Extended-duration dosing and distribution of dalbavancin into bone and articular tissue

Dalbavancin for the treatment of bone and joint infections: A meta-analysis

BACKGROUND

Bone and joint infections are challenging infectious diseases to treat and require prolonged antimicrobial treatment. Dalbavancin demonstrated promising pharmacokinetic/pharmacodynamic properties for the treatment of these infections. The objective of this meta-analysis is to compare the effectiveness of dalbavancin to standard of care (SOC) for the treatment of bone and joint infections.

METHODS

Two independent authors performed a comprehensive search through the major databases up to September 2023. Interventional and observational studies that compared the clinical success of dalbavancin to SOC for the treatment of osteoarticular infections (OAI) were included.

RESULTS

A total of 6 studies and 581 patients were included, 282 in dalbavancin group and 299 in SOC group. Only one study was randomized clinical trial. When the data from the 6 studies were pooled in a meta-analysis, clinical success did not differ in those who received dalbavancin versus SOC (OR = 1.55, 95 % CI = 0.95-2.55, I-squared = 15.89 %) for the treatment of OAI infections. Four studies compared the two groups in terms of hospital length of stay and demonstrated a significant shorter length of stay in dalbavancin group compared to SOC group. Treatment-emergent adverse effects were reported in up to 21.4 % of patients in the dalbavancin group and up to 36.7 % of patients in the SOC group.

CONCLUSION

This meta-analysis showed that dalbavancin is as effective as SOC for the treatment of patients with OAI infections. More data are needed to validate these findings.

Treatment of Complicated Gram-Positive Bacteremia and Infective Endocarditis

The Gram-positive cocci Staphylococcus aureus, Streptococcus spp., and Enterococcus spp. are the most frequent causative organisms of bloodstream infections and infective endocarditis. "Complicated bacteremia" is a term used in S. aureus bloodstream infections and originally implied the presence of metastatic infectious foci (i.e. complications of S. aureus bacteremia). These complications demand longer antimicrobial treatment durations and, frequently, interventional source control. Several risk factors for the incidence of bacteremia complications have been identified and are often used for the definition of complicated bacteremia. Here, we discuss management and diagnostic approaches and treatment options for patients with complicated bacteremia, with particular focus on infective endocarditis. We also summarize the available evidence regarding imaging modalities and the choice of antimicrobial mono- or combination therapy according to resistance patterns for these pathogens as well as treatment durations and optimized application routes. Finally, we synopsize current and future areas of research in complicated bacteremia and infective endocarditis.

Chronic antibiotic suppressive therapy with dalbavancin: a case series

Dalbavancin is a relatively new long-acting anti-Gram positive antimicrobial approved for the treatment of acute bacterial skin and skin structures infections. An increasing number of observational studies and case series were published on its off-label uses. Great interest is emerging about complicated cases where antibiotic treatment cannot be discontinued, and a chronic suppressive therapy is needed. We described a case series of 6 patients treated or ongoing on treatment with dalbavancin as chronic suppressive therapy (CAST) administered with the following regimen: dalbavancin 1500 mg on day 1 and 8 and then every 4 weeks. CAST median duration was 27 weeks. Five out of 6 patients reached a good clinical control of the infection (one of them completely resolved) while in one case we observed a recurrence of the infection. No adverse events were detected. Larger studies are needed to better clarify dalbavancin off-label uses and the most appropriate dose regimen.

Prevention and Modern Strategies for Managing Methicillin-Resistant Staphylococcal Infections in Prosthetic Joint Infections (PJIs)

Periprosthetic joint infections (PJIs) are a dangerous complication of joint replacement surgeries which have become much more common in recent years (mostly hip and knee replacement surgeries). Such a condition can lead to many health issues and often requires reoperation. Staphylococci is a bacterial group most common in terms of the pathogens causing PJIs. S. aureus and coagulase-negative staphylococci are found in around two-thirds of PJI cases. Recently, the numbers of staphylococci that cause such infections and that are methicillin-resistant are increasing. This trend leads to difficulties in the treatment and prevention of such infections. That is why MRSA and MRSE groups require extraordinary attention when dealing with PJIs in order to successfully treat them. Controlling carriage, using optimal prosthetic materials, and implementing perioperative antimicrobial prophylaxis are crucial strategies in infection prevention and are as essential as quick diagnosis and effective targeted treatment. The comprehensive professional procedures presented in this review show how to deal with such cases.

