Synovial Cultures Research Articles

Multiplex Polymerase Chain Reaction and Microcalorimetry in Synovial Fluid: Can Pathogen-based Detection Assays Improve the Diagnosis of Septic Arthritis?

To prospectively evaluate automated multiplex PCR and isothermal microcalorimetry tests for rapid and accurate diagnosis of septic arthritis. Patients with acute arthritis were prospectively included from October 2014 to September 2015. In synovial fluid (SF), leukocyte count and differential, culture, PCR, and microcalorimetry were determined. Septic arthritis was diagnosed by positive SF culture or (1) local clinical signs and symptoms, (2) increased SF leukocyte count, and (3) exclusion of noninfectious causes of inflammatory arthropathy. The performance of individual tests was compared with McNemar's test. Among 57 patients, 22 (39%) were diagnosed with septic arthritis. SF culture grew a pathogen in 10 patients (46%), PCR was positive in 5 (23%), and microcalorimetry in 10 (46%). Compared to SF culture, 49 concordant pairs were found for both methods (PCR and microcalorimetry; 86% agreement). In SF, PCR failed to detect Staphylococcus aureus (2 patients), Streptococcus pneumoniae (1 patient), Streptococcus dysgalactiae (1 patient), and Clostridium clostridioforme (1 patient). Microcalorimetry failed to detect S. dysgalactiae (1 patient), Streptococcus agalactiae (1 patient), and C. clostridioforme (1 patient). No statistical differences between the performance of SF culture, and PCR and microcalorimetry, respectively, were found. The processing time for PCR was 5 h and for microcalorimetry a median of 8.8 h (range, 2.3-64 h), whereas cultures required a median of 4.5 days (range, 3-14 days). Performance of SF PCR was inferior while microcalorimetry was similar to culture but provided results considerably faster. [Clinical trial registration number (https://www.clinicaltrials.gov): NCT02530229].

Multiplex PCR Unyvero i60 ITI application improves detection of low-virulent microorganisms in periprosthetic joint infections

PurposeThe aim of this study was to evaluate the pre-operative performance of an automated multiplex PCR (mPCR) system in patients with suspected periprosthetic joint infection (PJI).MethodsUnder sterile conditions, synovial fluid samples from patients with a suspected PJI were collected pre-operatively. One hundred eighty microliter of the aspirate was used for analysis in the mPCR. The remaining joint fluid was sent for microbiological analysis. PJI was diagnosed by using the Musculoskeletal Infection Society (MSIS) criteria. Total percentage agreement and Cohen’s kappa coefficient were calculated to measure overall agreement.ResultsOverall, 90 patients with a suspected PJI were included. Using MSIS criteria, 38 (42%) patients were classified as septic. Total percent agreement between mPCR and synovial fluid culture was 86% with a Cohen’s kappa of 0.68. The mPCR and synovial fluid culture showed sensitivities of 71% and 84%, respectively. Combined evaluation provided an even higher sensitivity of 92%. While Cutibacterium spp. were detected five times by mPCR, it could only be cultured once. A higher detection rate of CoNS by mPCR (n = 7) compared to conventional culture (n = 5) was also demonstrated. In comparison to synovial fluid culture, the mPCR missed Staphylococcus aureus five times.ConclusionWith a moderate agreement between synovial fluid mPCR and culture, the mPCR system could be a useful adjunct in diagnosing a PJI pre-operatively. Due to faster availability of results and a higher detection rate of low-virulent microorganisms, it can complement conventional culture.

