advantages of 1-stage surgery for the surgeon include shorter treatment time and more predictable results, while the benefits for the patient are good esthetic and functional results and improved quality of life.

Pediatric deep venous thrombosis associated with Staphylococcus aureus osteomyelitis

INTRODUCTION

Our objective was to evaluate clinical features of children with deep venous thrombosis (DVT) and acute hematogenous osteomyelitis (AHO) caused by Staphylococcus aureus.

METHODOLOGY

We analyzed 4 years of medical records of patients with AHO and DVT caused by Staphylococcus aureus (S. aureus) and compared clinical and biochemical characteristics of AHO with and without DVT, as well as patients whose DVT dissolved in ≥ 3 weeks.

RESULTS

DVT was found in 19/87 AHO individuals (22%). The median age was 9 years (range: 0.5-15 years). 74% (14/19) patients were boys. Methicillin-susceptible Staphylococcus aureus (MSSA) was present in 58% (11/19) cases. The femoral vein and common femoral vein were the two most damaged veins (9 cases each). Anticoagulation therapy with low molecular weight heparin was given to 18 (95%) patients. Within 3 weeks of anticoagulation, 7/13 (54%) with available data had completely resolved DVT. There was no rehospitalization due to bleeding or recurrent DVT. Patients with DVT were found to be older and had increased levels of C-reactive protein, procalcitonin, D-dimer, positive blood culture, incidence of intensive care unit admission, multifocal rate, and length of hospital stay. We did not find clinical difference between patients whose DVT dissolved within 3 weeks and those with > 3 weeks.

CONCLUSIONS

Over 20% of patients with S. aureus AHO developed DVT. MSSA accounted for more than half of the cases. DVT was completely resolved in more than half of the cases after 3 weeks of anticoagulant medication, with no sequelae.

CuCeO Bimetallic Oxide Rapidly Treats Staphylococcus aureus-Infected Osteomyelitis through Microwave Strengthened Microwave Catalysis and Fenton-Therapy

Osteomyelitis caused by bacteria is a deep-seated lesion and is often treated clinically with antibiotics. Long-term use of antibiotics may predispose bacteria to develop resistance. Here, CuCeO_x material is applied to treat infectious bacterial osteomyelitis using microwave (MW)-assisted bacterial killing. Heat generation occurs as a result of the dielectric properties of the material under MW irradiation, and the material generates reactive oxygen species (ROS) under MW irradiation. Heat and ROS increase the thermal sensitivity and permeability of bacterial cell membranes, and the released copper ions easily penetrate the bacterial membrane and react with H₂ O₂ to produce a toxic hydroxyl group inside the bacteria, leading to the bacteria's eventual death. This is due to the synergistic effect of the MW thermal effect, ROS, and the breaking of the equilibrium within the bacteria. CuCeO_x can effectively treat osteomyelitis caused by Staphylococcus aureus using MW irradiation. This study can safely and effectively address the challenge of deep tissue infections by shedding light on non-invasive antimicrobial systems and using MW thermal therapy and MW dynamics to achieve therapeutic results.

Atypical Skull-Base Osteomyelitis: Comprehensive Review and Multidisciplinary Management Viewpoints

Atypical skull-base osteomyelitis is a rare but fatal disease that usually involves infection of the ethmoid, sphenoid, occipital, or temporal bones that form the skull base. Unlike typical (so-called otogenic), atypical skull-base osteomyelitis has no otogenic cause. Instead, some authors call atypical skull-base osteomyelitis sinonasal, since the infection most often originates from the nose and paranasal sinuses. Diagnosing and treating this disease is challenging. To assist in managing atypical skull-base osteomyelitis, a review of the most recent literature, with patient cases and multidisciplinary perspectives from otolaryngologists, neurosurgeons, radiologists, infectious disease specialists, pathologists, and clinical microbiologists, is provided in this paper.

The Sinus Tract in Bone and Joint Infection: Minimally Invasive Salvation or Prolonged Suffering? A Multicenter Study

This study assessed the quality of life (QOL) and the functional outcome in daily living in patients with a chronic, treatment-resistant periprosthetic joint infection (PJI) or osteomyelitis, living with a natural or iatrogenic sinus tract.

METHODS

A follow-up examination in three national reference centers for septic bone and joint surgery was performed utilizing the Hospital Anxiety and Depression Scale (HADS-D/A), the Visual Analogue Scale (VAS), and the Short Form-36 (SF-36) score, including patients with a chronic sinus tract due to treatment-resistant PJI or osteomyelitis.

RESULTS

In total, 48 patients were included, with a mean follow-up time of 43.1 ± 23.9 months. The mean SF-36 Mental Component Summary (MCS) was 50.2 (±12.3) and the Physical Component Summary (PCS) was 33.9 (±11.3). The mean HADS-D was 6.6 (±4.4) and HADS-A was 6.2 (±4.6), and the VAS was 3.4 (±2.6). The SF-36 MCS showed no significant differences between the study group and the standard population (47.0, p = 0.10), as well as the HADS-A. The PCS in the study population was significantly worse (50.0, p < 0.001), as was the HADS-D.

CONCLUSIONS

A sinus tract represents a treatment option in selected cases with an acceptable QOL. The treatment should be considered for multimorbid patients with a high perioperative risk or if the bone or soft tissue quality prevents surgery.

Value of Diagnostic Tools in the Diagnosis of Osteomyelitis: Pilot Study to Establish an Osteomyelitis Score

Osteomyelitis (OM) remains one of the most feared complications in bone surgery and trauma. Its diagnosis remains a major challenge due to lack of guidelines. The aim of this study was to prospectively analyze the value of the most common and available diagnostic tools and to establish an OM score to derive treatment recommendations. All patients with suspected OM were included in a prospective pilot study. All patients underwent blood sampling for C-reactive protein and white blood cell count analysis. Magnetic resonance imaging (MRI), and microbiologic and histopathologic samples, were taken from representative sites of initial debridement. All patients were treated according to their OM test results and followed for at least one year. Subsequently, the value of individual or combined diagnostic tools was analyzed in patients with confirmed OM and in patients in whom OM was ruled out. Based on these findings, an OM score was developed that included MRI, microbiology, and histopathology. The score identified all control patients and all but one OM patient, resulting in a correct diagnosis of 93.3%, which was validated in a second independent larger cohort. This was the first study to analyze the value of the most commonly used tools to diagnose OM. The proposed OM score provides a simple scoring system to safely interpret test results with high accuracy.

Prospective Evaluation of Magnetic Resonance Imaging Features of Magnesium-Based Alloy Screw Resorption in Pediatric Fractures

BACKGROUND

The resorption of magnesium-based alloy bioabsorbable screws results in the release of hydrogen gas, which can mimic infection and enter the growth plate. The screw itself and the released gas may also affect image quality.

OBJECTIVE

The evaluation of magnetic resonance imaging (MRI) findings during the most active phase of screw resorption is the objective, with particular focus on the growth plate and to assess for the presence of metal-induced artifacts.

MATERIAL AND METHODS

In total, 30 prospectively acquired MRIs from 17 pediatric patients with fractures treated with magnesium screws were assessed for the presence and distribution of intraosseous, extraosseous, and intra-articular gas; gas within the growth plate; osteolysis along the screw; joint effusion; bone marrow edema; periosteal reaction; soft tissue edema; and metal-induced artifacts.

