Clinical findings, therapeutic approach, and outcome of brucellar vertebral osteomyelitis

A case report of acute renal failure caused by anti-brucellosis treatment

RATIONALE

Rifampicin, as a main chemotherapy drug treating brucellosis, is widely used in clinical practice. Rifampicin-associated ARF is not rare, especially in those rifampicin re-exposure patients. However, this was rare complication of severe renal involvement due to multiple factors including rifampicin, nephrotoxic gentamicin, and contrast medium, and few studies have reported it.

PATIENT CONCERNS

A 59-year-old male presented to our hospital with acute renal failure (ARF) caused by anti-brucellosis treatment with rifampicin (675 mg/day), gentamicin (320 mg/day), and doxycycline (200 mg/day). He had a contrast-enhanced CT of the upper abdomen before the onset of. After stopping rifampicin and undergoing integrated therapy, the patient's renal function gradually recovered.

DIAGNOSES

Considering that the patient had a history of using rifampicin for pulmonary tuberculosis in the past, based on the examination results, the patient was diagnosed with rifampicin-associated ARF.

INTERVENTIONS

Symptomatic treatment such as hemodialysis, and anti-brucella treatment with doxycycline and moxifloxacin were given.

OUTCOMES

The patient had significant anuric and polyuric periods and acute tubular necrosis is considered. After treatment, his renal function and urine volume returned to normal, and Brucella melitensis was not isolated from blood cultures.

LESSONS

The case reveals that severe renal involvement due to multiple factors including rifampicin, nephrotoxic gentamicin, and contrast medium. Misdiagnosis and mistreatment can deteriorate the patient's condition. Renal function should be closely monitored in the susceptible patients. Early recognition can provide appropriate therapy to patients. If unexplained renal failure during the use of rifampicin, especially in those rifampicin re-exposure patients, rifampicin-associated ARF should be considered.

Brucella Spondylitis: Current Knowledge and Recent Advances

The most prevalent zoonotic disease is brucellosis, which poses a significant threat for worldwide public health. Particularly in endemic areas, spinal involvement is a major source of morbidity and mortality and can complicate the course of the disease. The diagnosis of Brucella spondylitis is challenging and should be suspected in the appropriate epidemiological and clinical context, in correlation with microbiological and radiological findings. Treatment depends largely on the affected parts of the body. Available treatment options include antibiotic administration for an adequate period of time and, when appropriate, surgical intervention. In this article, we examined the most recent data on the pathophysiology, clinical manifestation, diagnosis, and management of spinal brucellosis in adults.

Brucella infection-induced hemophagocytic syndrome with subsequent development of the probable vanishing bile duct syndrome: A case report and literature review

Vanishing bile duct syndrome is a rare clinical manifestation, and many clinicians tend to classify vanishing bile duct syndrome as a surgical disease and perform emergency surgery, leading to poor prognosis for patients. In this report, we present a case of a patient initially diagnosed with probable vanishing bile duct syndrome. However, through a meticulous step-by-step investigation, we ultimately determined that the patient was suffering from Brucella infection-induced hemophagocytic syndrome, which contributed to the development of the probable vanishing bile duct syndrome. Once a definitive diagnosis was established, the patient underwent treatment following anti-Brucella and Hemophagocytic lymphohistiocytosis-2004 protocols, leading to an improvement in the patient's condition. We conducted a literature review on brucellosis, and it demonstrated the lack of specificity in diagnosing Brucella infections and the diverse range of clinical manifestations. Failure to arrive at a definitive diagnosis may result in clinical misdiagnosis and delayed treatment, thereby leading to grave consequences.

Osteoarticular Involvement in Childhood Brucellosis: Evaluation of Clinical, Laboratory and Radiologic Features of 185 Cases

BACKGROUNDS

Brucellosis is a systemic zoonotic disease. Osteoarticular (OA) system involvement is a common complication and the predominant manifestation of brucellosis in children. We aimed to evaluate the epidemiologic, demographic, clinical characteristics, and laboratory and radiologic findings of children with brucellosis and how these related to OA involvement.

METHODS

This retrospective cohort study consisted of all consecutive children and adolescents diagnosed as having brucellosis who were admitted to the pediatric infectious disease department of University of Health Sciences Van Research and Training Hospital between August 1, 2017, and December 31, 2018, in Turkey.

RESULTS

A total of 185 patients diagnosed as having brucellosis were evaluated, 50.8% had OA involvement (n = 94). Seventy-two patients (76.6%) exhibited peripheral arthritis involvement, among of them, hip arthritis (63.9%; n = 46) was the most common manifestation, followed by arthritis of knee (30.6%; n = 22), shoulder (4.2%; n = 3) and elbow (4.2%; n = 3). A total of 31 patients (33.0%) had sacroiliac joint involvement. Seven patients (7.4%) had spinal brucellosis. Erythrocyte sedimentation rate level above 20 mm/h at admission and age were independent predictor of OA involvement (respectively odds ratio [OR] = 2.82; 95% confidential interval [CI] = 1.41-5.64, OR peryear = 1.10; 95% CI: 1.01-1.19). Increasing age was associated types of OA involvement.

CONCLUSION

A half of brucellosis cases had OA involvement. These results can help physicians to make early identification and diagnosis of childhood OA brucellosis who present with arthritis and arthralgia to enable the disease to be treated in time.

Development and validation of a diagnostic model for differentiating tuberculous spondylitis from brucellar spondylitis using machine learning: A retrospective cohort study

Background

Tuberculous spondylitis (TS) and brucellar spondylitis (BS) are commonly observed in spinal infectious diseases, which are initially caused by bacteremia. BS is easily misdiagnosed as TS, especially in underdeveloped regions of northwestern China with less sensitive medical equipment. Nevertheless, a rapid and reliable diagnostic tool remains to be developed and a clinical diagnostic model to differentiate TS and BS using machine learning algorithms is of great significance.

Methods

A total of 410 patients were included in this study. Independent factors to predict TS were selected by using the least absolute shrinkage and selection operator (LASSO) regression model, permutation feature importance, and multivariate logistic regression analysis. A TS risk prediction model was developed with six different machine learning algorithms. We used several metrics to evaluate the accuracy, calibration capability, and predictability of these models. The performance of the model with the best predictability was further verified with the area under the curve (AUC) of the receiver operating characteristic (ROC) curve and the calibration curve. The clinical performance of the final model was evaluated by decision curve analysis.

