The History of Antibiotic Treatment of Osteomyelitis

"Once more, with feeling": no difference in outcomes between patients discharged on oral versus intravenous antibiotics for orthopedic infections in a propensity score matched cohort at a US medical center

Objective

To compare outcomes between patients discharged on intravenous (IV) versus oral (PO) antibiotics for the treatment of orthopedic infections, after creation of an IV-to-PO guideline, at a single academic medical center in the United States.

Methods

This was a retrospective, propensity score matched, cohort study of adult patients hospitalized for orthopedic infections from September 30, 2020, to April 30, 2022. Patients discharged on PO antibiotics were matched to patients discharged on IV antibiotics. The primary outcome was one-year treatment failure following discharge. Secondary outcomes were incidence of 60-day treatment failure, adverse drug events (ADE), readmissions, infectious disease clinic "no-show" rates, and emergency department (ED) encounters.

Results

Ninety PO-treated patients were matched to 90 IV-treated patients. Baseline characteristics were similar in the two groups after matching. There was no significant difference in the proportions of patients on PO versus IV antibiotics experiencing treatment failure at one year (26% vs 31%, P = .47). There were no significant differences for any secondary outcomes: treatment failure within 60 days (13% vs 14%, P = 1.00), ADE (13% vs 11%, P = .82), unplanned readmission (17% vs 21%, P = .57), or ED encounters (9% vs 18%, P = .54). Survival analyses identified no significant differences in time-to-event between PO and IV treatment for any of the outcomes assessed.

Conclusions

There were no appreciable differences in outcomes between patients discharged on PO compared to IV regimens. Antimicrobial stewardship interventions to increase prescribing of PO antibiotics for the treatment of orthopedic infections should be encouraged.

Switching from intravenous vancomycin to oral antibiotics reduces adverse events in a retrospective cohort of outpatients with orthopedic infections

INTRODUCTION

Vancomycin is frequently used for prolonged courses in treating osteoarticular infections despite a high rate of adverse drug events (ADE). The objective of this study was to evaluate the safety and effectiveness of transitioning to oral therapy compared to continuing parenteral vancomycin in patients with orthopedic infections.

METHODS

We conducted a single-center, retrospective cohort study of patients with orthopedic infections discharged on parenteral vancomycin with a planned duration of at least 4 weeks. We compared rates of ADE while on vancomycin to rates of ADE after switching to an oral regimen. As a secondary analysis, we compared unplanned hospital readmission within 60 days and treatment failure at 1 year between patients who were transitioned to oral antibiotics within 4 weeks of vancomycin initiation and those that were not.

RESULTS

Two hundred twenty-eight patients met the inclusion criteria. Vancomycin was associated with significantly greater toxicity compared to oral regimens. Fifty-one patients had an adverse event while on vancomycin (5.87 ADE per 1000 patient-days) while 9 patients had an adverse event on oral therapy (1.49 ADE per 1000 patient-days) (Rate difference 4.39 per 1000 patient days, 95% CI: 2.52 to 6.26 events per 1000 patient-days). In proportional hazards analysis, transition to an oral antibiotic regimen was independently associated with a lower rate of ADE (aHR 0.12, 95% CI: 0.02-0.86). Forty-one patients (18%) were transitioned to oral therapy within 4 weeks; these patients did not have an increased rate of unplanned readmission (12.2% vs 17.1%) or treatment failure (17.1% vs 21.9%).

CONCLUSIONS

Patients transitioned to oral therapy within 4 weeks of discharge had significantly fewer adverse events and similar incidences of 1-year treatment failure compared to patients maintained on parenteral vancomycin. Substituting oral antibiotics for parenteral vancomycin is a potential strategy to minimize vancomycin toxicity during the treatment of orthopedic infections.

