Aim. As the populations of patients who have multiple prosthetic joints increase these years, the fate of a single joint periprosthetic joint infection in these patients is still unknown. Risk factors leading to a subsequent infection in another prosthetic joint are unclear. Our goal is to identify the risk factors of developing a subsequent infection in another prosthetic joint and describe the organism profile to the second prosthetic infection. Method. We performed a retrospective cohort study of all PJI cases underwent surgical intervention at our institute, a tertiary care referral center over 11 years, during January 2006 to December 2016. We identified 96 patients with periprosthetic joint infection who had another prosthetic joint in place at the time of presentation. The comorbidity, number of prosthetic joints, date and type of each arthroplasty, times of recurrent infection at each prosthetic joint with subsequent debridement or 2-stage resection arthroplasty, organisms from every infection episode, the outcome of each periprosthetic joint infection in these patients were analyzed. Results. During January 2006 to May 2017, we retrospective collected 294 PJI cases (159 hips, 135 knees) in our institute. Patients with single prosthetic joint were excluded and finally 96 patients were included. Of the 96 patients, 19 (19.79%) developed a periprosthetic joint infection in a second joint. The type of organism was the same as the first infection in 12 (63.16%) of 19 patients. The time to developing a second infection averaged 2.16 years (range, 0–9.3 years). The risk factors leading to a subsequent infection in another prosthetic joint are albumin level (< 3.5 mg/dl), long-term steroid usage (> 5mg/day, > 3 months), history of necrotizing fasciitis, history of invasive dental procedure (> Grade IV procedure), 3-stage resection arthroplasty or more, and PJI caused by vacomycin-resistent enterococcus (VRE). Conclusions. A PJI might predispose patients to subsequent PJI in another prosthesis. Patients and surgeons must be aware of the risk factors contribute to this devastating complication. Most organisms in the second PJI are identical to the first one, and we believe the bacteremia may be the pathogenesis, but need further proved. The preventive policy may be needed in the future for this population who has multiple prosthetic joints

Aim. metagenomic next-generation sequencing (mNGS) has shown to be a useful method for pathogen detection in prosthetic joint infections (PJI). The technique promises to minimize the PJIs without the known causative agent. Our study aimed to compare diagnostic accuracies of cultures and mNGS. Method. In this study, a meta-analysis following PRISMA recommendations was performed. PubMed and OVID Medline databases were used for article search. The studies using mNGS whole-genome sequencing method and the ones where PJI diagnosis was based on one of the currently recognized criteria were included. Studies were excluded if they comprised less than twenty cases, the ones with insufficient data for the analyses (true positive, true negative, false positive and false negative values for both mNGS and culture results) and publications with strong duplication bias. Univariate metanalysis using a random-effect model has been performed in R studio with a “meta” package. Pooled sensitivity and pooled specificity were calculated. Results. Seven studies with a total of 822 cases were included in the meta-analysis, 476 cases defined as PJI and 346 controls. Two studies used IDSA (Infectious Diseases Society of America) diagnostic criteria and the Illumina HiSeq 2500 platform for sequencing and five studies used MSIS (MusculoSkeletal Infection society). Four of those used the BGISEQ-500 sequencing platform. For one study there was no data available. Studies were performed on prosthetic hip and knee joints. Through meta-analysis, it was observed that mNGS technique is more sensitive than cultures with 90% (CI 79%– 95%) and 74% (CI 68%-79%) respectively (p=0.006). The specificity between methods was similar, for mNGS reaching 94% (CI 89%-96%) and for cultures 97% (CI 90%-99%) (p=0.285). In the PJI group, 117 new possible pathogens that were not isolated by microbiological culture were detected by the mNGS, most frequently anaerobes and coagulase-negative staphylococci both in 20/117 (17.1%) cases. Fourteen new organisms were detected in the control group and were mostly regarded as contaminants. Conclusions. Metagenomic sequencing has shown to be more sensitive than microbiological cultures in pathogen detection and thus has a great potential to improve the diagnosis and treatment of PJI. More studies on different prosthetic joints and comparing different diagnostic criteria for PJI would be needed to better understand the true diagnostic power of this method