Results

Six variables were incorporated in the final model, namely, pain severity, CRP, x-ray intervertebral disc height loss, x-ray endplate sclerosis, CT vertebral destruction, and MRI paravertebral abscess. The analysis of appraising six models revealed that the logistic regression model developed in the current study outperformed other methods in terms of sensitivity (0.88 ± 0.07) and accuracy (0.79 ± 0.07). The AUC of the logistic regression model predicting TS was 0.86 (95% CI, 0.81-0.90) in the training set and 0.86 (95% CI, 0.78-0.92) in the validation set. The decision curve analysis indicated that the logistic regression model displayed a higher clinical efficiency in the differential diagnosis.

Conclusions

The logistic regression model developed in this study outperformed other methods. The logistic regression model demonstrated by a calculator exerts good discrimination and calibration capability and could be applicable in differentiating TS from BS in primary health care diagnosis.

Meta-Analysis and Data Mining-Based Study on the Expression Characteristics of Inflammatory Factors and Causes of Recurrence in Spinal Tuberculosis

With the rapid development of modern medical information technology, hospitals are accumulating huge amounts of clinical data while providing medical services to patients, and in the era of big data, how to mine valuable information from the huge amount of clinical data so as to make new contributions to future disease diagnosis and medical research. In order to solve this problem, more and more scholars have introduced data mining techniques into the medical field in recent years, and mining and analysing medical data is a hot topic at present. If spinal TB is detected and treated early, not only can spinal deformities be prevented and treated but also the course of treatment can be shortened, the financial burden on the patient can be reduced, spinal function can be maintained, and eradication can be achieved without the need for surgical intervention. Early detection of spinal tuberculosis is the key to preventing and treating it. Therefore, in this paper, we use meta-analysis and data mining techniques to process and analyse the medical data of spinal tuberculosis disease, its main inflammatory factors expression characteristics, and the causes of patient recurrence.

Differentiating brucella spondylitis from tuberculous spondylitis by the conventional MRI and MR T2 mapping: a prospective study

Background

Brucella spondylitis (BS) and tuberculous spondylitis (TS), caused initially by bacteremia, are the two leading types of granulomatous spinal infections. BS is easy to miss or may be misdiagnosed as TS. Our purpose aims to differentiate BS from TS in conventional MR imaging and MR T2 mapping.

Methods

We performed on 26 BS and 27 TS patients conventional MR imaging and MR T2 mapping. We analyzed the features in conventional MR imaging and measured T2 values of the lesion vertebrae (LV) and unaffected adjacent vertebrae (UAV) in BS and TS patients, respectively.

Results

There were no significant differences in sex, age, national between BS and TS. There was significantly lower severity of vertebral destruction, vertebral posterior convex deformity, dead bone, and abscess scope in BS when compared to TS (p  <  0.001, p  =  0.048, p  <  0.001, p  <  0.001, respectively). The vertebral hyperplasia was significantly higher in BS when compared to TS (p  <  0.001). The T2 value of the LV with BS was markedly higher than that in the UAV with BS and that in the LV and UAV with TS (p  <  0.001, p  <  0.037, p  <  0.001, respectively). The T2 value of the LV with TS was significantly higher than that of the UAV in TS and BS (p  <  0.001, p  <  0.001, respectively). There were no significant differences in the T2 value of the UAV between BS and TS (p  =  0.568).

Conclusions

The qualitative and quantitative evaluation may differentiate BS from TS. The conventional MR imaging helps to distinguish BS from TS by several distinctive features. MR T2 mapping has the additional potential to provide quantitative information between BS and TS.

Infections of the Spine and Spinal Cord

PURPOSE OF REVIEW

Infections of the spine and spinal cord are associated with a high risk of morbidity and mortality and, therefore, require prompt clinical recognition, efficient diagnostic evaluation, and interdisciplinary treatment. This article reviews the pathophysiology, epidemiology, clinical manifestations, diagnosis, and treatment of infections of the spine and spinal cord to help practicing clinicians recognize, evaluate, and manage patients with such infections.

RECENT FINDINGS

Aging of the population, increasing use of immunosuppressive medications, and other factors have contributed to increasing rates of spinal infections. Although the most common agents responsible for spinal infections remain bacteria and viruses, fungal infections occur in individuals who are immunocompromised, and parasitic infections are common in endemic regions, but patterns are in evolution with migration and climate change. Recent outbreaks of acute flaccid myelitis in children have been associated with enteroviruses A71 and D68.

SUMMARY

Infections of the spine and spinal cord can be challenging to diagnose, requiring a thorough history and neurologic examination, laboratory studies of serum and CSF, neuroimaging (particularly MRI), and, in some instances, biopsy, to establish a diagnosis and treatment regimen. Interdisciplinary management including collaboration with experts in internal medicine, infectious disease, and neurosurgery is important to improve clinical outcomes.

Surgical management for lumbar brucella spondylitis: Posterior versus anterior approaches

There has been no ideal surgical approach for lumbar brucella spondylitis (LBS). This study aims to compare clinical efficacy and safety of posterior versus anterior approaches for the treatment of LBS.From April 2005 to January 2015, a total of 27 adult patients with lumbar brucella spondylitis were recruited in this study. The patients were divided into 2 groups according to surgical approaches. Thirteen cases in group A underwent 1-stage anterior debridement, fusion, and fixation, and 14 cases in group B underwent posterior debridement, bone graft, and fixation. The clinical and surgical outcomes were compared in terms of operative time, intraoperative blood loss, hospitalizations, bony fusion time, complications, visual analog scale score, recovery of neurological function, deformity correction.Lumbar brucella spondylitis was cured, and the grafted bones were fused within 11 months in all cases. It was obviously that the operative time and intraoperative blood loss of group A were more than those of group B (P = .045, P = .009, respectively). Kyphotic deformity was signifcantly corrected in both groups after surgery; however, the correction rate was higher in group B than in group A (P = .043). There were no significant differences between the two groups in hospitalizations, bony fusion time, and visual analog scale score in the last follow-up (P = .055, P = .364, P = .125, respectively).Our results suggested that both anterior and posterior approaches can effectively cure lumbar brucella spondylitis. Nevertheless, posterior approach gives better kyphotic deformity correction, less surgical invasiveness, and less complications.

