bluuebunny/crossref_metadata_2025 huggingface dataset:
POLYMORPHISMS IN THE IL-1Β AND IL-10 GENES AFFECT THE RISK OF PERIPROSTHETIC JOINT INFECTION IN TOTAL HIP AND KNEE ARTHROPLASTY PATIENTS
Authors: Granata Valentina , Strina Dario , Possetti Valentina , Leone Roberto , Valentino Sonia , Chiappetta Katia , Bottazzi Barbara , Mantovani Alberto , Loppini Mattia , Asselta Rosanna , Sobacchi Cristina , Inforzato Antonio
Published: November 2024

Aim

Periprosthetic joint infection (PJI) is one of the most serious and frequent complications in prosthetic surgery. Despite significant improvements in the criteria for diagnosis of PJI, the diagnostic workflow remains complex and, sometimes, inconclusive. Host immune factors hold great potential as diagnostic biomarkers in bone and joint infections. We have recently reported that the synovial concentration of the humoral pattern recognition molecule long pentraxin 3 (PTX3) is a sensitive and specific marker of PJI in total hip and knee arthroplasty patients (THA and TKA) undergoing revision surgery [1]. However, the contribution to risk and diagnosis of PJI of the genetic variation in PTX3 and inflammatory genes that are known to affect its expression (IL-1b, IL-6, IL-10, and IL-17A) has not been addressed. Therefore, we assessed these relationships in a cohort of THA and TKA patients who underwent prosthesis revision by focusing on a panel of single nucleotide polymorphisms (SNPs) in the PTX3, IL-1β, IL-6, IL-10 and IL-17A genes.

Method

A case-control retrospective study was conducted on an historic cohort of patients that received THA or TKA revision and were diagnosed with PJI (cases) or aseptic complications (controls) [1]. Samples of saliva were collected from 93 subjects and used for extraction of genomic DNA to perform genotyping of the PTX3, IL-1β, IL-6, IL-10 and IL-17A polymorphisms. Moreover, whenever available, samples of synovial fluid and plasma [1] were used to measure the concentration of the IL-1β, IL-10, and IL-6 proteins by immunoassay. Uni-and multivariate analyses were performed to evaluate the relationships between genetic, biochemical, and clinical variables.

Results

The rs3024491 (IL-10) and rs2853550 (IL-1b) SNPs were found to be strongly associated with the risk of PJI. The synovial levels of PTX3, IL-1β, IL-10, and IL-6 were higher in cases than in controls, and a clear correlation emerged between the synovial concentration of PTX3 and IL-1b in cases only. Also, we identified a causal relationship between rs2853550, synovial concentration of IL-1b and that of PTX3 (that is induced by IL-1b).

Conclusions

Our findings suggest that SNPs in the IL-10 and IL-1b genes could be used for early identification of THA and TKA patients with high risk of PJI. It is therefore conceivable that integrating genetic data into current diagnostic criteria would improve diagnosis of PJI.
AN ANALYSIS OF THE DEFINITION OF VARIABLES IN PERIPROSTHETIC JOINT INFECTION RESEARCH
Authors: Tenorio Bettina Gabrielle , Yu Melody Hope Lee , Deslate Angelica Bernadette , Tai Geno
Published: November 2024

Aim

A substantial portion of periprosthetic joint infections (PJI) literature is comprised of observational studies. The Strengthening the Reporting of Observational Studies in Epidemiology guidelines emphasize the importance of clearly defining variables and providing diagnostic criteria. Well-defined variables in these studies play a crucial role in ensuring data consistency, fostering comparability among studies, and laying a robust foundation for evidence-based decision-making. We aimed to determine the definition of these variables and determine the objectivity of the definitions.

Method

We reviewed observational studies on hip or knee PJI that focused on variables and their association with treatment outcomes. The inclusion criteria comprised studies from Jan 2017 to Jan 2023. We focused on 13 variables that were possibly subjective. These were smoking, alcohol use, diabetes mellitus, hypertension, lung disease, rheumatoid arthritis, liver diseases, kidney diseases, cardiovascular diseases, malignancy, immunosuppression, use of antibiotics, and type of infection. The reviewers examined the text of the articles, along with any available online supplements or protocols, for definitions of the selected variables. We classified a definition as objective if there was the presence of time element, severity, staging, frequencies, laboratory cut-off, medication dependence, among others. Chart review was deemed subjective.

Results

We included 75 studies in the analysis. The most common factors studied were diabetes mellitus (79%), cardiovascular disease, smoking history, and rheumatoid arthritis (47% each). The variables that were objectively defined most often were antibiotic use (100%) and type of infection (95%). Smoking history (16%) and alcohol use (20%) were the least frequently objectively defined variables. Further analysis revealed that a considerable number of studies incorporated variables into their primary analyses without clear definitions. For instance, out of the 59 studies where diabetes was considered a variable, 41 studies (70%) included diabetes in their main analyses as a factor for PJI treatment outcomes, despite only 34 studies having defined this variable. Moreover, of the 34 provided definitions of diabetes mellitus, only 12 provided objective criteria for diagnosis. The rest of the provided definitions relied on “chart review” without further specification. Table 1 outlines the proportion of studies with variables defined and included in their analysis.

Conclusions

Study variables were not clearly defined in most of the observational studies raising concerns about the reproducibility and reliability of findings. Our study underscores the vital need for standardized variable definitions in PJI research. Professional societies may play a crucial role in setting standards for the definition of variables.