RESULTS

Gas locules were found in the bone and soft tissues in 100% of the examinations, intra-articular in 40%, and in 37% of unfused growth plates. Osteolysis and the periosteal reaction were present in 87%, bone marrow edema in 100%, soft tissue edema in 100%, and joint effusion in 50% of examinations. Pile-up artifacts were present in 100%, and geometric distortion in 0% of examinations. Fat suppression was not significantly impaired in any examination.

CONCLUSIONS

Gas and edema in the bone and soft tissues are normal findings during the resorption of magnesium screws and should not be misinterpreted as infection. Gas can also be detected within growth plates. MRI examinations can be performed without metal artifact reduction sequences. Standard fat suppression techniques are not significantly affected.

Efficacy of Silver Nanoparticles-Loaded Bone Cement against an MRSA Induced-Osteomyelitis in a Rat Model

Background and Objectives: The purpose of this study was to assess the cytotoxicity and antibacterial effects of AgNP-impregnated Tetracalcium phosphate-dicalcium phosphate dihydrate (TTCP-DCPD). Materials and Methods: Using in vitro experiments, the cytotoxicity of AgNP-impregnated TTCP-DCPD against fibroblasts and osteocytes was assessed in terms of cell viability by water-soluble tetrazolium salt assay. To assess antibacterial effects, a disc diffusion test was used; osteomyelitis was induced first in vivo, by injection of methicillin-resistant Staphylococcus aureus into the tibia of rats. AgNP-impregnated TTCP-DCPD bone cement was then applied at various silver concentrations for 3 or 12 weeks. Antibacterial effects were assessed by culturing and reverse transcription-polymerase chain reaction (RT-PCR). For histological observation, the bone tissues were stained using hematoxylin and eosin. Results: Cell viability was decreased by the impregnated bone cement but did not differ according to AgNP concentration. The diameter of the growth-inhibited zone of MRSA was between 4.1 and 13.3 mm on the disks treated with AgNP, indicating antimicrobial effects. In vivo, the numbers of bacterial colonies were reduced in the 12-week treatment groups compared to the 3-week treatment groups. The groups treated with a higher (10×) dose of AgNP (G2-G5) showed a tendency of lower bacterial colony counts compared to the group without AgNP (G1). The PCR analysis results showed a tendency of decreased bacterial gene expression in the AgNP-impregnated TTCP-DCPD groups (G2-G5) compared to the group without AgNP (G1) at 3 and 12 weeks. In the H&E staining, the degree of inflammation and necrosis of the AgNP-impregnated TTCP-DCPD groups (G2-G5) showed a tendency to be lower at 3 and 12 weeks compared to the control group. Our results suggest that AgNP-impregnated TTCP-DCPD cement has antimicrobial effects. Conclusions: This study indicates that AgNP-impregnated TTCP-DCPD bone cement could be considered to treat osteomyelitis.

Staphylococcus aureus Infection Induces the Production of the Neutrophil Chemoattractants CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7 by Murine Osteoblasts

Staphylococcus aureus is the principal causative agent of osteomyelitis, a serious bacterial infection of bone that is associated with progressive inflammatory damage. Bone-forming osteoblasts have increasingly been recognized to play an important role in the initiation and progression of detrimental inflammation at sites of infection and have been demonstrated to release an array of inflammatory mediators and factors that promote osteoclastogenesis and leukocyte recruitment following bacterial challenge. In the present study, we describe elevated bone tissue levels of the potent neutrophil-attracting chemokines CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7 in a murine model of posttraumatic staphylococcal osteomyelitis. RNA sequencing (RNA-Seq) gene ontology analysis of isolated primary murine osteoblasts showed enrichment in differentially expressed genes involved in cell migration and chemokine receptor binding and chemokine activity following S. aureus infection, and a rapid increase in the expression of mRNA encoding CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7, in these cells. Importantly, we have confirmed that such upregulated gene expression results in protein production with the demonstration that S. aureus challenge elicits the rapid and robust release of these chemokines by osteoblasts and does so in a bacterial dose-dependent manner. Furthermore, we have confirmed the ability of soluble osteoblast-derived chemokines to elicit the migration of a neutrophil-like cell line. As such, these studies demonstrate the robust production of CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7 by osteoblasts in response to S. aureus infection, and the release of such neutrophil-attracting chemokines provides an additional mechanism by which osteoblasts could drive the inflammatory bone loss associated with staphylococcal osteomyelitis.

Hyperglycemia Increases Severity of Staphylococcus aureus Osteomyelitis and Influences Bacterial Genes Required for Survival in Bone

Hyperglycemia, or elevated blood glucose, renders individuals more prone to developing severe Staphylococcus aureus infections. S. aureus is the most common etiological agent of musculoskeletal infection, which is a common manifestation of disease in hyperglycemic patients. However, the mechanisms by which S. aureus causes severe musculoskeletal infection during hyperglycemia are incompletely characterized. To examine the influence of hyperglycemia on S. aureus virulence during invasive infection, we used a murine model of osteomyelitis and induced hyperglycemia with streptozotocin. We discovered that hyperglycemic mice exhibited increased bacterial burdens in bone and enhanced dissemination compared to control mice. Furthermore, infected hyperglycemic mice sustained increased bone destruction relative to euglycemic controls, suggesting that hyperglycemia exacerbates infection-associated bone loss. To identify genes contributing to S. aureus pathogenesis during osteomyelitis in hyperglycemic animals relative to euglycemic controls, we used transposon sequencing (TnSeq). We identified 71 genes uniquely essential for S. aureus survival in osteomyelitis in hyperglycemic mice and another 61 mutants with compromised fitness. Among the genes essential for S. aureus survival in hyperglycemic mice was the gene encoding superoxide dismutase A (sodA), one of two S. aureus superoxide dismutases involved in detoxifying reactive oxygen species (ROS). We determined that a sodA mutant exhibits attenuated survival in vitro in high glucose and in vivo during osteomyelitis in hyperglycemic mice. SodA therefore plays an important role during growth in high glucose and promotes S. aureus survival in bone. Collectively, these studies demonstrate that hyperglycemia increases the severity of osteomyelitis and identify genes contributing to S. aureus survival during hyperglycemic infection.

Systematic review of the microbiology of osteomyelitis associated with war injuries in the Middle East and North Africa

Osteomyelitis is a serious complication associated with war-related limb injuries requiring complicated treatment regimens and management. Few reports have been published from the Middle-East and North-Africa regions about the microbial aetiology of osteomyelitis caused by war injuries. The aim of this review is to collect published data about the microbiology of osteomyelitis in war-related injuries in the region and to derive targeted treatment regimens to manage these serious and limb-threatening infections. A thorough literature search was done using six search engines for pertinent articles. Articles with a minimum of five cases of osteomyelitis from war wounds, citation of microbial aetiology and mention of the timing of cultures obtained in relation to injury were included. Nine studies that met the eligibility criteria were included, involving 1644 patients and a total of 2332 cultures. Gram-negative bacteria were isolated from 1184 cultures, and Gram-positive bacteria were identified from 1148 cultures. Antibiotic coverage should be tailored for Gram-negative organisms in the early stages and Gram-positives in the chronic phase, respectively, with broader coverage reserved for critically ill patients. There is a dire need for further and larger studies about osteomyelitis from war injuries for targeted treatment.