Preparation of fish collagen and vancomycin microspheres based on microfluidic technology and its application in osteomyelitis

At present, the clinical treatment of osteomyelitis and osteomyelitis-induced bone defects is challenging, easy to recur, drug toxic side effects, secondary or multiple surgeries, etc. The design of biodegradable composite biomaterials to improve antibiotics in the local precise anti-infection at the same time to complete the repair of bone defects is the current research hot spot. Herein, a composite hydrogel with a double bond at the end (FA-MA) was prepared by affinity addition reaction between fish collagen (FA) and methacrylic anhydride (MA) under photoinitiator initiation conditions, then, FA-MA was amino-activated by EDC/NHC, and vancomycin was attached to FA-MA via amide bonding to prepare FA-MA-Van hydrogels, and finally, the composite hydrogel microspheres were prepared by microfluidic technology. The structure of the hydrogel was confirmed by SEM (elemental analysis), optical microscopy, FTIR, and XPS to confirm the successful preparation. The composite hydrogel microspheres showed the better antimicrobial effect of hydrogel microspheres by bacterial coated plate experiments and SEM morphology results, with the antimicrobial class reaching 99.8%. The results of immunofluorescence staining and X-ray experiments showed that the hydrogel microspheres had a better effect on promoting bone repair. This engineered design of hydrogel microspheres provides clinical significance for treating osteomyelitis at a later stage.

Antibiotic Myths for the Infectious Diseases Clinician

Antimicrobials are commonly prescribed and often misunderstood. With more than 50% of hospitalized patients receiving an antimicrobial agent at any point in time, judicious and optimal use of these drugs is paramount to advancing patient care. This narrative will focus on myths relevant to nuanced consultation from infectious diseases specialists, particularly surrounding specific considerations for a variety of antibiotics.

Periprosthetic Joint Infection: Current Clinical Challenges

Over the last several decades, periprosthetic joint infection has been increasing in incidence and is occurring in more complex patients. While there have been advances in both surgical and medical treatment strategies, there remain important gaps in our understanding. Here, we share our current approaches to the diagnosis and management of periprosthetic joint infection, focusing on frequent clinical challenges and collaborative interdisciplinary care.

Injectable rBMSCs-laden hydrogel microspheres loaded with naringin for osteomyelitis treatment

Osteomyelitis, caused by purulent bacteria invading bone tissue, often occurs in long bones and seriously affects the physical and mental health and working ability of patients; it can even endanger life. However, due to bone cavity structure, osteomyelitis tends to occur inside the bone and thus lacks an effective treatment; anti-inflammatory treatment and repair of bone defects are necessary. Here, we developed injectable hydrogel microspheres loaded with naringin and bone marrow mesenchymal stem cells, which have anti-inflammatory and osteogenic properties. These homogeneous microspheres, ranging from 200 to 1000μm, can be rapidly fabricated using an electro-assisted bio-fabrication method. Interestingly, it was found that microspheres with relatively small diameters (200μm) were more conducive to the initial cell attachment, growth, spread, and later osteogenic differentiation. The developed microspheres can effectively treat tibial osteomyelitis in rats within six weeks, proving their prospects for clinical application.

Flourishing Antibacterial Strategies for Osteomyelitis Therapy

Osteomyelitis is a destructive disease of bone tissue caused by infection with pathogenic microorganisms. Because of the complex and long-term abnormal conditions, osteomyelitis is one of the refractory diseases in orthopedics. Currently, anti-infective therapy is the primary modality for osteomyelitis therapy in addition to thorough surgical debridement. However, bacterial resistance has gradually reduced the benefits of traditional antibiotics, and the development of advanced antibacterial agents has received growing attention. This review introduces the main targets of antibacterial agents for treating osteomyelitis, including bacterial cell wall, cell membrane, intracellular macromolecules, and bacterial energy metabolism, focuses on their mechanisms, and predicts prospects for clinical applications.

What Is the Best Oral Therapy for Staph aureus Osteomyelitis?

Best Oral Therapy for Staph aureus OsteomyelitisA 50-year-old patient with diabetes mellitus has a plantar ulcer at the base of the first metatarsal. Cortical erosions are noted; bone biopsy culture yields Staphylococcus aureus susceptible to methicillin, ciprofloxacin, clindamycin, doxycycline, trimethoprim/sulfamethoxazole, linezolid, and rifampin. The plan is for 4 weeks of antibiotic treatment. Which antibiotic should be prescribed?

