Effects of different tissue specimen pretreatment methods on microbial culture results in the diagnosis of periprosthetic joint infection

Improved cure rate of periprosthetic joint infection through targeted antibiotic therapy based on integrated pathogen diagnosis strategy

Objectives

This study aimed to determine whether combined of pathogen detection strategies, including specimen acquisition, culture conditions, and molecular diagnostics, can improve treatment outcomes in patients with periprosthetic joint infections (PJI).

Methods

This retrospective study included suspected PJI cases from three sequential stages at our institution: Stage A (July 2012 to June 2015), Stage B (July 2015 to June 2018), and Stage C (July 2018 to June 2021). Cases were categorized into PJI and aseptic failure (AF) groups based on European Bone and Joint Infection Society (EBJIS) criteria. Utilization of pathogen diagnostic strategies, pathogen detection rates, targeted antibiotic prescription rates, and treatment outcomes were analyzed and compared across the three stages.

Results

A total of 165 PJI cases and 38 AF cases were included in this study. With the progressive implementation of the three optimization approaches across stages A, B and C, pathogen detection rates exhibited a gradual increase (χ2 = 8.282, P=0.016). Similarly, utilization of targeted antibiotic therapy increased stepwise from 57.1% in Stage A, to 82.3% in Stage B, and to 84% in Stage C (χ2 = 9.515, P=0.009). The 2-year infection control rate exceeded 90% in both stages B and C, surpassing stage A (71.4%) (χ2 = 8.317, P=0.011). Combined application of all three optimized protocols yielded the highest sensitivity of 91.21% for pathogen detection, while retaining higher specificity of 92.11%.

Conclusion

The utilization of combined pathogen diagnostic strategies in PJI can increase pathogen detection rates, improve targeted antibiotic prescription, reduce the occurrence of antibiotic complications, and achieve better treatment outcomes.

Rapid high-throughput processing of tissue samples for microbiological diagnosis of periprosthetic joint infections using bead-beating homogenization

Enrichment of periprosthetic tissue samples in blood culture bottles (BCBs) for microbiological diagnosis of periprosthetic joint infections (PJI) is more reliable than the use of an enrichment broth. Nevertheless, the extremely time-consuming homogenization of the samples for BCB processing has so far limited its use, especially in high-throughput settings. We aimed to establish a highly scalable homogenization process of tissue samples for long-term incubation in BCBs. A protocol for homogenization of tissue samples using bead beating was established and validated. In a second step, the use of the homogenate for enrichment in BCBs was compared to the use of thioglycolate broth (TB) in terms of diagnostic accuracy using clinical tissue samples from 150 patients with suspected PJI. Among 150 analyzed samples, 35 samples met the microbiological criteria for PJI. Using BCB, 32 of 35 (91.4%) PJI were detected compared to 30 of 35 (85.7%) by TB. The use of BCB had a lower secondary contamination rate (2/115; 1.7% vs 4/115; 3.5%) but the trend was not significant due to low numbers of samples (P = 0.39). The time to process a batch of 12 samples using the established homogenization method was 23 ± 5 min (n = 10 batches). We established and validated a homogenization workflow that achieves the highest sensitivity in the microbiological diagnostic of PJI. The enrichment of the tissue homogenate in BCBs showed equally good results as the use of enrichment broth and allows semi-automated high-throughput processing while demonstrating lower contamination rates in our study.

Differences in Diagnostic Sensitivity of Cultures Between Sample Types in Periprosthetic Joint Infections: A Systematic Review and Meta-Analysis

BACKGROUND

Differences between the bacterial culture results of the preoperative fluid, intraoperative tissue, and sonication fluid of implants in the diagnosis of periprosthetic joint infection (PJI) are important issues in clinical practice. This study aimed to identify the differences in pooled diagnostic accuracy between culture sample types for diagnosing PJI by performing a systematic review and meta-analysis.

METHODS

This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. A comprehensive literature search of PubMed, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library databases was performed. Data extraction and study assessment using the quality assessment of diagnostic accuracy studies were performed independently by two reviewers. The pooled sensitivity, specificity, summary receiver operating characteristic curve, and area under the summary receiver operating characteristic curve were estimated for each sample type.

