Diagnosis of vertebral osteomyelitis

What Is the Accuracy of 16S PCR Followed by Sanger Sequencing or Next-generation Sequencing in Native Vertebral Osteomyelitis? A Systematic Review and Meta-analysis

BACKGROUND

Identifying a microorganism in patients with native vertebral osteomyelitis presents diagnostic challenges. Microorganism identification through culture-based methods is constrained by prolonged processing times and sensitivity limitations. Despite the availability of molecular diagnostic techniques for identifying microorganisms in native vertebral osteomyelitis, there is considerable variability in reported sensitivity and specificity across studies, leading to uncertainty in their clinical utility.

QUESTIONS/PURPOSES

What are the sensitivity, specificity, and diagnostic odds ratios for 16S broad-range PCR followed by Sanger sequencing (16S) and metagenomic next-generation sequencing (NGS) for detecting bacteria in native vertebral osteomyelitis?

METHODS

On June 29, 2023, we searched Cochrane, Embase, Medline, and Scopus for results from January 1970 to June 2023. Included studies involved adult patients with suspected native vertebral osteomyelitis undergoing molecular diagnostics-16S bacterial broad-range PCR followed by Sanger sequencing and shotgun or targeted metagenomic NGS-for bacteria detection. Studies involving nonnative vertebral osteomyelitis and cases of brucellar, tubercular, or fungal etiology were excluded. The reference standard for the diagnosis of native vertebral osteomyelitis was a composite clinical- and investigator-defined native vertebral osteomyelitis diagnosis. Diagnostic performance was assessed using a bivariate random-effects model. Risk of bias and diagnostic applicability were evaluated using the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. After a manual screening of 3403 studies, 10 studies (5 on 16S, 5 on NGS) were included in the present analysis, from which 391 patients were included from a total of 958 patients overall. Quality assessment via QUADAS-2 criteria showed moderate risk of bias and good applicability.

RESULTS

16S showed 78% (95% confidence interval [CI] 95% CI 31% to 96%) sensitivity and 94% (95% CI 73% to 99%) specificity, whereas NGS demonstrated 82% (95% CI 63% to 93%) sensitivity and 71% (95% CI 37% to 91%) specificity. In addition, the diagnostic ORs were 59 (95% CI 9 to 388) and 11 (95% CI 4 to 35) for 16S and NGS, respectively. Summary receiver operating characteristic curves showed high test performance for 16S (area under the curve for 16S 95% [95% CI 93% to 97%] and for NGS 89% [95% CI 86% to 92%]). Certainty in estimates was moderate because of sample size limitations.

CONCLUSION

This meta-analysis found moderate-to-high diagnostic performance of molecular methods on direct patient specimens for the diagnosis of native vertebral osteomyelitis. When used as a complementary test to microbiological analyses, a positive 16S result rules in the diagnosis of native vertebral osteomyelitis, while further studies are needed to understand the role of NGS in the diagnosis of native vertebral osteomyelitis. When available, these tests should be used in addition to conventional microbiology, especially in complex cases with extensively negative standard microbiological test results, to detect fastidious bacteria or to confirm the causative bacteria when their isolation and pathogenicity are unclear. A large sample size is needed in future research to understand the use of these techniques as standalone tests for diagnosis.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Expert Panel on Pediatric Imaging, Dahmoush H, Gaddam DS, Ho ML, Bauer DF, Bosemani T, Buchhalter J, Dasgupta RA, Glenn OA, Guimaraes CV, Nadel HR, Pfeifer CM, Radhakrishnan R, Reitman C, Thomas AK, Udayasankar UK, Wall JJ, Wright JN, Wusthoff CJ, Pruthi S. ACR Appropriateness Criteria® Back Pain-Child: 2024 Update

Nontraumatic back pain is a common chief complaint encountered in the pediatric population. Although there are many etiologies for pediatric back pain, most cases are attributable to benign mechanical causes. Serious conditions causing back pain such as inflammatory, infectious, and neoplastic etiologies are much less common but these pathologies can lead to long-term morbidity. Recent paradigm shift to judicious use of diagnostic imaging resources has come to the forefront. Although imaging is unlikely to be beneficial in transient back pain without neurologic deficit and normal physical examination, prompt imaging evaluation is required when there are clinical and laboratory findings suggesting an infectious or neoplastic etiology. For this document, various clinical scenarios are discussed by which a child may present with back pain. Imaging studies that might be most appropriate (based on the best available evidence or expert consensus) in these clinical scenarios are detailed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Current knowledge of vertebral osteomyelitis: a review