Paediatric actinomycosis: A 16-year, single-institution retrospective review of cases

AIM

Actinomycosis is a rare subacute to chronic granulomatous infection which can mimic other infectious or malignant diseases. This study examined the epidemiology and treatment outcome of actinomycosis in children.

METHODS

A retrospective study on children admitted for actinomycosis in a tertiary paediatric hospital in Singapore, from January 2004 to December 2020. Clinical profile, therapeutic interventions and outcomes were examined.

RESULTS

A total of 10 patients were identified; 7 were female. The median age at first presentation was 9.8 years (range 4.7-15.7). The most common presenting symptom was fever (n = 6, 60%), followed by facial or neck swelling (n = 3, 30%) and ear pain (n = 3, 30%). Actinomycosis occurred predominantly in the orocervicofacial region (n = 6, 60%). Four patients (40%) had preceding dental infections in the form of dental caries or gingivitis. One patient had poorly controlled insulin-dependent diabetes mellitus. Actinomycosis was confirmed via culture in four patients, histopathology in four patients and both methods in two patients. All except one patient (n = 9, 90%) underwent surgical procedures. All patients received ampicillin or amoxicillin/clavulanate or other beta-lactams, for a median duration of 6.5 months (range 1.5-14). Complications included osteomyelitis (n = 4, 40%), mastoiditis (n = 2, 20%), brain abscess (n = 1, 10%) and recurrent neck abscess (n = 1, 10%). There was no mortality and all patients achieved complete resolution.

CONCLUSIONS

Paediatric actinomycosis was rare in our 16-year review, but had a high complication rate. It can occur in immunocompetent patients, and dental infection was the predominant risk factor identified. Prognosis was excellent after surgical intervention and appropriate antimicrobial therapy.

Vitamin D deficiency triggers intrinsic apoptosis by impairing SPP1-dependent antiapoptotic signaling in chronic hematogenous osteomyelitis

Chronic hematogenous osteomyelitis (CHOM) is a common bone disease characterized by the development of sequestra after bacterial infection. Emerging evidence has shown that vitamin D (VD) deficiency raises the risk of osteomyelitis, but the underlying mechanisms remain obscure. Here, we establish a CHOM model in VD diet-deficient mice by intravenous inoculation of Staphylococcus aureus. Whole-genome microarray analyses using osteoblast cells isolated from sequestra reveal significant downregulation of SPP1 (secreted phosphoprotein 1). Molecular basis investigations show that VD sufficiency activates the VDR/RXR (VD receptor/retinoid X receptor) heterodimer to recruit NCOA1 (nuclear receptor coactivator 1) and transactivate SPP1 in healthy osteoblast cells. Secreted SPP1 binds to the cell surface molecule CD40 to activate serine/threonine-protein kinase Akt1, which then phosphorylates forkhead box O3a (FOXO3a), blocking FOXO3a-mediated transcription. By contrast, VD deficiency impairs the NCOA1-VDR/RXR-mediated overexpression of SPP1, leading to the inactivation of Akt1 and the accumulation of FOXO3a. FOXO3a then upregulates the expression of the apoptotic genes BAX (Bcl2-associated X-protein), BID (BH3 interacting death domain), and BIM (Bcl2-interacting mediator of cell death), to induce apoptosis. Administration of the NCOA1 inhibitor gossypol to the CHOM mice also promotes the occurrence of sequestra. VD supplementation can reactivate the SPP1-dependent antiapoptotic signaling and improve the outcomes of CHOM. Collectively, our data reveal that VD deficiency promotes bone destruction in CHOM by the removal of SPP1-dependent antiapoptotic signaling.

Hydrogel-Based Strategies for the Management of Osteomyelitis

Osteomyelitis is a type of bone infection caused by bacteria, with Staphylococcus sepsis being responsible for most cases. Osteomyelitis treatment generally requires a multifaceted approach that may include intervention of surgery and administration of antibacterial agents, where several materials have been utilized as delivery vehicles for antibiotics and other antibacterial materials. Hydrogel has become a popular candidate for osteomyelitis treatment due to its biocompatibility, water-containing porous structure, and adaptable physicochemical properties. In this review, we discuss several hydrogel-based strategies for osteomyelitis treatment and categorized them based on the encapsulated cargos (i.e., antibiotics, silver nanoparticles, protein and bacteriophage, and reactive oxygen species (ROS) generator). Several representative examples of osteomyelitis treatment using hydrogels are described here, focusing on their design, preparation, properties, and outcomes. We also provide our perspectives on the remaining concerns regarding fabricating advanced hydrogels for osteomyelitis treatment. This review will be valuable to the hydrogel community and inspire researchers to develop next-generation hydrogels for specific and practical clinical applications in osteomyelitis.

Solitary bone plasmacytoma of the tibia presenting as chronic osteomyelitis: A rare case report and literature review

RATIONALE

Plasmacytoma is a rare plasma cell dyscrasia that grows within the axial skeleton or soft tissue structures as solitary or multiple masses. The primary types are solitary plasmacytoma, including solitary bone plasmacytoma (SBP) and solitary extramedullary plasmacytoma, and multiple solitary plasmacytomas. SBP is characterized by localized proliferation of monoclonal plasma cells and is rare. However, SBP with chronic osteomyelitis is even rarer.

PATIENT CONCERNS

A 47-year-old man previously diagnosed with chronic osteomyelitis presented with repeated discharge and ulceration in the front of his right tibia.

DIAGNOSIS, INTERVENTIONS AND OUTCOMES

Lower extremity magnetic resonance imaging (MRI) and computed tomography (CT) examinations showed dead bone formation and surrounding inflammatory edema. Thus, the patient underwent dead bone excision and fenestration of the bone marrow cavity. The histopathologic examination results indicated plasmacytoma. Therefore, we administered radiotherapy with satisfactory results.

LESSONS

Physicians should pay close attention to chronic osteomyelitis because it may be accompanied by plasmacytoma. Postoperative pathological and immunohistochemical examinations are crucial, and surgical resection of the lesion and local radiotherapy are effective treatment methods.

Steady-State Piperacillin Concentrations in the Proximity of an Orthopedic Implant: A Microdialysis Porcine Study

Implant-associated osteomyelitis is one of the most feared complications following orthopedic surgery. Although the risk is low, sufficient antibiotic protection of the implant surface is important. The aim of this study was to assess steady-state piperacillin concentrations in the proximity of an orthopedic implant. Time above the minimal inhibitory concentration (fT>MIC) was evaluated for MIC of 8 (low target) and 16 μg/mL (high target). Six female pigs received an intravenous bolus infusion of 4 g/0.5 g piperacillin/tazobactam over 30 min every 6 h. Steady state was assumed achieved in the third dosing interval (12-18 h). Microdialysis catheters were placed in a cannulated screw in the proximal tibial cancellous bone, in cancellous bone next to the screw, and in cancellous bone on the contralateral tibia. Dialysates were collected from time 12 to 18 h and plasma samples were collected as reference. For the low piperacillin target (8 µg/mL), comparable mean fT>MIC across all the investigated compartments (mean range: 54-74%) was found. For the high target (16 µg/mL), fT>MIC was shorter inside the cannulated screw (mean: 16%) than in the cancellous bone next to the screw and plasma (mean range: 49-54%), and similar between the two cancellous bone compartments. To reach more aggressive piperacillin fT>MIC targets in relation to the implant, alternative dosing regimens such as continuous infusion may be considered.