Multifocale osteomyelitis en abdominale abcesvorming bij een warmbloedveulen

Volgens de auteurs is dit de eerste casuïstiek waarin het simultane voorkomen wordt beschreven van multifocale osteomyelitis en abdominale abcesvorming veroorzaakt door Salmonella bij een veulen met gewichtsverlies, diarree en koorts. Er was geen falen van het passieve immuunsysteem na de geboorte van het veulen. Radiografisch onderzoek toonde multifocale osteomyelitis (type P). In de bacteriële cultuur van het gewrichtsvocht werd Salmonella-species geïdentificeerd. De antibioticatherapie werd afgestemd op de resultaten van het antibiogram, echter zonder klinische verbetering. Abcessen ontwikkelden zich verder in de linkerdij en een Salter-Harrisfractuur type I van de linkerfemur werd vastgesteld. Er werd beslist om over te gaan tot euthanasie van het veulen. Postmortaal computertomografisch onderzoek toonde een grote massa in het caudale abdomen, die uitliep tot in de regio van het linkerbekken en achterbeen. Er werden eveneens multifocale osteomyelitis aangetoond. Middels het pathologisch onderzoek werd de massa als een abces met verschillende fistelgangen geïdentificeerd. Postmortem bacteriologisch onderzoek toonde eveneens Salmonella-species aan.

What Markers Best Guide the Timing of Reimplantation in Two-stage Exchange Arthroplasty for PJI? A Systematic Review and Meta-analysis.

There is no consensus on the appropriate marker to use when deciding to perform reimplantation after two-stage exchange arthroplasty for periprosthetic joint infection (PJI). What tests provide acceptable diagnostic value to guide appropriate timing of reimplantation in two-stage exchange arthroplasty for PJI? A search of online databases (MEDLINE, EMBASE, OVID, and Cochrane database) was performed containing articles that provided sensitivity and specificity values for accuracy for predicting reimplantation of the hip and/or knee. Twelve articles were included for final analysis, which included data from 1047 patients. Data that described the diagnostic accuracy of markers for reimplantation were evaluated and categorized into four main entities according to diagnostic method (serologic, synovial, tissue, and diagnostic imaging). Twelve parameters were examined, including serum erythrocyte sedimentation (ESR) rate, serum C-reactive protein (CRP), serum white blood cell (WBC) count, synovial fluid Gram stain, synovial fluid culture, synovial fluid sonication culture, synovial fluid WBC, synovial fluid polymorphonucleocyte percentage (PMN%), tissue Gram stain, tissue culture, positron emission tomography scan, and leukocyte scan. Each of the included articles was independently analyzed for risk of bias and applicability by using QUADAS-2. Statistical heterogeneity was calculated by using the Cochran Q test, and an α of 0.10 was considered significant for heterogeneity. Tissue culture (sensitivity 0.82 [0.72-0.90], specificity 0.91 [0.89-0.95], diagnostic odds ratio (DOR) 46.87 [95% confidence interval {CI}, 22.03-99.69], synovial fluid PMN% (sensitivity 0.77 [0.46-0.95], specificity 0.74 [0.67-0.81], DOR 11.27 [95% CI, 2.89-43.61]), and synovial fluid culture (sensitivity 0.64 [0.52-0.74], specificity 0.96 [0.93-0.98], DOR 27.07 [95% CI, 2.55-288.00]) showed relatively high diagnostic performance. Other parameters had poorer diagnostic accuracy: ESR (sensitivity 0.56 [0.40-0.72], specificity 0.60 [0.53-0.66], DOR 2.41 [95% CI, 0.60-9.72), CRP (sensitivity 0.53 [0.39-0.67], specificity 0.72 [0.66-0.78], DOR 2.25 [95% CI, 0.09-4.63), and synovial fluid WBC count (sensitivity 0.37 [0.19-0.58], specificity 0.49 [0.41-0.57], DOR 0.94 [95% CI, 0.06-14.74). However, interpretation is limited, because only two to three studies were available for each pooled analysis. Both risks of bias and applicability concerns were low in the four domains assessed in QUADAS-2. This meta-analysis suggests that no single marker was superior to all the others, and none (when used alone) is likely sufficient to confirm control of infection after the first stage of a two-stage protocol for PJI. Therefore, the current approach using multiple tools rather than a single marker is essential. Additionally, further studies must be conducted so that pooled analysis can be performed using multiple studies to determine ideal markers for reimplantation. Level III, diagnostic study.