PURPOSE

As life expectancy increases worldwide, the elderly population in every country is growing in both the size and proportion. This review aims to provide a comprehensive overview of the microbiology, clinical presentation, diagnostic strategies, and therapeutic approaches to vertebral osteomyelitis, summarizing the latest evidence to guide effective treatment.

METHODS

A comprehensive literature search was conducted using the Medline and Embase databases to identify relevant studies on vertebral osteomyelitis. The search included the following keywords: "vertebral osteomyelitis," "spinal infection," "discitis," "spondylitis," " spondylodiscitis," and "spinal epidural abscess." Both retrospective and prospective studies, case series, and reviews were considered.

RESULTS

This condition is commonly caused by bacteria such as Staphylococcus aureus or gram-negative bacilli, but can also be caused by other pathogens like fungi and parasites. The onset of vertebral osteomyelitis is insidious, with low specificity in clinical manifestations, often making early diagnosis difficult. Delayed or inadequate treatment may lead to sepsis, permanent neurological damage, or even death. Treatment strategies emphasize the importance of identifying the causative pathogen to guide effective antimicrobial therapy. Current consensus does not advocate for empirical antibiotic treatment unless patients exhibit signs of neurological impairment or severe sepsis. Severe cases involving neurological paralysis, spinal instability, or sepsis may require surgical intervention.

CONCLUSION

Vertebral osteomyelitis requires prompt diagnosis and treatment for a good prognosis. Delayed diagnosis and treatment can lead to permanent neurological deficits or death. Identifying the causative organism is crucial for guiding appropriate antimicrobial therapy. In addition to conservative and surgical treatments, local drug delivery systems offer new approaches to managing spinal osteomyelitis.

The utility of disc space and vertebral body specimens cell count differential for the diagnosis of native vertebral osteomyelitis: a prospective cohort study

BACKGROUND

Diagnostic methods for native vertebral osteomyelitis (NVO) often yield inconclusive results. Image-guided spine biopsies for culture are specific but diagnose NVO in only 50% of cases. Pre-exposure to antimicrobials further reduces diagnostic yield. Our study assesses the value of neutrophil percentage in disc space fluid and vertebral body (DS/VB) samples for diagnosing NVO.

METHODS

Adults referred for spine biopsy at Mayo Clinic from August 2022 to September 2023 were consented and enrolled at the time of biopsy. Following routine specimen collection, the biopsy needle was rinsed in saline into an EDTA tube for cell analysis. NVO diagnosis required organism identification in spine tissue or blood and/or positive histopathology, and consistent symptoms and imaging.

RESULTS

Sixty-eight patients were prospectively enrolled, comprising 14 with NVO and 54 with alternative diagnoses. The median biopsy sample polymorphonuclear (PMN) percentage for NVO patients was 80.5% (IQR 72.5-85.2), compared to 64.5% (IQR 54.0-69.0) for those without NVO (p < 0.001). Nine (64.3%) NVO patients received antibiotics within 10 days prior to spine biopsy. As a continuous measure, PMN differential showed a moderately strong ability in classifying NVO status with an area under ROC curve of 0.795; an optimal point on the curve of 71.5% corresponded to a sensitivity of 78.6%, specificity of 79.6%, negative predictive value of 93.5% and positive predictive value of 50.0%.

CONCLUSION

PMN differential in DS/VB biopsies may serve as an effective diagnostic tool in the evaluation of patients with NVO particularly in ambiguous cases with an initially negative spine biopsy. Future efforts will aim to implement these findings within routine clinical practice.

