Synovial Cultures Research Articles

What Is the Diagnostic “Algorithm” for Infected Total Ankle Arthroplasty (TAA)?

Patients who present with clinical symptoms and signs of periprosthetic ankle infection (pain, erythema, warmth, sinus tract, abscess around the wound) and sinus tracts communicating with the ankle/subtalar joint are likely to have total ankle arthroplasty (TAA) infection. In the absence of a sinus tract, elevated inflammatory markers (erythrocyte sedimentation rate [ESR] and C-reactive protein [CRP]) should prompt ankle joint aspiration for cell count, differential, and culture. The joint aspiration is to be repeated. If the same organism is identified in at least 2 cultures of synovial fluid, the patient is diagnosed to have an infection. If the repeat aspiration is negative, further investigation is warranted. In patients not requiring operative intervention for other reasons, nuclear imaging should be considered for diagnosis. If an operation is indicated, histologic examination (>5 neutrophils/high-power field) or synovial fluid analysis is conducted to confirm infection. Limited. Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).

Articular and skeletal affection in regularly dialyzed patients with end-stage renal disease

BackgroundPatients on regular hemodialysis (HD) are vulnerable to develop different articular and skeletal problems that interfere with life quality and affect morbidity and mortality in these patients. To, properly, overcome or even prevent the development of these complications, early detection, especially of the commonly affected parts, is required.AimThe aim was to detect articular and skeletal manifestations in patients with end-stage renal disease on regular HD, their relation to duration of dialysis, and which is more affected.Patients and methodsA total of 50 patients (34 males and 16 females) with end-stage renal disease on regular HD, who were attendants of the dialysis unit of Internal Medicine Department at Al-Azhar University hospital, New Damietta, with duration of dialysis ranging between 3 and 15 years and age ranging from 26 to 70 years old were recruited for the study. They were classified into three groups: group I: mild, group II: moderate, and group III: severe joint affection. Full history taking, thorough clinical examination, especially for uremic and rheumatologic manifestations; laboratory investigations (inflammatory and metabolic markers); synovial fluid analysis and culture; and radiological investigations (radiography, dual-energy X-ray absorptiometry scan, ultrasound, computed tomography, and MRI of the affected parts) were done.ResultsThere was a significant association between the duration of dialysis and the presence of joint affection. The most common affected joints were knee joints [n=23 patients (46%)] and shoulder joints [n=10 (20%)]. There was a statistically significant association between the severity of joints involvement and the prolonged duration of dialysis. The most common crystals present were the urate crystals (26%) followed by calcium pyrophosphate dihydrate (12%), and lastly oxalate crystals (8%). Carpal tunnel syndrome was diagnosed in 12 patients, with high significant association between the duration of dialysis and presence of carpal tunnel syndrome. There was increase in the level of parathyroid hormone with increase in the duration of renal dialysis. Moreover, 64% of patients had hyperparathyroid bone disease. The mean alkaline phosphatase level was increased in all groups of patients but was more in patients with severe joint affection. Serum albumin was maintained within normal level in HD patients. Radiological study of our HD patients showed that the most frequent radiological findings were signs of secondary hyperparathyroidism (subperiosteal resorption; acroosteolysis in the terminal tufts; pathological fracture, with two fractures in the spine, one in the neck of femur, and one fracture in the rib; and periarticular calcification, with one was found in the hand, and two were found in the pelvis). The incidence of these radiological findings increased with the increase of duration of HD. In addition, 18 patients had normal bone mineral density values, 18 patients had osteopenia, whereas 14 patients had osteoporosis.ConclusionThe increased duration of dialysis is associated with increased incidence of articular and skeletal complications mainly renal osteodystrophy in the form of crystal-induced arthritis, osteoporosis, and periarticular calcification. Knee and shoulder joints, spine, neck of femur, wrist joints, and ribs are the main targets for complications and then for proper prophylaxis.