Septicaemic Melioidosis Complicated by Septic Arthritis in A Bangladeshi male: A Case Report

Melioidosis is an uncommon disease in Bangladesh but in recent years increasing numbers of cases are being diagnosed. A case of septicaemic melioidosis occurring in a young Bangladeshi returning worker is reported here. The patient presented with fever and features of septic arthritis. Diagnostic work-up revealed the growth of Burkholderia pseudomallei from blood and synovial fluid cultures. This case highlights the importance of high index of clinical suspicion for melioidosis in appropriate clinical scenario.Bangladesh J Medicine Jul 2018; 29(2) : 94-96

Translational Biomarkers and Ex Vivo Models of Joint Tissues as a Tool for Drug Development in Rheumatoid Arthritis.

ObjectiveRheumatoid arthritis (RA) is a chronic and degenerative autoimmune joint disease that leads to disability, reduced quality of life, and increased mortality. Although several synthetic and biologic disease‐modifying antirheumatic drugs are available, there is still a medical need for novel drugs that control disease progression. As only 10% of experimental drug candidates for treatment of RA that enter phase I trials are eventually registered by the Food and Drug Administration, there is an immediate need for translational tools to facilitate early decision‐making in drug development. In this study, we aimed to determine if the inability of fostamatinib (a small molecule inhibitor of Syk) to demonstrate sufficient efficacy in phase III of a previous clinical study could have been predicted earlier in the development process.MethodsBiomarkers of bone, cartilage, and interstitial matrix turnover (C‐telopeptide of type I collagen [CTX‐I], matrix metalloproteinase–derived types I, II, and III collagen neoepitopes [C1M, C2M, and C3M]) were measured in 450 serum samples from the Oral Syk Inhibition in Rheumatoid Arthritis 1 study (OSKIRA‐1, a phase III clinical study of the efficacy of fostamatinib in RA) at baseline and follow‐up. Additionally, the same biomarkers were subsequently measured in conditioned media from osteoclast, cartilage, and synovial membrane cultured with the active metabolite of fostamatinib, R406, to assess the level of suppression induced by the drug.ResultsIn OSKIRA‐1 serum samples and osteoclast and cartilage cultures, fostamatinib suppressed the levels of CTX‐I and C2M. In OSKIRA‐1 serum samples and synovial membrane cultures, fostamatinib did not mediate any clinical or preclinical effect on either C1M or C3M, which have previously been associated with disease response and efficacy.ConclusionThese data demonstrate that translational biomarkers are a potential tool for early assessment and decision‐making in drug development for RA treatment.

Tests for predicting reimplantation success of two-stage revision for periprosthetic joint infection: A systematic review and meta-analysis.

Several tests are used before reimplantation to detect persistent infection in patients with periprosthetic joint infection (PJI) undergoing two-stage revision. However, there is no consensus as to the optimal tests for excluding persistent infection or predicting successful reimplantation by stage. We aimed to determine the accuracy of different tests used to detect persistent infection after the first stage, and/or predicting failure following reimplantation in patients with PJI. We conducted a systematic review and meta-analysis of PubMed, Embase and the Cochrane Library databases. Two reviewers independently conducted quality assessments and data extractions to estimate pooled sensitivity and specificity, diagnostic odds ratio and area under the receiver operating characteristic curves (AUSROC) for each test. We included 24 studies published between May 1999 and September 2017. Synovial fluid polymorphonuclear neutrophils (PMN)% had the highest sensitivity of 0.70, followed by serum erythrocyte sedimentation rate (0.57) and spacer sonication fluid culture (0.53). Synovial fluid culture had the highest specificity of 0.97, followed by frozen section (0.93) and the Musculoskeletal Infection Society criteria (0.92). Spacer sonication fluid culture was the most accurate test with an AUSROC of 0.8089, followed by synovial fluid culture (0.7749) and frozen section (0.7819). Spacer sonication fluid culture had a relatively high diagnostic accuracy. We emphasize that no test can be used alone to exclude persistent infection beyond the first stage and/or predict failed reimplantation beyond the second stage. II, systematic review and meta-analysis of level 2 to level 4 studies with inconsistent results.