RESULTS

There were thirty-two studies that were included in the analysis after screening and eligibility assessment. The pooled sensitivities of preoperative fluid, intraoperative tissue, and sonication fluid for the diagnosis of PJI were 0.63 (95% confidence interval [CI] 0.56 to 0.70), 0.71 (95% CI 0.63 to 0.79), and 0.78 (95% CI 0.68 to 0.85), while the specificities were 0.96 (95% CI 0.93 to 0.98), 0.92 (95% CI 0.86 to 0.96), and 0.91 (95% CI 0.83 to 0.95), respectively. The area under the curves for preoperative fluid, intraoperative tissue, and sonication fluid were 0.86, 0.88, and 0.90, respectively.

CONCLUSIONS

Sonication fluid culture demonstrated better sensitivity compared with the conventional culture method, and preoperative fluid culture provided lower sensitivity in diagnosing PJI.

Bacteria Living in Biofilms in Fluids: Could Chemical Antibiofilm Pretreatment of Culture Represent a Paradigm Shift in Diagnostics?

Biofilms are multicellular aggregates of bacteria immersed in an extracellular matrix that forms on various surfaces, including biological tissues and artificial surfaces. However, more and more reports point out the fact that even biological fluids and semifluid, such as synovial liquid, blood, urine, or mucus and feces, harbor "non-attached" biofilm aggregates of bacteria, which represent a significant phenomenon with critical clinical implications that remain to be fully investigated. In particular, biofilm aggregates in biological fluid samples have been shown to play a relevant role in bacterial count and in the overall accuracy of microbiological diagnosis. In line with these observations, the introduction in the clinical setting of fluid sample pretreatment with an antibiofilm chemical compound called dithiothreitol (DTT), which is able to dislodge microorganisms from their intercellular matrix without killing them, would effectively improve the microbiological yield and increase the sensitivity of cultural examination, compared to the current microbiological techniques. While other ongoing research continues to unveil the complexity of biofilm formation in biological fluids and its impact on infection pathogenesis and diagnosis, we here hypothesize that the routine use of a chemical antibiofilm pretreatment of fluid and semi-solid samples may lead to a paradigm shift in the microbiological approach to the diagnosis of biofilm-related infections and should be further investigated and eventually implemented in the clinical setting.

Diagnosis of periprosthetic joint infections in patients who have rheumatoid arthritis

Aims

To investigate the optimal thresholds and diagnostic efficacy of commonly used serological and synovial fluid detection indexes for diagnosing periprosthetic joint infection (PJI) in patients who have rheumatoid arthritis (RA).

Methods

The data from 348 patients who had RA or osteoarthritis (OA) and had previously undergone a total knee (TKA) and/or a total hip arthroplasty (THA) (including RA-PJI: 60 cases, RA-non-PJI: 80 cases; OA-PJI: 104 cases, OA-non-PJI: 104 cases) were retrospectively analyzed. A receiver operating characteristic curve was used to determine the optimal thresholds of the CRP, ESR, synovial fluid white blood cell count (WBC), and polymorphonuclear neutrophil percentage (PMN%) for diagnosing RA-PJI and OA-PJI. The diagnostic efficacy was evaluated by comparing the area under the curve (AUC) of each index and applying the results of the combined index diagnostic test.

Results

For PJI prediction, the results of serological and synovial fluid indexes were different between the RA-PJI and OA-PJI groups. The optimal cutoff value of CRP for diagnosing RA-PJI was 12.5 mg/l, ESR was 39 mm/hour, synovial fluid WBC was 3,654/μl, and PMN% was 65.9%; and those of OA-PJI were 8.2 mg/l, 31 mm/hour, 2,673/μl, and 62.0%, respectively. In the RA-PJI group, the specificity (94.4%), positive predictive value (97.1%), and AUC (0.916) of synovial fluid WBC were higher than those of the other indexes. The optimal cutoff values of synovial fluid WBC and PMN% for diagnosing RA-PJI after THA were significantly higher than those of TKA. The specificity and positive predictive value of the combined index were 100%.

Conclusion

Serum inflammatory and synovial fluid indexes can be used for diagnosing RA-PJI, for which synovial fluid WBC is the best detection index. Combining multiple detection indexes can provide a reference basis for the early and accurate diagnosis of RA-PJI.