Predictors of conversion surgery after conservative treatment for pyogenic spondylitis

BACKGROUND

Patient demographic and clinical characteristics may be factors associated with the success of conservative treatment for pyogenic spondylitis. The ability of imaging findings at initial diagnosis to predict patient outcomes remains unclear. The aim of this study was to investigate the risk factors associated with conversion surgery after conservative treatment for pyogenic spondylitis, with a special focus on the initial computed tomography (CT) findings.

METHODS

This study enrolled 35 patients with pyogenic spondylitis who underwent CT and magnetic resonance imaging (MRI) at diagnosis and were followed-up for more than 6 months. Patients were diagnosed by MRI, and the degree of bone destruction was assessed on CT cross-sectional images. Vertebral body destruction was classified as grades 0 (almost normal), 1 (endplate irregularity), 2 (vertebral body destruction not involving the posterior wall), and 3 (destruction involving the posterior wall). Patients were divided into four groups based on grade of bone destruction and their clinical characteristics were compared.

RESULTS

1, 11, 11, and 12 patients were classified as grades 0, 1, 2, and 3, respectively. Univariate analysis showed no significant differences in the demographic and clinical characteristics of the four groups. Eighteen (51.4 %) patients had been treated surgically, with the rate of surgical treatment being significantly higher in patients with grade 3 (83.3 %) than in those with grades 0 + 1 (25 %) and grade 2 (45.5 %) (P < 0.05). Multivariate analysis showed that epidural abscess on MRI (odds ratio [OR] 10.8, 95 % confidence interval [CI] 1.68-69.7), grade 3 bone destruction on CT (OR 3.97, 95 % CI 1.21-13.0), and C-reactive protein (CRP) improvement rate after 1 week of treatment (OR 0.95, 95 % CI 0.91-0.99) were risk factors for surgery.

CONCLUSIONS

Early surgical treatment should be considered for patients with pyogenic spondylitis who present with an epidural abscess on MRI and bone destruction extending to the posterior wall on CT at the time of diagnosis.

Culture-Negative Native Vertebral Osteomyelitis: A Narrative Review of an Underdescribed Condition

The incidence of culture-negative NVO (CN-NVO) cases is increasing, presenting significant diagnostic and therapeutic challenges due to the inability to isolate causative organisms with conventional microbiological methods. Factors influencing the diagnosis of CN-NVO include prior antimicrobial therapy, low pathogen burden, fastidious or intracellular organisms, technical issues, and non-infectious mimickers. Diagnosis often relies on imaging modalities like magnetic resonance imaging (MRI) and computed tomography (CT)-guided biopsy, though these methods can sometimes fail to yield positive microbiological results. Advanced diagnostic tools, such as polymerase chain reaction (PCR), metagenomic next-generation sequencing (mNGS), and cell-free DNA analysis, may be necessary to identify the pathogen. The causative pathogen cannot be isolated in some patients, among which an empirical antimicrobial therapy should be initiated. This narrative review discusses the management, monitoring, surgical indications, and outcomes for patients with CN-NVO.

It is time for a unified definition of native vertebral osteomyelitis: a framework proposal

In recent years, there has been a notable increase in research output on native vertebral osteomyelitis (NVO), coinciding with a rise in its incidence. However, clinical outcomes remain poor, due to frequent relapse and long-term sequelae. Additionally, the lack of a standardized definition and the use of various synonyms to describe this condition further complicate the clinical understanding and management of NVO. We propose a new framework to integrate the primary diagnostic tools at our disposal. These collectively fall into three main domains: clinical, radiological, and direct evidence. Moreover, they and can be divided into seven main categories: (a) clinical features, (b) inflammatory biomarkers, (c) imaging techniques, microbiologic evidence from (d) blood cultures and (e) invasive techniques, (f) histopathology, and (g) empirical evidence of improvement following the initiation of antimicrobial therapy. We provide a review on the evolution of these techniques, explaining why no single method is intrinsically sufficient to formulate an NVO diagnosis. Therefore, we argue for a consensus-driven, multi-domain approach to establish a comprehensive and universally accepted definition of NVO to enhance research comparability, reproducibility, and epidemiological tracking. Ongoing research effort is needed to refine these criteria further, emphasizing collaboration among experts through a Delphi method to achieve a standardized definition. This effort aims to streamline research, expedite accurate diagnoses, optimize diagnostic tools, and guide patient care effectively.