The correlation between synovial fluid cultures and gram staining in presumed joint infections

The correlation between synovial fluid cultures and gram staining in presumed joint infections

Laboratory Tests for Diagnosis of Chronic Periprosthetic Joint Infection Can Help Predict Outcomes of Two-Stage Exchange.

Although 2-stage exchange arthroplasty is the most effective treatment among available strategies for managing chronic periprosthetic joint infection (PJI), rates of its success vary greatly. The purpose of our study was to examine whether objective measurements collected at the time of the diagnosis of PJI could be used to identify patients at risk of failure of 2-stage exchange. We identified 205 patients across 4 institutions who underwent 2-stage exchange arthroplasty for the treatment of PJI following total hip or total knee arthroplasty. Demographic, surgical, and laboratory data were obtained for each patient from their medical chart. Laboratory values included serum erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) level, synovial fluid white blood-cell (WBC) count and neutrophil percentage, synovial fluid and/or tissue culture, and Gram stain. Patients who underwent revision surgery for recurrent infection were considered to have failed the 2-stage procedure. Demographic, surgical, and laboratory variables were compared between the 2 groups. Receiver operating characteristic (ROC) curves were constructed to determine threshold cutoffs for significant laboratory values. Risk ratios and 95% confidence intervals were calculated. Overall, 2-stage exchange was unsuccessful for 27.3% of the patients. Preoperative serum ESR (p = 0.035) and synovial fluid WBC count (p = 0.008) and neutrophil percentage (p = 0.041) were greater in patients with recurrent infection. ROC curve analysis revealed a threshold of >60,000 cells/μL for synovial fluid WBC count, >92% for synovial fluid WBC neutrophil percentage, and >99 mm/hr for serum ESR. Failure of 2-stage exchange was 2.5 times more likely for patients with an elevated preoperative synovial fluid WBC count, 2.0 times more likely for those with an elevated preoperative synovial fluid WBC neutrophil percentage, and 1.8 times more likely for those with an elevated preoperative serum ESR. Our results demonstrated that a greater number of patients in whom 2-stage exchange arthroplasty ultimately failed had a preoperative synovial fluid WBC count of >60,000 cells/μL, a synovial fluid WBC neutrophil percentage of >92%, or a serum ESR of >99 mm/hr. Patients with elevated laboratory values had 1.8 to 2.5 times the risk of treatment failure. These data can serve as a clinical guideline to identify patients most at risk for failure of 2-stage exchange. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Radiographic Study of Haematogenous Septic Arthritis in Dairy Calves.

(1) To develop an evaluation grid to provide a systematic interpretation of calves' articular radiographs, (2) to describe radiographic lesions of septic arthritis in dairy calves less than 6 months of age, (3) to investigate potential associations between demographic data or synovial bacteriological culture results and radiographic lesions (4) to determine whether an association is present between radiographic lesions, their severity and the long-term outcome. Medical records of 54 calves less than 180 days old treated for septic arthritis between 2009 and 2014 with radiographic images performed in the first 2 days after admission were reviewed. Most common radiographic findings were increased articular joint space height (n = 49), irregularity of the articular surfaces (n = 24) and subchondral bone lysis (n = 24). The number of lesions observed and their severity were associated with older calves (p = 0.02), increased time between onset of clinical signs and admission (p = 0.0001) and the culture of Trueperella pyogenes within the joint (p = 0.02). The radiographic lesions associated with negative long-term prognosis were reduction in the joint space height (p = 0.01) and subchondral bone lysis on weight-bearing surfaces (p = 0.02). An evaluation grid designed for veterinarians can facilitate systematic reading of articular radiographs and can be used for dairy calves with a presumptive diagnosis of septic arthritis. This diagnostic tool may aid in establishing a prognosis and decision-making process in terms of treatment.

Factors Related to Surgical Treatment and Outcomes of Thai Patients With Septic Arthritis.