Thermosensitive Nanotherapeutics for Localized Photothermal Ablation of MRSA-Infected Osteomyelitis Combined with Chemotherapy

Chronic osteomyelitis is an inflammatory skeletal disease caused by a bacterial infection that affects the periosteum, bone, and bone marrow. Methicillin-resistant Staphylococcus aureus (MRSA) is the most common causative agent. The bacterial biofilm formed on the necrotic bone is a considerable challenge to treating MRSA-infected osteomyelitis. Here, we developed an all-in-one cationic thermosensitive nanotherapeutic (TLCA) for treating MRSA-infected osteomyelitis. The prepared TLCA particles were positively charged and <230 nm in size, which allowed them to diffuse effectively into the biofilm. The positive charges of the nanotherapeutic accurately targeted the biofilm, and it subsequently regulated the drug release under near-infrared (NIR) light irradiation, thereby efficiently exerting the synergistic effect of NIR light-driven photothermal sterilization and chemotherapy. More than 80% of the antibiotics were abruptly released at 50 °C, which dispersed the biofilm by up to 90%. When applied to MRSA-infected osteomyelitis, with a localized temperature of 50 °C induced by 808 nm laser irradiation, it not only eliminated the bacteria and controlled infection but also inhibited the bone tissue inflammatory response, significantly reducing TNF-α, IL-1β, and IL-6 levels. In conclusion, we constructed an all-in-one antimicrobial treatment modality that provides a new and effective strategy for the topical treatment of chronic osteomyelitis.

Diabetic Foot Osteomyelitis: Is it all the Same?

Diabetic foot osteomyelitis (OM) requires a longer duration of therapy, a greater need for surgery and implies a higher rate of recidivism, a higher amputation risk, and lower treatment success. But do all bone infections behave the same way, require the same treatment, or imply the same prognosis? Actually, in clinical practice we can verify there are different clinical presentations of OM. The first one is that associated with the infected diabetic foot attack. It requires urgent surgery and debridement since "time is tissue." Clinical features and radiographs are enough for the diagnosis, and treatment should not be delayed. The second one is related to a sausage toe. It affects phalanges and it can be treated with a 6- or 8-week antibiotic course with a high rate of success. Clinical features and radiographs are sufficient for the diagnosis in this case. The third presentation is OM superimposed to Charcot's neuroarthropathy, which mainly comprises midfoot or hindfoot. It starts with a plantar ulcer in a foot that has developed a deformity. The treatment is based on an accurate diagnosis that often includes magnetic resonance, and requires a complex surgery to preserve the midfoot and to avoid recurrent ulcers or foot instability. The final presentation is that of an OM without large soft tissue compromise secondary to a chronic ulcer or a previous unsuccessful surgery secondary to minor amputation or debridement. There is often a small ulcer with a positive probe to bone test over a bony prominence. Diagnosis is made by clinical features, radiographs, and laboratory tests. Treatment includes antibiotic therapy guided by surgical or transcutaneous biopsy, but this presentation often requires surgery. Different presentations of OM mentioned above need to be recognized because the diagnosis, type of culture, antibiotic treatment, surgical treatment, and prognosis are different upon the presentation.

Invasive bone and joint infections from the French Scedosporiosis/lomentosporiosis Observational Study (SOS) cohort: no mortality with long-term antifungal treatment and surgery

Little is known about localized osteoarticular Scedosporiosis (LOS). Most data come from case reports and small case series. Here we present an ancillary study of the nationwide French Scedosporiosis Observational Study (SOS), describing 15 consecutive cases of LOS diagnosed between January 2005 and March 2017. Adult patients diagnosed with LOS defined by osteoarticular involvement without distant foci reported in SOS were included. Fifteen LOS were analyzed. Seven patients had underlying disease. Fourteen patients had prior trauma as potential inoculation. Clinical presentation was arthritis (n = 8), osteitis (n = 5), and thoracic wall infection (n = 2). The most common clinical manifestation was pain (n = 9), followed by localized swelling (n = 7), cutaneous fistulization (n = 7), and fever (n = 5). The species involved were Scedosporium apiospermum (n = 8), S. boydii (n = 3), S. dehoogii (n = 1), and Lomentospora prolificans (n = 3). The species distribution was unremarkable except for S. boydii, which was associated with healthcare-related inoculations. Management was based on medical and surgical treatment for 13 patients. Fourteen patients received antifungal treatment for a median duration of 7 months. No patients died during follow-up. LOS exclusively occurred in the context of inoculation or systemic predisposing factors. It has a non-specific clinical presentation and is associated with an overall good clinical outcome, provided there is a prolonged course of antifungal therapy and adequate surgical management.

A Prospective Study Comparing the Infection Rate Between Buried vs Exposed Kirschner Wires in Hand and Wrist Fixations

INTRODUCTION

Kirschner wires (K-wires) are used in fracture fixations but are often associated with pin tract infections. This prospective study compared the infection rate between buried and exposed K-wires in closed injuries of the wrist and hands in individuals with no comorbidities.

METHODS

Fifteen patients were recruited with a total of 41 K-wires (21 buried K-wires; 20 exposed K-wires). Clinical and radiographic evidence of infection was assessed at three months based on the Modified Oppenheim classification.

RESULTS

Two out of 21 wires in the buried group developed grade 4 infection, while 20 wires in the exposed group did not have any significant infection. No significant difference in infection rate based on K-wire size or number in both groups.

CONCLUSION

There is no significant difference in infection rate between buried and exposed K-wires in healthy individuals with closed injuries of the wrist and hand.

First Report of Clivus Osteomyelitis Caused by Nocardia veterana in a Lung Transplant Recipient

Nocardia species have been implicated as a cause of pulmonary, cutaneous, ocular, and disseminated central nervous system disease. Dissemination to the bones, commonly the spine, has also been described in the literature. However, isolated osteomyelitis of the skull base is rare. Additionally, advances in the use of molecular techniques have identified many new Nocardia species, including Nocardia veterana that was thought to be clinically insignificant when it was first identified. Here, we report the clinical features and treatment approach for a lung transplant patient who developed N. veterana clivus osteomyelitis secondary to sphenoid sinusitis. It is the first case of skull base osteomyelitis caused by this rare species of Nocardia.

Multimodality Treatment for Nonhealing Wound With Osteomyelitis in Sickle Cell Disease

We treated a 25-year-old male sickle cell disease (SCD) patient with a long-standing wound of the lower limb with radiologically confirmed osteomyelitis of the tibia, successfully managed by multimodality treatment. Culture of the wound after sequestrectomy revealed a Staphylococcus aureus infection, which was treated with appropriate antibiotics as per culture and sensitivity results. The patient had been under treatment for the same since 3 years in his home country with no improvement. He had a history of a leg ulcer due to injury and as is common in SCD patients, the ulcer led to bone infection. He had taken long courses of antibiotics and surgical drainage of pus, which are the usual treatment modalities used in such patients, with extended periods to healing and long durations of pain and tenderness. In this case systemic antibiotics were used only for 7 days. Low-molecular-weight heparin and dextran, negative pressure wound therapy coupled with nano silver dressings and hyperbaric oxygen treatment for 15 days led to the patient being pain free within 10 days of instituting treatment. The patient healed completely after 1 year and has been incident free since the past 10 years. In essence, this case has shown that multi-modality treatment may lead to faster wound closure and reduction in pain in SCD patients suffering from osteomyelitis.