Multiplex PCR-based next generation sequencing as a novel, targeted and accurate molecular approach for periprosthetic joint infection diagnosis

Objectives

Periprosthetic joint infection (PJI) diagnosis remains challenging, and the identification of the causative microorganism is, by far, the most important aspect. Here, we use multiple PCR-based targeted next-generation sequencing (tNGS) to detect pathogens in PJI. To explore 1. the ability of targeted next-generation sequencing (tNGS) to detect pathogens in PJI; 2. the consistency of tNGS, metagenomic NGS (mNGS), and culture results; and 3. the ability of tNGS to detect drug resistance genes in PJI.

Methods

PJI was diagnosed according to the Musculoskeletal Infection Society (MSIS) criteria. The microorganisms were detected by culture, mNGS and tNGS to compare the diagnostic effectiveness of the three methods for PJI and to compare their consistency in detecting microorganisms. Drug resistance genes were detected using tNGS. The costs and turnaround times of mNGS and tNGS were compared.

Results

Forty-three patients with PJI, 21 patients without PJI and 10 negative control cases were included. The culture, tNGS, and mNGS sensitivities for PJI diagnosis were 74.41%, 88.37%, and 93.02%, respectively, with no significant differences. The specificities were 90.48%, 95.24%, and 95.24%, respectively, with no significant differences. tNGS detected drug resistance genes in 37.5% of culture-positive PJIs. tNGS was superior to mNGS for turnaround time (14.5 h vs. 28 h) and cost ($150 vs. $260).

Conclusions

tNGS can effectively identify PJI pathogens and may provide drug resistance information, while tNGS is superior to mNGS regarding cost and turnaround time. A multidisciplinary, multi-technology based algorithm to diagnose PJI is appropriate.

Highlights

298 microorganisms and 86 drug resistance genes were included in the tNGS panel.Diagnostic efficacy of tNGS is not inferior to that of commonly used indicators.tNGS is superior to mNGS in cost and turnaround time.

Intraoperative Direct Sonication of Implants and Soft Tissue for the Diagnosis of Periprosthetic Joint Infection

BACKGROUND

Sonication is very efficacious for the microbiological diagnosis of periprosthetic joint infection (PJI), but it involves many steps and multiple workplaces and personnel and therefore carries a potential contamination risk. We present an innovative version of the sonication culture method that involves direct sonication of the retrieved implant and soft tissue, without a sonication tube, intraoperatively and incubation using a BACT/ALERT 3D blood culture system to enhance the efficacy of microbiological diagnosis of PJI.

METHODS

We performed a prospective study of consecutive patients requiring implant removal and classified them as having PJI or aseptic failure according to standard criteria. The removed prosthetic components and adjacent soft tissue were directly sonicated in a small metal container, without a sonication tube, during the operation. The sonication fluid was immediately incubated in blood culture bottles in the operating room and cultured in the BACT/ALERT 3D blood culture system. The synovial fluid was also cultured in the BACT/ALERT 3D system to serve as a comparison.

RESULTS

Of the 64 included patients, 36 had PJI and 28 had aseptic failure. Fluid from direct sonication and conventional synovial fluid showed sensitivities of 91.7% and 55.6% (p < 0.001) and specificities of 82.1% and 92.9%, respectively. Fourteen cases of PJI were detected by culture of fluid from direct sonication but not by culture of synovial fluid. Higher sensitivity was obtained by direct sonication of only tissue than by direct sonication of only the implant (88.9% versus 75.0%). No significant difference in detection time was found between Staphylococcus aureus and coagulase-negative Staphylococcus.

CONCLUSIONS

When combined with incubation in BACT/ALERT bottles, direct intraoperative sonication of implants and soft tissues without a sonication tube was more sensitive than conventional synovial fluid culture and could reliably and rapidly detect the bacteria commonly found in PJI.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Synovial fluid neutrophil extracellular traps could improve the diagnosis of periprosthetic joint infection

AIMS

This study aimed to explore the diagnostic value of synovial fluid neutrophil extracellular traps (SF-NETs) in periprosthetic joint infection (PJI) diagnosis, and compare it with that of microbial culture, serum ESR and CRP, synovial white blood cell (WBC) count, and polymorphonuclear neutrophil percentage (PMN%).