The current therapeutical strategies in human brucellosis

Prompt and adequate treatment of human brucellosis continues to be the most important strategy in its management, as eradication of animal brucellosis is not possible so far, and there is no adequate vaccine for humans. The goal of antibrucellar treatment is to alleviate and shorten the symptomatic period and reduce complications, relapses, and chronicity. Contemporary trends in the treatment of human brucellosis are postulated on the ability of Brucellae to persist in host macrophages through the inhibition of phagolysosome fusion and to survive for prolonged periods intracellularly without restricting basic cellular functions. As a result of this and despite satisfactory antibiotic treatment, relapses and therapeutical failures are inevitable to a certain degree. The current principles for the treatment of brucellosis advocate for a long enough treatment duration combined with antimicrobial regimens that possess activity in the intracellular acidic environment. In the future, other antimicrobial agents, immunomodulation, decrease in the intracellular acidic environment, or development of agents that would act on well-defined molecular bacterial targets, might be incorporated to improve the therapeutical effects.

Lumbar and sacral brucellosis due to queso fresco ingestion

Brucellosis is rare in the USA, with 100–200 cases reported annually. In this case we illustrate the complex management of spinal brucellosis. A 22-year-old male presented with 3 months of low back pain. Imaging revealed osteomyelitis/diskitis of L5/S1 and abscesses involving the pre-vertebral, epidural and pelvic recesses. Initial biopsies were inconclusive, but the patient later endorsed eating unpasteurized cheese (queso fresco) from Mexico; therefore, Brucella serology was sent and was positive. Despite aggressive antibiotic therapy there was disease progression. The patient underwent debridement of the involved vertebrae and drainage. Multiple cultures failed to grow the organisms, but Brucella polymerase chain reaction was positive. A month later he underwent a second vertebral debridement as well as placement of tobramycin impregnated beads in the vertebral space. He has since recovered. Surgery should be considered if there is a poor response to medical management and patients may need repeated debridement.

Defining Disc Biopsy Timing in Relation to Blood Culture Results for Inpatients with Suspected Discitis-Osteomyelitis

PURPOSE

To determine optimal timing of biopsy for suspected discitis-osteomyelitis (DOM) with respect to preliminary blood culture results and the effect of biopsy timing on hospital length of stay (LOS).

MATERIALS AND METHODS

This retrospective study reviewed disc/vertebral biopsies for suspected DOM performed between 2010 and 2018. A total of 107 disc/vertebral biopsies were performed on 96 inpatients (mean ± SD age 57.9 ± 14.5 years, 68 men/28 women) for suspected DOM, and 100 cases of DOM were clinically confirmed and treated. Descriptive and regression statistics were performed with LOS as the primary outcome.

RESULTS

Of disc biopsies in clinically confirmed cases, 68% were positive; 20% of all biopsies had preliminary positive blood cultures after 2 hospital days. There was no difference in LOS between cases with biopsy performed ≤ 2 days after blood culture and cases with biopsy performed > 2 days after blood culture (P = .40). Regression analysis showed no association between positive biopsy results and sepsis, white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), or C-reactive protein (CRP). Biopsy yield was not significantly decreased in patients previously taking antibiotics (P = .09).

CONCLUSIONS

Waiting 2 days for preliminary blood culture results could avoid disc/vertebral biopsy in 20% of patients and does not significantly impact hospital LOS. Additionally, clinical factors (sepsis, WBC count, CRP, and ESR) do not have predictive value for positive disc biopsy results.

Osteocyte-Related Cytokines Regulate Osteoclast Formation and Bone Resorption

The process of bone remodeling is the result of the regulated balance between bone cell populations, namely bone-forming osteoblasts, bone-resorbing osteoclasts, and the osteocyte, the mechanosensory cell type. Osteoclasts derived from the hematopoietic stem cell lineage are the principal cells involved in bone resorption. In osteolytic diseases such as rheumatoid arthritis, periodontitis, and osteoporosis, the balance is lost and changes in favor of bone resorption. Therefore, it is vital to elucidate the mechanisms of osteoclast formation and bone resorption. It has been reported that osteocytes express Receptor activator of nuclear factor κΒ ligand (RANKL), an essential factor for osteoclast formation. RANKL secreted by osteocytes is the most important factor for physiologically supported osteoclast formation in the developing skeleton and in pathological bone resorption such as experimental periodontal bone loss. TNF-α directly enhances RANKL expression in osteocytes and promotes osteoclast formation. Moreover, TNF-α enhances sclerostin expression in osteocytes, which also increases osteoclast formation. These findings suggest that osteocyte-related cytokines act directly to enhance osteoclast formation and bone resorption. In this review, we outline the most recent knowledge concerning bone resorption-related cytokines and discuss the osteocyte as the master regulator of bone resorption and effector in osteoclast formation.

Biological Factors, Metals, and Biomaterials Regulating Osteogenesis through Autophagy

Bone loss raises great concern in numerous situations, such as ageing and many diseases and in both orthopedic and dentistry fields of application, with an extensive impact on health care. Therefore, it is crucial to understand the mechanisms and the determinants that can regulate osteogenesis and ensure bone balance. Autophagy is a well conserved lysosomal degradation pathway, which is known to be highly active during differentiation and development. This review provides a revision of the literature on all the exogen factors that can modulate osteogenesis through autophagy regulation. Metal ion exposition, mechanical stimuli, and biological factors, including hormones, nutrients, and metabolic conditions, were taken into consideration for their ability to tune osteogenic differentiation through autophagy. In addition, an exhaustive overview of biomaterials, both for orthopedic and dentistry applications, enhancing osteogenesis by modulation of the autophagic process is provided as well. Already investigated conditions regulating bone regeneration via autophagy need to be better understood for finely tailoring innovative therapeutic treatments and designing novel biomaterials.

Joint EANM/ESNR and ESCMID-endorsed consensus document for the diagnosis of spine infection (spondylodiscitis) in adults

PURPOSE

Diagnosis of spondylodiscitis (SD) may be challenging due to the nonspecific clinical and laboratory findings and the need to perform various diagnostic tests including serologic, imaging, and microbiological examinations. Homogeneous management of SD diagnosis through international, multidisciplinary guidance would improve the sensitivity of diagnosis and lead to better patient outcome.

METHODS

An expert specialist team, comprising nuclear medicine physicians appointed by the European Association of Nuclear Medicine (EANM), neuroradiologists appointed by the European Society of Neuroradiology (ESNR), and infectious diseases specialists appointed by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), reviewed the literature from January 2006 to December 2015 and proposed 20 consensus statements in answer to clinical questions regarding SD diagnosis. The statements were graded by level of evidence level according to the 2011 Oxford Centre for Evidence-based Medicine criteria and included in this consensus document for the diagnosis of SD in adults. The consensus statements are the result of literature review according to PICO (P:population/patients, I:intervention/indicator, C:comparator/control, O:outcome) criteria. Evidence-based recommendations on the management of adult patients with SD, with particular attention to radiologic and nuclear medicine diagnosis, were proposed after a systematic review of the literature in the areas of nuclear medicine, radiology, infectious diseases, and microbiology.