Differentiation of Native Vertebral Osteomyelitis: A Comprehensive Review of Imaging Techniques and Future Applications

Native vertebral osteomyelitis, also termed spondylodiscitis, is an antibiotic-resistant disease that requires long-term treatment. Without proper treatment, NVO can lead to severe nerve damage or even death. Therefore, it is important to accurately diagnose the cause of NVO, especially in spontaneous cases. Infectious NVO is characterized by the involvement of 2 adjacent vertebrae and intervertebral discs, and common infectious agents include Staphylococcus aureus, Mycobacterium tuberculosis, Brucella abortus, and fungi. Clinical symptoms are generally nonspecific, and early diagnosis and appropriate treatment can prevent irreversible sequelae. Advances in pathologic histologic imaging have led physicians to look more forward to being able to differentiate between tuberculous and septic spinal discitis. Therefore, research in identifying and differentiating the imaging features of these 4 common NVOs is essential. Due to the diagnostic difficulties, clinical and radiologic diagnosis is the mainstay of provisional diagnosis. With the advent of the big data era and the emergence of convolutional neural network algorithms for deep learning, the application of artificial intelligence (AI) technology in orthopedic imaging diagnosis has gradually increased. AI can assist physicians in imaging review, effectively reduce the workload of physicians, and improve diagnostic accuracy. Therefore, it is necessary to present the latest clinical research on NVO and the outlook for future AI applications.

Imaging in osteoarticular infection in adults

BACKGROUND

Osteoarticular infections are uncommon and required a multimodal approach for diagnosis. Imaging forms an important component of this multimodal approach.

OBJECTIVES

In this narrative review, we describe the different imaging modalities, features of osteoarticular infections present on these imaging approaches and recommendations for which imaging modality should be considered in different types of osteoarticular infections.

SOURCES

This narrative review was based on literature review from PubMed and was limited to bacterial infections in adult patients.

CONTENT

Imaging modalities include modalities that provide information on the anatomy or radionuclide imaging that provides information about the metabolic activity of the area of interest. Anatomical imaging includes plain radiographs (X-ray), computed tomography, and magnetic resonance imaging. Radionuclide approaches include three-phase bone scintigraphy, gallium scans, white blood cell scintigraphy, and 18F-fluorodeoxy-glucose positron emission tomography. The optimal radiological modality for diagnosis is influenced by multiple factors, including infection location, presence of metalware, timing of infection from any preceding surgery or fracture, antibiotic use, and patient comorbidities. Local availability of scanning modality, tracer supply, technical expertise, and patient access also influences choice.

IMPLICATIONS

A collaborative approach with imaging, pathology and clinical input in a multidisciplinary setting is paramount for the diagnosis of osteoarticular infections. Increasing research and improvements in technology will further improve the utility and accuracy of imaging approaches for imaging in osteoarticular infections.

Application of Nuclear Medicine Techniques in Musculoskeletal Infection: Current Trends and Future Prospects

Nuclear medicine has become an indispensable discipline in the diagnosis and management of musculoskeletal infections. Radionuclide tests serve as a valuable diagnostic tool for patients suspected of having osteomyelitis, spondylodiscitis, or prosthetic joint infections. The choice of the most suitable imaging modality depends on various factors, including the affected area, potential extra osseous involvement, or the impact of previous bone/joint conditions. This review provides an update on the use of conventional radionuclide imaging tests and recent advancements in fusion imaging scans for the differential diagnosis of musculoskeletal infections. Furthermore, it examines the role of radionuclide scans in monitoring treatment responses and explores current trends in their application. We anticipate that this update will be of significant interest to internists, rheumatologists, radiologists, orthopedic surgeons, rehabilitation physicians, and other specialists involved in musculoskeletal pathology.