METHODS

In a single health centre, patients with suspected PJI were enrolled from January 2013 to December 2021. The inclusion criteria were: 1) patients who were suspected to have PJI; 2) patients with complete medical records; and 3) patients from whom sufficient synovial fluid was obtained for microbial culture and NET test. Patients who received revision surgeries due to aseptic failure (AF) were selected as controls. Synovial fluid was collected for microbial culture and SF-WBC, SF-PNM%, and SF-NET detection. The receiver operating characteristic curve (ROC) of synovial NET, WBC, PMN%, and area under the curve (AUC) were obtained; the diagnostic efficacies of these diagnostic indexes were calculated and compared.

RESULTS

The levels of SF-NETs in the PJI group were significantly higher than those of the AF group. The AUC of SF-NET was 0.971 (95% confidence interval (CI) 0.903 to 0.996), the sensitivity was 93.48% (95% CI 82.10% to 98.63%), the specificity was 96.43% (95% CI 81.65% to 99.91%), the accuracy was 94.60% (95% CI 86.73% to 98.50%), the positive predictive value was 97.73%, and the negative predictive value was 90%. Further analysis showed that SF-NET could improve the diagnosis of culture-negative PJI, patients with PJI who received antibiotic treatment preoperatively, and fungal PJI.

CONCLUSION

SF-NET is a novel and ideal synovial fluid biomarker for PJI diagnosis, which could improve PJI diagnosis greatly.Cite this article: Bone Joint Res 2023;12(2):113-120.

What is the Accuracy of a Rapid Strip Test That Detects D-lactic Acid in Synovial Fluid for the Diagnosis of Periprosthetic Joint Infections?

BACKGROUND

D-lactic acid is a specific marker produced almost exclusively by bacterial species; thus, the appearance of this marker in synovial fluid may indicate periprosthetic joint infection (PJI). Recently, studies have investigated the accuracy of enzyme-linked laboratory tests that detect D-lactic acid in synovial fluid to diagnose PJI. However, to our knowledge, no studies have determined the usefulness of rapid strip tests that detect D-lactic acid in synovial fluid in the diagnosis of PJI.

QUESTIONS/PURPOSES

(1) What is the best cutoff value for the rapid D-lactic acid strip test for diagnosing PJI? (2) What are the diagnostic accuracies (sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV]) of the rapid D-lactic acid strip test and two different rapid leukocyte esterase (LE) strip tests?

METHODS

This prospective study enrolled 157 patients who underwent revision THA or TKA from May 2021 to February 2022 at a single orthopaedic center. Seventy percent (110 of 157) were eligible for analysis; 10% of these patients (15 of 157) were excluded based on the exclusion criteria (causes of revisions and additional comorbidities that may interfere with the results), and 20% (32 of 157) of the synovial fluid samples could not be tested (dry taps and blood-contaminated samples that could not be centrifuged). We performed the following off-label diagnostic tests on synovial fluid samples collected from all patients: the D-lactic acid strip test (QuantiQuick TM , BioAssay System), two different LE strip tests (10 EA from ARKRAY and BM 10 from BioMaxima). Differently colored strips were marked with symbols (from [-] to [++++] for D-lactic acid and from [-] to [+++] for LE tests) according to the manufacturers' instructions. For the LE tests, results were different for (++), which corresponds to a minimal value of 250 leu/mL for 10 EA and 125 leu/mL for BM 10 tests. The diagnostic standard for the presence or absence of PJI in this study was the International Consensus Meeting (ICM) 2018 criteria; based on these criteria (without the application of an LE test as a minor criterion), all patients were assessed and divided into two groups. Patients who did not meet the criteria for PJI and underwent revision for aseptic loosening, implant malposition, instability, or implant damage were included in the aseptic revision total joint arthroplasty group (68 patients). Patients with a fistula penetrating the joint, those with two positive culture results of the same pathogen, or those with ≥ 6 points according to ICM 2018 minor criteria were enrolled in the PJI group (42 patients). To ascertain the best cutoff value for the rapid D-lactic acid and both LE strip tests for diagnosing PJI, we used collected results, generated a receiver operating characteristic curve, and calculated the Youden index. To determine the accuracies of the diagnostic tests, we calculated their sensitivities, specificities, PPVs, and NPVs against the diagnostic standard (the ICM 2018 criteria).