RESULTS

A diagnostic flow chart was developed based on the 20 consensus statements, scored by level of evidence according to the Oxford Centre for Evidence-based Medicine criteria.

CONCLUSIONS

This consensus document was developed with a final diagnostic flow chart for SD diagnosis as an aid for professionals in many fields, especially nuclear medicine physicians, radiologists, and orthopaedic and infectious diseases specialists.

Spinal brucellosis in Hulunbuir, China, 2011-2016

Purpose: To investigate the demographic, epidemiological, clinical, and laboratory characteristics; treatment options; and outcome of human brucellosis with spine involvement at a major hospital in Hulunbuir, a brucellosis epidemic region of China. Patients and methods: A total of 842 patients with human brucellosis treated in the Department of Brucellosis, Hulunbuir People's Hospital from January 2011 to December 2016 were included and analyzed in this study. The results of 67 brucellar spondylodiscitis (BS) cases were compared with those that were negative for spine involvements. Results: The mean age of spinal brucellosis patients was 50.5±10.2 years (43 males and 24 females; age range 29-70). The risk factors for transmission are direct contact with animals, such as working in the farm, and consumption of unpasteurized milk or daily products. Back pain (92.5%), fever (85.1%), sweating (62.7%), and fatigue (52.8%) were the most common symptoms. Magnetic resonance imaging (MRI) was performed in all the patients with spondylodiscitis. The sites of involvement were lumbar (81.2%), thoracic (8.7%), cervical (4.3%), thoracolumbar (2.9%), and lumbosacral (2.9%). All isolates from blood culture were identified as Brucella melitensis, with 61% biovar 3 and 39% biovar 1 isolates. The antimicrobial therapy for BS lasted for at least 3 months. In the presence of paravertebral or epidural abscess, longer treatment was conducted to avoid possible sequelae. Conclusion: In endemic areas such as Hulunbuir, BS should be considered in patients with back pain and fever. MRI is a highly sensitive imaging modality that can be used to differentiate BS from other spinal infections. This study will be helpful to establish strategies for prevention, surveillance, and management of spinal brucellosis in China.

Osteoarticular manifestations of human brucellosis: A review

Brucellosis is a common global zoonotic disease, which is responsible for a range of clinical manifestations. Fever, sweating and musculoskeletal pains are observed in most patients. The most frequent complication of brucellosis is osteoarticular involvement, with 10% to 85% of patients affected. The sacroiliac (up to 80%) and spinal joints (up to 54%) are the most common affected sites. Spondylitis and spondylodiscitis are the most frequent complications of brucellar spinal involvement. Peripheral arthritis, osteomyelitis, discitis, bursitis and tenosynovitis are other osteoarticular manifestations, but with a lower prevalence. Spinal brucellosis has two forms: focal and diffuse. Epidural abscess is a rare complication of spinal brucellosis but can lead to permanent neurological deficits or even death if not treated promptly. Spondylodiscitis is the most severe form of osteoarticular involvement by brucellosis, and can have single- or multi-focal involvement. Early and appropriate diagnosis and treatment of the disease is important in order to have a successful management of the patients with osteoarticular brucellosis. Brucellosis should be considered as a differential diagnosis for sciatic and back pain, especially in endemic regions. Patients with septic arthritis living in endemic areas also need to be evaluated in terms of brucellosis. Physical examination, laboratory tests and imaging techniques are needed to diagnose the disease. Radiography, computed tomography, magnetic resonance imaging (MRI) and bone scintigraphy are imaging techniques for the diagnosis of osteoarticular brucellosis. MRI is helpful to differentiate between pyogenic spondylitis and brucellar spondylitis. Drug medications (antibiotics) and surgery are the only two options for the treatment and cure of osteoarticular brucellosis.

Treatment algorithm for spontaneous spinal infections: A review of the literature

Background:

Primary spinal infections are rare pathologies with an estimated incidence of 5% of all osteomyelitis. The diagnosis can be challenging and this might result in a late identification. The etiological diagnosis is the primary concern to determine the most appropriate treatment. The aim of this review article was to identify the importance of a methodological attitude toward accurate and prompt diagnosis using an algorithm to aid on spinal infection management.

Methods:

A search was done on spinal infection in some databases including PubMed, ISI Web of Knowledge, Google Scholar, Ebsco, Embasco, and Scopus.

Results:

Literature reveals that on the basis of a clinical suspicion, the diagnosis can be formulated with a rational use of physical, radiological, and microbiological examinations. Microbiological culture samples can be obtained by a percutaneous computed tomography-guided procedure or by an open surgical biopsy. When possible, the samples should be harvested before antibiotic treatment is started. Indications for surgical treatment include neurological deficits or sepsis, spine instability and/or deformity, presence of epidural abscess and failure of conservative treatment.

Conclusion:

A multidisciplinary approach involving both a spinal surgeon and an infectious disease specialist is necessary to better define the treatment strategy. Based on literature findings, a treatment algorithm for the diagnosis and management of primary spinal infections is proposed.

A systematic review and meta-analysis of the prevalence of osteoarticular brucellosis

BACKGROUND

Infection of bones and joints remains one of the most commonly described complications of brucellosis in humans and is predominantly reported in all ages and sexes in high-risk regions, such as the Middle East, Asia, South and Central America, and Africa. We aimed to systematically review the literature and perform a meta-analysis to estimate the global prevalence of osteoarticular brucellosis (OAB).

METHODOLOGY

Major bibliographic databases were searched using keywords and suitable combinations. All studies reporting the incidence and clinical manifestations of osteoarticular brucellosis in humans, and demonstrated by two or more diagnostic methods (bacteriological, molecular, serological, and/or radiographic) were included. Random model was used, and statistical significance was set at 0.05.

PRINCIPAL FINDINGS

A total of 56 studies met the inclusion criteria and were included in the systematic review and meta-analysis. There was an evidence of geographical variation in the prevalence of osteoarticular disease with estimates ranging from 27% in low-risk regions to 36% in high-risk regions. However, the difference was not significant. Thus, brucellosis patients have at least a 27% chance of developing osteoarticular disease.

CONCLUSIONS

The prevalence of OAB is not dependent on the endemicity of brucellosis in a particular region. Hence, further research should investigate the potential mechanisms of OAB, as well as the influence of age, gender, and other socioeconomic factor variations in its global prevalence, as this may provide insight into associated exposure risks and management of the disease.