For any tables or figures, please contact the authors directly.
THE IMPORTANCE OF BIOMECHANICAL RESTORATION ON DISLOCATION RATES AFTER TWO-STAGE SPACER-FREE TOTAL HIP ARTHROPLASTY REVISION: RISK FACTOR ANALYSIS AND FUNCTIONAL OUTCOMES
Authors: Goumenos Stavros , Hipfl Christian , Michalski Bernhard , Pidgaiska Olga , Mewes Moritz-Guenther , Stöckle Ulrich , Perka Carsten , Meller Sebastian
Published: November 2024

Background

Postoperative dislocation is one of the main surgical complications and the primary cause for revision surgery after 2-stage implant exchange due to periprosthetic infection of a total hip arthroplasty.

Objective

The aims of our study were (1) to determine the incidence of dislocation after two-stage THA reimplantation without spacer placement, (2) to evaluate relevant risk factors for dislocation and (3) to assess the final functional outcome of those patients.

Method

We prospectively analyzed 187 patients who underwent a two-stage total hip arthroplasty (THA) revision after being diagnosed with periprosthetic joint infection (PJI) from 2013 to 2019. The mean duration of follow-up was 54.2 ± 24.9 months (>36 months). The incidence of postoperative dislocation and subsequent revision was estimated through Kaplan-Meier curves and potential risk factors were identified using Cox hazard regression. The functional outcome of the patients was assessed using the modified Harris Hip Score (mHHS).

Results

The estimated cumulative dislocation-free survival was 87.2% (95% CI: 81.2%-91.3%) with an estimated 10% and 12% risk for dislocation within the first 6 and 12 months, respectively. The use of a dual-mobility construct had no significant impact on the dislocation rate. Increasing body mass index (BMI) (HR=1.11, 95% CI: 1.02-1.19, p=0.011), abductor mechanism impairment (HR=2.85, 95% CI: 1.01-8.01, p=0.047), the extent of elongation of the affected extremity between stages (HR=1.04, 95% CI: 1.01-1.07, p=0.017), the final leg length discrepancy (HR=1.04, 95% CI: 1.01-1.08, p=0.018) and PJI recurrence (HR=2.76, 95% CI: 1.00-7.62, p=0.049) were found to be significant risk factors for dislocation. Overall revision rates were 17% after THA reimplantation. Dislocated hips were 62% more likely to undergo re-revision surgery (p<0.001, Log-rank= 78.05). A significant average increase of 30 points in mHHS scores after second-stage reimplantation (p=0.001, Wilcoxon-rank) was recorded, but no difference was noted in the final HHS measurements between stable and dislocated hips.

Conclusion

Dislocation rates after 2-stage THA reimplantation for PJI remain high, especially regarding overweight or re-infected patients. Careful leg length restoration and an intact abductor mechanism seem critical to ensure stability in these complex patients.
CHRONIC SUPPRESSIVE ANTIBIOTIC TREATMENT FOR PERIPROSTHETIC JOINT INFECTION
Authors: Aboltins Craig , Manning Laurens , Clark Benjamin , Soriano Alex , Davis Joshua
Published: November 2024

Aim

The intention of suppressive antimicrobial therapy (SAT) for prosthetic joint infection (PJI) is to minimise symptoms, maintain function and prevent further surgery in patients who cannot undergo further attempts at curative treatment(1). There is little high-quality evidence examining the role and efficacy of SAT for patients with PJI(1,2). The objective of this study was to describe the use of and outcomes after SAT in a large prospective PJI cohort.

Methods

A pre-planned analysis of a prospective multi-centre cohort of patients with PJI. SAT was defined as antimicrobial therapy for PJI continuing 12-months after diagnosis or where there was an intention for chronic suppressive antibiotics. The primary outcome was treatment failure at 24 months, defined as any of the development of PJI symptoms, further surgery or death from PJI. Secondary outcomes included Oxford Hip and Knee Scores.

Results

SAT was prescribed for 223 (31.0%) of the PJI cohort. Patients prescribed SAT for PJI were more likely to be older, have comorbidities, chronic PJI, higher CRP, a sinus tract and be treated with retention of their prosthesis than those not prescribed SAT. At 24-months, treatment failure was more common in the SAT group 75/185(40.1%) compared with the non-SAT group 85/447(19.0%). Propensity score adjusted analysis did not demonstrate an association between SAT and treatment failure in patients with chronic PJI (OR[95% CI] 1.57[0.63-3.91), late-acute PJI(1.87[0.90-3.87]), a sinus tract (2.74[0.89-8.39]), ongoing symptoms at day 90 (1.19[0.43-3.23]), treatment with DAIR(1.61[0.87-2.99]) or Staphylococcus aureus PJI (1.25[0.62-2.54]). There were similar improvements between SAT and non-SAT patients in functional joint scores (OHS median (IQR) +8.5(19.0) vs +7.0(22.0);p=0.78 and OKS +8.0(20.0) vs +7.0(22.0);p=0.53).

Conclusion

SAT use for PJI is common. The lack of demonstrated evidence in this study for its benefit in controlling infection across multiple subgroups of patients but with some improvements in functional scores, suggest that the advantages of SAT are at best complex.
DISC PENETRATION SIGN: A DISTINCTIVE MRI SIGN INDICATING THE SEVERITY OF PYOGENIC SPONDYLITIS
Authors: Jiang Yutao , Wang Liang
Published: November 2024

Aim

This study seeks to outline the clinical, laboratory, and imaging features of patients with pyogenic spondylitis. It aims to define a novel imaging sign that could indicate the severity of suppurative spondylitis, aiding in its early diagnosis and treatment.

Method

This retrospective study included 137 patients from 2013 to 2023. Through the analysis and summary of imaging characteristics among all patients, we identified a distinct MRI sign known as ‘the Disc Penetration sign’ (DP). This sign is defined as an image finding on sagittal MRI depicting the anterior and posterior penetration of an abscess through the intervertebral disc space, affecting both the anterior margin of the vertebrae and the structures within the spinal canal. Observational parameters included WBC, ESR, CRP, hemoglobin, and albumin levels. Documentation of the study included location and segment of the lesion, presence or absence of spinal cord compression, and paravertebral abscesses.

