Gori, Andrea

Abstract Background Dalbavancin is increasingly used off-label for chronic Gram-positive bone and joint infections (BJIs) requiring prolonged antimicrobial therapy, but optimal dosing strategies and the role of therapeutic drug monitoring (TDM) remain unclear. We evaluated the real-world implementation of a proactive TDM-guided dalbavancin workflow within an outpatient parenteral antimicrobial therapy (OPAT) programme. Methods Single-centre prospective observational implementation study including adult patients with BJIs consecutively treated with dalbavancin in OPAT service between July 2022 and August 2025. A multidisciplinary team developed a workflow incorporating TDM-guided pharmacokinetic modelling to individualize dosing intervals after fixed initial administrations (Days 1, 8 and 43). Target Cmin concentrations were ≥8 mg/L, later increased to ≥15 mg/L after European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoint revision. Primary outcomes included implementation metrics (feasibility, fidelity and appropriateness). Secondary outcomes were clinical effectiveness, safety and overall workflow success. Results The workflow was applied to 101 patients accounting for 418 TDM-guided dalbavancin administrations (feasibility). Three patient-driven treatment discontinuations were observed (3/101, 3.0%), and scheduled administrations occurred within the predefined time window in 335/418 (83.5%) of cases (fidelity). Pharmacological target attainment was achieved in 285/342 (89.6%) of administrations without dosing delays (appropriateness). Clinical effectiveness was achieved in 55/73 (75.3%) patients completing therapy, with 28/101 (28%) still on treatment. Adverse events–related discontinuation occurred in 3/101 (3%) patients. Overall workflow success was observed in 74/101 (73.2%) patients. Conclusions A multidisciplinary TDM-guided dalbavancin workflow within an OPAT programme was feasible and safe, achieving high target attainment and favourable clinical outcomes. This approach supports individualized long-acting dalbavancin therapy for complex chronic BJIs.

Abstract Background Prosthetic joint infection (PJI) represents an important complication of total joint arthroplasty, affecting approximately 2% of patients. However, considerable heterogeneity in outcome definitions renders cross-study and clinical comparisons challenging. Methods We performed a meta-epidemiological study and systematic review of cohort studies and randomized controlled trial (RCTs) reporting clear definitions of PJI outcomes. Relevant data regarding outcome definitions of treatment success or failure were extracted and categorized into 7 outcome domains: clinical signs and symptoms, imaging, microbiology, mortality, antibiotics-related, surgical-related, and histology. A network plot was generated to visualize domains combinations. Data on patient-reported outcome measures (PROMs) were also collected. Based on these results, we finally proposed a working definition of PJI core outcome set. Results The literature search identified 7585 references, leading to 461 studies. The majority were retrospective (416/461, 90.2%), with limited representation of prospective studies (37/461, 8.0%) and RCTs (8/461, 1.7%). Outcome reporting was highly heterogeneous, with the clinical criterion being the most frequently used domain, combined with microbiological, surgical, and mortality-related outcomes. In contrast, histopathological, imaging, and antibiotic-related criteria were rarely reported. Thirty-six PROMs were included in only 111 (24.1%) studies, most commonly the Knee Society Score (26%) and Harris Hip Score (23%). Conclusions We showed substantial heterogeneity in PJI outcome definitions, with inconsistent reporting across key domains, limiting comparability and evidence synthesis. Standardized, consensus-based outcomes incorporating patient-reported and antibiotic-related measures are needed, and the proposed core outcome set may support harmonized research and clinical practice aligned with the new PJI definition.

The incidence of culture-negative NVO (CN-NVO) cases is increasing, presenting significant diagnostic and therapeutic challenges due to the inability to isolate causative organisms with conventional microbiological methods. Factors influencing the diagnosis of CN-NVO include prior antimicrobial therapy, low pathogen burden, fastidious or intracellular organisms, technical issues, and non-infectious mimickers. Diagnosis often relies on imaging modalities like magnetic resonance imaging (MRI) and computed tomography (CT)-guided biopsy, though these methods can sometimes fail to yield positive microbiological results. Advanced diagnostic tools, such as polymerase chain reaction (PCR), metagenomic next-generation sequencing (mNGS), and cell-free DNA analysis, may be necessary to identify the pathogen. The causative pathogen cannot be isolated in some patients, among which an empirical antimicrobial therapy should be initiated. This narrative review discusses the management, monitoring, surgical indications, and outcomes for patients with CN-NVO.