A rare case of hereditary sensory and autonomic neuropathy type II

We describe the follow-up of a 29-year-old man diagnosed with hereditary sensory and autonomic neuropathy type II, including the different complications that presented since his childhood. Despite efforts to maintain an optimal quality of life, the lack of an early diagnosis led to an unfavorable prognosis and life condition.

Treatment of Septic Tenosynovitis and Osteoarthritis in an American White Pekin (Anas platyrhynchos domesticus) with Repeated Intravenous Regional Limb Perfusion and Antibiotic-Impregnated Calcium Sulfate Beads

A 2-year-old female American white pekin (Anas platyrhynchos domesticus) was assessed for a 2-month history of chronic lameness and swelling involving the left leg. Radiographic images of the left leg showed soft tissue swelling of the digits and tarsometatarsus with osteolysis of the tarsometatarsal-phalangeal joint. A complete blood count revealed marked leukocytosis and hyperproteinemia. A Streptococcus species was isolated from a bacterial culture of fluid obtained from the left tarsometatarsal-phalangeal joint. Biweekly intravenous regional limb perfusions of the left leg with ampicillin-sulbactam and amikacin were performed on the patient. Despite initial improvement in left leg lameness and swelling, follow-up radiographic images showed progressive osteolysis of the tarsometatarsal-phalangeal joint and associated digits. Surgical placement of antibiotic-impregnated calcium sulfate beads into the left tarsometatarsal-phalangeal joint was next performed with concurrent, repeated intravenous regional limb perfusion using the same antibiotic. Following the placement of antibiotic-impregnated beads and continued intravenous regional limb perfusion, the duck had decreased lameness and swelling of the left leg. Repeated antibiotic treatment through intravenous regional limb perfusion and concurrent placement of antibiotic-impregnated calcium sulfate beads is a practical treatment option for complicated distal limb infections in avian species. This therapeutic protocol has great potential in treating aggressive distal leg infections in many avian species because regional limb perfusion alone may not penetrate the joint adequately to achieve complete resolution of infection.

Short Antibiotic Treatment Duration for Osteomyelitis Complicating Pressure Ulcers: A Quasi-experimental Study

Background

Osteomyelitis-complicating pressure ulcers are frequent among patients with spinal cord injuries (SCIs), and the optimal management is unknown. In our referral center, the current management is debridement and flap coverage surgeries, followed by a short antibiotic treatment. We aimed to evaluate patients' outcomes a year after surgery.

Methods

We performed a quasi-experimental retrospective before/after study on SCI patients with presumed osteomyelitis associated with perineal pressure ulcers. We included all patients who underwent surgery with debridement and flap covering, followed by effective antibiotic treatment, between May 1, 2016, and October 30, 2020. The effective antimicrobial treatment duration included the 10 days leading up to January 1, 2018 (before period), and the 5 to 7 days after (after period). We also compared the efficacy of 5-7-day vs 10-day antibiotic treatment and performed uni- and multivariable analyses to identify factors associated with failure.

Results

Overall, 415 patients were included (77.6% male patients; mean age ± SD, 53.0 ± 14.4 years). Multidrug-resistant organisms (MDROs) were involved in 20.7% of cases. Favorable outcomes were recorded in 69.2% of cases: 117/179 (65.3%) in the 10-day treatment group vs 169/287 (71.9%) in the 5-7-day treatment group (P = .153). The only factor associated with failure in the multivariate analysis was a positive culture from suction drainage (odds ratio, 1.622; 95% CI, 1.005-2.617; P = .046). Effective treatment duration >7 days and intraoperative samples negative for MDROs were not associated with better outcomes (P = .153 and P = .241, respectively).

Conclusions

A treatment strategy combining surgical debridement and flap covering, followed by 5 to 7 days of effective antibiotic treatment seems safe.

A rare case of Salmonella Paratyphi C osteomyelitis: A genetic analysis and review of Salmonella osteomyelitis in England

Salmonella osteomyelitis is rare in patients without sickling hemoglobinopathies. Invasive disease caused by Salmonella Paratyphi C is rarer still with only one case reported in the United Kingdom in the last 15 years. We report a case of relapsing S. Paratyphi C osteomyelitis in a newly diagnosed diabetic patient from Ghana. Our patient was initially treated successfully with surgical debridement followed by 6 weeks of IV ceftriaxone before recrudescence 9 months later. Due to the rarity of S. Paratyphi C and the lack of recent travel, genomic analysis was undertaken to assess possible sources with the closest related strain being from Cote d'Ivoire. The patient had likley picked up the strain several years before presentation. We review current Salmonella osteomyelitis literature and audit all cases referred to the England and Wales Salmonella national reference laboratory over the last 15 years.

A novel scoring system concept for de novo spinal infection treatment, the Spinal Infection Treatment Evaluation Score (SITE Score): a proof-of-concept study

OBJECTIVE

De novo infections of the spine are an increasing healthcare problem. The decision for nonsurgical or surgical treatment is often made case by case on the basis of physician experience, specialty, or practice affiliation rather than evidence-based medicine. To create a more systematic foundation for surgical assessments of de novo spinal infections, the authors applied a formal validation process toward developing a spinal infection scoring system using principles gained from other spine severity scoring systems like the Spine Instability Neoplastic Score, Thoracolumbar Injury Classification and Severity Score, and AO Spine classification of thoracolumbar injuries. They utilized an expert panel and literature reviews to develop a severity scale called the "Spinal Infection Treatment Evaluation Score" (SITE Score).

METHODS

The authors conducted an evidence-based process of combining literature reviews, extracting key elements from previous scoring systems, and obtaining iterative expert panel input while following a formal Delphi process. The resulting basic SITE scoring system was tested on selected de novo spinal infection cases and serially refined by an international multidisciplinary expert panel. Intra- and interobserver reliabilities were calculated using the intraclass correlation coefficient (ICC) and Fleiss' and Cohen's kappa, respectively. A receiver operating characteristic analysis was performed for cutoff value analysis. The predictive validity was assessed through cross-tabulation analysis.

RESULTS

The conceptual SITE scoring system combines the key variables of neurological symptoms, infection location, radiological variables for instability and impingement of neural elements, pain, and patient comorbidities. Ten patients formed the first cohort of de novo spinal infections, which was used to validate the conceptual scoring system. A second cohort of 30 patients with de novo spinal infections, including the 10 patients from the first cohort, was utilized to validate the SITE Score. Mean scores of 6.73 ± 1.5 and 6.90 ± 3.61 were found in the first and second cohorts, respectively. The ICCs for the total score were 0.989 (95% CI 0.975-0.997, p < 0.01) in the first round of scoring system validation, 0.992 (95% CI 0.981-0.998, p < 0.01) in the second round, and 0.961 (95% CI 0.929-0.980, p < 0.01) in the third round. The mean intraobserver reliability was 0.851 ± 0.089 in the third validation round. The SITE Score yielded a sensitivity of 97.77% ± 3.87% and a specificity of 95.53% ± 3.87% in the last validation round for the panel treatment decision.

