Prosthetic joint infection after total hip arthroplasty caused by Lactobacillus paracasei

Dual-Energy Computed Tomography Iodine Maps: Application in the Diagnosis of Periprosthetic Joint Infection in Total Hip Arthroplasty

BACKGROUND

The challenge of early and rapid diagnosis of periprosthetic joint infection (PJI) remains important. This study aimed to assess the efficacy of dual-energy computed tomography (CT) (DECT) iodine maps for diagnosing PJI in total hip arthroplasty.

METHODS

We prospectively enrolled 68 patients who had postoperative joint pain after hip arthroplasty. All patients underwent preoperative DECT iodine imaging to quantify iodine concentration (IC) in periprosthetic tissues during arterial and venous phases. The diagnostic efficacy of DECT iodine maps was evaluated by constructing receiver operating characteristic (ROC) curves according to the Musculoskeletal Infection Society criteria.

RESULTS

Compared with erythrocyte sedimentation rate (Area Under the Curve (AUC) = 0.837), polymorphonuclear cell percentage (AUC = 0.703), and C-reactive protein (AUC = 0.837), periprosthetic tissue venous-phase iodine concentration (IC) (AUC = 0.970) and arterial-phase IC (AUC = 0.964) exhibited outstanding discriminative capability between PJI and aseptic failure. The PJI cut-off point was venous IC = 1.225 mg/ml, with a sensitivity of 92.31% and specificity of 90.48%; for arterial IC = 1.065 mg/ml, the sensitivity was 96.15%, and a specificity was 90.70%.

CONCLUSION

This study demonstrates the great potential of DECT iodine maps for the diagnosis of PJI around hip arthroplasty, which helps to differentiate between periprosthetic infection and aseptic failure after hip arthroplasty.

Current Status and Perspectives of Diagnosis and Treatment of Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) is a catastrophic complication following joint replacement surgery, posing significant challenges to orthopedic surgeons. Due to the lack of a definitive diagnostic gold standard, timely treatment initiation is problematic, resulting in substantial economic burdens on patients and society. In this review, we thoroughly analyze the complexities of PJI and emphasize the importance of accurate diagnosis and effective treatment. The article specifically focuses on the advancements in diagnostic techniques, ranging from traditional pathogen culture to advanced molecular diagnostics, and discusses their role in enhancing diagnostic accuracy. Additionally, we review the latest surgical management strategies, including everything from debridement to revision surgeries. Our summary aims to provide practical information for the diagnosis and treatment of PJI and encourages further research to improve diagnostic accuracy and treatment outcomes.

Extracellular Proteins Isolated from L. acidophilus as an Osteomicrobiological Therapeutic Agent to Reduce Pathogenic Biofilm Formation, Regulate Chronic Inflammation, and Augment Bone Formation In Vitro

Periprosthetic joint infection (PJI) is a challenging complication that can occur following joint replacement surgery. Efficacious strategies to prevent and treat PJI and its recurrence remain elusive. Commensal bacteria within the gut convey beneficial effects through a defense strategy named "colonization resistance" thereby preventing pathogenic infection along the intestinal surface. This blueprint may be applicable to PJI. The aim is to investigate Lactobacillus acidophilus spp. and their isolated extracellular-derived proteins (LaEPs) on PJI-relevant Staphylococcus aureus, methicillin-resistant S. aureus, and Escherichia coli planktonic growth and biofilm formation in vitro. The effect of LaEPs on cultured macrophages and osteogenic, and adipogenic human bone marrow-derived mesenchymal stem cell differentiation is analyzed. Data show electrostatically-induced probiotic-pathogen species co-aggregation and pathogenic growth inhibition together with LaEP-induced biofilm prevention. LaEPs prime macrophages for enhanced microbial phagocytosis via cathepsin K, reduce lipopolysaccharide-induced DNA damage and receptor activator nuclear factor-kappa B ligand expression, and promote a reparative M2 macrophage morphology under chronic inflammatory conditions. LaEPs also significantly augment bone deposition while abating adipogenesis thus holding promise as a potential multimodal therapeutic strategy. Proteomic analyses highlight high abundance of lysyl endopeptidase, and urocanate reductase. Further, in vivo analyses are warranted to elucidate their role in the prevention and treatment of PJIs.