Case report: Anaerobiospirillum prosthetic joint infection in a heart transplant recipient

BackgroundWe report a case of prosthetic hip joint infection in a heart transplant recipient due to Anaerobiospirillum succiniciproducens, a genus of spiral-shaped curved anaerobic gram-negative rod which colonizes the gastrointestinal tract of cats and dogs. Invasive infections in humans are rare and typically occur in immunocompromised hosts.Case presentationA 65-year-old male dog breeder with a history of rheumatoid arthritis, bilateral hip arthroplasties, and non-ischemic cardiomyopathy with a heart transplant 10 years ago presented with a three month history of progressive left hip pain and frank purulence on hip aspiration. He underwent irrigation and debridement of the left hip and one-stage revision with hardware exchange. Although gram stain and culture from synovial fluid and intraoperative cultures were initially negative, anaerobic cultures from tissue specimens later grew a spiral-shaped gram-negative rod, identified as Anaerobiospirillum spp. by 16S rRNA gene sequencing. The patient was treated with ceftriaxone 2 g daily for 6 weeks with a good response to treatment. A similar organism was unable to be isolated from culture of 2 of the patient’s dogs, however, they were thought to be the most likely source of his infection.ConclusionAnaerobiospirillum spp. should be considered in immunocompromised patients with exposure to dogs or cats who present with bacteremia, gastrointestinal infection, pyomyositis, or prosthetic joint infections, especially in cases of culture-negative or with anaerobic culture growth.

Bilateral septic arthritis of the knee caused by group B streptococci: a case report

Septic arthritis (SA) remains to be a critical diagnosis for a swollen knee at the emergency department. Here, we report a rare case of bilateral knee arthritis in a 59-year-old diabetic woman who had been immobilized 5 months prior to admission. Her right knee swelling exacerbated in 10 days leading to left knee involvement. In 5 days the clear synovial tap in the first hospital turned purulent in the second hospital and empirical antibiotics get started with high WBC count, dominant neutrophils, and Gram-positive cocci in smear. Knee arthrotomy was performed after 6 days in the third hospital with the same smear results but negative blood and synovial cultures of both knees. When followed in retrograde, two positive blood cultures were reported for Streptococcus agalactiae in the second hospital. Vancomycin was changed to ampicillin and symptoms were resolved in 4 weeks. Despite improvement, mobility was not retained. Uncommon etiologic agents of knee arthritis should be in mind specifically in debilitated patients. Timely initiation of proper antibiotics hinders permanent sequels, hence clinicians should be suspicious of such organisms.

Low frequency of septic arthritis after arthrocentesis and intra-articular glucocorticoid injection

Objective: The aim of this study was to evaluate the risk of septic arthritis (SA) in patients who received an intra-articular (IA) glucocorticoid (GC) injection and to describe the characteristics of these patients.Methods: All patients undergoing IA procedures at the orthopaedic and rheumatological departments on the Danish island of Funen from January 2006 to December 2013 were identified in the central database and included by register extraction. Patients who developed a clinically inflamed joint and positive synovial fluid culture within 14 days after IA GC injection were considered as having SA. Retrospectively, data on age, gender, affected joint location, bacterial agent, pre-existing inflammatory disorder, and death within 30 days were extracted from the patient files. According to local recommendations, a non-touch sterile technique was used for IA procedures. Patients were informed about the risk of SA and advised to seek medical attention on suspicion of infection or lack of improvement.Results: In total, 22 370 IA procedures were performed. Among these, 14 118 GC injections and 8252 arthrocenteses were undertaken. Only 11 patients were diagnosed with SA (0.08%, 95% confidence interval 0.03–0.12). Risk factors for SA were male gender, age, and pre-existing joint disease.Conclusion: We found a low frequency of SA subsequent to IA GC injections. Older patients with pre-existing joint disease are at higher risk of developing SA.