Collection of 4–5 independent peri-prosthetic tissue samples is recommended for microbiological diagnosis of prosthetic joint infections. Sonication of explanted prostheses has also been shown to increase microbiological yield in some centres. We compared sonication with standard tissue sampling for diagnosis of prosthetic joint and other orthopaedic device related infections. We used standard protocols for sample collection, tissue culture and sonication. Positive tissue culture was defined as isolation of a phenotypically indistinguishable organism from ≥2 samples; and positive sonication culture as isolation of an organism at ≥50 cfu/ml. We compared the diagnostic performance of each method against an established clinical definition of infection (Trampuz 2011), and against a composite clinical and microbiological definition of infection based on international consensus (Gehrke & Parvizi 2013). 350 specimens were received for sonication, including joint prostheses (160), exchangeable components (76), other orthopaedic hardware and cement (104), and bone (10). A median of 5 peri-prosthetic tissue samples were received from each procedure (IQR 4–5). Tissue culture was more sensitive than sonication for diagnosis of prosthetic joint and orthopaedic device related infection using both the clinical definition (66% versus 57%, McNemar's Χ2 test p=0.016) and the composite definition of infection (87% vs 66%, p<0.001). The combination of tissue culture and sonication provided optimum sensitivity: 73% (95% confidence interval 65–79%) against the clinical definition and 92% (86–96%) against the composite definition. Results were similar when analysis was confined to joint prostheses and exchangeable components; other orthopaedic hardware; and patients who had received antibiotics within 14 days prior to surgery. Tissue sampling appears to have higher sensitivity than sonication for diagnosis of prosthetic joint and orthopaedic device infection at our centre. This may reflect rigorous collection of multiple peri-prosthetic tissue samples. A combination of methods may offer optimal sensitivity, reflecting the anatomical and biological spectrum of prosthetic joint and other device related infections

Aim. Prompt recognition and identification of the causative microorganism in acute septic arthritis of native and prosthetic joints is vital to increase the chances of successful treatment. The aim of this study was to independently assess the diagnostic accuracy of the multiplex BIOFIRE® Joint Infection (JI) Panel (investigational use only) in synovial fluid for rapid diagnosis. Method. Synovial fluid samples were prospectively collected at the University Medical Center Groningen from patients who had a clinical suspicion of a native septic arthritis, early acute (post-operative, within 3 months after arthroplasty) periprosthetic joint infection (PJI) or late acute (hematogenous) PJI. JI Panel results were compared to culture-based methods as reference standard. Results. A total of 45 samples were analyzed. The BIOFIRE JI Panel showed a high specificity (100%, 95% CI 73 – 100) and positive predictive value (100%, 95% CI 79 – 100) in all patient categories. Sensitivity and negative predictive value were 83% (95% CI 36 – 99) and 88% (95% CI 47 – 99) respectively for patients with a clinical suspicion of native septic arthritis (n=12), 77% (95% CI: 46 – 94) and 63% (95% CI: 26 – 90) for patients with a clinical suspicion of a late acute PJI (n=14), and 27% (95% CI 7 – 61) and 27% (95% CI: 7 – 61) for patients with a clinical suspicion of an early acute PJI (n=19). Conclusions. The results of this pilot study indicate a clear clinical benefit of the BIOFIRE JI Panel in patients with a suspected native septic arthritis and late acute (hematogenous) PJI, but a low clinical benefit in patients with an early acute (post-operative) PJI due to the absence of low-grade microorganisms in the panel

Background. Currently, the gold standard for the microbiological diagnosis remains the culturing of preoperative aspirated joint fluid and intraoperative periprosthetic tissue samples, which give false negative results in about 7 % of cases. Lytic bacteriophages are viruses that specifically infect and lyse bacteria within their replication cycle. Aim. The aim of our study was to explore possibilities for the use of bacteriophage K for the detection of live Staphylococcus spp. bacteria in sonicate fluid of infected prosthetic joints, to possibly contribute to the development of a faster, more sensitive, specific and at the same time economical and handy method for the establishment of the right diagnosis. Material and methods. Sonicate fluid samples obtained from 104 patients with revision arthroplasty were analysed. After the optimisation two indirect phage-based methods were used: a) bioluminescence detection of bacterial intracellular ATP released by bacteriophage K mediated lysis and b) q-PCR with primers specific for bacteriophage K DNA. The results were compared with classical microbiological cultivation methods. Results. With both methods the analysis of sonicate fluid and the analysis of its over-night culture achieved 100 % specificity and predictive value, as there were no false positive results. The sensitivity of the methods was lower when analysing sonicate fluid samples directly, without cultivation. The sensitivity of qPCR detection was higher (81.25 %) compared to the sensitivity of ATP detection (62.5 %) in sonicate fluid directly as a result of 3 false negative results with the qPCR method compared to 6 false negatives with the ATP detection method. The sensitivity of the methods was significantly improved (to 94.12 %) with overnight cultivation of sonicate fluid samples prior to analysis, with no difference in detection between the methods. With both methods, with pre-cultivation of sonicate fluid samples, only one of the tested samples resulted in a false negative result. However, the same sample was negative even when tested with standard microbiological methods. In this patient, only the microbiological cultivation of the periprosthetic tissue sample was positive. The bioluminescence method took 3h with a limit of detection (LOD) in the bacterial concentration range of 10. 3. CFU/mL. The method with qPCR took 4h and had a LOD of 10. 2. CFU/mL. Conclusion. Detection of staphylococci within sonicate fluid with bacteriophage K based methods is a rapid, sensitive and specific approach