The aim of this study was to identify factors associated with the surgical treatment of Thai patients with septic arthritis. This cohort study used a university hospital database in Thailand to identify 450 adult patients with confirmed septic arthritis. Data related to baseline characteristics, clinical and laboratory findings, treatment, and outcomes were collected. A multivariate analysis identified the factors related to surgical treatment. The patients had a mean age (±SD) of 53.6 (±17.8) years, and 51% were male. Surgical drainage was performed on 332 patients (74%). The factors identifed as relating to the need for surgical drainage included preexisting joint disease (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.3-4.9), hip involvement (OR, 36.3; 95% CI, 4.1-320.5), abscess formation (OR, 5.6; 95% CI, 1.1-27.1), osteomyelitis (OR, 4; 95% CI, 1.1-14.9), and positive synovial fluid culture (OR, 3.8; 95% CI, 2-7.2). In contrast, patients who were treated with steroids (OR, 0.2; 95% CI, 0.1-0.4) or had septic shock (OR, 0.31; 95% CI, 0.13-0.83) were less likely to undergo surgery. This model correctly predicted 35% of cases. Patients treated with surgical drainage had a significant longer length of stay (median [interquartile range], 21 [11-34] days vs 14 [7-24] days; p < 0.0001) and were less likely to achieve complete recovery (26% vs 53%, p < 0.0001). However, the mortality rate was lower (2.4% vs 10.2%). Patients with septic arthritis who had underlying joint disease, hip involvement, abscess formation, osteomyelitis, and organisms in their synovial fluid were more likely to undergo surgical intervention with a significantly prolonged length of stay but had a lower mortality rate.

Synovial Fluid Aspiration Should Not Be Routinely Performed during the Two-Stage Exchange of the Knee.

Purpose Detection of infection persistence during the two-stage exchange of the knee for periprosthetic joint infection is challenging. Synovial fluid culture (SFC) and synovial white blood cell count (SWBCC) before joint reimplantation are widespread diagnostic means for this indication. The sensitivity and specificity of SFC and of SWBCC for infection persistence before planned reimplantation were evaluated. Methods 94 two-stage exchanges of the knee with synovial fluid aspiration performed after a drug holiday of at least 14 days and before reimplantation or spacer exchange (planned reimplantation) were retrospectively analyzed. Only cases with at least 3 intraoperative samples at planned reimplantation were included. SFC and SWBCC were compared to pathogen detection (SFC(culture)/SWBCC(culture)) and to histopathological signs of infection persistence (SFC(histo)/SWBCC(histo)) from intraoperative samples at planned reimplantation. For SFC, the sensitivity and specificity were calculated. For SWBCC, the optimal cut-off value with its sensitivity and specificity was calculated with the Youden-Index. Results Sensitivity and specificity of SFC(culture) were 0.0% and 98.9%. Sensitivity and specificity of SFC(histo) were 3.4% and 100%. The optimal cut-off value for SWBCC(culture) was 4450 cells/μl with a sensitivity of 50.0% and a specificity of 86.5%. The optimal cut-off value for SWBCC(histo) was 3250 cells/μl with a sensitivity of 35.7% and a specificity of 92.9%. Conclusion The detection of infection persistence remains challenging and a consented approach is lacking. The results do not warrant the routine performance of SFC during the two-stage exchange at the knee. SWBCC can be used to confirm infection persistence at high cut-offs, but they only occur in few patients and are therefore inappropriate for the routine use.

Hip Synovial Fluid Cell Counts in Children From a Lyme Disease Endemic Area.

