Dyslipidaemia is associated with Cutibacterium acnes hip and knee prosthetic joint infection.

PURPOSE: Optimization of medical factors including diabetes and obesity is a cornerstone in the prevention of prosthetic joint infection (PJI). Dyslipidaemia is another component of metabolic syndrome which has not been thoroughly investigated as an individual, modifiable risk factor. This study examined the association of dyslipidaemia with PJI caused by the lipophilic microbe Cutibacterium acnes (C. acnes). METHODS: A retrospective chart review examined patients with positive C. acnes culture at hip or knee arthroplasty explantation. A control group with methicillin-sensitive Staphylococcus aureus (MSSA) positive cultures at explantation was matched for age, sex, and surgical site, as well as a second control group with no infection. A total of 80 patients were included, 16 with C. acnes, 32 with MSSA, and 32 with no infection. All patients had a lipid panel performed within one year of surgery. Lipid values and categories were compared using multinomial logistic regressions. RESULTS: High or borderline triglycerides (TG) (relative risk ratio (RRR) = 0.13; P = 0.013) and low high-density lipoprotein (HDL) (RRR = 0.13; P = 0.025) were significantly associated with C. acnes PJI compared to MSSA-PJI. High or borderline TG (RRR = 0.21; P = 0.041) and low HDL (RRR = 0.17; P = 0.043) were also associated with a greater probability of C. acnes infection compared to no infection. CONCLUSIONS: The presence of elevated TG and low HDL were both associated at a statistically significant level with C. acnes hip or knee PJI compared to controls with either MSSA PJI or no infection. This may represent a specific risk factor for C. acnes PJI that is modifiable.

Rare Bipolaris Species Fungal Periprosthetic Hip Infection in an Immunocompetent Host: A Case Report.

CASE: We present a case report of a 64-year-old man who developed a rare Bipolaris species fungal periprosthetic joint infection (PJI) after revision arthroplasty for complications associated with a metal-on-metal total hip arthroplasty. The patient underwent a 2-stage debridement with antibiotic bead placement and implant retention, along with chronic antifungal suppression. At the 2-year follow-up, the patient remained asymptomatic. CONCLUSION: Fungal PJI with filamentous fungi such as Bipolaris species is a rare clinical entity. This case report highlights the clinical presentation and management of this rare condition.

Procalcitonin as a Predictor of Septic Knee Arthritis: A Retrospective Cohort Study.

INTRODUCTION: Differentiating septic arthritis from aseptic arthritis (AA) of the knee is difficult without arthrocentesis. Although procalcitonin (PCT) has shown diagnostic value in identifying bacterial infections, it has not been established as a reliable marker for identifying septic arthritis (SA). Recent studies have shown promise in the use of PCT as a useful systemic marker for identifying septic arthritis versus AA. This observational retrospective review compares PCT with routine inflammatory markers as a tool for differentiating septic arthritis versus AA in patients with acute, atraumatic knee pain. METHODS: Fifty-three consecutive patients (24 SA, 29 AA) were retrospectively reviewed at one institution with concern for SA. SA was diagnosed based on a physical examination, laboratory markers, and arthrocentesis. Laboratory indices were compared between the septic arthritis and AA groups. Data analysis was conducted to define sensitivity and specificity. Receiver operator characteristic curve analysis and regression were conducted to determine the best marker for acute SA of the knee. RESULTS: Using multiple logistic regression, bacteremia (OR 6.75 ± 5.75) was determined to be the greatest predictor of SA. On linear regression, concomitant bacteremia (coef 3.07 ± 0.87), SA (coef 2.18 ± 0.70), and the presence of pseudogout crystals (coef 1.80 ± 0.83) on microscopy predicted an increase in PCT. Using a PCT cutoff of 0.25 ng/mL yields a sensitivity of 91.7% and specificity of 55.2% for predicting SA; however, the ideal cutoff in our series was 0.32 ng/mL with a sensitivity of 79.2% and specificity of 72.4%. PCT was superior to the white blood cell count, erythrocyte sedimentation rate, and C-reactive protein in the area under the receiver-operating characteristic curve analysis. DISCUSSION: Procalcitonin seems to be the most sensitive and specific systemic marker in differentiating septic from AA.