Implementation of new diagnostic methods (i.e. MALDI-TOF MS) has made it possible to identify coagulase-negative staphylococci (CoNS) to species level in routine practice. Further knowledge about clinical and microbiological characteristics of prosthetic joint infections (PJIs) caused by different CoNS may both facilitate interpretation of microbiological findings and improve clinical algorithms. The aim of this study was clinical and microbiological characterization of PJIs caused by Staphylococcus capitis. Patients with PJIs caused by S. capitis (growth in ≥2 perioperative tissue samples, n=19, identified by MALDI-TOF MS) from three centres between 2005–2014 were included. Medical records were examined (n=16). Further characterization of S. capitis was performed; rep-PCR (Diversilab, BioMerieux), standard antibiotic susceptibility testing, GRD Etest and macromethod Etest for detection of heteroresistant subpopulations and microtitre plate assay for detection of biofilm production. Multi-drug resistant (MDR) S. capitis (R≥3 antibiotic groups) was detected in 5/19(26%) of isolates, 1/19(5%) were ciprofloxacin resistant and no isolates was rifampin resistant. Biofilm formation was present in 14/19(74%). The dendrograms created by rep-PCR showed two distinct clusters, including one that contained isolates from all centres, as well as the reference isolates. Furthermore, three additional clusters were identified, all of these mainly obtained from single centres. In two of these, MDR was highly prevalent. In one of these clusters, 4 of the 8 strictly monomicrobial infections were found. All of the PJIs were defined as either early postinterventional (10/16) or chronic (6/16). No late haematogenous infection was found. The highest CRP values were reported in monomicrobial infections. Wound healing disturbances was noted in 8/10 early postinterventional infections. Fever was absent in chronic infections, sinus tracts rare (1/6), while pain was a common symptom (5/6). S. capitis has the potential to cause PJIs, both by itself as well as part of a polymicrobial infection. The antibiotic susceptibility patterns were more favourable than has previously been reported in S. epidermidis isolated from PJIs(1). Clinical data suggests that PJIs caused by S. capitis were acquired perioperatively or in the early postoperative phase. The clustering found by rep-PCR together with data showing high prevalence of S. capitis in the air of operation rooms during prosthetic joint surgery(2) implicates that nosocomial spread might be present. Epidemiological surveillance may be of value in order to ensure early detection of nosocomial transmission. Grants were received from the research committees of Värmland County Council and Örebro University, Sweden

Aim. C-reactive protein(CRP) and erythrocyte sedimentation rate(ESR) are non-specific markers with variable reported accuracy in the diagnosis of prosthetic joint infection(PJI). They are often used as a part of the initial diagnostics as they are widely available and inexpensive. Given its high false-negative rate, CRP is an insufficient screening tool for PJI especially in low virulence microorganisms. Nevertheless, many advocate ESR offers no added advantage and is useless in this setting. Our goal is to determine if the combined measurement of ESR and CRP offers increased sensitivity for the preliminary screening of PJI over isolated CRP measurement. Method. We retrospectively evaluated every single- or first-stage for presumed aseptic or known infected revision total hip/knee arthroplasty procedures between 2013–2018. Cases without preoperative CRP and ESR measurement as well those without synovial fluid for differential leukocyte count and/or no multiple cultures including sonication of removed implant obtained during surgery were excluded. Diagnostic accuracy was compared against two different PJI definitions: 2013 International Consensus Meeting and ProImplant Foundation definitions. Results. A total of 398 revision were performed during the study period. After excluding 293 cases with insufficient information, a total of 105 patients were studied. Naturally, CRP and ESR mean values were significantly higher among PJI cases compared to aseptic cases. When compared against 2013 International Consensus Meeting definition, CPR has a sensibility 86.5% (45/52) that increases to 94.2% (49/52) with the combined measurement (ESR and CRP). The sensitivity also increased when compared against the ProImplant Foundation definition (72.6% (45/62) vs 85.5% (53/62)). Conclusions. After the inciting insult, CRP raises and drops rapidly and ESR response is slower but also much more enduring. One can only hypothesize that chronic PJI runs perhaps a fluctuating inflammatory course that can sometimes be more accurately picked up by ESR and not CRP measurement. Our results seem to corroborate that ESR measurement is a valid adjunct to isolated CRP measurement in the initial screening of PJI in painful total joint arthroplasties