Magnetic Composite Rapidly Treats Staphylococcus aureus-Infected Osteomyelitis through Microwave Strengthened Thermal Effects and Reactive Oxygen Species

It is difficult to effectively treat bacterial osteomyelitis using photothermal therapy or photodynamic therapy due to poor penetration of light. Here, a microwave (MW)-excited magnetic composite of molybdenum disulfide (MoS₂ ) / iron oxide (Fe₃ O₄ ) is reported for the treatment of bacteria-infected osteomyelitis. In in vitro and in vivo experiments, MoS₂ /Fe₃ O₄ is shown to effectively eradicate bacteria-infected mouse tibia osteomyelitis, due to MW thermal enhancement and reactive oxygen species (ROS) (¹ O₂ and ·O₂ ^- ) production under MW radiation. In addition, the mechanism of MW heat generation is proposed by MW network vector analysis. By the density functional theory and finite element method, the ROS generation mechanism is proposed. The synergy or conductive network between dielectric MoS₂ and magnetic Fe₃ O₄ can reach both enhancement of the dielectric and magnetic attenuation capability. In addition, abundant interfaces are generated to enhance the attenuation of electromagnetic waves by MoS₂ and Fe₃ O_4, introducing multiple reflections and interfacial polarization. Therefore, MoS₂ /Fe₃ O₄ has excellent MW absorption ability based on the synergy or conductive network between MoS₂ and magnetic Fe₃ O₄ as well as multiple dielectric reflections and interfacial polarization.

A self-assembled bilayer polypeptide-engineered hydrogel for spatiotemporal modulation of bactericidal and anti-inflammation process in osteomyelitis treatment

Background

Drug resistance of pathogens and immunosuppression are the main causes of clinical stagnation of osteomyelitis. The ideal treatment strategy for osteomyelitis is to achieve both efficient antibacterial and bone healing through spatiotemporal modulation of immune microenvironment.

Methods

In this study, a bilayer hydrogel based on genetically engineered polypeptide AC10A and AC10ARGD was prepared by self-assembly. Ag2S QDs@DSPE-mPEG2000-Ce6/Aptamer (AD-Ce6/Apt) was loaded in the top layer AC10A hydrogel (AA) for antibacterial, and bone marrow-derived mesenchymal stem cells (BMSCs) were loaded in the lower layer AC10ARGD hydrogel (MAR) for bone healing. The AD-Ce6/Apt can be released from the AA hydrogel to target S. aureus before bacterial biofilm formation and achieved significant bactericidal effect under irradiation with a 660 nm laser. Moreover, AD-Ce6/Apt can induce M1 type polarization of macrophages to activate the immune system and eliminate residual bacteria. Subsequently, BMSCs released from the MAR hydrogel can differentiate into osteoblasts and promote the formation of an anti-inflammatory microenvironment by regulating the M2 type polarization of macrophages. The bilayer AA-MAR hydrogel possessed good biocompatibility.

Results

The in vitro and in vivo results showed that the AA-MAR hydrogel not only realized efficient photodynamic therapy of S. aureus infection, but also promoted the transformation of immune microenvironment to fulfill the different needs of each stage, which ultimately improved bone regeneration and mechanical properties post-surgery.

Conclusion

This work presents an approach for spatiotemporal modulation of immune microenvironment in the treatment of osteomyelitis.

Graphical Abstract

Excellent Outcomes With the Selective Use of Oral Antibiotic Therapy for Bone and Joint Infections: A Single-Center Experience

Background and objective

Recent studies have challenged the notion that prolonged intravenous (IV) antibiotics are preferable to oral antibiotics for treating musculoskeletal infections. Our institution’s orthopedic surgery and orthopedic infectious disease (ID) groups have established consensus criteria for the use of oral antibiotics in musculoskeletal infections. In this study, we examine one-year and two-year outcomes of the selective use of oral antibiotics for musculoskeletal infections in a real-world setting.

Methods

We conducted a single-center retrospective analysis of adults seen in our orthopedic ID clinic over a six-month period for the first episode of surgically managed osteomyelitis, native joint septic arthritis (NJSA), prosthetic joint infection (PJI), or other musculoskeletal hardware infection with an established microbiologic etiology who received surgical interventions and >2 weeks of antimicrobial treatment. Patients were evaluated for treatment failure at one year and two years following their index surgery, which we defined as death, unplanned surgery, or the initiation of chronic antibiotic suppression.

Results

One-year treatment failure rates were 0/23 (0%) in patients who switched to oral therapy versus 6/17 (35%) in patients who remained on IV treatment. Two-year treatment failure rates were 0/23 (0%) in patients who switched to oral therapy versus 8/17 (47%) in patients who remained on IV treatment.