B. Abortus Modulates Osteoblast Function Through the Induction of Autophagy

Osteoarticular brucellosis is the most common localization of human active disease. Osteoblasts are specialized mesenchymal-derived cells involved in bone formation and are considered as professional mineralizing cells. Autophagy has been involved in osteoblast metabolism. The present study demonstrates that Brucella abortus infection induces the activation of the autophagic pathway in osteoblast cells. Autophagy was revealed by upregulation of LC3II/LC3I ratio and Beclin-1 expression as well as inhibition of p62 expression in infected cells. Induction of autophagy was also corroborated by using the pharmacological inhibitors wortmannin, a PI 3-kinase inhibitor, and leupeptin plus E64 (inhibitors of lysosomal proteases). Autophagy induction create a microenvironment that modifies osteoblast metabolism by the inhibition of the deposition of organic and mineral matrix, the induction of matrix metalloproteinase (MMP)-2, osteopontin, and RANKL secretion leading to bone loss. Accordingly, autophagy is also involved in the down-modulation of the master transcription factor in bone formation osterix during B. abortus infection. Taking together our results indicate that B. abortus induces the activation of autophagy pathway in osteoblast cells and this activation is involved in the modulation of osteoblast function and bone formation.

One-stage surgical management for lumber brucella spondylitis with anterior debridement, autogenous graft, and instrumentation

Literature reporting on lumber brucella spondylitis (LBS) is rare, therefore, the purpose of this study was to evaluate the outcomes of one-stage surgical management for lumber brucella spondylitis by anterior debridement, autogenous grafts, and instrumentation. This was a retrospective cohort study including 16 patients with lumber brucella spondylitis by treated from January 2009 to October 2011 in our department. All cases underwent one-stage anterior internal fixation, debridement, and bone fusion; clinical and radiographic results were analyzed and compared. All patients were followed up for an average of 35.3 ± 8.1 months (range, 24-48 months). Brucella spondylitis was completely cured in all patients with bone fusion achieved in 4.8 ± 1.3 months. Visual analog scale (VAS) scores were significantly improved between the preoperative and last follow-up visit and neurological function classification showed significant improvement after surgical intervention. Preoperatively, the Cobb angle was 20.7 ± 9.8°, and measured 8.1 ± 1.3° at the last follow-up visit. The outcomes of follow-up demonstrated that one-stage surgical treatment with anterior debridement, fusion, and instrumentation can be an effective and feasible treatment method for lumber brucella spondylitis.

Acute liver failure complication of brucellosis infection: a case report and review of the literature

Background

Brucellosis is one of the most widespread zoonoses worldwide. It can affect any organ system, particularly the gastrointestinal system, but there is no report of acute liver failure as a brucellosis complication.

Case presentation

We present a case of acute liver failure secondary to brucellosis infection. A 75-year-old Hispanic man presented to a University Hospital in Chía, Colombia, with a complaint of 15 days of fatigue, weakness, decreased appetite, epigastric abdominal pain, jaundice, and 10 kg weight loss. On examination in an emergency room, abdomen palpation was normal with hepatosplenomegaly and the results of a liver function test were elevated. The diagnosis of brucellosis was confirmed by epidemiological contact and positive Rose Bengal agglutination with negative enzyme-linked immunosorbent assay immunoglobulin M for Brucella. He was then treated with doxycycline plus trimethoprim/sulfamethoxazole, with a favorable clinical outcome.

Conclusions

The clinical presentation of brucellosis can be very imprecise because it can affect any organ system; however, there is no report of acute liver failure as a brucellosis complication. This is the first reported case in the Colombian literature of acute liver failure due to brucellosis. We found this case to be of interest because it could be taken into account for diagnosis in future appearances and we described adequate treatment and actions to be taken at presentation.

An Imported Case of Brucella melitensis Infection in South Korea

Brucellosis is a zoonotic infection that is usually transmitted from cattle to humans through ingestion of animal milk, direct contact with animal parts, or inhalation of aerosolized particles. In Korea, brucellosis seem to be transmitted through close contact with blood, fetus, urine, and placenta of domestic cow that has been infected by Brucella abortus, or inhalation of B. arbortus while examining or slaughtering cow. Brucella melitensis infection is rare in Korea and there have been no reported cases of B. melitensis originating from other countries until now. This report details a case of complicated brucellosis with infective spondylitis in a 48-year-old male construction worker recently returned from Iraq. Infection with B. melitensis was confirmed using 16s rRNA sequencing and omp31 gene analysis. The patient was successfully treated using a combination of rifampin, doxycycline, and streptomycin, in accordance with WHO guidelines. This is the first reported case of complicated brucellosis with infective spondylitis in Korea caused by B. melitensis originating from Iraq.

Brucella melitensis prosthetic joint infection

Periprosthetic joint infection (PJI) due to Brucella spp. is rare. We report a case in a 75-year-old man and review 29 additional cases identified in a literature search. The diagnosis of Brucella PJI is challenging, in particular in non-endemic countries. Serological tests prior to joint aspiration or surgical intervention are reasonable. Involvement of infection control and timely information to laboratory personnel is mandatory upon diagnosis. There is no uniform treatment concept, neither with respect to surgical intervention nor for the duration of antimicrobials. Most cases have a successful outcome, irrespective of surgical modality, and with an antimicrobial combination regimen for 12 or more weeks.

Boar hunting and brucellosis caused by Brucella suis

Brucellosis remains as a significant public health concern in many areas where the infection persists in domestic hosts (i.e. goats, cattle, and domestic swine) with subsequent risk of transmission to human populations. Brucellosis caused by B. suis remains an important threat to human populations in many countries exposed to domestic and feral swine. In the U.S., swine brucellosis has been under control for many years. Meanwhile, it is a widespread infection among feral swine, particularly in the Southeastern United States; and exposure to infected animals pose a growing threat to humans. We present the case of a 31-year male hunter who six weeks after a knife injury to his hand while field dressing a wild boar, developed a febrile illness associated with hematologic abnormalities and splenic abscesses caused by Brucella suis infection.