Optimization of the empirical antibiotic choice during the treatment of acute prosthetic joint infections: a retrospective analysis of 91 patients

Background and purpose — The preferred treatment of an acute prosthetic joint infection (PJI) is debridement, antibiotics, irrigation and retention of the prosthesis (DAIR). The antibiotic treatment consists of an empirical and targeted phase. In the empirical phase, intravenous antibiotics are started after surgery before micro-organisms are determined in microbiological cultures. Which empirical antibiotic is used differs between hospitals, partly reflecting geographic differences in susceptibility spectrums. We investigated whether flucloxacillin should remain the antibiotic of choice in our hospital for empiric treatment of acute PJI with DAIR.Patients and methods — We retrospectively analyzed 91 patients treated for PJI with DAIR between 2012 and 2016. The susceptibility of micro-organisms was determined in multiple cultures of periprosthetic tissue and synovial fluid for 3 antibiotics: amoxicillin/clavulanic acid, cefazolin, and flucloxacillin.Results — Positive microbiological cultures from 68 patients were analyzed. Staphylococcus aureus was the predominant pathogen, cultured in half of the patients. In one-third of patients more than 1 micro-organism was found. On a patient level, the data showed that 65% were responsive to flucloxacillin, 76% to amoxicillin/clavulanic acid, and 79% to cefazolin.Interpretation — Flucloxacillin appeared to be a suboptimal choice in our patient population treated with DAIR. We therefore changed our practice to cefazolin as the preferred antibiotic in the empirical treatment of acute PJI with DAIR.

Determining the Risk of Septic Arthritis Following Intra-Articular Injection of Drugs Mixed At A Tertiary Care Center, 2012–2017

BACKGROUND Intra-articular corticosteroid injections are commonly used for the outpatient treatment of osteoarticular pain. Practitioners may choose to administer additional medications such as anesthetics. While medications are compounded in the pharmacy following stringent environmental requirements, occasionally injections with additional components for immediate use are mixed at the point of care under less strict environmental conditions due to turnaround time requirement. We assessed if mixing multiple drugs in a single syringe in outpatient settings was associated with subsequent septic arthritis. METHODS We reviewed electronic pharmacy medication administration records of patients who received an intra-articular corticosteroid injection at a tertiary care center during 2012–2017. We extracted basic patient demographics. Exposure was defined as receiving more than one intra-articular medication during a single injection-encounter. The outcome was culture-confirmed septic arthritis defined as a?positive synovial fluid culture within 90?days following an intra-articular?injection. We present case counts, ranges, and frequencies. RESULTS 7,072 unique patients received an intra-articular injection. Mean age was 55?years (range: 9 – 104) and 41% were male. There were 13,089 distinct intra-articular injection-encounters. Of the unique encounters, 306 (2%) intra-articular injection involved only one medication; 12,080 (92%) received 2 medications; 596 (5%) received 3 medications; 104 (0.8%) received 4 medications; and 3?(0.02%) received 5 medications. There were no infections following single intra-articular medication injection-encounters. Two septic arthritis cases were identified in patients who received two intra-articular medications (triamcinolone and lidocaine 1%). The microorganisms were: Staphylococcus aureus and Enterobacter cloacae. CONCLUSIONS Intra-articular corticosteroid injection practices in outpatient settings are heterogeneous. Septic arthritis following intra-articular injection was infrequent. We were unable to associate septic arthritis with mixing intra-articular injectables outside the pharmacy.

Loosening of total knee arthroplasty – always aseptic?

PurposeWhen revision surgery is needed in total knee arthroplasty (TKA) the most frequent reasons are aseptic loosening (AL) and periprosthetic joint infection (PJI). However preoperative distinction between AL and PJI remains challenging. Aim of this study is to determine the incidence of PJI in patients with suspected AL after TKA and to evaluate a diagnostic algorithm for reliable differential diagnosis. MethodsIn this study a total of 149 symptomatic patients with radiographic signs of prosthetic loosening and suspected AL were included. Preoperatively all patients underwent a standardized diagnostic algorithm. For each patient demographics, as well as the results of laboratory and microbiological testing were collected from the medical records. ResultsOf the included patients 117 (78.5%) were diagnosed with AL and 32 (21.5%) with PJI. The latency period from primary arthroplasty to the presentation with symptomatic implant loosening was significantly shorter for PJI compared to AL (p < 0.05). The initial CRP values were significantly higher in patients with PJI compared to patients with AL (p < 0.05). Elevated count of white blood cells or percentage of neutrophils within the synovial fluid support the diagnosis of PJI. The sensitivity of synovial cell count (CC) count for PJI in patients with radiographic signs of loosening was 0.84 (CI 0.81–0.87) with a specificity of 0.96 (CI 0.92–0.98). The single best measure for the diagnosis of PJI was synovial fluid cultures with a specificity of 1, however this measure provides poor sensitivity. ConclusionPatients with radiographic signs of loosening in TKA need thorough diagnostics. Information about primary TKA, serological testing, and results of joint aspiration can rule out a PJI in most cases.