Patients with septic hip arthritis require surgical drainage, but they can be difficult to distinguish from patients with Lyme arthritis. The ability of synovial fluid white blood cell (WBC) counts to help discriminate between septic and Lyme arthritis of the hip has not been investigated. We assembled a retrospective cohort of patients ≤21 years of age with hip monoarticular arthritis and a synovial fluid culture obtained who presented to 1 of 3 emergency departments located in Lyme disease endemic areas. Septic arthritis was defined as a positive synovial fluid culture result or synovial fluid pleocytosis (WBC count ≥50 000 cells per µL) with a positive blood culture result. Lyme arthritis was defined as positive 2-tiered Lyme disease serology results and negative synovial fluid bacterial culture results. All other patients were classified as having other arthritis. We compared median synovial fluid WBC counts by arthritis type. Of the 238 eligible patients, 26 (11%) had septic arthritis, 32 (13%) had Lyme arthritis, and 180 (76%) had other arthritis. Patients with septic arthritis had a higher median synovial fluid WBC count (126 130 cells per µL; interquartile range 83 303-209 332 cells per µL) than patients with Lyme arthritis (53 955 cells per µL; interquartile range 33 789-73 375 cells per µL). Eighteen patients (56%) with Lyme arthritis had synovial fluid WBC counts ≥50 000 cells per µL. Of the 94 patients who underwent surgical drainage, 13 were later diagnosed with Lyme arthritis. In Lyme disease endemic areas, synovial fluid WBC counts cannot always help differentiate septic from Lyme arthritis. Rapid Lyme diagnostics could help avoid unnecessary operative procedures in patients with Lyme arthritis.

Aggrecanase degradation of type III collagen is associated with clinical knee pain

There is a lack of biochemical markers for non-invasive and objective assessment of symptomatic osteoarthritis (OA). Aggrecanase activity has been shown to be associated with joint deterioration and symptomatic disease through the degradation of extracellular matrix proteins, such as type III collagen. Our study aimed to identify and develop a novel biomarker by measuring an aggrecanase-mediated type III collagen neoepitope, and correlate levels of this biomarker with OA joint pain. Mass spectrometric analysis of purified type III collagen, degraded by the aggrecanase A Disintigrin and Metalloproteinase with Thrombospondin motif (ADAMTS), revealed a fragment generated by ADAMTS-1, -4 and -8. A monoclonal antibody was raised against the neoepitope of this fragment (COL3-ADAMTS) and a competitive ELISA was developed and tested; using serum samples from a cross-sectional cohort of patients with different degrees of knee OA (n = 261). The COL3/ADAMTS ELISA was technically robust and specific for the ADAMTS-1, -4 and -8 generated neoepitope. COL3/ADAMTS was released form cytokine stimulated synovial cultures, indicating a biologic link between the marker and synovium. In OA patients, serum COL3/ADAMTS was independently associated with pain scores (rho = −0.13–0.17, p < 0.05). This association was associated significantly with the presence of radiographic OA. Together, these data indicate that COL3/ADAMTS could be a marker of early osteoarthritis and the underlining pathology.

Real-Time PCR Assay for Detection of Kingella kingae in Children

Background Kingella kingae is a known cause of osteoarticular infections in children younger than 4 years of age, but it is not always recoverable in culture. Molecular methods are increasingly used for diagnosis. Methods To facilitate diagnosis of K. kingae septic arthritis, we developed a real-time polymerase chain reaction (PCR) assay for the detection of K. kingae that targets the repeat-in-toxin gene (rtxB). Results We present three pediatric patients with K. kingae septic arthritis at our institution who were diagnosed using the real-time PCR assay. All underwent arthrotomy with irrigation and debridement and were symptom-free after 3 weeks of therapy with β-lactam antibiotics. Cultures of synovial fluid or tissue grew K. kingae in two of three; K. kingae real-time PCR was positive in all three patients. In addition, 11 cases of K. kingae osteoarticular infection were diagnosed through Mayo Medical Laboratories using this assay. The limit of detection of the real-time PCR assay was 73.7 colony-forming unit (CFU)/µL for tissue and 1.3 CFU/µL for synovial fluid. Conclusions PCR-based detection methods are faster and more sensitive than conventional culture-based methods for the diagnosis of K. kingae osteoarticular infections in children.

The efficacy of 16S ribosomal DNA sequencing in the diagnosis of bacteria from blood, bone and synovial fluid samples of children with musculoskeletal infections.