A case of Staphylococcus epidermidis osteomyelitis in the absence of spine hardware

Staphylococcus epidermidis is a typically indolent pathogen that is often considered a blood culture contaminant. It is a rare and unexpected cause of osteomyelitis, especially in the absence of recent surgical intervention or orthopedic implants. We highlight a case in which a 90-year-old Caucasian male with no recent spine surgery was found to have osteomyelitis of the lumbar spine and repeat positive blood cultures for methicillin resistant Staphylococcus epidermidis (MRSE). Further investigation revealed a history of mitral valve replacement and a new diagnosis of endocarditis leading to persistent bacteremia and seeding of his lumbar vertebrae. This case demonstrates that S. epidermidis can cause vertebral osteomyelitis resulting in severe complications that are more similar to highly pathogenic bacteria. We describe the steps to diagnosing this chronic undetected infection and related comorbidities.

Association between radiographic and functional outcome in vertebral osteomyelitis SPONDIMMO, a 6-month prospective multicenter cohort

OBJECTIVES

This study aimed to describe radiographic and functional evolution over 6 months in a large cohort of VO patients.

METHODS

We prospectively recruited patients with VO from 2016 to 2019 in 11 French centers. X-rays were performed at baseline, 3 months, and 6 months to assess progression using structural and static criteria. Functional impairment was evaluated using the Oswestry Disability Index (ODI) at 3 months and 6 months.

RESULTS

Two hundred and twenty-two patients were included. Mean age was 67.8±14 years, mostly men (67.6%). After 3 months, there was a significant increase in vertebral fusion (16.4% vs 52.7%), destruction of vertebral bodies (10.1% vs 22.8%), and of all the static features (frontal angulation (15.2% vs 24.4%), segmental (34.6% vs 56%) and regional (24.5% vs 41%) kyphosis). From 3 to 6 months, among the different X-ray abnormalities, only the complete fusion progressed significantly (16.6% vs 27.2%). Median ODI showed significant improvement from 3 to 6 months (24, IQR [11.5-38] vs 16, IQR [6-34]). At 6 months, 14.1% of the patients had a severe disability, 2% a major disability. The persistence of vertebral destruction at 6 months was associated with a higher ODI (16, IQR [7.5-30.5] vs 27, IQR [11.5-44.5]). No differences in radiological progression were observed with immobilization using a rigid brace.

CONCLUSION

Our study demonstrates structural and static radiographic progression after 3 months. Only the complete fusion progressed over the long-term. Functional impairment was associated with persistence of vertebral destruction.

A Comprehensive Review of Pyogenic Spondylitis Management for Neurosurgeons

Older populations have been increasing recently, resulting in an increase in cases of pyogenic spondylitis. Neurosurgeons who frequently treat the elderly are at a higher risk of encountering this condition. Therefore, this article provides a summary of the literature and our experience to help neurosurgeons effectively manage pyogenic osteomyelitis. It is important not to rule out pyogenic spondylosis when examining a patient with back pain, even in the absence of a fever. This is because the chronic type is common, easily overlooked, and early diagnosis and treatment are crucial. Empirical antibiotics should be avoided in cases where blood culture and biopsy are negative, to prevent microbial resistance and an increase in difficult-to-treat cases. Biopsies, such as computed tomography-guided percutaneous biopsy and full endoscopic debridement and drainage, should be attempted. Currently, 6 weeks of parenteral antibiotic therapy is the main treatment for pyogenic spondylitis. Surgical treatment is recommended if this method is ineffective. However, in the early stages, full endoscopic debridement and drainage and percutaneous pedicle screw fixation are optional.

The use of MRI, PET/CT, and nuclear scintigraphy in the imaging of pyogenic native vertebral osteomyelitis: a systematic review and meta-analysis

BACKGROUND CONTEXT

Native vertebral osteomyelitis (NVO) is a severe infection with an increasing incidence globally. Although there is no widely agreed upon reference standard for diagnosis of the disease, imaging plays a crucial role. Magnetic resonance imaging (MRI) is currently the imaging modality of choice. In recent years, advances in imaging have allowed for a larger role for alternative imaging techniques in the setting of NVO.

PURPOSE

Our aim was to evaluate the diagnostic accuracy of MRI, PET/CT, and nuclear imaging, namely 67Gallium and 99mTechnetium scintigraphy, in the diagnosis of pyogenic NVO.

STUDY DESIGN/SETTING

We conducted a systematic review of five medical databases and included all studies from 1970 to September 2021 that compared imaging techniques and provided sufficient data for diagnostic test accuracy meta-analysis.