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The analysis of synovial fluid has proved to be of crucial importance in the diagnostic process of prosthetic joint infections (PJI), suggesting the presence of an infection before the microbiological culture results. In this context, several studies illustrated the efficacy of synovial calprotectin in supporting the diagnosis of PJI [1, 2]. However, several testing methods have been explored to detect synovial calprotectin levels, emphasizing the need to use a standardized, rapid and rapid test.

In this study, synovial calprotectin was analyzed by means of a commercial stool test [3] to explore whether the detected levels might predict PJIs and, therefore, being a promising tool for the fast and reliable diagnosis of this complication.

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Prosthetic joint infection (PJI) due to Candida spp. is a severe complication of arthroplasty but is little reported. This study describes Candida PJI epidemiology, management, and outcome.

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There is growing evidence that bacteria encountered in periprosthetic joint infections (PJI) form surface-attached biofilms on prostheses, as well as biofilm aggregates embedded in synovial fluid and tissues. However, models allowing the investigation of these biofilms and the assessment of their antimicrobial susceptibility in physiologically relevant conditions are currently lacking. To address this, we developed a synthetic synovial fluid (SSF) model and we validated this model in terms of growth, aggregate formation and antimicrobial susceptibility testing, using multiple PJI isolates.

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Prosthetic joint infection (PJI) represents the second most frequent complication of total joint arthroplasty (TJA) with up to 20% of low-grade PJI treated as aseptic failure. Sensitive diagnostic criteria have been provided by EBJIS. However, to date there is no single test to reliably diagnose all PJIs. Studies of Mazzucco et al. and Fu et al. suggest that synovial fluid (SF) viscosity could be considered as an important marker for PJI. The primary aim of our study was to determine if SF viscosity is a more reliable diagnostic criterion of PJI than the SF cell count with differential (CCD), and the combined diagnostic value of SF viscosity and CCD.

Aim. Diagnosing prosthetic joint infections(PJI) is sometimes difficult. Being able to identify the bacteria involved in intraoperative samples is an essential diagnostic criterion. There are however some cases in which the traditional cultures are not capable of providing a definitive diagnosis. In this regard, implant sonication has emerged as a complementary test. The aim of this study was to analyze the results of microbiological studies obtained with and without implants sonication, in order to understand its real contribution to diagnosis. Method. We retrospectively evaluated all cases of infected total hip or knee arthroplasty surgically treated between January 2009 and December 2013. The definition of infection met the criteria set out recently in the international consensus meeting. The number and type of bacteria identified in each patient and the type of microbiological study made were registered. Two different groups were created, with and without sonication, and the results were compared. Results. In a total of 93 patients with PJI, there were only three cases (3.2%) in which we failed to isolate any microorganism. In the 41 cases in which sonication was not used, 54 different microorganisms (an average of 1.32 per patient) were found and no microorganism was found in two cases (4.9%). In the 52 patients in whom sonication was used, we identified 74 different microorganisms (an of average 1.42 per patient) and only one case (1.9%) of negative cultures. In 25 patients (27 microorganisms) there was complete correspondence between the findings of sonication and traditional tissue culture. In 22 cases, 34 different microorganisms were found in tissue samples and sonication offered negative cultures. On the other hand, there were four patients in with 13 microorganisms were identified in sonication with negative tissue cultures. Conclusions. An analysis made in our institution several years ago, showed a percentage of culture negative PJI of almost 20%. Since then, several changes have been introduced in our clinical practice. Of these, sonication, whose value has been amply demonstrated in the literature, is the most demanding in terms of logistics. The authors believe that the implementation and especially the widespread adoption of simple rules for proper sampling is effective for a significant reduction in cases where it is not possible to isolate any microorganism in PJI's. We believe sonication should be seen as an additional diagnostic tool that contributes to increasing sensitivity but should not be considered a substitute for traditional study

Aim

There is a constant increase of total joint arthroplasties to improve the quality of life of an aging population. Prosthetic-joint infections are rare, with an incidence of 1–2%, but they represent serious complications in terms of morbidity and mortality. Different therapeutic options exist, but the role of the surgeon's experience has never been investigated. The aim of this retrospective study is to assess the infection eradication success rate depending on the involvement of a septic surgeon.