CONCLUSIONS

The SITE scoring concept showed statistically meaningful reliability parameters. Hopefully, this effort will provide a foundation for a future evidence-based decision aid for treating de novo spinal infections. The SITE Score showed promising inter- and intraobserver reliability. It could serve as a helpful tool to guide physicians' therapeutic decisions in managing de novo spinal infections and help in comparison studies to better understand disease severity and outcomes.

Achieving Fast Charge Separation by Ferroelectric Ultrasonic Interfacial Engineering for Rapid Sonotherapy of Bacteria-Infected Osteomyelitis

Bacteria-infected osteomyelitis is life-threatening without effective therapeutic methods clinically. Here, a rapid and effective therapeutic strategy to treat osteomyelitis through ferroelectric polarization interfacial engineering of BiFeO₃ /MXene (Ti₃ C₂ ) triggered by ultrasound (US) is reported. Under US, the ferroelectric polarization induces the formation of the piezoelectric field. US cavitation effect induced sonoluminescence stimulates BiFeO₃ /Ti₃ C₂ to produce photogenerated carriers. With synergistic action of the polarization electric field and Schottky junction, BiFeO₃ /Ti₃ C₂ accelerates the separation of electrons and holes and simultaneously inhibits the backflow of electrons, thus improving the utilization of polarized charges and photogenerated charges and consequently enhancing the yield of reactive oxygen species under US. As a result, 99.87 ± 0.05% of Staphylococcus aureus are efficiently killed in 20 min with the assistance of ultrasonic heating. The theory of ferroelectric ultrasonic interfacial engineering is proposed, which brings new insight for developing ferroelectric ultrasonic responsive materials used for the diagnosis and therapy of deep tissue infection and other acoustoelectric devices.

What Is the Appropriate Dose, Route, and Duration of Antibiotic Therapy for Pediatric Acute Hematogenous Osteomyelitis (AHO)? I Wish I Knew

Treatment of pediatric AHO requires antibiotic/surgical management. Considerable clinical experience exists, but with current knowledge of antibiotic pharmacokinetics and pharmacodynamics, recommendations for dosages for old or new antibiotics should be based on current standards for drug development whenever possible.

Socioeconomic Disparities in Outcomes Following Conservative Treatment of Spinal Epidural Abscesses

BACKGROUND

Primary spinal epidural abscess (SEA) is a rare but serious pathology that may result in severe neurologic injury. While certain literature has identified medical risk factors for failure of conservative therapy, no current evidence has been published regarding socioeconomic risk factors associated with failure of medical therapy.

METHODS

A retrospective review was conducted of patients presenting with SEA from primary spinal infections. Patients presenting with magnetic resonance imaging evidence of SEA treated conservatively in the absence of neurologic deficits were included. Baseline clinical and socioeconomic characteristics were collected. Failure of medical management was defined as requiring surgical intervention despite maximal medical therapy due to the development of neurologic deficits or clinically significant deformity.

RESULTS

A total of 150 patients were identified as presenting with magnetic resonance imaging evidence of SEAs without evidence of neurologic deficit. Of these patients, 42 required surgical intervention compared with 108 whose infection was successfully treated with medical therapy alone. Estimated average annual income was $64,746 vs $62,615 in those who successfully cleared their infection with medical management without requiring surgery, which was not statistically significant (P = 0.5). Insured patients were 5 times more likely to be successfully treated with antibiotics alone compared with uninsured patients (OR = 5.83, P = 0.008). Payer type, employment status, and incarceration status were not associated with failure of conservative therapy.

CONCLUSIONS

In the treatment of primary SEA, absence of medical insurance is associated with failure of medical management. Payer status, employment status, average salary, and incarceration are not significant risk factors for failure of conservative management.

LEVEL OF EVIDENCE: 3

[Application of homemade antibiotic bone cement rod in tibial screw canal osteomyelitis]

Objective

To investigate the effectiveness of homemade antibiotic bone cement rod in the treatment of tibial screw canal osteomyelitis by Masquelet technique.

Methods

A clinical data of 52 patients with tibial screw canal osteomyelitis met the criteria between October 2019 and September 2020 was retrospectively analyzed. There were 28 males and 24 females, with an average age of 38.6 years (mean, 23-62 years). The tibial fractures were treated with internal fixation in 38 cases and external fixation in 14 cases. The duration of osteomyelitis was 6 months to 20 years with a median of 2.3 years. The bacterial culture of wound secretions showed 47 positive cases, of which 36 cases were infected with single bacteria and 11 cases were infected with mixed bacteria. After thorough debridement and removal of internal and external fixation devices, the locking plate was used to fixed the bone defect. The tibial screw canal was filled with the antibiotic bone cement rod. The sensitive antibiotics were given after operation and the 2nd stage treatment was performed after infection control. The antibiotic cement rod was removed and the bone grafting in the induced membrane was performed. After operation, the clinical manifestations, wound, inflammatory indexes, and X-ray films were monitored dynamically, and the postoperative bone infection control and bone graft healing were evaluated.

Results

Both patients successfully completed the two stages of treatments. All patients were followed up after the 2nd stage treatment. The follow-up time was 11 to 25 months (mean, 18.3 months). One patient had poor wound healing and the wound healed after enhanced dressing change. X-ray film showed that the bone grafting in the bone defect healed and the healing time was 3-6 months, with an average of 4.5 months. The patient had no recurrence of infection during the follow-up period.

Conclusion

For the tibial screw canal osteomyelitis, the homemade antibiotic bone cement rod can reduce the recurrence rate of infection and obtain a good effectiveness, and has the advantages of simple operation and less postoperative complications.

Sodium-glucose co-transporter-2 inhibitor (SGLT2i) treatment and risk of osteomyelitis: A pharmacovigilance study of the FAERS database

Background and purpose: Several clinical trials have indicated that the use of canagliflozin increases the risk of lower extremity amputation. Although the US Food and Drug Administration (FDA) has withdrawn its black box warning about amputation risk for canagliflozin, the risk still exists. We sought to estimate the association between hypoglycemic medications, especially sodium-glucose co-transporter-2 inhibitors (SGLT2is), and adverse events (AEs) before the irreversible outcome of amputation as a promising early warning, based on the FDA Adverse Event Reporting System (FAERS) data. Methods: Publicly available FAERS data were analyzed using a reporting odds ratio (ROR) method and validated by a Bayesian confidence propagation neural network (BCPNN) method. The developing trend of the ROR was investigated by a series of calculations based on the accumulation of data in the FAERS database quarter by quarter. Results: Ketoacidosis, infection, peripheral ischemia, renal impairment, and inflammation including osteomyelitis might be more likely to occur among users of SGLT2is, especially canagliflozin. Osteomyelitis and cellulitis are AEs unique to canagliflozin. Among 2,888 osteomyelitis-related reports referring to hypoglycemic medications, 2,333 cases were associated with SGLT2is, with canagliflozin accounting for 2,283 of these cases and generating an ROR value of 360.89 and a lower limit of information component (IC₀₂₅) of 7.79. No BCPNN-positive signal could be generated for drugs other than insulin and canagliflozin. Reports suggesting that insulin could generate BCPNN-positive signals span from 2004 to 2021, whereas reports with BCPNN-positive signals emerged only since the second quarter (Q2) of 2017, 4 years since the approval of SGLT2is in Q2 of 2013, for canagliflozin and drug groups containing canagliflozin. Conclusion: This data-mining investigation revealed a strong association between canagliflozin treatment and developing osteomyelitis that might be a crucial forewarning to lower extremity amputation. Further studies with updated data are needed to better characterize the risk of osteomyelitis associated with SGLT2is.