Brucella and Osteoarticular Cell Activation: Partners in Crime

Osteoarticular brucellosis is the most common presentation of human active disease although its prevalence varies widely. The three most common forms of osteoarticular involvement are sacroiliitis, spondylitis, and peripheral arthritis. The molecular mechanisms implicated in bone damage have been recently elucidated. B. abortus induces bone damage through diverse mechanisms in which TNF-α and the receptor activator of nuclear factor kappa-B ligand (RANKL)-the natural modulator of bone homeostasis are involved. These processes are driven by inflammatory cells, like monocytes/macrophages, neutrophils, Th17 CD4⁺ T, and B cells. In addition, Brucella abortus has a direct effect on osteoarticular cells and tilts homeostatic bone remodeling. These bacteria inhibit bone matrix deposition by osteoblasts (the only bone cells involved in bone deposition), and modify the phenotype of these cells to produce matrix metalloproteinases (MMPs) and cytokine secretion, contributing to bone matrix degradation. B. abortus also affects osteoclasts (cells naturally involved in bone resorption) by inducing an increase in osteoclastogenesis and osteoclast activation; thus, increasing mineral and organic bone matrix resorption, contributing to bone damage. Given that the pathology induced by Brucella species involved joint tissue, experiments conducted on synoviocytes revealed that besides inducing the activation of these cells to secrete chemokines, proinflammatory cytokines and MMPS, the infection also inhibits synoviocyte apoptosis. Brucella is an intracellular bacterium that replicates preferentially in the endoplasmic reticulum of macrophages. The analysis of B. abortus-infected synoviocytes indicated that bacteria also replicate in their reticulum suggesting that they could use this cell type for intracellular replication during the osteoarticular localization of the disease. Finally, the molecular mechanisms of osteoarticular brucellosis discovered recently shed light on how the interaction between B. abortus and immune and osteoarticular cells may play an important role in producing damage in joint and bone.

Diagnosing pyogenic, brucella and tuberculous spondylitis using histopathology and MRI: A retrospective study

The present study examined the histopathological and magnetic resonance imaging (MRI) features of pyogenic, brucella and tuberculous spondylitis (PS, BS and TS, respectively). A total of 22 PS, 20 BS and 20 TS patients were included in the study. Histopathological examination was used to assess the lesion structure and composition, and the MRI observation identified the lesion location and signal features. The following histopathological and MRI features were identified significantly more in patients with PS than in patients with BS and TS: Predominant neutrophil infiltration, abnormal intervertebral disk signal, lesions on the ventral and lateral sides of the vertebral bodies, and thick and irregular abscess walls. The following histopathological and MRI features were identified significantly more in patients with BS than in patients with PS and TS: Predominant lymphocyte infiltration, new bone formation, epithelioid granuloma, lesions on the ventral sides of the vertebral bodies, no, or very mild, vertebral body deformation, no abnormal paraspinal soft tissue signal, no intraosseous or paraspinal abscesses, and thin and irregular abscess walls. The following histopathological and MRI features were identified significantly more in patients with TS than in patients with BS and PS: Sequestrum, Langerhans giant cells, caseous necrosis, lesions primarily in the thoracic region and on the lateral sides of the vertebral bodies, no obvious intervertebral disk damage, obvious vertebral body deformation, abnormal paraspinal soft tissue signal, intraosseous or paraspinal abscesses, and thin and smooth abscess walls. In conclusion, it can be suggested that these significant differences in histopathological and MRI features between the three different types of spondylitis may contribute towards the differential diagnosis of the diseases.

Brucella abortus Invasion of Osteocytes Modulates Connexin 43 and Integrin Expression and Induces Osteoclastogenesis via Receptor Activator of NF-κB Ligand and Tumor Necrosis Factor Alpha Secretion

Osteoarticular brucellosis is the most common localization of human active disease. Osteocytes are the most abundant cells of bone. They secrete factors that regulate the differentiation of both osteoblasts and osteoclasts during bone remodeling. The aim of this study is to determine if Brucella abortus infection modifies osteocyte function. Our results indicate that B. abortus infection induced matrix metalloproteinase 2 (MMP-2), receptor activator for NF-κB ligand (RANKL), proinflammatory cytokines, and keratinocyte chemoattractant (KC) secretion by osteocytes. In addition, supernatants from B. abortus-infected osteocytes induced bone marrow-derived monocytes (BMM) to undergo osteoclastogenesis. Using neutralizing antibodies against tumor necrosis factor alpha (TNF-α) or osteoprotegerin (OPG), RANKL's decoy receptor, we determined that TNF-α and RANKL are involved in osteoclastogenesis induced by supernatants from B. abortus-infected osteocytes. Connexin 43 (Cx43) and the integrins E11/gp38, integrin-α, integrin-β, and CD44 are involved in cell-cell interactions necessary for osteocyte survival. B. abortus infection inhibited the expression of Cx43 but did not modify the expression of integrins. Yet the expression of both Cx43 and integrins was inhibited by supernatants from B. abortus-infected macrophages. B. abortus infection was not capable of inducing osteocyte apoptosis. However, supernatants from B. abortus-infected macrophages induced osteocyte apoptosis in a dose-dependent manner. Taken together, our results indicate that B. abortus infection could alter osteocyte function, contributing to bone damage.

2015 Infectious Diseases Society of America (IDSA) Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adultsa

These guidelines are intended for use by infectious disease specialists, orthopedic surgeons, neurosurgeons, radiologists, and other healthcare professionals who care for patients with native vertebral osteomyelitis (NVO). They include evidence and opinion-based recommendations for the diagnosis and management of patients with NVO treated with antimicrobial therapy, with or without surgical intervention.

Central nervous system tuberculosis

Tuberculosis (TB) has shown a resurgence in nonendemic populations in recent years and accounts for 8 million deaths annually in the world. Central nervous system involvement is one of the most serious forms of this infection, acting as a prominent cause of morbidity and mortality in developing countries. The rising number of cases in developed countries is mostly attributed to factors such as the pandemic of acquired immunodeficiency syndrome and increased migration in a globalized world. Mycobacterium TB is responsible for almost all cases of tubercular infection in the central nervous system. It can manifest in a variety of forms as tuberculous meningitis, tuberculoma, and tubercular abscess. Spinal infection may result in spondylitis, arachnoiditis, and/or focal intramedullary tuberculomas. Timely diagnosis of central nervous system TB is paramount for the early institution of appropriate therapy, because delayed treatment is associated with severe morbidity and mortality. It is therefore important that physicians and radiologists understand the characteristic patterns, distribution, and imaging manifestations of TB in the central nervous system. Magnetic resonance imaging is considered the imaging modality of choice for the study of patients with suspected TB. Advanced imaging techniques including magnetic resonance perfusion and diffusion tensor imaging may be of value in the objective assessment of therapy and to guide the physician in the modulation of therapy in these patients.