Debridement, antibiotics and implant retention (DAIR) is successful in the management of acutely infected unicompartmental knee arthroplasty: a case series.

BACKGROUND: Infections are rare and poorly studied complications of unicompartmental knee arthroplasty (UKA) surgery. They are significantly less common compared to infections after total knee arthroplasties (TKAs). Optimal management of periprosthetic joint infections (PJIs) after a UKA is not clearly defined in the literature. This article presents the results of the largest multicentre clinical study of UKA PJIs treated with Debridement, Antibiotics and Implant Retention (DAIR). MATERIALS AND METHODS: In this retrospective case series, patients presenting between January 2016 and December 2019 with early UKA infection were identified at three specialist centres using the Musculoskeletal Infection Society (MSIS) criteria. All patients underwent a standardized treatment protocol consisting of the DAIR procedure and antibiotic therapy comprising two weeks of intravenous (IV) antibiotics followed by six weeks of oral therapy. The main outcome measure was overall survivorship free from reoperation for infection. RESULTS: A total of 3225 UKAs (2793 (86.2%) medial and 432 (13.8%) lateral UKAs) were performed between January 2016 and December 2019. Nineteen patients had early infections necessitating DAIR. The mean follow-up period was 32.5 months. DAIR showed an overall survivorship free from septic reoperation of 84.2%, with overall survivorship free from all-cause reoperation of 78.95%.The most common bacteria were Coagulase-negative Staphylococci, Staphylococcus aureus and Group B Streptococci. Three patients required a second DAIR procedure but remained free from re-infection at follow-up obviating the need for more demanding, staged revision surgery. CONCLUSIONS: In infected UKAs, the DAIR procedure produces a high rate of success, with a high survivorship of the implant.Key messagesDebridement, Antibiotics and Implant Retention (DAIR) is a successful and minimally invasive surgical option for the management of periprosthetic joint infections (PJIs) after UKA.The surface area available for bacteria to colonise is much smaller in UKAs compared to total knee arthroplasties (TKAs), and this may account for the higher success rates of the DAIR procedure in infected UKAs versus infected TKAs.A second DAIR procedure can be considered in the management of the early recurrence of PJIs with a well-fixed UKA.

Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee: a systematic review of the literature.

BACKGROUND: Periprosthetic joint infection (PJI) of the knee represents a severe complication after 1.5% to 2% of primary total knee replacement. Although two-stage revision was considered the gold-standard treatment for PJI of the knee, in the last decades, more studies reported the outcomes of one-stage revisions. This systematic review aims to assess reinfection rate, infection-free survival after reoperation for recurrent infection, and the microorganisms involved in both primary and recurrent infection. MATERIAL AND METHODS: A systematic review of all studies reporting the outcome of one-stage revision for PJI of the knee up to September 2022, according to PRISMA criteria and AMSTAR2 guidelines, was performed. Patient demographics, clinical, surgical, and postoperative data were recorded. PROSPERO ID: CRD42022362767. RESULTS: Eighteen studies with a total of 881 one-stage revisions for PJI of the knee were analyzed. A reinfection rate of 12.2% after an average follow-up of 57.6 months was reported. The most frequent causative microorganism were gram-positive bacteria (71.1%), gram-negative bacteria (7.1%), and polymicrobial infections (8%). The average postoperative knee society score was 81.5, and the average postoperative knee function score was 74.2. The infection-free survival after treatment for recurrent infection was 92.1%. The causative microorganisms at reinfections differed significantly from the primary infection (gram-positive 44.4%, gram-negative 11.1%). CONCLUSION: Patients who underwent a one-stage revision for PJI of the knee showed a reinfection rate lower or comparable to other surgical treatments as two-stage or DAIR (debridement, antibiotics, and implant retention). Reoperation for reinfection demonstrates a lower success compared to one-stage revision. Moreover, microbiology differs between primary infection and recurrent infection. Level of evidence Level IV.