Coexistence of septic and crystal-induced arthritis: A diagnostic challenge. A report of 25 cases

ObjectiveSeptic arthritis is a medical emergency and crystal-induced arthritis is a risk factor for its development. If both occur simultaneously, crystal-induced arthritis may mask the diagnosis of infection and delay antibiotic therapy. MethodRetrospective analysis of patients with coexistence of septic and crystal-induced arthritis. We included only patients with isolation of crystals in synovial fluid analysis and positive culture of synovial fluid and/or blood culture. ResultsA total of 25 patients (17 men and 8 women) with a mean age of 67 years. The most commonly affected joint was the knee. In synovial fluid cytological studies, the most frequently identified crystals were monosodium urate. Risk factors included diabetes and chronic renal failure. The most frequently isolated germs were methicillin-sensitive Staphylococcus aureus (48%), methicillin-resistant S. aureus (12%) and Mycobacterium tuberculosis (12%). In all, 36% of subjects required surgical drainage (excluding those caused by M. tuberculosis). Clinical outcome was favourable in 56%, although intercurrent complications were usual (40%). Mortality was 8%. ConclusionsCoexistence of septic and crystal-induced arthritis represents a diagnostic challenge and requires a high index of suspicion. Gout was the most prevalent crystal-induced arthritis. S. aureus was the most commonly causative pathogen, with a high rate of methicillin-resistant S. aureus infection. If treated early, the outcome is usually favourable, making synovial fluid microbiological study imperative.

Epidemiology, Management, and Outcomes of Large and Small Native Joint Septic Arthritis in Adults.

Native joint septic arthritis (NJSA) is poorly studied. We describe the epidemiology, treatment, and outcomes of large joint NJSA (LNJSA) and small joint NJSA (SNJSA) in adults at Middlemore Hospital, Auckland, New Zealand. This was a coding-based retrospective study of patients ≥16 years old admitted between 2009 and 2014. Prosthetic joint infections were excluded. Five hundred forty-three NJSA episodes were included (302 LNJSA, 250 SNJSA). Only 40% had positive synovial fluid culture. Compared to SNJSA, LNJSA has higher incidence (13 vs 8/100 000 person-years [PY]), occurs in older, more comorbid patients, and is associated with greater rates of treatment failure (23% vs 12%) and mortality, despite longer antibiotic treatment. Total incidence is higher than previously reported (21/100 000 PY), with marked interethnic variation. Incidence rises with age (LNJSA only) and socioeconomic deprivation (LNJSA and SNJSA). Tobacco smokers and males are overrepresented. The most commonly involved joints were knee (21%) and hand interphalangeal (20%). Staphylococcus aureus was the most common pathogen (53%). Mean antibiotic duration was 25 days for SNJSA and 40 days for LNJSA, and the mean number of surgical procedures was 1.5 and 1.6, respectively. Treatment failure was independently associated with LNJSA, age, intra-articular nonarthroplasty prosthesis, and number of surgical procedures. This is the largest contemporary series of adult NJSA. SNJSA has better outcomes than LNJSA and may be able to be safely treated with shorter antimicrobial courses. Incidence is high, with significant ethnic and socioeconomic variation. Microbiological NJSA case ascertainment underestimates case numbers as it frequently excludes SNJSA.

Performance of automated multiplex polymerase chain reaction (mPCR) using synovial fluid in the diagnosis of native joint septic arthritis in adults.