Update on treatment options for spinal brucellosis

We evaluated the efficacy and tolerability of antibiotic regimens and optimal duration of therapy in complicated and uncomplicated forms of spinal brucellosis. This is a multicentre, retrospective and comparative study involving a total of 293 patients with spinal brucellosis from 19 health institutions. Comparison of complicated and uncomplicated spinal brucellosis was statistically analysed. Complicated spinal brucellosis was diagnosed in 78 (26.6%) of our patients. Clinical presentation was found to be significantly more acute, with fever and weight loss, in patients in the complicated group. They had significantly higher leukocyte and platelet counts, erythrocyte sedimentation rates and C-reactive protein levels, and lower haemoglobulin levels. The involvement of the thoracic spine was significantly more frequent in complicated cases. Spondylodiscitis was complicated, with paravertebral abscess in 38 (13.0%), prevertebral abscess in 13 (4.4%), epidural abscess in 30 (10.2%), psoas abscess in 10 (3.4%) and radiculitis in 8 (2.7%) patients. The five major combination regimens were: doxycycline 200 mg/day, rifampicin 600 mg/day and streptomycin 1 g/day; doxycycline 200 mg/day, rifampicin 600 mg/day and gentamicin 5 mg/kg; doxycycline 200 mg/day and rifampicin 600 mg/day; doxycycline 200 mg/day and streptomycin 1 g/day; and doxycycline 200 mg/day, rifampicin 600 mg/day and ciprofloxacin 1 g/day. There were no significant therapeutic differences between these antibiotic groups; the results were similar regarding the complicated and uncomplicated groups. Patients were mostly treated with doxycycline and rifampicin with or without an aminoglycoside. In the former subgroup, complicated cases received antibiotics for a longer duration than uncomplicated cases. Early recognition of complicated cases is critical in preventing devastating complications. Antimicrobial treatment should be prolonged in complicated spinal brucellosis in particular.

Brucella abortus invasion of synoviocytes inhibits apoptosis and induces bone resorption through RANKL expression

Arthritis is one of the most common complications of human active brucellosis, but its pathogenic mechanisms have not been completely elucidated. In this paper, we describe the role of synoviocytes in the pathogenesis of brucellar arthritis. Our results indicate that Brucella abortus infection inhibited synoviocyte apoptosis through the upregulation of antiapoptotic factors (cIAP-2, clusterin, livin, and P21/CIP/CDNK1A). In contrast, infection did not change the expression of proteins that have been involved in apoptosis induction such as Bad, Bax, cleaved procaspase 3, CytC, and TRAIL, among others; or their expression was reduced, as occurs in the case of P-p53(S15). In addition, B. abortus infection induced upregulation of adhesion molecules (CD54 and CD106), and the adhesion of monocytes and neutrophils to infected synoviocytes was significantly higher than to uninfected cells. Despite this increased adhesion, B. abortus-infected synoviocytes were able to inhibit apoptosis induced by supernatants from B. abortus-infected monocytes and neutrophils. Moreover, B. abortus infection increased soluble and membrane RANKL expression in synoviocytes that further induced monocytes to undergo osteoclastogenesis. The results presented here shed light on how the interactions of B. abortus with synovial fibroblasts may have an important role in the pathogenesis of brucellar arthritis.

Brucella abortus-infected macrophages modulate T lymphocytes to promote osteoclastogenesis via IL-17

The pathogenic mechanisms of bone loss caused by Brucella species have not been completely deciphered. Although T lymphocytes (LTs) are considered important to control infection, the mechanism of Brucella-induced T-cell responses to immunopathological features is not known. We present in vitro and in vivo evidence showing that Brucella abortus-induced inflammatory response leads to the activation of LTs, which further promote osteoclastogenesis. Pre-activated murine LTs treated with culture supernatant from macrophages infected with B. abortus induced bone marrow-derived monocytes (BMMs) to undergo osteoclastogenesis. Furthermore, osteoclastogenesis was mediated by CD4(+) T cells. Although B. abortus-activated T cells actively secreted the pro-osteoclastogenic cytokines RANKL and IL-17, osteoclastogenesis depended on IL-17, because osteoclast generation induced by Brucella-activated T cells was completely abrogated when these cells were cultured with BMMs from IL-17 receptor knockout mice. Neutralization experiments indicated that IL-6, generated by Brucella infection, induced the production of pro-osteoclastogenic IL-17 from LTs. By using BMMs from tumor necrosis factor receptor p55 knockout mice, we also demonstrated that IL-17 indirectly induced osteoclastogenesis through the induction of tumor necrosis factor-α from osteoclast precursors. Finally, extensive and widespread osteoclastogenesis was observed in the knee joints of mice injected with Brucella-activated T cells. Our results indicate that activated T cells, elicited by B. abortus-infected macrophages and influenced by the inflammatory milieu, promote the generation of osteoclasts, leading to bone loss.

Brucellar spondylodiscitis: comparison of patients with and without abscesses

Brucellosis is an important cause of spondylodiscitis in endemic areas. Brucellar spondylodiscitis is a serious complication because of its association with abscess formation. Prospective studies comparing patients with and without abscesses are lacking. The objective of this study was to determine the frequency and demographic, clinical, laboratory, and radiological features of brucellar spondylodiscitis and to compare patients with and without abscesses regarding treatment and outcome. Out of 135 consecutive patients with brucellosis, 31 patients with spondylodiscitis were recruited for the study. Patients were grouped according to magnetic resonance imaging findings. The frequency of spondylodiscitis was 23.0 %. Sites of involvement were lumbar (58.1 %), lumbosacral (22.6 %), cervical (9.7 %), thoracolumbar (6.5 %), and thoracic (3.2 %). Abscesses occurred in 19 (61.3 %) patients and were associated with low hemoglobin levels. Medical treatment included a combination of streptomycin (for the first 3 weeks), doxycycline, and rifampin. The total duration of treatment was 12-39 (mean 17.0 ± 8.5 SD) weeks. By 12 weeks of treatment, evidence of clinical improvement (67 vs. 28 %) and radiological regression (92 vs. 50 %) was significantly greater in patients without abscesses. The duration of treatment was longer if an abscess was present. Two female patients with abscesses required surgical intervention. Both patients presented with high fever, neurologic deficit, and high Brucella standard tube agglutination test titers. Each patient should be evaluated individually, based on clinical findings, laboratory data, and radiological results, when undergoing treatment for brucellar spondylodiscitis. If abscesses are found, a longer course of treatment and even surgical intervention may be needed.