A Comparison of Outcomes of Culture positive and Culture negative Acute Knee Prosthetic Joint Infection following Debridement, Antibiotics and Implant Retention (DAIR).

PURPOSE: We aim to compare the outcome of culture-positive (CP PJI) and culture-negative (CN PJI) acute knee prosthetic joint infection (PJI) following debridement, antibiotics and implant retention (DAIR) with polyethylene insert exchange. We also aim to analyze the factors associated with the successful outcome of DAIR and the influence of failed DAIR on the outcome of subsequent two-stage revision arthroplasty. METHODS: We performed a retrospective review of 36 consecutive patients who underwent DAIR for acute PJI between January 2013 and January 2018. The patient's demographic data, McPherson grade, surgical details, laboratory and microbiology data were retrieved from the medical records. All the patients have been followed up for a minimum of 3 years or until re-operation, revision or death and any complications, incidence of DAIR failure, revision and mortality were noted. RESULTS: The mean follow-up was 4.9 ± 2.4 years. Among the 36 patients, 16 had CP PJI and 20 had CN PJI. Among the 16 patients with CP PJI, 8 patients had success with DAIR and 8 patients had a recurrence of infection (50%) at a mean of 21 months (range, 2 weeks to 55 months). Among the 20 patients with CN PJI, 14 patients had success with DAIR and 6 patients had a recurrence of infection [30% (6/20)] at a mean of 69 months (range, 13-221 months) (p < .05). The Kaplan-Meir survival analysis showed survivorship did not vary significantly between both groups (p > .05). Univariate regression analysis showed symptom duration of more than one month found to be significantly associated with the DAIR failure. There was no difference in failure rate after DAIR between age, Charlson comorbidity index, early postoperative versus acute hematogenous group and type of organism grown. Ten out of 14 DAIR failures were successfully managed with two-stage revision surgery with no recurrence of infection till the final follow-up. In the remaining 4 patients, one underwent re-debridement, two underwent arthrodesis and one was left with an antibiotic cement spacer. CONCLUSION: DAIR with polyethylene exchange will give comparable results irrespective of the culture positivity. Symptom duration of more than 30 days for DAIR is significantly associated with DAIR failure. DAIR failures can be successfully managed with two-stage revision.

Endogenous neutralization of TGF-ß and IL-6 ameliorates septic arthritis by altering RANKL/OPG interaction in lymphocytes.

Septic arthritis is an inflammatory joint disease caused by S. aureus. Hematogenous entry of the bacteria to the synovium produces pro-inflammatory cytokines TGF-ß and IL-6, which alter the Th17/Treg balance. Hence, targeting TGF-ß and IL-6 could be beneficial in ameliorating arthritis. Antibody neutralization of TGF-ß and IL-6 to modulate Th17/Treg homeostasis and RANKL/OPG ratio are not investigated so far in S. aureus-induced septic arthritis. Contribution of synovial lymphocyte-derived cytokines IL-10, IL-12, and CXCL-8; along with OPN, OPG, CRP, cellular ROS, antioxidant enzymes, and the expressions of RANKL, SAPK-JNK, MMP2, SOD, CAT, GPx, TGF-ß and IL-6 were studied in lymphocytes of blood, spleen and synovial tissues of mice treated with antibody against of TGF-ß and IL-6 after induction of septic arthritis. Dual neutralization of TGF-ß and IL-6 is effective in shifting the Th17 cell into immunosuppressive Treg cell of the arthritic mice and enhances the RANKL/OPG interaction leading to the down-regulation of osteoclastic activity and reduces the production of OPN, IL-12, CXCL-8, and CRP. Additionally, it reduces oxidative stress via enhancing the activities of antioxidant enzymes including SOD, catalase, and GPx in lymphocytes. Thus it can be concluded that dual endogenous neutralization of TGF-ß and IL-6 may be chosen as an alternative therapeutic approach for controlling the severity of septic arthritis through Treg-derived IL-10 that could ameliorate the inflammatory consequences of septic arthritis via influencing RANKL/OPG interaction in lymphocytes.