Results

56 patients presented with the Disc Penetration sign(DP) and 81 did not. In both groups, there were no significant differences in gender ratio or age (P > 0.05). However, significant differences were observed in the presence of comorbid diabetes and chronic kidney disease (p < 0.05). The DP group had a significantly greater ESR level (74.30±33.79 mm/h vs. 51.46±30.46 mm/h, P < 0.001) and CRP level (47.28 mg/L vs. 26.18 mg/L, P = 0.003). Additionally, the DP group had a significantly lower Hb (100.66±19.82 g/L vs. 116.99±19.99g/L,P < 0.001) and the serum albumin level (28.81±6.59 g/L vs. 34.09±6.17 g/L,P < 0.001). Imaging results showed no significant differences in affected spinal segments or parts (p>0.05). Patients in the DP group showed a higher likelihood of developing paravertebral abscesses compared to those in the non-DP group (n = 54 [96.4%] vs. n = 33 [40.7%], P < 0.001), and also exhibited a higher incidence of spinal cord compression(n = 32 [57.1%] vs. n = 17 [21.0%], P < 0.001).

Conclusions

The study suggests that the Disc Penetration sign in pyogenic spondylitis patients correlates with more severe inflammation and higher incidence of paraspinal abscess, pointing to worse stability of the spine, longer bone restructuring time, and potentially poorer prognosis. These findings enable clinicians to rapidly assess the severity of the disease and prognosticate outcomes more effectively We emphasize the need for early, pathogen-specific diagnosis and treatment, particularly considering surgical intervention for patients demonstrating substantial paraspinal abscesses or spinal instability.
SOFT-TISSUE COVERAGE WITH VASTUS LATERALIS FLAP IN GIRDLESTONE RESECTION ARTHROPLASTY FOR MANAGING CHRONIC HIP SEPTIC ARTHRITIS AND PROXIMAL FEMUR OSTEOMYELITIS IN PATIENTS WITH SPINAL CORD INJURIES: A CASE SERIES
Authors: De Meo Daniele , Lo Torto Federico , Gumina Stefano , Ribuffo Diego
Published: November 2024

Aim

Decubitus ulcers are found in approximately 4.7% of hospitalized patients, with a higher prevalence (up to 30%) among those with spinal cord injuries. These ulcers are often associated with hip septic arthritis and/or osteomyelitis involving the femur. Girdlestone resection arthroplasty is a surgical technique used to remove affected proximal femur and acetabular tissues, resulting in a substantial defect. The vastus lateralis flap has been employed as an effective option for managing this dead space. The aim of this study was to evaluate the long-term outcomes of this procedure in a consecutive series of patients.

Method

A retrospective single-center study was conducted from October 2012 to December 2022, involving 7 patients with spinal cord injuries affected by chronic severe septic hip arthritis and/or femoral head septic necrosis as a consequence of decubitus ulcers over trochanter area. All patients underwent treatment using a multidisciplinary approach by the same surgical team (orthopedic and plastic surgeons) along with infectious disease specialists. The treatment consisted of a one-stage procedure combining Girdlestone resection arthroplasty with unilateral vastus lateralis flap reconstruction, alongside targeted antibiotic therapy. Complications and postoperative outcomes were assessed and recorded. The mean follow-up period was 8 years (range 2-12).

Results

Of the 7 patients, 5 were male and 2 were female, with a mean age of 50.3 years at the time of surgery. Minor wound dehiscence occurred in 28.6% of the flap sites, and 2 patients required additional revisional procedures—one for hematoma and the other for bleeding. There were no instances of flap failure, and complete wound healing was achieved in an average of 32 days (range 20-41), with the ability to load over the hip area. No cases of infection recurrence or relapse were observed.

Conclusions

An aggressive surgical approach is strongly recommended for managing chronic hip septic arthritis or proximal femur osteomyelitis in patients with spinal cord injuries. A single-stage procedure combining Girdlestone resection arthroplasty with immediate vastus lateralis muscle flap reconstruction proves to be an effective strategy for dead space management and localized antibiotic delivery through the vastus muscle, giving reliable soft tissue coverage around the proximal femur to avoid the recurrence of pressure ulcers. The implementation of a standardized multidisciplinary protocol contributes significantly to the success of reconstruction efforts.
ENHANCED EFFICACY AGAINST MRSA BIOFILMS: EVALUATION OF ENZYMATIC COCKTAIL ADJUVANT WITH RIFAMPICIN AND VANCOMYCIN DUAL THERAPY
Authors: Mbuku Randy Buzisa , Poilvache Hervé , Van Bambeke Francoise , Cornu Olivier
Published: November 2024

Aim

The management of PJIs is slowed down by the presence of bacteria forming biofilms where they may withstand antibiotic therapy. The use of adjuvant strategies, such as hydrolytic enzymes cocktail targeting biofilm matrices and facilitating their dispersion, is a promising option to limit impact of biofilms. Our aim was to evaluate the effect of enzymes cocktail combined with antibiotic dual therapy of rifampicin and vancomycin in a relevant in-vitro model.