Prosthetic joint infection caused by an imipenem-resistant Mycobacterium senegalense

Periprosthetic joint infection (PJI) remains one of the most common complications of total knee arthroplasty. Although mainly caused by Staphylococcus aureus and other Gram-positive microorganisms, occasionally, commensal or environmental bacteria are reported as causative agents of these infections. The present work aimed to report a case of PJI caused by an imipenem-resistant Mycobacterium senegalense strain. A bacterial strain isolated from the culture of intraoperative samples was observed by optical microscopy after Gram and Ziehl-Neelsen staining. The species identification was performed by mass spectrometry analysis and partial sequencing of the heat shock protein 65 (hsp65) gene. The antimicrobial profile of the clinical isolate was determined according to the Clinical and Laboratory Standards Institute. Mass spectrometry and gene sequencing analysis identified the bacterial isolate as Mycobacterium fortuitum complex and M. senegalense, respectively. The isolated was found exhibiting an imipenem-resistant profile. The accurate and timely identification, as well as investigation of the antimicrobial susceptibility profile, of fast-growing nontuberculous mycobacteria species are crucial for establishing the prompt and correct treatment of the infection, particularly in cases of patients at greater risk for opportunistic and severe infections.

The prevalence and risk factors of dislocation after primary total hip arthroplasty

This study aimed to investigate the occurrence of dislocation and risk factors following primary total hip arthroplasty (THA). Retrospective analysis was done on the clinical data of 441patients with primary total hip arthroplasty who were admitted to our hospital between May 2018 and early December 2020. A total of 294 patients without posterior soft tissue repair were included as control group, and a total of 147 patients with repair of the short external rotator muscle and joint capsule were assigned to the repair group. All operated patients were observed to analyze the occurrence and risk of early postoperative dislocation. Within 6 months after hip arthroplasty, the early hip dislocation rate in the repair group was 0.68%, which was significantly lower than that in the control group (4.78%) (P < 0.05). The results of multifactorial analysis showed that age ≥75 years, combined limb or mental illness, artificial femoral head diameter <30 mm, posterolateral approach and prosthesis placement outside the safety zone, and improper handling were risk factors for dislocation (P < 0.05); The incidence of re-dislocation was lower in the targeted intervention group (P < 0.05). The occurrence of dislocation after THA is related to age, gender, and type of orthopedic disease. The risk factors should be explored to develop targeted intervention protocol, decreasing the dislocation rate and improving the prognosis.

Lactobacilli Infection Case Reports in the Last Three Years and Safety Implications

Lactobacilli constitute the dominant microbiota in many fermented foods and comprise widely used probiotics. However, these bacteria cause rare infections mostly in diabetic and immunocompromised subjects in presence of risk factors such as prosthetic hearth valves and dental procedures or caries. The scope of this survey was re-assessing the pathogenic potential of lactobacilli based on the infection case reports published in the last three years. In 2019, 2020, and 2021, total of 17, 15, and 16 cases, respectively, including endocarditis, bacteremia, and other infections, were reported. These annual numbers are higher than those observed previously. Lacticaseibacillus rhamnosus (13 cases), comprising strain GG (ATCC 53103) with established applications in healthcare, L. paracasei (7 cases), Lactobacillus acidophilus (5 cases), L. jensenii (5 cases), Lactiplantibacillus plantarum (3 cases), L. paraplantarum, L. delbrueckii subsp. delbrueckii, L. gasseri, L. paragasseri, Limosilactobacillus fermentum, and L. reuteri (1 case each) were involved. Virulence characterization of two strains that caused infections, a derivative of L. rhamnosus GG and L. paracasei LP10266, indicated that increased biofilm-forming capacity favors pathogenicity and it is determined by variable genetic traits. This survey highlights that the strains of lactobacilli that cause infections are little characterized genetically. Instead, to avoid that these bacteria become a hazard, genetic stability should be periodically re-evaluated by whole genome sequencing (WGS) to ensure that only non-pathogenic variants are administered to vulnerable individuals.