Evaluation of two different semi-automated homogenization techniques in microbiological diagnosis of periprosthetic joint infection: disperser vs. bead milling method.

BACKGROUND: In microbiological diagnosis of periprosthetic joint infection (PJI) there is no consensus regarding the most suitable and optimal number of specimens to be cultured or the most effective technique of tissue processing. This comparative study analysed the accuracy of two semi-automated homogenization methods with special focus on the volume and exact origin of each sample. METHODS: We investigated a total of 722 periprosthetic tissue samples. PJI was defined according to the new scoring system for preoperative and intraoperative criteria. We compared the performance of our routinely used single tissue processing by disposable high-frequency disperser with the bead milling method. RESULTS: Eighty patients were included. Among forty classified PJIs, 34 patients yielded positive culture results. In 23 cases (68%) exact concordant results were generated with both techniques. However, in seven cases (20%) processing by the disperser and in four cases (12%) by bead milling provided additional positive samples, but without significant difference since the major definition criteria were met in all cases. The percentage of positive results was influenced by the volume and origin of the tissue samples. Results for small tissue samples tended to be better using the bead milling method. This might lead to improved preoperative arthroscopic diagnosis, as the volume of biopsies is generally limited. Six patients had negative results due to previous antimicrobial therapy. Forty other patients were classified as aseptic failures. Neither procedure resulted in any contamination. CONCLUSION: Both methods enable reliable processing of tissue samples for diagnosis of PJI and are suitable for routine use.

A recurrent prosthetic joint infection caused by Erysipelothrix rhusiopathiae: case report and literature review.

Prosthetic knee joint infection caused by Erysipelothrix rhusiopathiae is uncommon and only one case of recurrent infection has previously been described. Here, we describe the case of a 77-year-old male patient who was admitted to the teaching hospital of Rennes (France) with bilateral and nocturnal gonalgia evolving for 1 month. He had bilateral knee prosthesis 10 years ago, and a history of large B-cell lymphoma in remission. A diagnosis of infective endocarditis, with prosthetic knee infection, was made, with positive cultures of synovial fluids and blood; colonies of E. rhusiopathiae were identified by MALDI-TOF MS. Initial treatment involved debridement, implant retention surgery and intravenous amoxicillin (12 g day-1) for 6 weeks with gentamicin 3 mg kg-1 day-1 added for the first 4 days. One year later, a second episode of E. rhusiopathiae infection occurred, suggesting a recurrence or reinfection due to the same bacterial species. The patient was finally cured after a two-stage exchange with a cemented articulated spacer and a 3 month course of amoxicillin (12 g day-1, iv). Different characteristics of E. rhusiopathiae infection were discussed, with a review of all cases of prosthetic joint infections caused by Erysipelothrix species. This case highlights the need for a long-term survey of patients, and a good knowledge of their environment to avoid any risk of reinfection.

Fungal Osteomyelitis due to Phaeoacremonium venezuelense: A Case Report.

CASE: A 56-year-old immunosuppressed man presented with pain and swelling in the medial and anterior right foot with accompanied numbness in the second and third toes 1 month after a puncture wound by a Sylvester palm tree thorn. An intraoperative culture/biopsy returned positive for septic arthritis of the naviculocuneiform joint and fungal osteomyelitis of the navicular, medial, and intermediate cuneiforms due to Phaeoacremonium venezuelense. CONCLUSION: Fungal osteomyelitis is extremely rare. Only 5 cases by Phaeoacremonium venezuelense have been reported previously in the literature. To the best of our knowledge, this is the first case of osteomyelitis by this strain.

Factors associated with late microbiological documentation of prosthetic joint infection.