This study aimed to assess the performance of an automated multiplex polymerase chain reaction (mPCR) technique for rapid diagnosis of native joint septic arthritis. Consecutive patients with suspected septic arthritis undergoing aseptic diagnostic joint aspiration were included. The aspirate was used for analysis by mPCR and conventional microbiological analysis. A joint was classed as septic according to modified Newman criteria. Based on receiver operating characteristic (ROC) analysis, the area under the ROC curve (AUC) values of the mPCR and the synovial fluid culture were compared using the z-test. A total of 72 out of 76 consecutive patients (33 women, 39 men; mean age 64 years (22 to 92)) with suspected septic arthritis were included in this study. Of 72 patients, 42 (58%) were deemed to have septic joints. The sensitivity of mPCR and synovial fluid culture was 38% and 29%, respectively. No significant differences were found between the AUCs of both techniques (p = 0.138). A strong concordance of 89% (Cohen's kappa: 0.65) was shown. The mPCR failed to detect Staphylococcus aureus (n = 1) and Streptococcus pneumoniae (n = 1; no primer included in the mPCR), whereas the synovial fluid culture missed six microorganisms (positive mPCR: S. aureus (n = 2), Cutibacterium acnes (n = 3), coagulase-negative staphylococci (n = 2)). The automated mPCR showed at least a similar performance to the synovial fluid culture (the current benchmark) in diagnosing septic arthritis, having the great advantage of a shorter turnaround time (within five hours). Cite this article: Bone Joint J 2019;101-B:288-296.

Probing the Molecular Interactions and Lubrication Mechanisms of Purified Full-Length Recombinant Human Proteoglycan 4 (rhPRG4) and Hyaluronic Acid (HA).

Probing the adsorption and lubrication behavior of lubricin, also known as proteoglycan 4 (PRG4), is important for understanding the ultralow friction of cartilage lubrication. Most previous research has focused on native lubricin either purified from synovial fluid or articular cartilage explant culture media. In this work, the adsorption behavior and lubrication mechanism of full-length recombinant human PRG4 (rhPRG4) on mica as well as the effect of adding hyaluronic acid (HA, a polysaccharide) were systematically investigated using a surface forces apparatus (SFA) technique. A low friction coefficient (μ ∼ 0.04) was measured when multilayer rhPRG4 (∼31 nm) was confined in between mica surfaces, even when the load increased to ∼1.2 MPa. Intriguingly, a previously unreported ultralow friction coefficient (μ < 0.005) was observed at a low sliding velocity ( v = 0.14 μm/s) with the applied load P reaching ∼3.6 MPa when a diluted rhPRG4 solution (∼90 μg/mL) was used. The distinct friction behavior is likely due to the smooth and more close-packed lubricin coating, as made evident by the atomic force microscope imaging. Adding HA onto multilayer rhPRG4-coated mica increased the friction coefficient μ to ∼0.1; however, the load bearing property increased, indicating potential synergistic effect between rhPRG4 and HA, which was further demonstrated by the weak adhesion observed when separating rhPRG4-coated mica and HA-coated aminopropyltriethoxysilane-mica (APTES-mica). Alternatively, adding premixed rhPRG4-HA on mica had a friction coefficient (μ ∼ 0.1) close to that of injecting concentrated rhPRG4 (∼450 μg/mL) with lower load sustainability. Our results provide fundamental insights into the adsorption and lubrication behavior of lubricin and its interaction with HA, with useful implications for the underlying mechanism of ultralow friction provided by synovial fluid.

Clinical Presentation, Management, and Prognosis of Pseudogout in Joint Arthroplasty: A Retrospective Cohort Study.