RESULTS

The best cutoff value for D-lactic acid was 22.5 mg/L, which corresponded to a reading of (+) on the test strip. For D-lactic acid, in the diagnosis of PJI, the sensitivity was 83% (95% confidence interval [CI] 68% to 92%) and specificity was 100% (95% CI 93% to 100%). For both LE strip tests, the best cutoff value was the same as that proposed in the ICM 2018 criteria. For LE (10 EA), the sensitivity was 81% (95% CI 66% to 91%) and specificity was 99% (95% CI 91% to 100%); for LE (BM 10), sensitivity was 81% (95% CI 65% to 91%) and specificity was 97% (95% CI 89% to 100%).

CONCLUSION

A rapid off-label D-lactic acid strip test is valuable for diagnosing PJI. The results of this study indicate very good accuracy with comparable sensitivity and specificity for both LE strip tests. The usefulness of the test in a group of patients with chronic inflammatory diseases and the reproducibility of the reading by different researchers were not analyzed in this study and require further investigations. Before a rapid D-lactic strip test is routinely used for diagnosing PJI, multicenter studies on a larger group of patients should be conducted.Level of Evidence Level II, diagnostic study.

Patient-Reported Outcome on Quality of Life and Pain after Revision Arthroplasty for Periprosthetic Joint Infection: A Cross-Sectional Study

This study aims to explore the quality of life (QOL) and pain after revision surgery for periprosthetic joint infection (PJI) based on patients' reported outcomes. A cross-sectional questionnaire survey was conducted and 137 valid responses were included (response rate 64.0%). A total of 42 patients underwent debridement with implant retention (DAIR), 31 underwent one-stage revision, and 64 underwent two-stage revision. The average overall SF-36 score was 70.3. The DAIR group had significantly higher SF-36 than the two-stage revision group (p = 0.01). There was no significant difference between the one-stage revision group and the other two groups. A total of 74.5% of patients reported pain with an average McGill Pain Questionnaire (MPQ) score of 8.6. There was no significant difference in the MPQ scores among the three groups. Simple linear regression analyses demonstrated that higher preoperative PMN%, VAS, and shorter hospital stay were associated with pain (adjusted R² = 4%, p = 0.020; adjusted R² = 2.1%, p = 0.048; adjusted R² = 2.1%, p = 0.049; respectively). We concluded that the overall QOL of patients after revision surgery for PJI is generally satisfactory. Persistent pain is prevalent, but the severity was mostly mild. Preoperative PMN%, VAS, and hospital stay were associated with postoperative pain.

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.

The role of metagenomic next-generation sequencing in the pathogen detection of invasive osteoarticular infection

OBJECTIVE

This study aimed to analyzed the pathogenic bacteria spectrum in invasive and primary osteoarticular infection (IOI and POI), and compared the pathogen detection rate of metagenomic next-generation sequencing (mNGS) and microbial culture in IOI and POI.

METHODS

The suspected POI and IOI cases from 2008 to 2021 were included. The diagnosis of POI or IOI were made by at least two orthopaedic surgeons, two infectious diseases specialist and one senior microbiologist. Demographic characteristics, microbial culture results and so on were recorded. The pathogenic bacteria spectrum in IOI and POI were analyzed and the ability of mNGS and microbial culture in pathogen detection in IOI and POI were compared.

RESULTS

There were 63 POI cases and 92 cases, the common pathogen in POI and IOI were both Staphylococcus aureus. There are more cases with negative microbial culture results and multiple infections in IOI, and many cases were caused by rare and fastidious bacteria. The introduction of the mNGS could significantly increase the pathogen detection rate to 92.39% in IOI, which was 8.69% higher than that of microbial culture (P=0.007), while the improvement in POI was limited to about 2%.

CONCLUSIONS

mNGS was an ideal tool for IOI pathogen detection.