Conclusions

Our consensus criteria for the switch to oral antibiotics for musculoskeletal infections identified patients who went on to have excellent outcomes at one year and two years, suggesting that these criteria can effectively identify patients at low risk for treatment failure. Collaboration between ID specialists and orthopedic surgeons to select antimicrobial regimens can avoid significant burdens, costs, and complications associated with prolonged IV therapy.

A review of the first wave of lower limb amputees from the Great March of Return in Gaza: Taking stock and preparing for the task ahead

AIM

Ballistic injuries during the Great March of Return (GMR) protests in Gaza have resulted in young, civilian amputees. This article defines this unique population, their injuries and clinical variables that impacted on amputation.

METHOD

A multidisciplinary team (MDT) assessed 103 lower limb amputees (104 stumps). Individualized prescriptions of care were formulated and applied for both stump and prosthesis management. The cohort's health state was assessed at screening by applying the EQ-5D-L5 questionnaire. The EQ-5D-L5 will be repeated on completion of the prescription of care.

RESULTS

The population is predominantly young, male, suffering unilateral amputation with an equal ratio of above knee (AKA) to below knee (BKA) amputations. 18% were amputated immediately and 82% with delay. Most amputations occur within 15 days of gunshot wound (GSW). All tissue elements were affected by the severe, ballistic injury. Division, gapping and tissue loss consolidated the decision for amputation rather than limb salvage. Knee zone injury was common, influencing the high numbers AKAs. Primary injury ramified beyond the amputated leg: 38% have contralateral leg injuries. 20% had physiological challenges requiring Intensive care unit (ICU) admissions. Infection was reported in 49% of amputees with 12% reporting acute sepsis. Psychologically, 49% reported severe, or extreme, anxiety and depression. AKAs were associated with greater morbidity: amputees are significantly younger, have more proximal vascular injuries, receive delayed amputations and experience longer time intervals to stump healing. ICU care and contralateral leg injuries were more frequent. One third of amputees used their prostheses', one third did not and one third do not have a prosthesis yet. The limiting factor for repair was supply of materials. 11% of amputees needed no adjustment to stump or prosthesis. Surgical stump revision was recommended in 26% of stumps and prosthetic management in 41%. A further 22%, subject to the success or failure of prescribed prosthetic adjustment, could require stump revision.

CONCLUSION

Youth, proximal injury, high numbers of AKA, psychosocial issues and the need for stump and prosthetic support define this group of amputees. Unifying expertise within a National MDT will promote continuity of care necessary for decades to come. The ultimate aim is an evidence-based amputee care system in Gaza, with lower limb specialists promoting best outcomes, judicious allocation of funds and maximising amputee quality of life.

Experimental study of β-TCP scaffold loaded with VAN/PLGA microspheres in the treatment of infectious bone defects

Antibiotic bone cement filling technology has been widely used in the treatment of infectious bone defects for decades. However, the current treatment requires multiple complicated procedures, which would lead to pain and financial burden for patients. Repairing bone defects and control infection at the same time is the pain spot of orthopaedic area. In this study, we develop a composite scaffold that aiming at effectively repair infectious bone defects simultaneously. Vancomycin hydrochloride(Van) /Poly(lactic-co-glycolic) acid(PLGA) microspheres prepared by double emulsion method were successfully loaded into β-tricalcium phosphate scaffold through electrostatic and physical crosslinking. Full characterization, including mechanical properties, biocompatibility, in vitro release profile and antibacterial properties of the composite scaffolds(CPSFs) were performed. The rabbit osteomyelitis model based on big hole and small hole methods was established. Pharmacodynamics study, including the local bacteriostatic and osteogenic ability were evaluated by X-ray, Micro-CT and histopathology at 4 months after surgery. These findings indicate that a reliable rabbit model of local bone defect infection successfully established by big hole approach. The CPSFs with significant histocompatibility and biocompatibility could sustained release vancomycin for extended duration. It exhibited great application potential in clinical aim at the indication of local infectious bone defects.