Introduction: Calcium pyrophosphate deposition disease (CPPD), or pseudogout, is rare in prosthetic joints, but can mimic prosthetic joint infection (PJI) according to case reports. The purpose of this case series is to describe the demographics, presentation, management, and outcomes of a cohort of these patients seen at our academic medical center.Methods: Patients with post-implant pseudogout, who were evaluated at our medical center between January 1, 2000 and June 30, 2016, were identified from our EHR. Data pertaining to demographics, presentation, management, and outcomes were abstracted, and patients were categorized into two groups based on presence of concomitant infection along with positive CPDD findings in synovial fluid.Results: 22 patients were included. 90.9% of cases involved a TKA. The most common indication for arthroplasty was degenerative joint disease. Only four patients had a history of previous gout or pseudogout, three of which belonged to the group with no evidence of concomitant joint infection. Clinical features for patients without concomitant infection included pain (100%), swelling at the joint (88.9%), redness (33.3%), fever (22.2%), and decreased range of motion (100%). 45.5% of patients received antibiotics prior to joint aspiration (44.4% of patients with negative synovial fluid cultures, 46.2% of patients with concomitant infection).Conclusion: Our study suggests similar clinical presentation between post-implant pseudogout and PJI. Among patients with pseudogout as well as in those with PJI, the first dose of antibiotics should not be given before sampling for synovial culture. Unfortunately, many patients receive antibiotics prior to culture ascertainment, which raises concern for antibiotic overuse.

Utility of point-of-care synovial lactate to identify septic arthritis in the emergency department

BackgroundSynovial lactate is a promising biomarker to distinguish septic from aseptic arthritis. If available as a point-of care test, synovial lactate would be rapidly available to aid the emergency provider in clinical decision making. This study assesses the test characteristics of synovial lactate obtained using an EPOC© point-of-care (POC) analyzer to rapidly distinguish septic from aseptic arthritis in the emergency department. MethodsWe enrolled a convenience sample of patients with possible septic arthritis presenting to the emergency department at a large urban academic center between October 2016 and April 2018. Enrolled patients underwent arthrocentesis based on the clinical judgment of the treating provider. We obtained synovial lactate levels (SLL) from the POC device. Standard laboratory analysis, synovial fluid culture, emergency and hospital course, operative procedures, antibiotics, and discharge diagnosis were abstracted from the electronic medical record. ResultsThirty-nine patients undergoing forty separate arthrocentesis procedures were enrolled in this study over the two-year period. The sensitivity and specificity of SLL ≥ 5 mmol/L was 0.55 and 0.76 respectively, with +LR 2.3 and −LR 0.6. The sensitivity and specificity of SLL ≥ 10 mmol/L was 0.27 and 0.97 respectively, with +LR 7.9 and −LR 0.8; SLL ≥ 10 mmol/L performed similarly to overall synovial WBC ≥ 50,000/μL by conventional laboratory testing. ConclusionIt is feasible to obtain a synovial lactate level using the EPOC© POC device. In our study, POC SLL performs similarly to other markers used to diagnose septic arthritis. Further study with larger sample sizes is warranted.

PARVIMONAS MICRA AND FUSOBACTERIUM NUCLEATUM SEPTIC ARTHRITIS: A RARE ANAEROBIC DOUBLE TROUBLE

Septic arthritis is a condition initiated by pathogenic inoculation of joints either by direct or hematogenous route, necessitating immediate medical attention. Among aerobic bacteria, Staphylococcus aureus and Streptococcus spp. are commonly found in association with septic joints. Anaerobes are very rarely involved in the causation of septic arthritis with an estimated rate of &lt;1%. We are presenting a case of septic arthritis of knee joint by Parvimonas micra and Fusobacterium nucleatum, both being constituents of microbial flora in the oral cavity and gastrointestinal tract. Gram stain and anaerobic culture incorporated along with the aerobic culture of synovial fluid have played an important role in the preliminary diagnosis of anaerobic septic arthritis in this case.