In vitro elution characteristics of antibiotic-loaded polymethylmethacrylate cement and a calcium sulfate bone substitute using staphylococci isolated from orthopedic implant-associated infections

Polymethylmethacrylate (PMMA) remains the gold standard antibiotic carrier in the management of osteomyelitis. However, biodegradable ceramic carriers may exhibit more efficient antibiotic elution properties. Through zone of inhibition (ZOI) testing and biofilm killing assays, we assessed the in vitro elution efficacy of vancomycin released from calcium sulfate (PG-CSH) and PMMA beads as carriers on clinical strains of Staphylococcus aureus and Staphylococcus epidermidis, which were isolated from sonication fluid of orthopedic implant-associated infections. Overall, vancomycin-loaded PMMA and PG-CSH beads showed potency (ZOI above 4 cm² ) for up to 14 days against ATCC and clinical strains. Vancomycin-loaded PG-CSH beads displayed higher rates, exhibited a more stable antibiotic elution, had greater impacts on bacterial colony-forming unit counts and produced higher ZOIs; additionally, statistically significant differences (Student's t test) were observed in different time sets during the experiment. In the biofilm killing assay, PG-CSH loaded with vancomycin resulted in more bacterial deaths. In conclusion, in the present study, both PG-CSH and PMMA beads acted as good carriers, but greater antimicrobial elution and biofilm bacterial killing were observed with PG-CSH than PMMA. Future in vitro research should focus on testing other difficult-to-treat clinical strains, including multidrug resistant coagulase-negative staphylococci and Gram-negative bacilli.

Osteomyelitis of the Lower Limb: Diagnostic Accuracy of Dual-Energy CT versus MRI

BACKGROUND

MRI is the preferred imaging technique for the identification of osteomyelitis. The key element for diagnosis is the presence of bone marrow edema (BME). Dual-energy CT (DECT) is an alternative tool which is able to identify BME in the lower limb.

PURPOSE

To compare the diagnostic performance of DECT and MRI for osteomyelitis, using clinical, microbiological, and imaging data as reference standards.

MATERIALS AND METHODS

This prospective single-center study enrolled consecutive patients with suspected bone infections undergoing DECT and MRI imaging from December 2020 to June 2022. Four blinded radiologists with various experience levels (range of 3-21 years) evaluated the imaging findings. Osteomyelitis was diagnosed in the presence of BMEs, abscesses, sinus tracts, bone reabsorption, or gaseous elements. The sensitivity, specificity, and AUC values of each method were determined and compared using a multi-reader multi-case analysis. A p value < 0.05 was considered significant.

RESULTS

In total, 44 study participants (mean age 62.5 years ± 16.5 [SD], 32 men) were evaluated. Osteomyelitis was diagnosed in 32 participants. For the MRI, the mean sensitivity and specificity were 89.1% and 87.5%, while for the DECT they were 89.0% and 72.9%, respectively. The DECT demonstrated a good diagnostic performance (AUC = 0.88), compared with the MRI (AUC = 0.92) (p = 0.12). When considering each imaging finding alone, the best accuracy was achieved by considering BME (AUC for DECT 0.85 versus AUC of MRI of 0.93, with p = 0.07), followed by the presence of bone erosions (AUC 0.77 for DECT and 0.53 for MRI, with p = 0.02). The inter-reader agreement of the DECT (k = 88) was similar to that of the MRI (k = 90).

CONCLUSION

Dual-energy CT demonstrated a good diagnostic performance in detecting osteomyelitis.

Outcomes of Partial Oral Antibiotic Treatment for Complicated Staphylococcus aureus Bacteremia in People Who Inject Drugs

BACKGROUND

Staphylococcus aureus represents the leading cause of complicated bloodstream infections among persons who inject drugs (PWID). Standard of care (SOC) intravenous (IV) antibiotics result in high rates of treatment success but are not feasible for some PWID. Transition to oral antibiotics may represent an alternative treatment option.

METHODS

We evaluated all adult patients with a history of injection drug use hospitalized from January 2016 through December 2021 with complicated S. aureus bloodstream infections, including infective endocarditis, epidural abscess, vertebral osteomyelitis, and septic arthritis. Patients were compared by antibiotic treatment (standard of care intravenous [SOC IV] antibiotics, incomplete IV therapy, or transition from initial IV to partial oral) using the primary composite endpoint of death or readmission from microbiologic failure within 90 days of discharge.

RESULTS

Patients who received oral antibiotics after an incomplete IV antibiotic course were significantly less likely to experience microbiologic failure or death than patients discharged without oral antibiotics (P < .001). There was no significant difference in microbiologic failure rates when comparing patients who were discharged on partial oral antibiotics after receiving at least 10 days of IV antibiotics with SOC regimens (P > .9).

CONCLUSIONS

Discharge of PWID with partially treated complicated S. aureus bacteremias without oral antibiotics results in high rates of morbidity and should be avoided. For PWID hospitalized with complicated S. aureus bacteremias who have received at least 10 days of effective IV antibiotic therapy after clearance of bacteremia, transition to oral antibiotics with outpatient support represents a potential alternative if the patient does not desire SOC IV antibiotic therapy.

Sustained Release of Antifungal and Antibacterial Agents from Novel Hybrid Degradable Nanofibers for the Treatment of Polymicrobial Osteomyelitis

This study aimed to develop a drug delivery system with hybrid biodegradable antifungal and antibacterial agents incorporated into poly lactic-co-glycolic acid (PLGA) nanofibers, facilitating an extended release of fluconazole, vancomycin, and ceftazidime to treat polymicrobial osteomyelitis. The nanofibers were assessed using scanning electron microscopy, tensile testing, water contact angle analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The in vitro release of the antimicrobial agents was assessed using an elution method and a high-performance liquid chromatography assay. The in vivo elution pattern of nanofibrous mats was assessed using a rat femoral model. The experimental results demonstrated that the antimicrobial agent-loaded nanofibers released high levels of fluconazole, vancomycin, and ceftazidime for 30 and 56 days in vitro and in vivo, respectively. Histological assays revealed no notable tissue inflammation. Therefore, hybrid biodegradable PLGA nanofibers with a sustainable release of antifungal and antibacterial agents may be employed for the treatment of polymicrobial osteomyelitis.