The Antibiotic Use in Osteomyelitis Infection: A Systematic Review

Introduction: Osteomyelitis is a serious infection of the bone. One of the therapies for osteomyelitis is antibiotic treatment. Antibiotic treatment has evolved substantially, but bone infections are still a challenge. Antimicrobial therapy is also difficult, caused by antibiotic-resistant organisms.  Therefore, a systematic review is needed to assess antibiotic use in osteomyelitis infection. Method: Articles were searched using Pubmed with keywords “antibiotics”, “osteomyelitis”, and its combination. The authors used five years publication date and English language to select the appropriate journal. Result: The author identified 13 relevant articles with antibiotics use in osteomyelitis. All of the cases were about chronic osteomyelitis and osteomyelitis in diabetic foot ulcers. Osteomyelitis in other sites of long bones needs longer duration treatment than long bone osteomyelitis. In acute osteomyelitis in children, antibiotic treatment can switch from IV to oral antibiotics. Furthermore, chronic osteomyelitis needs longer treatment to resolve than acute osteomyelitis. Conclusion: Antibiotics still mainstay treatment with surgery for osteomyelitis treatment. With acute, children, and long bone only need shorter treatment than chronic, adult, and non-long bone osteomyelitis.

Bone Healing and Inflammation: Principles of Fracture and Repair

Bones comprise a significant percentage of human weight and have important physiologic and structural roles. Bone remodeling occurs when healthy bone is renewed to maintain bone strength and maintain calcium and phosphate homeostasis. It proceeds through four phases: (1) cell activation, (2) resorption, (3) reversal, and (4) bone formation. Bone healing, on the other hand, involves rebuilding bone following a fracture. There are two main types of bone healing, primary and secondary. Inflammation plays an integral role in both bone remodeling and healing. Therefore, a tightly regulated inflammatory response helps achieve these two processes, and levels of inflammation can have detrimental effects on bone healing. Other factors that significantly affect bone healing are inadequate blood supply, biomechanical instability, immunosuppression, and smoking. By understanding the different mechanisms of bone healing and the factors that affect them, we may have a better understanding of the underlying principles of bony fixation and thereby improve patient care.

Single-Stage Treatment of Fracture-related Infections

Fracture-related infections (FRIs) remain a significant problem. Many approach FRI cases in a staged fashion, focusing on infection eradication initially and fracture union during subsequent procedures. The literature quotes high success rates with this strategy. However, associated patient morbidity and economic impact are noteworthy. A single-stage FRI treatment, using an antibiotic-coated locked intramedullary nail, also exists. This video details low-cost, antibiotic-coated locked intramedullary nail fabrication in the operating room alongside preliminary results using this technique for acute FRI and septic nonunion treatment.

What is the burden of osteomyelitis in Germany? An analysis of inpatient data from 2008 through 2018

Background

The epidemiology of osteomyelitis in Germany is unknown, which makes it difficult to estimate future demands. Therefore, we aimed to analyse how the numbers of cases have developed over the last decade as a function of osteomyelitis subtype, age group, gender, and anatomical localization.

Methods

Osteomyelitis rates were quantified based on annual ICD-10 diagnosis codes from German medical institutions between 2008 through 2018, provided by the Federal Statistical Office of Germany (Destatis).

Results

Overall osteomyelitis prevalence increased by 10.44% from 15.5 to 16.7 cases per 100,000 inhabitants between 2008 through 2018. Out of 11,340 cases in 2018, 47.6% were diagnosed as chronic, 33.2% as acute and 19.2% as unspecified osteomyelitis. Men were often affected than women with 63.4% of all cases compared to 36.6%. The largest proportion of patients comprised the age group 60–69 years (22.1%), followed by 70–79 years (21.7%). A trend towards more osteomyelitis diagnoses in older patients was observed. Lower extremities were most frequently infected with 73.8% of all cases in 2018 (+ 10.8% change).

Conclusions

Osteomyelitis remains a serious problem for orthopedic and trauma surgery. Prevention methods and interdisciplinary approaches are strongly required.