Prospective study of blackthorn injury and synovitis in 35 horses

SummaryThe objective of this prospective clinical study was to investigate the cause and describe the presentation, diagnosis, treatment techniques and outcome of Prunus spinosa (blackthorn) injury and synovitis in the horse. In all cases presented with blackthorn injury and synovitis, surgical treatment was performed within 24 h, using a two‐stage procedure: 1‐Perisynovial technique using ultrasound guided electrosurgical dissection; 2‐Endoscopic technique. The diagnosis was confirmed by retrieval of black plant material from or close to the affected synovial structure. Mean lameness score on presentation was 4/5 (range 1–5). The most commonly affected structures were extensor tendon sheaths (12/35) and fetlock joints (11/35). All cases had thorn material removed, 80% had thorn material removed at surgery and in 49% it was intra‐synovial. On presentation, the mean synovial fluid total protein level (TP) was 47.6 g/L (range 18–66); mean total nucleated cell count (TNCC) was 176 × 109 cells/L (range 12–312). Two days post‐surgery, mean total protein levels were 33 g/L (range 16–52), mean TNCC was 13 × 109 cells/L (range 1–35). At 5 days post‐surgery, the mean total protein was 23 g/L (range 12–28) and TNCC was 5 × 109 cells/L (range 1–12). All synovial fluid cultures were negative. Twenty‐eight (80%) horses were sound 5 days post‐operatively, seven (20%) were not lame in walk; they all returned to full work in an average time of 8 weeks (range 3–48 weeks). Surgery achieved accurate identification and removal of thorn material. In contrast to previous studies of synovial sepsis, these cases had a positive outcome despite high pre‐ and post‐operative synovial fluid TP and TNCC. These findings suggest that Prunus spinosus (blackthorn) synovitis has a different aetiology to synovitis originating from sepsis or other types of contamination.

Successful Daptomycin Therapy for Postsurgical Shoulder Arthritis With Propionibacterium acnes

To the Editor: We have read with interest numerous studies investigating the clinical role of daptomycin, particularly in invasive infections with hypothesized biofilm formation as an important pathogenic mechanism of infection.1 This is true for Propionibacterium acnes, a commensal microbe with an opportunistic ability to cause serious central nervous system, endovascular, and orthopedic infections. Given its ability to treat biofilm-forming infections, particularly in the setting of indwelling prosthetic material, as well as its convenient once-daily dosing, daptomycin is an attractive option for treatment of serious infections due to P. acnes. Previously, Ghosh et al2 and Taylor et al3 have published a case report of P. acnes osteomyelitis of the skull treated with daptomycin. P. acnes septic arthritis in native joints and postoperatively after shoulder surgery has been reported.3,4 Here, we report a case of P. acnes septic arthritis of the left shoulder treated with daptomycin. A middle-aged man with a history of well-controlled diabetes (hemoglobin A1c 6.3%) presented to our hospital with a 1-week history of low-grade fevers and left shoulder pain with movement. He underwent arthroscopic rotator cuff repair of the same shoulder 3 weeks before hospital presentation. Arthrocentesis was performed for synovial fluid analysis, revealing 104,000 white blood cells/mm3 with 92% polymorphonuclear cells. Gram stain showed no organisms. The C-reactive protein was 237 mg/L, and the erythrocyte sedimentation rate was 115 mm/h. Serum white blood cell count was 12,500 cells/mm3 with 72% polymorphonuclear cells. The patient was started on empiric daptomycin dosed at 6 mg/kg intravenous daily and proceeded for operative drainage and washout of the shoulder on first hospital day. On hospital day 5, initial synovial fluid culture showed that P. acnes evolved under anaerobic conditions. Subsequent surgical cultures on repeat surgical washouts were sterile. The patient was continued on daptomycin on hospital discharge and completed 6 weeks of therapy. After completion of therapy, the erythrocyte sedimentation rate was 17 mm/h and the result from the C-reactive protein test was negative. He regained full range of motion shortly after hospitalization and remained well without recurrence thereafter. P. acnes is a facultative gram-positive anaerobic bacillus. Shoulder infections due to P. acnes have become an emerging problem. P. acnes was the most commonly reported organism in a recent meta-analysis of shoulder periprosthetic joint infections, representing 38.9% of infections.5 Risk factors included increased age, male sex, increased body mass index, and diabetes mellitus. Antibiotic management is not clearly defined. Penicillin G, amoxicillin plus rifampin (RIF), clindamycin plus RIF, and linezolid plus RIF have been used.4 Clinicians must be aware that microbiological diagnosis can be difficult because anaerobic conditions and prolonged duration are necessary for culture. Clinicians should also be aware of the high incidence of P. acnes infection after shoulder surgery. Our case illustrates the utility of daptomycin as a convenient and promising treatment for serious P. acnes orthopedic infections. Rahul Mahapatra, DO Stony Brook University Hospital Stony Brook, NYGeorge Psevdos, MD Veterans Affairs Medical Center Northport, NY Stony Brook University School of Medicine Stony Brook, NY [email protected]