Method

Mature methicillin-resistant Staphylococcus aureus biofilms were grown on Ti-6Al-4V coupons by adding 1mL of a 8Log10 ATCC 33591 suspension in TGN (TSB + 1% glucose + 2% NaCl) to 24-wells plates containing the coupons and incubating the plates for 24h at 37°C with a continuous 50rpm agitation. The samples were rinsed and placed in 6 wells plates containing 1ml of the enzymatic cocktail (C.D.D.) solution (tris-buffered (pH 7.0) solution of 400 U/ml of aspecific DNA/RNA endonuclease, 50 U/ml of endo-1,4-b-D-glucanase, and 0.06 U/ml of β-N-acetylhexosaminidase). 9ml of TGN or TGN containing antibiotics RIF/VAN (rifampicin 5µg/mL + vancomycin 8µg/mL) at clinically relevant concentrations found locally in bone or joints, was then added and the samples were incubated in identical conditions for 24h. The samples were then recovered and rinsed. CFU counts were obtained by recovering the bacteria with sonication, serial dilutions, and TSA plating. Biomass was determined via crystal violet staining, followed by dye solubilization in acetic acid, and absorbance measurement using a spectrophotometer.

Results

Significant reductions in bacterial counts were observed in biofilms exposed to either RIF/VAN or RIF/VAN+CDD, by respectively 2,6 and 3,7Log10 when compared to samples reincubated with TGN alone (p <0.05). Additionally, CFU counts in samples exposed to RIF/VAN+CDD were reduced by 1,1Log10 when compared to those exposed to RIF/VAN (p<0,05). Significant reduction in biomass (-29,8%, p<0.05) was observed for coupons exposed to RIF/VAN+CDD when compared to C.D.D alone (figure 1).

Conclusions

The concurrent utilization of enzymes with rifampicin and vancomycin, holds promise as a feasible method to address periprosthetic joint infections (PJIs).

For any tables or figures, please contact the authors directly.
GALLERIA MELLONELLA LARVAE: A PROMISING ANIMAL MODEL TO STUDY BIOFILM MATURATION IN ORTHOPAEDIC INFECTIONS
Authors: Youf Raphaelle , Ruth Schewior , Mannala Gopala , Zhao You , Alt Volker , Riool Martijn
Published: November 2024

Aim

In trauma surgery, the development of biomaterial-associated infections (BAI) is one of the most common complications affecting trauma patients, requiring prolonged hospitalization and the intensive use of antibiotics. Following the attachment of bacteria on the surface of the biomaterial, the biofilm-forming bacteria could initiate a chronic implant-related infection. Despite the use of conventional local and systemic antibiotic therapies, persistent biofilms involve various resistance mechanisms that contribute to therapeutic failures. The development of in vivo chronic BAI models to optimize antibiofilm treatments is a major challenge. Indeed, the biofilm pathogenicity and the host response need to be finely regulated, and compatible with the animal lifestyle. Previously, a Galleria mellonella larvae model for the formation of an early-stage biofilm on the surface of a Kirschner (K)-wire was established. In the present study, two models of mature biofilm using clinical Staphylococcus aureus strains were assessed: one related to contaminated K-wires (in vitro biofilm maturation) and the second to hematogenous infections (in vivo biofilm maturation). Rifampicin was used as a standard drug for antibiofilm treatment.

Method

In the first model, biofilms were formed following an incubation period (up to 7 days) in the CDC Biofilm Reactor (CBR, BioSurface Technologies). Then, after implantation of the pre-incubated K-wire in the larvae, rifampicin (80 mg/kg) was injected and the survival of the larvae was monitored. In the second model, biofilm formation was achieved after an incubation period (up to 7 days) inside the larvae and then, after removing the K-wires from the host, in vitro rifampicin susceptibility assays were performed (according to EUCAST).

Results

The first model indicate that in vitro biofilm maturation affects the bacterial pathogenicity in the host, depending on the S. aureus strain used. Furthermore, the more the biofilm is matured, the more the rifampicin treatment efficiency is compromised. The second model shows that, despite the fast in vivo biofilm formation in the host, the number of bacteria, either attached to the surface of the K-wire surface or in surrounding tissue of the larvae, was not increased over time.

Conclusions

Altogether, these results allow the establishment of biofilm models using G. mellonella larvae in order to understand the impact of biofilm maturation on both the bacterial pathogenicity and the efficiency of antibiofilm treatments.
ANTIBACTERIAL PROPERTIES OF NISIN LAYER-BY-LAYER BASED COATING ON TITANIUM K-WIRES IN GALLERIA MELLONELLA IMPLANT-ASSOCIATED INFECTION MODEL
Authors: Mannala Gopala , Labat Beatrice , Ladam Guy , Pascal Thebault , Walter Nike , Szymski Dominik , Riool Martijn , Alt Volker , Rupp Markus
Published: November 2024

Aim

Orthopedic implants play a tremendous role in fixing bone damages due to aging as well as fractures. However, these implants tend to get colonized by bacteria on the surface, leading to infections and subsequently prevention of healing and osteointegration. Recently, Roupie et al. showed that a nisin layer-by-layer based coating applied on biomaterials has both osteogenic and antibacterial properties. The Galleria mellonella larva is a well-known insect infection model that has been used to test the virulence of bacterial and fungal strains as well as for the high throughput screening of antimicrobial compounds against infections. Recently, we have developed an insect infection model with G. mellonella larvae to study implant-associated biofilm infections using Kirschner (K)-wires as implant material. Here, we would like to test the antibacterial capacity of nisin layer-by-layer based coatings on K-wires against Staphylococcus aureus in the G. mellonella larva implant infection model.

Method

Prior to the implantation procedure, G. mellonella larvae are maintained at room temperature on wheat germ in an incubator. The larvae received bare titanium K-wires (uncoated), or either control-coated or nisin-coated K-wires. After one hour, the larvae were injected with 5×105S. aureus bacteria per larva (i.e., hematogenous implant infection model). Next, the larvae were incubated at 37oC in an incubator and the survival of the larvae was monitored for five days. Moreover, the number of bacteria on the implant surface and in the surrounding tissue was determined after 24h of incubation. Further, scanning electron microscopy (SEM) analyses were performed to study the effect of nisin on biofilm formation.