Staphylococcus aureus Genomic Analysis and Outcomes in Patients with Bone and Joint Infections: A Systematic Review

Many studies have been published assessing the association between the presence of S. aureus genes and outcomes in patients with bone and joint infections (BJI), but it is not known if they have had similar findings. A systematic literature review was performed. All available data on studies in Pubmed between January 2000 to October 2022 reporting the genetic characteristics of S. aureus and the outcomes of BJIs were analyzed. BJI included prosthetic joint infection (PJI), osteomyelitis (OM), diabetic foot infection (DFI), and septic arthritis. Because of the heterogeneity of studies and outcomes, no meta-analysis was performed. With the search strategy, 34 articles were included: 15 articles on children and 19 articles on adults. In children, most BJI studied were OM (n = 13) and septic arthritis (n = 9). Panton Valentine leucocidin (PVL) genes were associated with higher biological inflammatory markers at presentation (n = 4 studies), more febrile days (n = 3), and more complicated/severe infection (n = 4). Other genes were reported anecdotally associated with poor outcomes. In adults, six studies reported outcomes in patients with PJI, 2 with DFI, 3 with OM, and 3 with various BJI. Several genes were associated with a variety of poor outcomes in adults, but studies found contradictory results. Whereas PVL genes were associated with poor outcomes in children, no specific genes were reported similarly in adults. Additional studies with homogenous BJI and larger sample sizes are needed.

Vancomycin-Loaded, Nanohydroxyapatite-Based Scaffold for Osteomyelitis Treatment: In Vivo Rabbit Toxicological Tests and In Vivo Efficacy Tests in a Sheep Model

The treatment for osteomyelitis consists of surgical debridement, filling of the dead space, soft tissue coverage, and intravenous administration of antimicrobial (AM) agents for long periods. Biomaterials for local delivery of AM agents, while providing controllable antibiotic release rates and simultaneously acting as a bone scaffold, may be a valuable alternative; thus, avoiding systemic AM side effects. V-HEPHAPC is a heparinized nanohydroxyapatite (nHA)/collagen biocomposite loaded with vancomycin that has been previously studied and tested in vitro. It enables a vancomycin-releasing profile with an intense initial burst, followed by a sustained release with concentrations above the Minimum Inhibitory Concentration (MIC) for MRSA. In vitro results have also shown that cellular viability is not compromised, suggesting that V-HEPHAPC granules may be a promising alternative device for the treatment of osteomyelitis. In the present study, V-HEPHAPC (HEPHAPC with vancomycin) granules were used as a vancomycin carrier to treat MRSA osteomyelitis. First, in vivo Good Laboratory Practice (GLP) toxicological tests were performed in a rabbit model, assuring that HEPHAPC and V-HEPHAPC have no relevant side effects. Second, V-HEPHAPC proved to be an efficient drug carrier and bone substitute to control MRSA infection and simultaneously reconstruct the bone cavity in a sheep model.

Antibacterial and anti-inflammatory effects of genistein in Staphylococcus aureus induced osteomyelitis in rats

Methicillin-resistant Staphylococcus aureus (MRSA) is a highly infectious Gram-positive pathogen known to cause severe diseases such as endocarditis, food poisoning, pneumonia, osteomyelitis, and septicemia. MRSA is a major public health issue. Among these, osteomyelitis is inflammation of the bone caused by the invasion of the bacterial pathogen in the bones. Its prominent symptoms include fever, pain, and redness of bones. In the case of children, it affects the long bones of arms and legs, whereas in the case of adults it affects the hip, feet, and spine. Bacterial osteomyelitis can trigger pathological remodeling of bones and hence causes substantial morbidity and mortality. The present study aims to evaluate the isoflavone genistein's (5,7-dihydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one,4',5,7 trihydroxyisoflavone) antimicrobial and anti-inflammatory effects against osteomyelitis induced by MRSA in male Wistar rats. Classification of the animals was into the following: sham (Group I), osteomyelitis (Group II, control), genistein (25 mg/kg body weight, Group III), and genistein (50 mg/kg body weight, Group IV). The rats did not receive any treatment for 4 weeks after bacterial inoculation. Genistein was then administered twice daily for 2 weeks. Bacterial growth, mean body weight bone infection status, and side effects of genistein treatment were assessed. Furthermore, lipid peroxidation, superoxide dismutase, glutathione (GSH) peroxidase, catalase, reduced GSH, tumor necrosis factor-α (TNF-α), and interleukin (IL)-6 were also determined. Two days after treatment, it was found that genistein significantly suppressed bacterial growth and reduced serum pro-inflammatory cytokines TNF-α and IL-6. Therefore, the study suggests that genistein could be a promising lead against MRSA-induced osteomyelitis.

Antibiotic-Loaded Coatings to Reduce Fracture-Related Infections: Retrospective Case Series of Patients with Increased Infectious Risk

Local antibiotic delivery strategies have been increasingly employed for the prevention of fracture-related infections (FRIs). The aim of this study is to evaluate the efficacy and safety of antibiotic-coated implants in the prevention of FRIs after surgical treatment in patients with increased infectious risk. A retrospective observational study has been conducted on patients with upper and lower limb fractures treated with internal fixation or prosthetic replacements, using a gentamicin coated nail (CN) and/or antibiotic-loaded hydrogel applied to the implant of choice (ALH). The study included 37 patients (20 M, 17 F), with a mean age of 63 years. The mean estimated preoperative infectious risk score was 6.4%. ALH was used in 27 cases, tibial CNs were implanted in 4 cases, and both were employed in 6 cases. The antibiotics used locally were gentamicin in 72.97% of cases (27 patients) and a combination of gentamicin + vancomycin in 27.03% of cases (10 patients). Mean follow-up was 32 months. Only one case (2.94%) showed onset of FRI at 5 months after surgery. Local antibiotic prophylaxis by coating resulted in a reduction in the incidence FRI, as compared to the estimated preoperative risk. The use of ALH allows for the choice of antibiotic; however, the application of antibiotics seems more nonuniform when applied to a nail.

Septic Olecranon Bursitis With Osteomyelitis Attributed to Cutibacterium acnes: Case Report and Literature Overview of the Dilemma of Potential Contaminants and False-Positives

We report an unusual case of acute septic olecranon bursitis, with probable olecranon osteomyelitis, where the only organism isolated in culture was initially considered a contaminant, Cutibacterium acnes. However, we ultimately considered it the likely causal organism when treatment for most of the other more likely organisms failed. This typically indolent organism is prevalent in pilosebaceous glands, which are scarce in the posterior elbow region. This case illustrates the often challenging empirical management of a musculoskeletal infection when the only organism isolated might be a contaminant, but successful eradication requires continued treatment as if it is the causal organism. The patient is a Caucasian 53-year-old male who presented to our clinic with a second episode of septic bursitis at the same location. Four years prior, he had septic olecranon bursitis from methicillin-sensitive Staphylococcus aureus that was treated uneventfully with one surgical debridement and a one-week course of antibiotics. In the current episode reported here, he sustained a minor abrasion. Cultures were obtained five separate times because of no growth and difficulty eradicating the infection. One culture grew C. acnes on day 21 of incubation; this long duration has been reported. The first several weeks of antibiotic treatment failed to eradicate the infection, which we ultimately attributed to inadequate treatment of C. acnes osteomyelitis. Although C. acnes has a well-known propensity for false-positive cultures as typically reported in post-operative shoulder infections, treatment for our patient's olecranon bursitis/osteomyelitis was successful only after several surgical debridements and a prolonged course of intravenous and oral antibiotics that targeted it as the presumptive causal organism. However, it was possible that C. acnes was a contaminant/superinfection, and another organism was the culprit, such as a Streptococcus or Mycobacterium species that was eradicated by the treatment regime targeted for C. acnes.