Regulation of Bone Cell Differentiation and Activation by Microbe-Associated Molecular Patterns

Gut microbiota has emerged as an important regulator of bone homeostasis. In particular, the modulation of innate immunity and bone homeostasis is mediated through the interaction between microbe-associated molecular patterns (MAMPs) and the host pattern recognition receptors including Toll-like receptors and nucleotide-binding oligomerization domains. Pathogenic bacteria such as Porphyromonas gingivalis and Staphylococcus aureus tend to induce bone destruction and cause various inflammatory bone diseases including periodontal diseases, osteomyelitis, and septic arthritis. On the other hand, probiotic bacteria such as Lactobacillus and Bifidobacterium species can prevent bone loss. In addition, bacterial metabolites and various secretory molecules such as short chain fatty acids and cyclic nucleotides can also affect bone homeostasis. This review focuses on the regulation of osteoclast and osteoblast by MAMPs including cell wall components and secretory microbial molecules under in vitro and in vivo conditions. MAMPs could be used as potential molecular targets for treating bone-related diseases such as osteoporosis and periodontal diseases.

Prediction of Adverse Outcomes in Pediatric Acute Hematogenous Osteomyelitis

BACKGROUND

Clinicians cannot reliably predict complications of acute hematogenous osteomyelitis (AHO).

METHODS

Consecutive cases of AHO from 2 pediatric centers in the United States were analyzed retrospectively to develop clinical tools from data obtained within 96 hours of hospitalization to predict acute and chronic complications of AHO. Two novel composite prediction scores derived from multivariable logistic regression modeling were compared with a previously published severity of illness (SOI) score, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) using area under the receiver operating characteristic curve analyses.

RESULTS

The causative organisms were identified in 73% of 261 cases. Bacteremia (45%), abscesses (38%), and associated suppurative arthritis (23%) were relatively common. Acute or chronic complications occurred in 24% and 11% of patients, respectively. Multivariable logistic regression identified bone abscess (odds ratio [OR], 2.3 [95% confidence interval {CI}, 1.0-5.2]), fever > 48 hours (OR, 2.7 [95% CI, 1.2-6.0]), suppurative arthritis (OR, 3.2 [95% CI, 1.3-7.5]), disseminated disease (OR, 4.6 [95% CI, 1.5-14.3]), and delayed source control (OR, 5.1 [95% CI, 1.4-19.0]) as strong predictors of acute complications. In a separate model, CRP ≥ 100 mg/L at 2-4 days after antibiotics (OR, 2.7 [95% CI, 1.0-7.3]), disseminated disease (OR, 3.3 [95% CI, 1.1-10.0]), and requirement for bone debridement (OR, 6.7 [95% CI, 2.1-21.0]) strongly predicted chronic morbidity. These variables were combined to create weighted composite prediction scores for acute (A-SCORE) and chronic (C-SCORE) osteomyelitis, which were superior to SOI, CRP, and ESR and had negative predictive values > 90%.

CONCLUSIONS

Two novel composite clinical scores were superior to existing tools to predict complications of pediatric AHO.

Local treatment of experimental mandibular osteomyelitis with an injectable biomimetic gentamicin hydrogel using a new rabbit model

Mandibular osteomyelitis (OM) is a challenging disease. Our objective was to assess a new OM model in rabbits induced by arsenic trioxide and to assess the efficacy of local treatment of OM using injectable gentamicin-collagen hydrogels (GNT-COLL). OM was induced unilaterally by controlled confinement of arsenic trioxide paste to the root canal of lower incisors of rabbits, while OM progression was characterized for 16 weeks. On the other hand, two injectable COLL hydrogels functionalized with GNT were prepared and characterized for physicochemical properties; a simple GNT-COLL and a nanohydroxyapatite (nHA)- loaded hydrogel (GNT-COLL/nHA). The two hydrogels were evaluated to treat OM model, while a multidose intramuscular GNT solution served as positive control. Outcomes were assessed by standard methods at 4 and 12 weeks post-surgery. The clinical, radiographical, and histopathological findings provided evidence for the validity of the arsenic-induced OM. The results demonstrated that a single intra-lesional injection of the two hydrogels was more suppressive to OM compared to multidose systemic GNT. The composite GNT-COLL/nHA hydrogel proved to induce early preservation of alveolar bone (ridge) length and higher amount of bone area\total area at 4 weeks (40.53% ± 2.34) followed by GNT-COLL (32.21% ± 0.72). On the other hand, the positive control group revealed the least ridge length and bone area\total area (26.22% ± 1.32) at 4 weeks. Both hydrogels successfully arrested OM with no signs of recurrence for up to 12 weeks. Therefore, results support the greater advantages of the composite hydrogel as an osteogenic/antibiotic delivery system in OM treatment.