Results

The larvae receiving the nisin-coated K-wires showed significantly higher survival rates compared to uncoated titanium K-wires, although not when compared to control-coated K-wires. A more than 1-log reduction in number of bacteria on the implant surface and in the surrounding tissue was observed in larvae receiving the nisin-coated K-wires, when compared to uncoated titanium K-wires SEM analysis showed reduced colonization of the bacteria nisin-coated K-wires compared to the controls

Conclusions

In conclusion, the antimicrobial nisin layer-by-layer based coating applied on titanium surfaces is able to prevent implant-related S. aureus biofilm infection in G. mellonella and is a promising antimicrobial strategy to prevent implant-related infections.
COMBINATION OF SONICATION WITH DITHIOTHREITOL TREATMENT DOES NOT IMPROVE BACTERIAL DISLODGING FROM BIOFILM IN AN IN VITRO MODEL
Authors: De Vecchi Elena , Riccardi Mila , Mastroianni Nicolò
Published: November 2024

Aim

Diagnosis of prosthetic joint infection are often complicated by the presence of biofilm, which hampers bacteria dislodging from the implants, thus affecting sensitivity of cultures. In the last 20 years several studies have evidenced the usefulness of implant sonication to improve microbial recovery from biofilm formed on inert substrates. More recently, treatment of prosthetic joints and tissues with Dithiothreitol, a sulphur compound already used in routine diagnostic workflow for fluidification of respiratory samples, has proved to be not inferior to sonication in microbiological diagnosis of prosthetic joint infections.

This study aimed to evaluate if the combination of the two treatments could further improve microbial retrieval from biofilm in an in vitro model.

Method

Three isolates of Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Eschericha coli and Pseudomonas aeruginosa responsible of prosthetic joint infections were used. They were grown onto 3 titanium discs (20 mm diameter) and incubated in 3 sterile plastic containers with 15 mL of Triptyc Soy Broth. After overnight incubation, not adhered cells were removed and fresh broth was added to each sample. After 48 hours incubation, the exausted broth was removed and one sample was used for sonication, one for treatment with 0,1% (v:v) Dithiothreitol and one treated with Dithiothreitol followed by sonication. Treated fluids were plated on Muller Hinton Agar plates for colony count.

One-way ANOVA analysis was performed to evidence statistical differences between treatments.

Results

Similar colony counts were observed for the 3 treatments: 10.1± 0.77 log CFU/mL for Dithiothreitol, 10.0 ± 0.75 for sonication and 10.1 ±0.73 for dithiothreitol + sonication.

No statistical differences between the 3 treatments were evidenced by ANOVA analysis.

Conclusions

Results seems to confirm that treatment with dithiothreitol is equivalent to sonication in recovering bacteria from biofilm grown on inert surface. Combining dithiotreitol treatment with sonication does not significantly improve bacterial recovery in respect to each treatment alone.
INOCULATION OF HOMOGENIZED TISSUE AND BONE BIOPSIES IN BLOOD CULTURE BOTTLES FOR DIAGNOSING ORTHOPAEDIC DEVICE-RELATED INFECTIONS: PRELIMINARY RESULTS FROM AN ONGOING STUDY
Authors: Jacob Ann-Sophie , Onsea Jolien , Bessems Laura , Spoormans Pauline , Vles Georges , Metsemakers Willem-Jan , Depypere Melissa
Published: November 2024

Aim

The primary objective is to evaluate the diagnostic performance of inoculating homogenized tissue and bone biopsies in blood culture bottles (BCB) for patients with (suspected) orthopaedic device-related infections. As secondary objective the time to positivity (TTP) of BCB and Wilkins-Chalgren broth (conventional method) will be evaluated.

Method

Patients undergoing revision surgery due to suspected or proven fracture-related infection (FRI) or periprosthetic joint infection (PJI) according to respectively Consensus definition and EBJIS definition are included.1,2 A minimal of three macroscopic infected/inflamed tissue/bone samples are collected in a container with saline and glass beads. 1.5 mL of the homogenized suspension is inoculated in BacT/ALERT FA and FN Plus bottles for 14 days. The remaining suspension is inoculated in Wilkins-Chalgren broth for 10 days and subcultured when cloudy or after 10 days. TTP is defined as the time until definite identification of the pathogen in the Laboratory Information System.

Results

Up to now, 25 patients have been included, 11 (44%) had concordant results in BCB and the CM. In 11 patients cultures showed negative results for both methods. Three patients tested positive with BCB but remained negative with the same pathogen in CM. In the first patient, the CM failed to identify anaerobic bacteria (i.e. Fusobacterium nucleatum). In the second patient, three BCB were positive with Staphylococcus capitis. The third patient showed an infection with Escherichia coli, which was detected in all samples from the BCB, while all cultures obtained with the CM remained negative. A possible explanation for this discrepancy could be that this patient already received antibiotic therapy. BCB contain resins, which are capable of neutralizing antibiotic activity. Another case illustrating superiority of BCB involved an infection with Cutibacterium acnes, which showed positivity in six BCB, while only three were positive using the CM. We observed the shortest TTP with BCB. The median TTP of BCB was 32.0 hours (IQR 29.8) compared to a median TTP of 77.5 hours (IQR 107.6) when culturing with the CM.

Contamination was seen in three patients with both methods, in eight patients contamination was only seen with the CM. For the remaining 14 patients no contamination was found.