BackgroundMusculoskeletal infections are among the most common bacterial infections in children leading to hospitalization, invasive procedures and prolonged antibiotic administration. Blood, synovial and sometimes tissue cultures are essential for the diagnosis and treatment of musculoskeletal infections; 16S ribosomal DNA (rDNA) sequencing is a novel diagnostic tool for the detection of bacteria.While the yield of 16S rDNA sequencing in synovial fluid was previously assessed, data regarding the efficacy of this method from blood samples or partially treated children with suspected musculoskeletal infections is lacking.In this study we assessed the yield of 16S rDNA sequencing in blood, bone and synovial samples of children with musculoskeletal infections.MethodsBlood, synovial and bone samples were collected from children with suspected musculoskeletal infections and analyzed for the presence of 16S rDNA, the results were then compared with the benchmark microbial cultures.ResultsDuring the study period, 41 children (18 boys and 23 girls) with suspected acute musculoskeletal infection were enrolled. A positive blood culture was found in 6/31 cases (19.4%) with methicillin-susceptible Staphylococcus aureus being the most commonly isolated bacterium. No significant 16S rDNA detection in blood samples was recorded.Synovial fluid culture was positive in 6/28 samples (21%), Kingella kingae being the most common pathogen. When using the 16S rDNA sequencing method, the rate of positive results in synovial fluid was higher with bacterial detection in 12/23 (52%) samples. The 16S rDNA sequencing method was also able to identify pathogens in samples taken from partially treated children where cultures were negative with 16S rDNA detection in 5/5 samples.ConclusionAlthough 16S rDNA sequencing may increase the yield of bacterial detection in synovial samples of patients with musculoskeletal infections, there is no benefit from applying this method on blood samples. The 16S rDNA sequencing method may be particularly beneficial when antibiotic treatment was started prior to synovial fluid sampling.Level of EvidenceLevel-II diagnostic study

Paper #19 - Analysis of Synovial Fluid Cytokine Profiles in Determining Significance of Positive Culture Results in Patients Undergoing Primary Total Shoulder Arthroplasty for Glenohumeral Osteoarthritis

Introduction: Determining the significance of a positive culture result in revision shoulder arthroplasty can be challenging, due to the indolent nature of the commonly cultured organisms, most notably P. acnes. Recent studies have also shown a significant positive culture rate with P. acnes following primary shoulder arthroplasty in patients with no prior history of shoulder surgery. These findings suggest that some P. acnes culture growth following shoulder arthroplasty may represent culture contaminant or non-infectious colonization, rather than true infection. However, further data is needed to clarify such distinctions. We have previously demonstrated the benefit of synovial fluid cytokine analysis in the diagnosis of shoulder periprosthetic joint infection (PJI). The purpose of this study was to compare synovial fluid cytokine profiles and culture results in patients with primary glenohumeral osteoarthritis (OA) undergoing primary total shoulder arthroplasty (TSA) to non-arthritic patients undergoing primary arthroscopic rotator cuff repair (RCR), in order to determine if cytokine levels can distinguish the significance of a positive culture result.

Presentation and Investigation of Pediatric Bone and Joint Infections in the Pediatric Emergency Department.

The objective of this study was to evaluate the presenting features of bone and joint infections with a view to identify distinguishing trends that will be useful for pediatric emergency departments. We performed a retrospective review of patient records over a 12-year period in the pediatric emergency department of a large regional pediatric teaching center serving a diverse population. There were 88 cases of osteoarticular infections during the study period. Pain, fever, and impaired function were commonly reported, but overall, there was inconsistency in the presenting features. Inflammatory makers were sensitive tools, particularly in combination. When C-reactive protein, total white cell count, and erythrocyte sedimentation rate were all abnormal, 98% of bone and joint infections were identified.Causative organisms were identified in only 38% of cases, mostly from cultures of synovial fluid and bone. Streptococcal organisms were significantly more likely to be isolated in children under 5 years than in children over 5 years (P = <0.014). Staphylococcal organisms were significantly more likely to be isolated in children over 5 years than in children under 5 years (P = <0.001). Identification of virulent organisms such as Panton-Valentine leukocidin Staphylococcus aureus and methicillin-resistant S. aureus in our study should prompt review of diagnostic techniques and antibiotic choices. Overall, children under 5 years were significantly more likely to be diagnosed with septic arthritis than osteomyelitis (P = 0. 006). Children over 12 years were significantly more likely to be diagnosed with osteomyelitis than septic arthritis (P = 0. 019). These trends are useful to consider at presentation and in cases of diagnostic uncertainty.