Metal Artifact Reduction Sequences MRI: A Useful Reference for Preoperative Diagnosis and Debridement Planning of Periprosthetic Joint Infection

The diagnosis and treatment of periprosthetic joint infection (PJI) is complex and the use of MRI in PJI is gaining attention from orthopedic surgeons as MR technology continues to advance. This study aimed to investigate whether metal artefact reduction sequence (MARS) MRI could be used as an adjunct in the preoperative diagnosis of PJI and to explore its role in PJI debridement planning. From January 2020 to November 2021, participants with metal joint prostheses that needed to be judged for infection were prospectively enrolled. According to Musculoskeletal Infection Society standards, 31 cases were classified as infection, and 20 as non-infection. The sensitivity and specificity of MARS MRI for the diagnosis of PJI were 80.65% and 75%, respectively. In MARS MRI, the incidence of bone destruction, lamellar synovitis, and extracapsular soft tissue oedema were significantly higher in PJI than in non-PJI. Fourteen suspicious occult lesions were found in the preoperative MARS MRI in 9 cases, and the location of 9 infection lesions was confirmed intraoperatively. In conclusion, MARS MRI is an effective diagnostic tool for PJIand can provide a visual reference for preoperative surgical planning.

Application of 68Ga-citrate PET/CT for differentiating periprosthetic joint infection from aseptic loosening after joint replacement surgery

AIMS

We aimed to evaluate the utility of ⁶⁸Ga-citrate positron emission tomography (PET)/CT in the differentiation of periprosthetic joint infection (PJI) and aseptic loosening (AL), and compare it with ^99mTc-methylene bisphosphonates (^99mTc-MDP) bone scan.

METHODS

We studied 39 patients with suspected PJI or AL. These patients underwent ⁶⁸Ga-citrate PET/CT, ^99mTc-MDP three-phase bone scan and single-photon emission CT (SPECT)/CT. PET/CT was performed at ten minutes and 60 minutes after injection, respectively. Images were evaluated by three nuclear medicine doctors based on: 1) visual analysis of the three methods based on tracer uptake model, and PET images attenuation-corrected with CT and those not attenuation-corrected with CT were analyzed, respectively; and 2) semi-quantitative analysis of PET/CT: maximum standardized uptake value (SUVmax) of lesions, SUVmax of the lesion/SUVmean of the normal bone, and SUVmax of the lesion/SUVmean of the normal muscle. The final diagnosis was based on the clinical and intraoperative findings, and histopathological and microbiological examinations.

RESULTS

Overall, 23 and 16 patients were diagnosed with PJI and AL, respectively. The sensitivity and specificity of three-phase bone scan and SPECT/CT were 100% and 62.5%, 82.6%, and 100%, respectively. Attenuation correction (AC) at 60 minutes and non-AC at 60 minutes of PET/CT had the same highest sensitivity and specificity (91.3% and 100%), and AC at 60 minutes combined with SPECT/CT could improve the diagnostic efficiency (sensitivity = 95.7%). Diagnostic efficacy of the SUVmax was low (area under the curve (AUC) of ten minutes and 60 minutes was 0.814 and 0.806, respectively), and SUVmax of the lesion/SUVmean of the normal bone at 60 minutes was the best semi-quantitative parameter (AUC = 0.969).

CONCLUSION

⁶⁸Ga-citrate showed the potential to differentiate PJI from AL, and visual analysis based on uptake pattern of tracer was reliable. The visual analysis method of AC at 60 minutes, combined with ^99mTc-MDP SPECT/CT, could improve the sensitivity from 91.3% to 95.7%. In addition, a major limitation of our study was that it had a limited sample size, and more detailed studies with a larger sample size are warranted. Cite this article: Bone Joint Res 2022;11(6):398-408.

Development and Evaluation of a Film Forming System Containing Myricetin and Miconazole Nitrate for Preventing Candida albicans Catheter-Related Infection