Conclusions

The results in this ongoing study indicate that the recovery of pathogens and TTP is better using BCB compared to CM. In addition, contamination occurs less frequently with the BCB method. Culturing tissue or bone biopsies in BCB seems a promising and faster detection method.
DEVELOPMENT AND VALIDATION OF A MULTIPLEX PCR FOR THE DETECTION OF THE MOST COMMON PATHOGENS IN PERIPROSTHETIC JOINT INFECTIONS
Authors: Erbeznik Anja , Smrdel Katja Strašek , Kišek Tjasa Cerar , Cvitković-Špik Vesna , Triglav Tina , Vodicar Polona Maver
Published: November 2024

Aim

The aim of this study was to develop an in-house multiplex PCR real-time assay on the LightCycler 480 system (Roche, Basel, Switzerland) with the aim of rapid detection of common pathogens in prosthetic joint infections (PJI), followed by validation on clinical samples (sonication fluid and tissue biopsies) routinely collected for PJI diagnosis.

Methods

Using the PrimerQuest and CLC WorkBench tool, we designed six primer sets with specific fluorescently labelled TaqMan probes for the nuc gene in different Staphylococcus species (S. aureus, S. epidermidis, S. capitis, S. lugdunensis, S. hominis, S. haemolyticus). In addition, primers previously developed by Renz et al. (2022) for C. acnes were integrated into our assay with internal control of isolation, leading to the development of specific mPCR assay with seven included targets. Analytical sensitivity and specificity were evaluated using reference bacterial strains. To determine the assay's limit of detection (LOD), we conducted serial dilutions of eluates containing known concentrations of bacterial DNA copies/µl. The overall LOD in spiked clinical samples, including sample preparation and DNA isolation on MagnaPure24, was measured through 10-fold serial dilutions (from 109 to 10-1 CFU/ml) including additional dilutions of 5000, 500, 50 and 5 CFU/ml.

Results

The results with LOD in serial dilutions of eluates and spiked clinical samples, together with analytical sensitivity and specificity, are shown in Table 1.

Conclusion

The mPCR assay showed excellent analytical sensitivity and specificity, but with considerably lower LOD after sample preparation and further DNA isolation in spiked clinical samples. Although still promising in diagnostics of acute infections, the use of mPCR could be challenging in chronic, low-grade infections with lower microbial burden. Nevertheless, PCR offers significant advantages in terms of speed and can shorten the time to result, especially for C. acnes infections. Additionally, it represents a promising complementary approach in patients with suspected PJI on antibiotic therapy with negative culture results.

For any tables or figures, please contact the authors directly.
CAN MOLECULAR TECHNIQUES BECOME THE NEW “GOLD STANDARD” IN DIAGNOSTICS OF PERIPROSTHETIC JOINT INFECTIONS?
Authors: Erbeznik Anja , Šturm Andraž Celar , Smrdel Katja Strašek , Triglav Tina , Cvitković-Špik Vesna , Kišek Tjasa Cerar , Kocjancic Boštjan , Pompe Borut , Dolinar Drago , Mavcic Blaz , Mercun Aljaz , Kolar Matic , Avsec Klemen , Papst Lea , Vodicar Polona Maver
Published: November 2024

Aim

We prospectively evaluated four different microbiological tools for diagnostics of prosthetic joint infections (PJI), and assessed their impact on the categorization of infection according to EBJIS guidelines. We compared culture, in-house real-time mPCR for S. aureus, S. lugdunensis, S. hominis, S. epidermidis, S. capitis, S. haemolyticus, C. acnes (mPCR), broad-spectrum PCR (Molzym) with 16S rRNA V3-V4 amplicon Sanger sequencing (16S PCR), and 16S rRNA V3-V4 amplicon next-generation sequencing (16S NGS) on MiSeq (Ilumina).

Methods

A total of 341 samples (sonication fluid, tissue biopsy, synovial fluid) were collected from 32 patients with suspected PJI who underwent 56 revision surgeries at the Orthopaedic Centre University Hospital Ljubljana, between 2022 and 2024. Samples were processed using standard protocols for routine culture, followed by DNA isolation using the MagnaPure24 (Roche). All samples were tested with mPCR, and an additional ≥4 samples from each revision (244 in total) were subjected to further metagenomic analysis. Culture results were considered positive if the same microorganism was detected in ≥2 samples, ≥50 CFU/ml were present in the sonication fluid, or ≥1 sample was positive for a more virulent microorganism or if the patient had received antibiotic treatment.

Results

Each tool demonstrated high sensitivity for correct EBJIS categorization (100% culture and 16S NGS, 96.88% mPCR and 16S PCR). The highest specificity was observed with mPCR and 16S PCR (87.5%), while culture (79.17%) and NGS (37.5%) showed lower specificity. In 27% (15/56) of revisions, all microbiological tests were negative, although infection was confirmed with histology in one case, and four cases were classified as infection-likely based on clinical signs. In 20% (11/56) of cases, all microbiological tests were positive; in three cases a combination of other EBJIS criteria (without microbiology) categorized the episodes as infection-likely and one as infection-unlikely, emphasizing the importance of microbiological tests in diagnostic criteria. In 43% (24/56) of revisions categorized as infection-unlikely using a combination of other EBJIS criteria, five had positive culture, and three had positive mPCR and 16S PCR. Fifteen (62%) had positive 16S NGS, 12 due to a low number of reads, which may indicate low-grade infection or possible contamination.