Purpose: To describe the number of prosthetic joint infections (PJIs) with late documentation and to identify associated factors. Methods: Bacterial PJIs with surgical management between November 2015 and November 2019 in a French center were analyzed. Results of short (72 h) and late culture (at 14 days) were analyzed. Results: A total of 160 PJIs were reported with 215 bacteria. Twenty-nine patients had late documentation (18.1%). The bacteria most involved were coagulase-negative staphylococci and Cutibacterium spp. (60%). In multivariate analysis, late chronic PJI (odds ratio = 2.47) and antibiotic therapy before surgery (odds ratio = 3.13) were associated with late-documented infection. Conclusion: A better knowledge of the factors associated with late-documented infections is essential in order to simplify antibiotic treatment at the appropriate time.

Prosthetic joint infections (PJIs) are rare and occur in around 1% of cases. They are often complex and require multidisciplinary management. The identification of bacteria and the implementation of an effective intravenous antibiotic therapy as soon as the surgery is performed are important points in PJI management. Some bacteria take longer to be cultivated, which is why samples are cultured for at least 14 days after surgery. As soon as the bacteria have been identified, the antibiotic therapy can be taken orally to allow the patient to be discharged early from hospital. The aim of this study was to investigate the factors associated with a positive late culture (day 14 after surgery) compared with an early culture (day 3). We showed that patients who had received antibiotic therapy within 1 month before surgery and patients with chronic PJI (i.e., more than 1 year after surgery) were at greater risk of having long-culture-positive specimens. We also showed that late samples were more often positive for two types of bacteria (Cutibacterium acnes and coagulase-negative staphylococci). In practice, when early samples are positive, oral antibiotics are given rapidly, except for patients who have had prior antibiotic therapy or who have a chronic infection for whom other samples may be positive late (14 days). Moreover, in patients with negative early culture, oral antibiotic therapy active against Cutibacterium acnes and coagulase-negative staphylococci (the two main bacteria in late culture) could be prescribed, waiting for the result of late culture.

Case report of arthritis caused by Legionella anisa and review of the literature.

BACKGROUND: Legionella spp. is recognized as a common cause of community acquired pneumonia, with Legionella pneumophila serogroup 1 being the most prevalent. At least 70 species are described so far but few are identified in pathogenic conditions. Data on extrapulmonary infections are scarce. CASE PRESENTATION: A 73-yar-old male with chronic lymphoid leukemia was hospitalized for an insidious wrist arthritis. Ultrasound of the wrist showed a carpal and radiocarpal fluid effusion with positive Doppler signal. While routine bacterial cultures remained sterile, 16S rRNA PCR identified Legionella anisa. Ciprofloxacin 500 mg twice a day for a period of six weeks improved arthritis with full recovery at the end of the treatment. CONCLUSION: Legionella non pneumophila are a rare cause of septic arthritis especially found in immunosuppressed patients and identification of species could help clinician to adapt antibiotherapy.

Human transcriptomic response to periprosthetic joint infection.

Periprosthetic joint infection (PJI), a devastating complication of total joint replacement, is of incompletely understood pathogenesis and may sometimes be challenging to clinically distinguish from other causes of arthroplasty failure. We characterized human gene expression in 93 specimens derived from surfaces of resected arthroplasties, comparing transcriptomes of subjects with infection- versus non-infection-associated arthroplasty failure. Differential gene expression analysis confirmed 28 previously reported potential biomarkers of PJI, including bactericidal/permeability increasing protein (BPI), cathelicidin antimicrobial peptide (CAMP), C-C-motif chemokine ligand 3 (CCL3), 4(CCL4) and C-X-C-motif chemokine ligand 2 (CXCL2), colony stimulating factor 2 receptor beta (CSF2RB), colony stimulating factor 3 (CSF3), alpha-defensin (DEFA4), Fc fragment of IgG receptor 1B (CD64B), intercellular adhesion molecule 1 (ICAM1), interferon gamma (IFNG), interleukin 13 receptor subunit alpha 2 (IL13RA2), interleukin 17D (IL17D), interleukin 1 (IL1A, IL1B, IL1RN), interleukin 2 receptors (IL2RA, IL2RG), interleukin 5 receptor (IL5RA), interleukin 6 (IL6), interleukin 8 (IL8), lipopolysaccharide binding protein (LBP), lipocalin (LCN2), lactate dehydrogenase C (LDHC), lactotransferrin (LTF), matrix metallopeptidase 3 (MMP3), peptidase inhibitor 3 (PI3), and vascular endothelial growth factor A (VEGFA), and identified three novel molecules of potential diagnostic use for detection of PJI, namely C-C-motif chemokine ligand CCL20, coagulation factor VII (F7), and B cell receptor FCRL4. Comparative analysis of infections caused by staphylococci versus bacteria other than staphylococci and Staphylococcus aureus versus Staphylococcus epidermidis showed elevated expression of interleukin 13 (IL13), IL17D, and MMP3 in staphylococcal infections, and of IL1B, IL8, and platelet factor PF4V1 in S. aureus compared to S. epidermidis infections. Pathway analysis of over-represented genes suggested activation of host immune response and cellular maintenance and repair functions in response to invasion of infectious agents. The data presented provides new potential targets for diagnosis of PJI and for differentiation of PJI caused by different infectious agents.