METHODS

Abstract screening, full text review, and data extraction were done by a pair of independent reviewers. Nonnative and nonpyogenic patients were excluded. A bivariate random effect model was used for meta-analysis.

RESULTS

Twenty studies were included in the meta-analysis, encompassing a total of 1,123 imaging studies. The meta-analysis sensitivity and specificity of MRI were 90% and 72% respectively; those of PET/CT were 93% and 80%; those of 67Ga were 95% and 88%; those of 99mTc were 86% and 39%; and the sensitivity and specificity of combined Ga and Tc were 91% and 92% respectively in the setting of suspected NVO.

CONCLUSIONS

67Ga has the highest sensitivity for NVO, and its specificity is augmented when combined with 99mTc. MRI and PET/CT are both highly sensitive modalities, although the specificity of PET/CT is slightly better. MRI remains an appropriate initial test depending on the availability of other modalities.

Patterns of Vertebral Bone Marrow Edema in the Normal Healing Process of Lumbar Interbody Fusion: Baseline Data for Diagnosis of Pathological Events

STUDY DESIGN

Retrospective investigation using a prospectively collected database.

OBJECTIVE

To examine the appearance and characteristics of vertebral bone marrow edema (BME) in the normal healing of lumbar interbody fusion.

SUMMARY OF BACKGROUND DATA

Although BME in pathological spinal conditions has been well-documented, the patterns and characteristics of BME in the normal healing process of spinal fusion remains unexplored.

MATERIALS AND METHODS

We reviewed imaging from 225 patients with normal healing following posterior lumbar interbody fusion or transforaminal lumbar interbody fusion. BME was identified on magnetic resonance imaging at the third postoperative week and categorized with respect to its appearance, including assessment of area and extension within the relevant vertebrae.

RESULTS

Three hundred eighty-nine of the 450 instrumented vertebrae (86.4%) displayed evidence BME. All instances of BME were associated with the area of contact with the endplate. The average extent of BME was 32.7±1.0%. BME within normal healing following interbody fusion could be categorized into four types: no edema (13.6%), anterior corner (36.6%), around-the-cage focal (48.0%), and diffuse (1.8%). Anterior corner BME was significantly associated with instances of single cage placement than in dual cages (42.6% vs. 24.7%, P =0.0002). Single cages had a significantly higher rate of BME than dual cages (92.0% vs. 75.3%, P <0.0001). The extent of BME was significantly greater in the single cage cohort (36.9% vs. 24.2% in dual cages, P <0.0001).

CONCLUSIONS

This serves as the first study demonstrating the patterns of BME associated with normal healing following lumbar interbody fusion procedures. Anterior corner BME and around-the-cage focal BME were the most common patterns encountered, with diffuse BME a relatively rare pattern. These findings might contribute to the better differentiation of postoperative pathological events from normal healing following lumbar interbody fusion.

LEVEL OF EVIDENCE

4.

[A vertebral polymicrobial osteomyelitis with atypicial microorganisms: A case report]

Vertebral Osteomyelitis (VO) is a rare disease, which has seen a gradual increase in its incidence over the past years. Here, we report a case, showing how difficult it can be to diagnose and manage a therapy in case of atypical microorganism. A 68-year-old man was hospitalized for a VO documented by blood cultures at Bacteroides fragilis. He first progressed favorably, but an increase in lumbar pain prompted, after an IRM, a percutaneous needle biopsy (PNB) that documented a recurrent VO at Corynebacterium striatum. In the face of this multi-microbial VO with atypicals microorganisms, a first PNB could have been discussed despite the positive blood cultures. This case report illustrates the complexity of management of VO, and its evolution according to the latest recommendations (interest of RMI during the follow-up, place of the TEP-scan, terms and conditions of immobilization, antibiotic administration methods).