Conclusion

To date, no test can be established as the ultimate gold standard. The lack of interpretation criteria can result in low specificity of some methods, as the threshold is difficult to determine. A multidisciplinary approach with combination of microbiological tools is still considered the most efficient.
NOVEL MOLECULAR APPROACH IS USEFUL IN CULTURE-NEGATIVE PERIPROSTHETIC HIP AND KNEE JOINT INFECTIONS
Authors: Gardete-Hartmann Susana , Sebastian Sujeesh , Berdalli Sofia , Simon Sebastian , Hofstaetter Jochen
Published: November 2024

Aim

Unexpected negative-cultures (UNC) are a common diagnostic problem in periprosthetic joint infection (PJI) of the hip and knee when using culture-based methods. A novel molecular approach (MC)1 based on the identification of the vast majority of bacterial species in a single assay using species-specific bacterial interspacing region length polymorphisms and phylum-specific 16S rDNA sequence polymorphisms has demonstrated clinical utility in PJI diagnostics (1). In addition, MC provides an estimate of the leukocyte concentration in the specimen analysed. The aim of this retrospective, blinded study was to evaluate the performance of MC in identifying the microbiological content and determining the leukocyte count in synovial fluid (SF) collected from hip and knee revision arthroplasty cases with UNC. It was also assessed whether antibiotic treatment would have been changed if the result from MC had been known.

Method

A total of 89 SF samples from 70 patients (43 female; 27 male) who underwent revision arthroplasty (14 hip; 75 knee) were included. Using European and Bone Joint Infection Society (EBJIS) criteria, 82 cases were classified as infected (77 UNC and 5 septic culture-positive controls), five as non-infected (aseptic culture-negative controls), and two as likely infected, but infected by clinical observation. MC was performed and evaluated together with SF parameters. Antibiotic treatment, clinical outcome, patient demographics and surgical details were analysed.

Results

Overall, 29.1% (23/79) of UNC had a positive yield by MC, of which 2/23 (8.7%) had two microorganisms detected simultaneously. Of the 25 microorganisms identified by MC, 12/25 (48%) were clinically relevant after re-evaluation of the patients’ microbiological history. The microorganisms detected were 5/25 (20%) Streptococcus pneumoniae/mitis, 4/25 (16%) Staphylococcus epidermidis, 3/25 (12%) Cutibacterium acnes, 3/25 (12%) Streptococcus agalactiae, 2/25 (8%) Streptococcus bovis, 2/25 (8%) Staphylococcus aureus, and 2/25 (8%) Haemophilus parainfluenzae. The prevalence of Enterococcus faecalis, Bacteroides fragillis, Staphylococcus lugdunensis, Corynebacterium striatum among all MC results was 1/25 (4%) each species. In total, 13/23 (56%) cases were associated with patients receiving antibiotic therapy at the time of SF collection. The yield for leukocyte counts provided the molecular technique was consistently much higher in the UNC and clearly septic groups than in the clearly aseptic group. Overall, 20/61 (32.8%) patients with UNC could have been managed differently and more accurately after MC assessment.

Conclusions

MC shows clinical value in the diagnosis and management of PJI with UNC. The included leukocyte count shows promising results.

Acknowledgments

This work was partially funded by Inbiome.
IS ONE DOSE NON-INFERIOR TO FOUR DOSES OF SYSTEMIC ANTIBIOTIC PROPHYLAXIS AGAINST PERIPROSTHETIC JOINT INFECTION IN PRIMARY ARTHROPLASTY?
Authors: Lutro Olav , Tjørhom Marianne Bollestad , Fenstad Anne Marie , Leta Tesfaye H. , Hallan Geir , Bruun Trond , Furnes Ove , Gjertsen Jan-Erik , Dale Håvard
Published: November 2024

Aim

The current recommendation in Norway is to use four doses of a first-generation cephalosporin (cefazolin or cephalotin) as systemic antibiotic prophylaxis (SAP) the day of surgery in primary joint arthroplasty. Due to shortage of supply, scientific development, changed courses of treatment and improved antibiotic stewardship, this recommendation has been disputed. We therefore wanted to assess if one dose of SAP was non-inferior to four doses in preventing periprosthetic joint infection (PJI) in primary joint arthroplasty.

Method

We included patients with primary hip- and knee arthroplasties from the Norwegian Arthroplasty Register and the Norwegian Hip Fracture Register for the period 2005-2023. We included the most used SAPs (cephalotin, cefazolin, cefuroxime, cloxacillin and clindamycin), administered as the only SAP in 1-4 doses, starting preoperatively. Risk of revision (Hazard rate ratio; HRR) for PJI was estimated by Cox regression analyses with adjustment for sex, age, ASA class, duration of surgery, reason for- and type of arthroplasty, and year of primary arthroplasty. The outcome was 1-year reoperation or revision for PJI. Non-inferiority margins were calculated for 1, 2 and 3 doses versus reference of 4 doses of SAP at the day of surgery, against a predetermined limit of 15% increased risk of PJI.

Results

In total 274,188 primary arthroplasties (total hip 133,985, hemi hip 51,442, and total knee 88,761) were included. Of these primary arthroplasties, 2,996 (1.1%) had subsequent revisions for PJI during the first postoperative year. One dose of SAP was given in 9,603 arthroplasties, two doses in 10,068, three doses in 18,351, and four doses in 236,166 arthroplasties. With the recommended four doses as reference, the HRR (95% CI) for 1-year revision for infection was 0.9 (0.7-1.1) for one dose, 1.0 (0.8-1.2) for two doses, and 0.9 (0.8-1.1) for three doses. The corresponding adjusted 1-year revision incidences for PJI was 0.9 (0.7-1.1), 1.0 (0.8-1.2), 0.9 (0. 8-1.1) and 1.0 (1.0-1.1) for one, two, three and four doses respectively, and less than four doses was found to be non-inferior.