Immunomodulatory effects of berberine on Staphylococcus aureus-induced septic arthritis through down-regulation of Th17 and Treg signaling pathways.

OBJECTIVES: The preseaant study was aimed to investigate the immunomodulatory effects of berberine on Staphylococcus aureus-induced septic arthritis through the downstream signaling mechanism of Th17 and Treg, in the control and prevention of disease progression of Staphylococcus aureus induced septic arthritis of blood, spleen and synovial joints. METHODS: The study was conducted in mice induced with septic arthritis by S. aureus for 15 days. The infected mice were treated with berberine (50 or 100 or 200 mg/Kg) to evaluate the effects on the isolated cells of Th17 and Treg from synovial joints, blood and spleen against the septic arthritic induced mice followed by JNK, RANKL and NF-κB expressions in the lysates of Th17 and Tregs isolated cells. The evaluation of serum IL-21 and TGF-ß levels was also conducted after 15 days post-infection in Th17 and Treg population. RESULTS: Our findings showed that berberine exerted excellent inhibitory effects on the S. aureus (AS-789) strain for inducing sepsis-induced arthritis. The results from the S. aureus testing revealed that at concentrations below 640 µg/mL, the strain was more resistant to berberine, as it had an increased rate of growth. The assessment of S. aureus induced septic arthritis (joint swelling and arthritis index) substantial reduction in the joint swelling and arthritis index (p<0.01) in the berberine-treated groups. The percentage of Th17 cells with CD4 and RORγt; Treg cells with CD4, CD25 and FOXp3 in the synovial joints, blood and spleen was substantially declined in the drug-treated groups (p<0.01) as compared to the S. aureus infected mice. The TGF-ß and IL-21 serum levels determinations in S. aureus induced septic arthritis revealed a substantial decrease in serum TGF-ß levels (p<0.01) in drug-treated groups compared to the infected animals. The post hoc test revealed a substantial decrease in JNK, NF-κB and RANKL expressions in the lysates of Th17 and Treg isolated cells in the drug-treated animals (p<0.01) when compared to the S. aureus-infected cluster. CONCLUSION: Our findings demonstrated that a possible strategy for combating disease severity with berberine treatment in Staphylococcus aureus induced septic arthritis in mice, which targets the Th17 and Treg cells have driven the NF-κB/JNK-RANKL axis.

Septic arthritis of the fingers: is short-term oral antibiotic therapy appropriate?