A Prosthetic Joint infection (PJI) is an orthopedic disaster. There is a direct correlation between persistent wound drainage (>72 hours) and the development of a PJI. It is unknown if early wound drainage (<12 hours) is correlated with PJI. We included 753 consecutive patients treated with a Total Hip Arthroplasty (THA) or Total Knee Arthroplasty (TKA) operated between December 2012 and December 2013. All patients were treated according to our local fast track joint surgery protocol. We retrospectively analyzed the prospectively collected data on wound drainage and PJI. The diagnosis PJI was established according to the definition by the International Consensus Group on Prosthetic Joint Infections. Per PJI-case, two control-cases were matched on type of surgery (THA or TKA) and day of surgery. Analysed variables were co-morbidities, medication, use of drains, haematoma, wound drainage and dressing changes. Statistical analysis was done using Kaplan Meier logistic regression with statistic significance set at p<0.005. In 753 included patients, 25 PJI-cases were identified and 50 controls were matched. Cases had significant more wound drainage (88% vs 36% P=0.001)) and wound dressing changes (56% vs 18% P=0.006) in the direct postoperative phase (<12 uur postoperative). Cases had more haematoma (44% vs 10% P=0.005). We found no association between PJI and co-morbidity, medication and use of drains. We found that wound drainage directly postoperative (<12hr) correlated with PJI. We believe that direct post operative drainage is of crucial importance in the development of PJI and inhibition of drainage offers opportunities for prevention of PJI. The use of tranexamic acid, suction drains and critical evaluation of guidelines for preventing thrombo embolic events all offer reducing the risk on wound drainage and the development of PJI

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One of the surgical therapeutic options for periprosthetic joint infection (PJI) includes debridement, antibiotics, and implant retention (DAIR). Prognostically favorable criteria for DAIR include short duration of symptoms, stable implant, pathogen susceptible to a ‘biofilm-active’ antimicrobial agent, and intact soft-tissue conditions. Despite this, there is a proportion of failures after DAIR, possibly because the duration of infection is underestimated. With the hypothesis that the duration of infection correlates with the bacterial load, and hence, the bacterial load is associated with failure after DAIR, we aimed to investigate the association of bacterial load in the sonication fluid of mobile parts and clinical outcome after DAIR.

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Currently, gram-negative bacteria (GNB), including multidrug-resistant (MDR-GNB) pathogens, are gaining importance in the aetiology of prosthetic joint infection (PJI). To characterize the antimicrobial resistance patterns of Gram-negative bacteria (GNB) causing hip prosthetic joint infections in elderly patients treated at a Brazilian tertiary academic hospital.

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To describe the risk factors, microbiology and treatment outcome polymicrobial prosthetic joint infections (PJI) compared to monomicrobial PJI.

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Synovial calprotectin point-of-care test (POC) has shown promising clinical value in diagnosing periprosthetic joint infections (PJIs). However, limited data are available in unclear cases. Moreover, cut-off values for calprotectin lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) need to be adapted. The aim of this study was to evaluate the performance of an upgraded and more sensitive version of a synovial calprotectin LFA along with ELISA immunoassay in patients with septic, aseptic, and unclear cases.

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Culture negative (CN) prosthetic joint infections (PJI) account for approximately 10% of all PJIs and present significant challenges for clinicians. We aimed to explore the significance of CN PJI within a large prospective cohort study, and to compare their characteristics and outcomes with culture positive cases.

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A septic revision of an artificial joint is routinely split up in a so-called dirty phase and a clean phase. The measures taken to initiate the start of the clean phase vary significantly between musculoskeletal infection centers. We performed simulations of one-step exchanges of infected THAs and sought to 1) determine the effect of different clean phase protocols on the sterile field, and 2) determine whether or not it is possible to re-implant the new prosthesis completely clean.