Conclusions

One preoperative dose of SAP in primary joint arthroplasty surgery seems to be non-inferior to the current recommendation of four doses of a first-generation cephalosporin as PJI-prophylaxis. This finding may simplify the course of treatment for arthroplasty patients, save costs, and improve antibiotic stewardship.
POSTOPERATIVE ANTIBIOTIC TREATMENT DOES NOT LOWER RE-REVISION RATE IN PRESUMED ASEPTIC HIP AND KNEE REVISION ARTHROPLASTIES WITH UNEXPECTED POSITIVE INTRAOPERATIVE CULTURES: A PROPENSITY SCORE-MATCHED COHORT STUDY
Authors: Simon Sebastian , Wouthuyzen-Bakker Marjan , Mitterer Jennyfer A , Gardete-Hartmann Susana , Frank Bernhard J.H. , Hofstaetter Jochen
Published: November 2024

Aim

It still remains unclear whether postoperative antibiotic treatment is advantageous in presumed aseptic revision-arthroplasties of the hip (rTHA) and knee (rTKA) with unexpected-positive-intraoperative-cultures (UPIC). The aim of this study was to evaluate if there is a difference in the septic and/or aseptic re-revision rate in patients with or without postoperative antibiotics.

Method

In this retrospective propensity-score (PS) matched cohort-study we compared the re-revision rate and the microbiological spectrum in rTHA and rTKA treated with (AB-Group; n=70) and without (non-AB-Group; n=70) antibiotic treatment in patients with UPIC. Baseline covariates for PS-matching were type of revision, sex, Body-Mass-Index, age, Surgical-Site-Infection-Score, American-Society-of-Anesthesiologists-Classification, serum C-reactive-protein.

All patients received routine antibiotic prophylaxis, but empiric AB treatment was started only in patients in the AB-Group. Post-operative treatment was decided on an individual basis according to the preference of the surgeon and the infectious disease specialist for a minimum duration of two weeks. In total, 90 rTHA (45 AB-Group, 45 in non-AB-Group) patients with UPICs and 50 rTKA (25 AB-Group, 25 in non-AB-Group) were included in the study. There was no significant variation in patient demographics.

Results

After a median follow-up of 4.1 (IQR: 2.9-5.5) years after rTHA and rTKA, there was no higher re-revision rate (p=0.813) between the AB-group 10/70 (14.3%), and the non-AB-group 11/70 (15.7%). In the AB group, 4.3% (3/70) of patients underwent revision due to septic complications compared to 5.7% (4/70) in the non-AB group (survival log-rank: p=0.691).

In total, 30/70 (42.9%) of patients in the AB-group and 23/70 (32.9%) of patients in the non-AB group were diagnosed as having an “infection likely” according to the PJI diagnostic criteria of EBJIS (p=0.223). All UPICs comprised low virulent microorganisms and were considered as a contaminant. In total, 68/70 (97.1%) of the patients in the AB-group received a dual antibiotic treatment for a mean duration of 41 (IQR: 23.5-56.5) days.

Conclusion

Postoperative antibiotic treatment did not result in a decreased re-revision rate compared to non-antibiotic treatment in patients with UPIC in presumed aseptic rTHA and rTKA. UPICs with pathogens are likely to be a containment and therefore the classification of “infection likely” according to the EBJIS definition can be safely ignored.
SONICATION FLUID INCUBATION IN BLOOD CULTURE BOTTLES IS MORE SENSITIVE FOR PERIPROSTHETIC JOINT INFECTION THAN CLASSICAL CULTIVATION OF SONICATION FLUID
Authors: Roskar Samo , Rak Mitja , Mihalic Rene , Trebse Rihard
Published: November 2024

Aim

Periprosthetic joint infection (PJI) is one of the most devastating complications after joint replacement. It is associated with high morbidity and economic burden when misdiagnosed as an aseptic failure. Among all cases of PJI, up to 25% could yield negative cultures. Conversely, among cases of aseptic failures, up to 30% may actually be undiagnosed PJIs. In PJIs microbiological diagnosis is a key step for successful treatment. Sonication of the removed prosthesis is more sensitive than conventional periprosthetic-tissue culture, especially in patients who received antimicrobial therapy before surgery. This study aimed to compare the diagnostic value of classic sonication fluid cultures (SF-C) and sonication fluid incubation in blood culture bottle (SF-BCB).

Method

Between 2016 and 2018 we analysed 160 revision procedures of joint arthroplasties. For each procedure, at least 5 microbiological and multiple histopathological samples were harvested, and explant sonication was performed which was further analysed by SF-C and SF-BCB. For SF-C classical cultivation of sonication fluid was performed. While for SF-BCB, 10 mL of sonication fluid was inoculated into aerobic and anaerobic lytic blood culture bottles. The definite diagnosis of PJI was based on the EBJIS definition.

Results

Among 160 revisions, 59 PJIs were identified, 15 patients were treated with the debridement and implant retention, 7 patients with the one-stage and 35 with the two-stage exchange, remaining 2 were partial revisions. The sensitivity of SF-C and SF-BCB were 81.5% and 94.9%, respectively. The mismatch of microbe identification was observed in 5 cases. We observed positive SF-C while negative SF-BCB in 4 cases, among them having 2 positive histology. While 12 patients have negative SF-C and positive SF-BCB, among them 3 have positive and 6 negative histology. Among these 12 patients, typical low-grade microbes were identified in 9 cases (5 cases of C. acnes, 3 cases of S. epidermidis, and 1 case of S. capitis).

Conclusions

The weakest point in all PJI diagnostic criteria is their sensitivity. SF-BCB demonstrates higher sensitivity in diagnosing PJI compared to SF-C. Therefore, it appears prudent to incorporate SF-BCB into the diagnostic protocol for all patients exhibiting either low-grade PJI symptoms or experiencing undiagnosed, presumably aseptic failures, where the likelihood of misdiagnosing infection is greatest.