Management of vertebral osteomyelitis in adults

Vertebral osteomyelitis is a condition that predominantly affects older men with chronic comorbidities, such as diabetes, renal and hepatic failure, or immunosuppression. Symptoms develop insidiously and a high index of suspicion is required to diagnose the condition; this is achieved through serological testing and imaging. The mainstay of treatment is long-term antibiotic therapy, lasting a minimum of 6 weeks; however, surgical debridement with stabilisation is required when conservative treatment is proving ineffective and infection progresses. It is critically important that sufficient treatment is provided for those experiencing vertebral osteomyelitis, as not doing so could lead to severe neurological compromise and death.

Factors Impacting the Yield of Image-Guided Biopsy in Native Vertebral Osteomyelitis: A 10-Year Retrospective Study

Background

Image-guided biopsies in patients with suspected native vertebral osteomyelitis (NVO) are recommended to establish the microbiological diagnosis and guide antibiotic therapy. Despite recent advances, the microbiological yield of this procedure remains between 48% and 52%. A better understanding of factors associated with this low yield may lead to improved microbiological diagnosis.

Methods

We retrospectively identified patients with suspected NVO undergoing image-guided biopsies from January 2011 to June 2021 at our institution. Two hundred nine patients undergoing 248 percutaneous biopsies were included. Demographic data, biopsy and microbiologic techniques, clinical characteristics, and antibiotic use were collected. Multivariable logistic regression analysis was conducted to determine factors associated with microbiological yield.

Results

A total of 110 of 209 (52.6%) initial image-guided biopsies revealed positive microbiological results. This number increased to 121 of 209 (57.9%) when repeat image-guided biopsies were included. In multivariable analysis, aspiration of fluid was associated with a 3-fold increased odds of yielding a positive result (odds ratio [OR], 3.13; 95% confidence interval [CI], 1.39-7.04; P = .006), whereas prior antibiotic use was associated with a 3-fold decreased yield (OR, 0.32; 95% CI, .16-.65; P = .002). A univariate subgroup analysis revealed a significant association between the length of the antibiotic-free period and microbiological yield, with the lowest rates of pathogen detection at 0-3 days and higher rates as duration increased (P = .017).

Conclusions

Prior antibiotic use in patients with suspected NVO was associated with a decrease in the microbiological yield of image-guided biopsies. An antibiotic-free period of at least 4 days is suggested to maximize yield. Successful fluid aspiration during the procedure also increases microbiological yield.

Mini Review Therapeutic Strategies Targeting for Biofilm and Bone Infections

Bone infection results in a complex inflammatory response and bone destruction. A broad spectrum of bacterial species has been involved for jaw osteomyelitis, hematogenous osteomyelitis, vertebral osteomyelitis or diabetes mellitus, such as Staphylococcus aureus (S. aureus), coagulase-negative Staphylococcus species, and aerobic gram-negative bacilli. S. aureus is the major pathogenic bacterium for osteomyelitis, which results in a complex inflammatory response and bone destruction. Although various antibiotics have been applied for bone infection, the emergence of drug resistance and biofilm formation significantly decrease the effectiveness of those agents. In combination with gram-positive aerobes, gram-negative aerobes and anaerobes functionally equivalent pathogroups interact synergistically, developing as pathogenic biofilms and causing recurrent infections. The adhesion of biofilms to bone promotes bone destruction and protects bacteria from antimicrobial agent stress and host immune system infiltration. Moreover, bone is characterized by low permeability and reduced blood flow, further hindering the therapeutic effect for bone infections. To minimize systemic toxicity and enhance antibacterial effectiveness, therapeutic strategies targeting on biofilm and bone infection can serve as a promising modality. Herein, we focus on biofilm and bone infection eradication with targeting therapeutic strategies. We summarize recent targeting moieties on biofilm and bone infection with peptide-, nucleic acid-, bacteriophage-, CaP- and turnover homeostasis-based strategies. The antibacterial and antibiofilm mechanisms of those therapeutic strategies include increasing antibacterial agents’ accumulation by bone specific affinity, specific recognition of phage-bacteria, inhibition biofilm formation in transcription level. As chronic inflammation induced by infection can trigger osteoclast activation and inhibit osteoblast functioning, we additionally expand the potential applications of turnover homeostasis-based therapeutic strategies on biofilm or infection related immunity homeostasis for host-bacteria. Based on this review, we expect to provide useful insights of targeting therapeutic efficacy for biofilm and bone infection eradication.