The management of septic arthritis of the hand is poorly described and there is no consensus. It is based on how septic arthritis of the large joints is managed, despite certain specificities related to the hand, typically involving inpatient management and intravenous antibiotic therapy. The primary objective of this work was to evaluate our postoperative protocol for the management of septic arthritis of the hand with short-term antibiotic therapy. The secondary objective was to determine the risk factors for treatment failure. We conducted a retrospective, descriptive, single-center study and analyzed the medical records of patients managed for septic arthritis of the fingers over a 1-year period from January 2018 to December 2018. We collected patient demographics and all pre-, intra-, and postoperative data. A total of 128 patients were included. The median age was 52.4 years (41-66). An exogenous source of contamination was reported in 98% of cases (animal bite, plant thorn, wound, cyst trituration, etc.). The most frequently isolated microorganism was Staphylococcus aureus (45%), followed by Streptococcus spp. (22%) and Pasteurella spp. (18%). The vast majority of patients (79%) were treated with oral amoxicillin/clavulanic acid. This treatment was continued in 91% of patients after microbiological results were obtained for a median treatment duration of 8 days (7-15). Nine percent of patients failed treatment. The risk factors identified were crush wounds (p = 0.04), initial radiological abnormalities (chondrolysis and/or osteolysis) (p = 0.016) and infection with Pasteurella spp. (p = 0.015). Our study suggests that simplified antibiotic therapy is feasible for the management of septic arthritis of the hand with short duration, broad spectrum oral antibiotics in the absence of identified risk factors.

Meta-analysis of synovial fluid polymerase chain reaction for diagnosing periprosthetic hip and knee infection.

BACKGROUND AND OBJECTIVE: The purpose of this study was to estimate the diagnostic performance of synovial fluid polymerase chain reaction (PCR) in periprosthetic hip and knee infection, and whether synovial fluid PCR has greater diagnostic significance than conventional methods. METHODS: The literature databases PubMed, Scopus, and the Web of Science were searched for English articles describing periprosthetic joint infection (PJI) diagnosis by synovial fluid PCR. Articles were limited to the period between January 1990 and December 2019. Subsequently, conventional methods that were used on at least two occasions were included for further analysis. Data analysis was performed using the Meta-DiSc and Stata software. RESULTS: Eleven studies with 1360 cases were included in the meta-analysis. The pooled sensitivity, specificity, and diagnostic odds ratio (DOR) of synovial fluid PCR were 0.70 (95% CI 0.66-0.74), 0.92 (95% CI 0.90-0.93), and 37.4 (95% CI 17.77-78.74), respectively. CONCLUSIONS: Synovial fluid PCR provides an effective tool for rapid diagnosis of PJI, and also in the early stages of culture-negative bacterial infections.

Microbiological pathogen analysis in native versus periprosthetic joint infections: a retrospective study.

BACKGROUND: The presence or absence of an implant has a major impact on the type of joint infection therapy. Thus, the aim of this study was the examination of potential differences in the spectrum of pathogens in patients with periprosthetic joint infections (PJI) as compared to patients with native joint infections (NJI). METHODS: In this retrospective study, we evaluated culture-positive synovial fluid samples of 192 consecutive patients obtained from January 2018 to January 2020 in a tertiary care university hospital. For metrically distributed parameters, Mann-Whitney U was used for comparison between groups. In case of nominal data, crosstabs and Chi-squared tests were implemented. RESULTS: Overall, 132 patients suffered from periprosthetic joint infections and 60 patients had infections of native joints. The most commonly isolated bacteria were coagulase-negative Staphylococci (CNS, 28%), followed by Staphylococcus aureus (S. aureus, 26.7%), and other bacteria, such as Streptococci (26.3%). We observed a significant dependence between the types of bacteria and the presence of a joint replacement (p < 0.05). Accordingly, detections of CNS occurred 2.5-fold more frequently in prosthetic as compared to native joint infections (33.9% vs. 13.4% p < 0.05). In contrast, S. aureus was observed 3.2-fold more often in NJIs as compared to PJIs (52.2% vs. 16.4%, p < 0.05). CONCLUSION: The pathogen spectra of periprosthetic and native joint infections differ considerably. However, CNS and S. aureus are the predominant microorganisms in both, PJIs and NJIs, which may guide antimicrobial therapy until microbiologic specification of the causative pathogen.

Globulin and albumin to globulin ratio precisely diagnose periprosthetic joint infection and determine the timing of second-stage reimplantation.