Puncture Protocol in the Diagnostic Work-Up of a Suspected Chronic Prosthetic Joint Infection of the Hip

BackgroundDiagnosing a chronic prosthetic joint infection (PJI) can be challenging. We hypothesized that obtaining preoperative tissue samples for culture in hip arthroplasty will increase the likelihood of diagnosing an infection before revision surgery. The aim of this cohort study was to determine the diagnostic accuracy of 2 tissue acquiring biopsy strategies to diagnose a PJI. MethodsPatients with a painful hip arthroplasty, in which a chronic PJI was suspected, were included. Tissue samples were obtained either by ultrasound guidance with a 16-Gauge needle (2012-2013) or in the operating room with a thick-bore needle (2013-2016). Revision surgery tissue biopsies were used as the gold standard. Sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were calculated. ResultsA total of 16 patients in the ultrasound cohort and 29 patients in the surgical cohort were included. Thirty-one percent (n = 14) were finally diagnosed with a PJI. The addition of thick bore needle tissue biopsies resulted in 9% more diagnosed PJIs compared with synovial fluid alone. The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio was 33%, 85%, 33%, 85%, 2.2, and 0.8, respectively, for the ultrasound-guided biopsy cohort and 82%, 100%, 100%, 90%, infinite, and 0.2, respectively, for the surgical biopsy cohort. ConclusionObtaining multiple good quality tissue biopsies in a sterile environment will contribute to the diagnosis of a chronic PJI of the hip, with a higher diagnostic accuracy compared with ultrasound-guided thin needle biopsies and compared with synovial fluid culture alone.

Does Use of Lidocaine Affect Culture of Synovial Fluid Obtained to Diagnose Periprosthetic Joint Infection (PJI)? An In Vitro Study.

BackgroundSynovial fluid culture (SFC) is recommended as one of the major diagnostic criteria by the Musculoskeletal Infection Society (MSIS) for diagnosing periprosthetic joint infection (PJI). Local anesthetic agents are used for anesthesia and analgesia in some clinical settings to relieve pain. As a local anesthetic, lidocaine is safely used in arthrocentesis to obtain synovial fluid. The goal of this study was to determine if infiltration anesthesia with additive-free lidocaine 2% has antibacterial effects that might interfere with subsequent SFC.Material/MethodsEight isolates of reference strains of Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Streptococcus pyogenes, and Candida albicans were incubated on the plates. Each bacterial suspension was formed by 50-fold dilution before the test lidocaine 2% was added. For each strain, bacterial suspension was divided into 2 groups (5 samples each) exposed either lidocaine 2% or sterile non-bacteriostatic 0.45% saline. The antimicrobial property of lidocaine 2% was determined by measuring the bacterial density on agar plates incubated for 24 h and comparing it with controls unexposed to lidocaine 2%.ResultsExposure to lidocaine 2% negatively affected microbial viability in vitro. Of the lidocaine 2% exposure, reference strains but no Streptococcus pyogenes strain resulted in fewer colony-forming units compared with the sterile saline control. The antibacterial property of lidocaine 2% appears to affect the ability to culture the organism in synovial fluid.ConclusionsLidocaine 2% has strong antimicrobial activities against some commonly encountered bacterial strains in PJI. As a result, infiltration anesthesia with additive-free lidocaine 2% before the arthrocentesis procedure may affect the results of SFC. To further evaluate its potential antibacterial usefulness in clinical applications, studies are needed to assess the ability of lidocaine to reduce the risk of iatrogenic infections.