Background: Candida albicans catheter-related infection (CRI) is a great challenge in clinic now, mainly due to the difficulty in eradicating the biofilms. Purpose: In this study, the mechanism of the antibiofilm effect of myricetin (MY) on C. albicans was illustrated. A film forming system (FFS) containing MY and miconazole nitrate (MN) was developed, optimized, and evaluated. The anti-infection effect of MY+MN@FFS against C. albicans CRI was investigated in vivo. Study Design and Methods: To clarify the mechanism of the action of MY, the influence of MY on each key process of the formation of C. albicans biofilms was evaluated. To deliver MY and MN into the skin and form a drug reservoir on the surface of the skin, the FFS was used as a carrier and MY+MN@FFS was developed, optimized, and evaluated. After preliminary confirmation of drug safety, a percutaneously inserted C. albicans CRI mouse model was established to investigate the in vivo anti-infection effect of MY+MN@FFS by fluorescence microscopy and scanning electron microscopy on the outer surface of the catheters, hematoxylin/eosin staining, and periodic acid-Schiff staining of the mice skin tissues. Results: MY was found to inhibit the morphological transition of C. albicans and the secretion of exopolysaccharides, resulting in a reduction in biofilms. MY+MN@FFS exhibited excellent properties and no irritation to mice skin. In an in vivo anti-infection study, MY+MN@FFS exhibited an excellent preventive effect against percutaneously inserted C. albicans CRI. Conclusion: MY+MN@FFS might be a potential approach for effectively preventing percutaneously inserted C. albicans CRI in clinic.

Is sonication superior to dithiothreitol in diagnosis of periprosthetic joint infections? A meta-analysis

PURPOSE

Even though effective techniques in diagnosis of periprosthetic joint infections (PJIs) have been developed, the optimal modality has yet to be determined. The present meta-analysis aimed to compare the diagnostic accuracy of dithiothreitol (DTT) and sonication against the Musculoskeletal Infection Society criteria in patients undergoing revision joint surgery.

METHODS

We searched the PubMed, Scopus, and Central Cochrane register of controlled trials as well as gray literature until the 9th of November, 2021. We included articles considering the comparative diagnostic accuracy of sonication and DTT in adult patients having revision hip and knee arthroplasty for septic or aseptic reasons. We calculated pooled sensitivity, specificity, and diagnostic accuracy of the above diagnostic techniques against the Musculoskeletal Infection Society (MSIS) criteria and created receiver operating characteristics (ROC) curves to enable comparisons between each other. The quality of included papers was evaluated utilizing QUADAS-2 and QUADAS-C tools.

RESULTS

Data from five comparative studies totaling 726 implants were pooled together. The diagnostic accuracy of DTT and sonication were 86.7% (95% CI 82.7 to 90.1) and 83.9% (95% CI 79.7 to 87.5), respectively. Pooled sensitivity and specificity showed no statistically significant differences between DTT and sonication (0.7 [95% CI 0.62 to 0.77] vs 0.72 [95% CI 0.65 to 0.78], p = 0.14; and 0.99 [95% CI 0.97 to 1] vs 0.97 [95% CI 0.93 to 0.99], p = 5.5, respectively).

CONCLUSIONS

This meta-analysis did not identify any clinically meaningful difference between the diagnostic potential of sonication and the chemical-based biofilm dislodgment methods. This finding remained robust after adjusting for the administration of antibiotics prophylaxis, implementation of the polymerase chain reaction of sonicated fluid, and study quality.

What is the appropriate extended duration of antibiotic prophylaxis after two-stage revision for chronic PJI?

Aims

To explore the effect of different durations of antibiotics after stage II reimplantation on the prognosis of two-stage revision for chronic periprosthetic joint infection (PJI).

Methods

This study involved a retrospective collection of patients who underwent two-stage revision for chronic PJI and continued to use extended antibiotic prophylaxis in two regional medical centres from January 2010 to June 2018. The patients were divided into a short (≤ one month) or a long (> one month) course of treatment based on the duration of antibiotics following stage II reimplantation. The difference in the infection control rate between the two groups was compared, and prognostic factors for recurrence were analyzed.

Results

A total of 105 patients with chronic PJI were enrolled: 64 patients in the short course group and 41 patients in the long course group. For 99 of the patients, the infection was under control during a follow-up period of at least 24 months after two-stage revision. For the short course group, the mean duration of antibiotic prophylaxis after stage II reimplantation was 20.17 days (SD 5.30) and the infection control rate was 95.3%; for the long course group these were 45.02 days (SD 15.03) and 92.7%, respectively. There was no significant difference in infection control rates between the two groups (p = 0.676). Cox regression analysis found that methicillin-resistant staphylococcus infection (p = 0.015) was an independent prognostic factor for recurrence.

Conclusion

After stage II reimplantation surgery of two-stage revision for chronic PJI, extended antibiotic prophylaxis for less than one month can achieve good infection control rate.

Cite this article: Bone Joint Res 2021;10(12):790–796.