BACKGROUND: Periprosthetic joint infection (PJI) is one of the most challenging complications of total joint arthroplasty (TJI). An early and accurate diagnosis of PJI is associated with better treatment outcomes. However, whether the platelet-related markers and globulin-related markers can be used to assist the diagnosis of PJI remains elusive. METHODS: A total of 206 patients who underwent revision hip or knee arthroplasty in our institution were divided into two groups: 79 patients in PJI group and 127 patients in aseptic failure group. The levels of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), platelet-related markers including platelet count (PLT), mean platelet volume (MPV), plateletcrit (PCT) and PLT to MPV ratio (PMR) and globulin-related markers such as globulin (GLB), albumin to globulin ratio (AGR) and PLT to AGR ratio were compared. The diagnostic value was measured using area under the curve (AUC) after constructing receiver operating characteristic (ROC) curves. The potential of each marker for determining the timing of second-staged reimplantation was also evaluated. RESULTS: Significantly increased levels of ESR, CRP, PLT, PCT, PMR, GLB and PLT to AGR ratio were identified in PJI group, while decreased levels of MPV and AGR were also found. The diagnostic values of all platelet-related markers and GLB were considered as fair, and good diagnostic values of AGR and PLT to AGR ratio were found, which were comparable to those of ESR and CRP. The levels of GLB and AGR can also be used to predict negative culture result and the timing of second-stage reimplantation. CONCLUSIONS: Globulin and albumin to globulin ratio were found to have good diagnostic values for PJI, and they can precisely predict the culture results and persistent infection.

The Great Masquerader - TB Osteoarthritis.

OBJECTIVES: TB arthritis is a rarely reported entity in Western literature and its ability to masquerade as many other diseases makes it difficult to diagnose. We report an interesting case of TB arthritis of the ankle. METHODS: We present a 44 year-old diabetic Chinese male with a recent history of worsening pain, swelling, and redness in his left foot with an abscess and X-ray findings consistent with Charcot foot. RESULTS: At first, the presentation was believed to be Charcot's foot with MSSA osteomyelitis but after the wound culture and bone biopsy were both positive for Mycobacterium tuberculosis as well, the diagnosis of tuberculous arthritis was confirmed. CONCLUSIONS: While the prevalence of TB and other diseases is low in the majority of the United States, we still need to be aware of such diseases in populations with increasing migration and be cognizant of the potential impact of a patient's background on a diagnosis is critical to properly diagnosing and treating patients. Vascular surgeons may be seeing patients with abscesses of the lower extremities and may miss the diagnosis if cultures for TB are not sought.

Fast and specific detection of staphylococcal PJI with bacteriophage-based methods within 104 sonicate fluid samples.

The number of prosthetic joint infection (PJI) cases is increasing along with total joint arthroplasties. There is currently no diagnostic test available with 100% sensitivity to identify PJI. The aim of the study was to assess and compare two different bacteriophage K-based methods with standard microbiological culturing methods to detect staphylococci. Samples were retrieved from 104 patients undergoing revision surgery due to suspected PJI. Implants were subjected to sonication and sonicate fluid (SF) was assessed with the methods of qPCR detection of bacteriophage K DNA and adenosine triphosphate (ATP) detection after bacteriophage K lysis. The results were compared with the results of standard microbiological culturing methods. PJI was confirmed in 33 cases according to the PJI definition. Using the methods of ATP and bacteriophage K DNA detection 100% specificity and predictive value were achieved. The sensitivity of qPCR detection was higher (81.25%) than the sensitivity of ATP detection (62.50%) when analyzing SF directly. The sensitivity of the methods significantly improved (to 94.12%) with SF pre-cultivation. Importantly, both methods provided results in 3-4 h when analyzing SF directly, while results from pre-cultivated SF were obtained 19-20 h after sample collection. Our results suggest that bacteriophage-based methods are specific and sensitive and importantly, faster than standard culturing methods. The addition of new bacteriophages to expand the bacterial detection spectrum could lead to the development of a faster, more sensitive, specific, and also economical, and handy method for PJI diagnosis.