Aims. This study aimed to explore the role of small colony variants (SCVs) of Staphylococcus aureus in intraosseous invasion and colonization in patients with periprosthetic joint infection (PJI). Methods. A PJI diagnosis was made according to the MusculoSkeletal Infection Society (MSIS) for PJI. Bone and tissue samples were collected intraoperatively and the intracellular invasion and intraosseous colonization were detected. Transcriptomics of PJI samples were analyzed and verified by polymerase chain reaction (PCR). Results. SCVs can be isolated from samples collected from chronic PJIs intraoperatively. Transmission electron microscopy (TEM) and immunofluorescence (IF) showed that there was more S. aureus in bone samples collected from chronic PJIs, but much less in bone samples from acute PJIs, providing a potential mechanism of PJI. Immunofluorescence results showed that SCVs of S. aureus were more likely to invade osteoblasts in vitro. Furthermore, TEM and IF also demonstrated that SCVs of S. aureus were more likely to invade and colonize in vivo. Cluster analysis and principal component analysis (PCA) showed that there were substantial differences in gene expression profiles between chronic and acute PJI. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that these differentially expressed genes were enriched to chemokine-related signal pathways. PCR also verified these results. Conclusion. Our study has shown that the S. aureus SCVs have a greater ability to invade and colonize in bone, resulting in S. aureus remaining in bone tissues long-term, thus explaining the pathogenesis of chronic PJI. Cite this article: Bone Joint Res 2022;11(12):843–853

Aims. Flucloxacillin is commonly administered intravenously for perioperative antimicrobial prophylaxis, while oral administration is typical for prophylaxis following smaller traumatic wounds. We assessed the time, for which the free flucloxacillin concentration was maintained above the minimum inhibitory concentration (fT > MIC) for methicillin-susceptible Staphylococcus aureus in soft and bone tissue, after intravenous and oral administration, using microdialysis in a porcine model. Methods. A total of 16 pigs were randomly allocated to either intravenous (Group IV) or oral (Group PO) flucloxacillin 1 g every six hours during a 24-hour period. Microdialysis was used for sampling in cancellous and cortical bone, subcutaneous tissue, and the knee joint. In addition, plasma was sampled. The flucloxacillin fT > MIC was evaluated using a low MIC target (0.5 μg/ml) and a high MIC target (2.0 μg/ml). Results. Intravenous administration resulted in longer fT > MIC (0.5 μg/ml) compared to oral administration, except for cortical bone. In Group IV, all pigs reached a concentration of 0.5 μg/ml in all compartments. The mean fT > MIC (0.5 μg/ml) was 149 minutes (95% confidence interval (CI) 119 to 179; range 68 to 323) in subcutaneous tissue and 61 minutes (95% CI 29 to 94; range 0 to 121) to 106 minutes (95% CI 76 to 136; range 71 to 154) in bone tissue. In Group PO, 0/8 pigs reached a concentration of 0.5 μg/ml in all compartments. For the high MIC target (2.0 μg/ml), fT > MIC was close to zero minutes in both groups across compartments. Conclusion. Although intravenous administration of flucloxacillin 1 g provided higher fT > MIC for the low MIC target compared to oral administration, concentrations were surprisingly low, particularly for bone tissue. Achievement of sufficient bone and soft tissue flucloxacillin concentrations may require a dose increase or continuous administration. Cite this article: Bone Joint Res 2021;10(1):60–67

Aims. CERAMENT|G is an absorbable gentamicin-loaded biocomposite used as an on-site vehicle of antimicrobials for the treatment of chronic osteomyelitis. The purpose of the present study was to investigate the sole effect of CERAMENT|G, i.e. without additional systemic antimicrobial therapy, in relation to a limited or extensive debridement of osteomyelitis lesions in a porcine model. Methods. Osteomyelitis was induced in nine pigs by inoculation of 10. 4. colony-forming units (CFUs) of Staphylococcus aureus into a drill hole in the right tibia. After one week, the pigs were allocated into three groups. Group A (n = 3) received no treatment during the study period (19 days). Groups B (n = 3) and C (n = 3) received limited or extensive debridement seven days postinoculation, respectively, followed by injection of CERAMENT|G into the bone voids. The pigs were euthanized ten (Group C) and 12 (Group B) days after the intervention. Results. All animals presented confirmatory signs of bone infection post-mortem. The estimated amount of inflammation was substantially greater in Groups A and B compared to Group C. In both Groups B and C, peptide nucleic acid fluorescence in situ hybridization (PNA FISH) of CERAMENT|G and surrounding bone tissue revealed bacteria embedded in an opaque matrix, i.e. within biofilm. In addition, in Group C, the maximal measured post-mortem gentamicin concentrations in CERAMENT|G and surrounding bone tissue samples were 16.6 μg/ml and 6.2 μg/ml, respectively. Conclusion. The present study demonstrates that CERAMENT|G cannot be used as a standalone alternative to extensive debridement or be used without the addition of systemic antimicrobials. Cite this article: Bone Joint Res 2020;9(7):394–401

Aims

The management of periprosthetic joint infection (PJI) remains a major challenge in orthopaedic surgery. In this study, we aimed to characterize the local bone microstructure and metabolism in a clinical cohort of patients with chronic PJI.

Aims

With the ageing population, fragility fractures have become one of the most common conditions. The objective of this study was to investigate whether microbiological outcomes and fracture-healing in osteoporotic bone is worse than normal bone with fracture-related infection (FRI).

Aims

Although low-intensity pulsed ultrasound (LIPUS) combined with disinfectants has been shown to effectively eliminate portions of biofilm in vitro, its efficacy in vivo remains uncertain. Our objective was to assess the antibiofilm potential and safety of LIPUS combined with 0.35% povidone-iodine (PI) in a rat debridement, antibiotics, and implant retention (DAIR) model of periprosthetic joint infection (PJI).

Aims

Prompt and sufficient broad-spectrum empirical antibiotic treatment is key to preventing infection following open tibial fractures. Succeeding co-administration, we dynamically assessed the time for which vancomycin and meropenem concentrations were above relevant epidemiological cut-off (ECOFF) minimal inhibitory concentrations (T > MIC) in tibial compartments for the bacteria most frequently encountered in open fractures. Low and high MIC targets were applied: 1 and 4 µg/ml for vancomycin, and 0.125 and 2 µg/ml for meropenem.

Objective

In the present study, we aimed to assess whether gelatin/β-tricalcium phosphate (β-TCP) composite porous scaffolds could be used as a local controlled release system for vancomycin. We also investigated the efficiency of the scaffolds in eliminating infections and repairing osteomyelitis defects in rabbits.

Objectives

The aim of this study was to analyze drain fluid, blood, and urine simultaneously to follow the long-term release of vancomycin from a biphasic ceramic carrier in major hip surgery. Our hypothesis was that there would be high local vancomycin concentrations during the first week with safe low systemic trough levels and a complete antibiotic release during the first month.