The Limitations of Gram-stain Microscopy of Synovial Fluid in Concomitant Septic and Crystal Arthritis.

Rapid diagnosis of septic arthritis from Gram-stain microscopy is limited by an inherent false-negative rate of 25-78%. The presence of concomitant crystal arthritis in 5% of cases represents a particular diagnostic challenge. This study aims to investigate the effects that a concomitant crystal arthropathy has on the ability of Gram-stain microscopy of synovial fluid to diagnose a septic arthritis. This is a 22-year retrospective cohort study. Inclusion criteria were a positive synovial fluid culture result with a positive clinical diagnosis of septic arthritis. Results were correlated with the presence or absence of urate and calcium pyrophosphate crystals, and Gram-stain result. During this time our collection and analysis methods remained unchanged. All samples were collected in Lithium Heparin containers. Chi-squared test with a p value < 0.05 was considered significant. 602 synovial fluid samples were included. 162 cases of concomitant crystal arthritis were identified (27%). Of these, 16 (10%) had an initial negative Gram-stain. Out of the 440 samples with no crystals detected, 18 (4%) had an initial negative Gram-stain microscopy result (p < 0.05). The incidence of concurrent septic and crystal arthritis may be higher than previously thought. Synovial fluid samples in concomitant septic and crystal arthritis are significantly less likely to have a positive Gram-stain at microscopy than in cases of an isolated septic arthritis. We would advise the clinician to maintain a high index of suspicion for septic arthritis in these patients.

Normal CRP and WBC values in total hip arthroplasty (THA) with signs of loosening. Do we need a joint aspiration?

PurposeOverall Total hip arthroplasty (THA) is a very successful procedure. However, in case of complication dedicated management is required. Two major complications of THA failures are aseptic loosening (AL) and periprosthetic joint infection (PJI). The primary hypothesis of this study was that joint aspirations in patients with signs of loosening after THA are capable to detect PJI in suspected AL with negative serologic testing. MethodsIn this study a total of 108 symptomatic patients with radiographic signs of prosthetic loosening and hip pain in THA were included. Based on a standardized algorithm all patients underwent serological testing followed by joint aspiration preoperatively. Intraoperatively harvested samples were subjected to microbiological testing and served as the gold standard in differential diagnosis. Demographics, as well as the results of serologic and microbiological testing were collected from the medical records. ResultsOf the included patients 85 were finally diagnosed with an AL and 23 with PJI. Within the patients with PJI 13 (56%) patients demonstrated elevated CRP and WBC counts, as well as positive synovial cultures after joint aspiration. In ten patients (44%) diagnosed with PJI neither CRP nor WBC were abnormal. ConclusionThe diagnosis of PJI can be difficult in THA with radiographic signs of loosening. Clinical features including pain, fever, and local sings of infection are uncommon especially a long period after index operation. First-line screening testing relies on serological evaluation of CRP and WBC. However, normal CRP and WBC values cannot rule out a PJI. These cases can be detected by joint aspiration and synovial cultures reliably.

Rheumatoid Arthritis and Tuberculosis Link, 3 Cases of T.B. Tenosynovitis Wrist

Three cases of sever synovitis and tenosynovitis of the wrist were sent to the author for surgical synovectomy and tenosynovectomies after failure of the medical treatment with biological and disease modifying drugs all of them turn to be tuberculous tenosynovitis after incidental soft tissue and synovial fluid culture, a discussion for the link between both different entity diseases and Awareness of Drug-specific risk of tuberculosis in patients with rheumatoid arthritis.