Surgical management of cervical spinal epidural abscess caused by Brucella melitensis : report of two cases and review of the literature

Spinal epidural abscess, if especially caused by Brucellosis is a very rare disease which is usually a consequence of spondylodiscitis. The spinal column can be affected at any joint; however, the lumbar spine is the most common region, especially at the level of the L4-5 and L5-S1. The frequency of spinal involvement usually seen at the lumbar, thoracic and cervical spine respectively. As an occupational disease in farmers, veterinaries, butchers, laboratory staff and shepherds, brucellosis can also occur by direct contact to animals and infected materials or ingestion of raw cheese, milk or unpasteurized milk products. In this study, we presented two cases with cervical spinal epidural abscess caused by brucella melitensis, which was successfully treated by surgical approach. Initial treatment was combined with antibiotic therapy after the surgery for 3 months.

IFN-γ-deficient mice develop IL-1-dependent cutaneous and musculoskeletal inflammation during experimental brucellosis

Human brucellosis exhibits diverse pathological manifestations that can affect almost any organ. In particular, osteoarticular complications are the most common focal manifestation of brucellosis and occur in 40-80% of patients. In immunocompetent mice, Brucella replication is generally restricted to the spleen, liver, and to a lesser extent, LNs, thereby limiting their use for study of focal inflammation often found in brucellosis. Here, we report that nasal, oral, or peritoneal infection of IFN-γ(-/-) mice with WT Brucella melitensis or Brucella abortus results in joint and periarticular tissue inflammation. Histological analysis of the affected joints revealed inflammatory infiltrates and debris within the joint space colocalizing with Brucella antigen. Osteoarthritis, necrosis, periarticular soft tissue inflammation, and substantial brucellae burdens were observed. Oral rifampicin was effective in clearing infection and halting further progression of focal inflammation from infected IFN-γ(-/-) mice, although some symptoms and swelling remained. Elevated IL-1 β, but not TNF-α, IL-6, or IL-17, was detected in joint homogenates from infected IFN-γ(-/-) mice. Whereas more susceptible to systemic infection, IL-1R(-/-) mice depleted of IFN-γ were more resistant to focal inflammation than WT mice similarly depleted of IFN-γ. Collectively, these results show IFN-γ(-/-) mice represent a potential model for study of focal inflammation attributed to Brucella infection and will allow evaluation of intervention strategies targeting IL-1, IL-1R, or other inflammatory mediators, with the potential to complement antibiotic-based therapies.

Brucella abortus invasion of osteoblasts inhibits bone formation

Osteoarticular brucellosis is the most common presentation of the active disease in humans. Loss of bone is a serious complication of localized bacterial infection of bones or the adjacent tissue, and brucellosis proved not to be the exception. The skeleton is a dynamic organ system which is constantly remodeled. Osteoblasts are responsible for the deposition of bone matrix and are thought to facilitate the calcification and mineralization of the bone matrix, and their function could be altered under infectious conditions. In this article, we describe immune mechanisms whereby Brucella abortus may invade and replicate within osteoblasts, inducing apoptosis, inhibiting mineral and organic matrix deposition, and inducing upregulation of RANKL expression. Additionally, all of these mechanisms contributed in different ways to bone loss. These processes implicate the activation of signaling pathways (mitogen-activated protein kinases [MAPK] and caspases) involved in cytokine secretion, expression of activating molecules, and cell death of osteoblasts. In addition, considering the relevance of macrophages in intracellular Brucella survival and proinflammatory cytokine secretion in response to infection, we also investigated the role of these cells as modulators of osteoblast survival, differentiation, and function. We demonstrated that supernatants from B. abortus-infected macrophages may also mediate osteoblast apoptosis and inhibit osteoblast function in a process that is dependent on the presence of tumor necrosis factor alpha (TNF-α). These results indicate that B. abortus may directly and indirectly harm osteoblast function, contributing to the bone and joint destruction observed in patients with osteoarticular complications of brucellosis.

Vertebral osteomyelitis: eight years' experience of 100 cases

To evaluate the etiology and characteristics of vertebral osteomyelitis cases in our country, patients with vertebral osteomyelitis between January 2000 and December 2007 were included in this study. Clinical and laboratory data of the patients were collected from the medical records retrospectively. Of these 100 patients, 44 had pyogenic, 24 had brucellar, and 32 had tuberculous spondylodiscitis. The age of the patients ranged from 13 to 82 years, with a mean of (SD±) 55 ± 15.6 years. Within the pyogenic group, 10 (22.7%) patients had a spinal surgery history, and in 18 patients of the pyogenic group, an etiological agent was isolated. Ten (56%) of these 18 were methicillin-sensitive Staphylococcus aureus. While all of the patients included in this study suffered from pain, 49 of these had fever. Sixty-nine percent of the patients had lumbar involvement. The etiological distribution may differ according to geographical areas. Although brucella and tuberculosis (TB) are endemic in our country, pyogenic vertebral osteomyelitis was more frequent. The most common involved area in our patients was the lumbar vertebrae. Although thoracic involvement may be more predominant in tuberculous vertebral osteomyelitis, it does not strongly suggest TB. Magnetic resonance imaging may exclude some disorders mimicking vertebral osteomyelitis and may delineate the degree of the involvement. Microbiological and/or histopathological examination of computerized tomography-guided fine-needle aspiration biopsies are the mainstays for the diagnosis. Suspicion and early diagnosis seem critical for preventing sequelae development.

Macrophage-elicited osteoclastogenesis in response to Brucella abortus infection requires TLR2/MyD88-dependent TNF-α production

Osteoarticular complications are common in human brucellosis, but the pathogenic mechanisms involved are largely unknown. In this manuscript, we described an immune mechanism for inflammatory bone loss in response to infection by Brucella abortus. We established a requirement for MyD88 and TLR2 in TNF-α-elicited osteoclastogenesis in response to B. abortus infection. CS from macrophages infected with B. abortus induced BMM to undergo osteoclastogenesis. Although B. abortus-infected macrophages actively secreted IL-1β, IL-6, and TNF-α, osteoclastogenesis depended on TNF-α, as CS from B. abortus-infected macrophages failed to induce osteoclastogenesis in BMM from TNFRp55⁻/⁻ mice. CS from B. abortus-stimulated MyD88⁻/⁻ and TLR2⁻/⁻ macrophages failed to express TNF-α, and these CS induced no osteoclast formation compared with that of the WT or TLR4⁻/⁻ macrophages. Omp19, a B. abortus lipoprotein model, recapitulated the cytokine production and subsequent osteoclastogenesis induced by the whole bacterium. All phenomena were corroborated using human monocytes, indicating that this mechanism could play a role in human osteoarticular brucellosis. Our results indicate that B. abortus, through its lipoproteins, may be involved in bone resorption through the pathological induction of osteoclastogenesis.