Modifications of Hydroxyapatite by Gallium and Silver Ions-Physicochemical Characterization, Cytotoxicity and Antibacterial Evaluation

Hydroxyapatite (HA) powders enriched with silver or gallium ions or both were synthesized by two different routes: standard precipitation and the solid-state method. The powders were characterized by using several methods: inductively coupled plasma optical emission spectrometry (ICP-OES), powder X-ray diffractometry (PXRD), transmission electron microscopy (TEM), infrared spectroscopy (FT-IR) and solid-state nuclear magnetic resonance spectroscopy (ssNMR). The effects of enrichment of the HAs in Ag⁺ or Ga³⁺ or both on in vitro cytotoxicity and microbiological activity were discussed. PXRD experiments showed that the samples obtained by the wet method consisted of single-phase nanocrystalline HA, while the samples prepared via the solid-state method are microcrystalline with a small amount of calcium oxide. The introduction of higher amounts of silver ions was found to be more effective than enriching HA with small amounts of Ag⁺. Gallium and silver ions were found not to affect the lattice parameters. Ga³⁺ affected the crystallinity of the samples as well as the content of structural hydroxyl groups. Among samples synthesized by the wet method, only one (5Ag-HAw) was cytotoxic, whereas all Ga-containing samples obtained by the dry method showed cytotoxicity. In the preliminary antimicrobial test all the materials containing "foreign" ions showed high antibacterial activity.

Treatment of Acute Osteomyelitis with Once-Weekly Oritavancin: A Two-Year, Multicenter, Retrospective Study

Background

Acute osteomyelitis is typically caused by Gram-positive pathogens, commonly antibiotic-resistant Staphylococcus species. Standard antibiotic treatment is challenging due to required multiple daily doses, therapeutic drug monitoring, and parenteral administration for at least 4 weeks. Oritavancin is a long-acting lipoglycopeptide antibiotic approved as a single 1200 mg dose for the treatment of adult patients with acute bacterial skin and skin structure infections.

Objective

To characterize the real-world use, efficacy, and safety of oritavancin in adult patients with acute osteomyelitis.

Methods

This was a 2-year, multicenter, retrospective, descriptive study of patients treated for acute osteomyelitis with weekly doses of oritavancin. End of therapy evaluation (ETE) was defined as evaluation at 7–10 days after the last dose of oritavancin, and post-therapy assessment (PTE) was at 3 months and 6 months. At ETE and PTE, patients were interviewed via telephone for clinical outcomes, using a standard questionnaire. Electronic medical record review was also conducted.

Results

134 patients were treated with oritavancin for acute osteomyelitis across 20 different Metro Infectious Disease Consultants infusion centers in six states. Of total positive cultures, 71.9% (92/128) were methicillin-resistant Staphylococcus aureus (MRSA) from deep wounds, bone, or joint culture; an additional nine (6.7%) of 134 patients presented with concomitant MRSA bacteremia. Oritavancin was administered via intravenous catheter; patients received an initial treatment of 1200 mg and then 800 mg weekly thereafter for a total number of doses of four (n = 118) or five (n = 16). 118 patients (88.1%) of the baseline 134 patients achieved clinical success at the ETE timepoint. 130 patients were available for PTE at 3 months and 6 months. Overall, relapse or persistent infection was diagnosed in 13/134 (9.7%) patients. Nine (6.7%) of 134 patients were admitted to the hospital during the follow-up period but none for osteomyelitis. Adverse events were reported in five (3.7%) patients including hypoglycemia-related symptoms (three patients), tachycardia (one patient), and tachycardia with chest pain (one patient). None of these patients were hospitalized due to adverse events, and all patients eventually finished their treatment regimens.

Conclusion

This is the largest real-world clinical study of adult patients treated with oritavancin for acute osteomyelitis. Use of oritavancin for acute osteomyelitis infection resulted in a high rate of positive clinical outcomes and a low incidence of adverse events, thereby providing potential for a convenient, effective, and safe therapeutic option. Future prospective and comparative studies are needed to validate these findings.

Lipid-polymer hybrid nanoparticles carrying linezolid improve treatment of methicillin-resistant Staphylococcus aureus (MRSA) harbored inside bone cells and biofilms

Methicillin-resistant Staphylococcus aureus (MRSA) is the most prevalent pathogen causing osteomyelitis. The tendency of MRSA to evade standard antibiotic treatment by hiding inside bone cells and biofilms is a major cause of frequent osteomyelitis recurrence. In this study, we developed a lipid-polymer hybrid nanoparticle loading the antibiotic linezolid (LIN-LPN), and focused on evaluating if this new nanoantibiotic can achieve significant in vitro activities against these intracellular and biofilm-embedded MRSA. The optimal LIN-LPN formulation demonstrated both high linezolid payload (12.0% by weight of nanoparticles) and controlled release characteristics (gradually released the entrapped antibiotic in 120 h). Although it achieved lower activities against bacteria including USA300-0114, CDC-587, RP-62A in planktonic form, it was substantially superior against the intracellular MRSA reservoir inside osteoblast cells. The differences of intracellular activities between LIN-LPN and linezolid were 87.0-fold, 12.3-fold, and 12.6-fold in CFU/ml (p < 0.05 or < 0.01) at 2 µg/ml, 4 µg/ml, and 8 µg/ml linezolid concentrations, respectively. LIN-LPN also suppressed the MRSA biofilm growth to 35-60% of the values achieved with free linezolid (p < 0.05). These enhanced intracellular and anti-biofilm activities of LIN-LPN were likely contributed by the extensive accumulation of LIN-LPN inside the MRSA-infected osteoblasts and biofilms as revealed in the confocal microscope images. The study thus validates the feasibility of exploiting the good nanoparticle-host cell and nanoparticle-biofilm interactions for improving the antibiotic drug activities against the poorly accessible bacteria, and supports LIN-LPN as a new alternative therapy for preventing the recurrence of MRSA-mediated bone infections.

Hydrogen sulfide promotes lipopolysaccharide-induced apoptosis of osteoblasts by inhibiting the AKT/NF-κB signaling pathway

Apoptosis of osteoblasts plays a crucial role in osteomyelitis. Hydrogen sulfide (H₂S) levels are increased in the pathophysiological processes of osteomyelitis. However, the effect of H₂S on the apoptosis of osteoblasts remains unclear. To investigate the specific role of H₂S in osteoblast apoptosis, MC3T3-E1 and hFOB cells were treated with NaHS or Na₂S, a donor of H₂S, and lipopolysaccharide (LPS), during osteomyelitis. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, flow cytometry analysis, western blotting, immunofluorescence, polymerase chain reaction, and Alizarin red staining were performed to examine the effects of H₂S on osteoblast cell apoptosis, cell osteogenic differentiation, and AKT kinase (AKT)/nuclear factor kappa B (NF-κB) signaling. Hydrogen sulfide increased cell apoptosis, and inhibited the proliferation and osteogenic differentiation of osteoblast cells impaired by LPS. H₂S increased apoptosis through upregulation of the FAS ligand (FASL) signaling pathway. H₂S-induced apoptosis was alleviated using a FAS/FASL signaling pathway inhibitor. Treatment with NaHS also increased cell apoptosis by downregulating AKT/NF-κB signaling. In addition, treatment with an AKT signaling pathway activator decreased apoptosis and reversed the inhibitory effects of H₂S on osteogenic differentiation. Hydrogen sulfide promotes LPS-induced apoptosis of osteoblast cells by inhibiting AKT/NF-κB signaling.

Chronic femoral diaphyseal osteomyelitis with radiographs initially concerning for Paget disease of the bone

Chronic osteomyelitis can be difficult to diagnose given its similar radiographic appearance to other lesions. This case report describes a 48-year-old woman, who presented with left thigh pain and on radiography a large disorganized sclerotic lesion involving nearly the entire femoral diaphysis, concerning for Paget disease or malignancy. Biopsy suggested chronic osteomyelitis but did not identify a causative organism. Treatment with antibiotics led to resolution of pain and improvement of biochemical markers. This case exemplifies the role of radiographic imaging in the diagnosis of chronic osteomyelitis and the possible utility of antibiotics for culture-negative chronic osteomyelitis. We review imaging modalities for the diagnosis of chronic osteomyelitis and Paget disease.

Oral Flucloxacillin for Staphylococcal Osteomyelitis: Obsolete or Underused?

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