Experience with expanded use of oritavancin in a tertiary hospital: indications, tolerability and outcomes

Background

Oritavancin is a lipoglycopeptide antibacterial agent used to treat infections caused by Gram-positive organisms. It is FDA-approved for the treatment of acute bacterial skin and soft tissue infections (ABSSIs) but is increasingly being used off-label to treat invasive bacterial infections such as osteomyelitis, prosthetic joint infection and infective endocarditis.

Objectives

This study describes the clinical outcomes and adverse reactions related to oritavancin.

Patients and methods

This was a retrospective study conducted over a 5 year period at a tertiary care medical centre. Ninety-five adult patients were included in this study and were followed for 1 year after the last dose of oritavancin.

Results

The most common indication for oritavancin at our institution was osteomyelitis, followed by ABSSI. Other indications were vertebral infection, hardware-associated infection, bacteraemia and infective endocarditis. Fourteen percent (13/95) of patients developed an adverse reaction to oritavancin during the study period. Cure with no recurrence up to 1 year after the last dose of oritavancin was achieved in 74% (53/71) of patients, and the treatment failure rate was 19% (14/71 patients).

Conclusions

Oritavancin is an effective agent that can be used to treat invasive Gram-positive bacterial infections other than ABSSI. Adverse events requiring drug discontinuation were common.

Safety and Efficacy of Dalbavancin in Real Life: Retrospective Analysis of a Large Monocentric Case Series of Patients Treated for Skin/Soft Tissue and Other Difficult-to-Treat Infections

Background: Dalbavancin is a long-acting lipoglycopeptide, approved for treatment of skin and skin structure infections. Its PK/PD profile and safety allow for short hospital stays even in the case of difficult-to-treat infections requiring long courses of therapy, e.g., osteomyelitis, cardiovascular, and prosthetic infections. Objectives: We aimed to evaluate the safety and efficacy of dalbavancin in real life settings for both in-label and off-label indications. Methods: retrospective evaluation of all consecutive patients treated with dalbavancin at our site between May 2017 and September 2021. Results: A total of 100 patients treated with dalbavancin and followed up for 6 months after treatment (58% male; median age 63.5 years, median Charlson Comorbidity Index CCI = 2.7, 28% inpatients) were included with the following indications: acute bacterial skin and skin structure infections (22%), bone and prosthetic infections (57%), and cardiovascular infections (19%). Infections were caused by MSSA (30%), MRSA (5%), MR-CoNS (20%), and Streptococcus spp. (8%). In 32 cases, no isolate was obtained. The average number of infusions was 5 (s.d. = 3). Neither ensuing alteration of renal function nor neutropenia or thrombocytopenia were observed during treatment and follow-up. Two self-limiting skin rashes occurred. The overall clinical success rate was 84%-91% for registered and 82% for unregistered indications. The prescription of higher loading doses was the only predictor independently associated with better outcomes in multivariate models (OR: 5.2, 95%CI: 1.5-17.9, p < 0.01). Conclusions: Dalbavancin proved to be effective for skin and skin structure infections, as well as for difficult-to-treat infections in highly comorbid patients. Regarding tolerability, our results support the use of dalbavancin for long-lasting treatments of deep-seated infections.

Liquid Chromatography-Tandem Mass Spectrometry Method for Therapeutic Drug Monitoring of Dalbavancin in Plasma of Pediatric and Young Adult Patients

BACKGROUND

Dalbavancin, an antimicrobial lipoglycopeptide, is authorized in Europe for treating acute bacterial infections of the skin and skin structures in adults and pediatric patients aged 3 months and older. However, off-label dosing regimens have been proposed for various indications beyond acute bacterial infections of the skin and skin structures. This study presents a novel bioanalytical method using liquid chromatography-tandem mass spectrometry to quantify dalbavancin in low-volume plasma samples (50 μL).

METHODS

The method underwent validation in accordance with international guidelines for bioanalytical method validation and was applied to 9 clinical samples obtained from pediatric and young adult patients undergoing dalbavancin therapy. Liquid chromatography-tandem mass spectrometry analyses were conducted at the G. Gaslini Institute in Genoa, Italy, utilizing an Ultimate 3000 ultra high performance liquid chromatography system coupled to a TSQ Quantiva Triple Quadrupole system (Thermo Fisher Scientific, Milan, Italy). The analytical procedure involved the addition of deuterated dalbavancin as internal standard and a rapid extraction from 50 µL of human plasma, followed by chromatographic separation on a Thermo Scientific Accucore Polar Premium column. Accurate quantification of the analyte was achieved through multiple reaction monitoring detection.

RESULTS

The assay exhibited linearity within the concentration range of 0.66-400 mcg/mL in plasma, demonstrating accuracy and reproducibility in the absence of matrix effects. Stability testing was conducted on both quality controls and real samples to establish a robust protocol under real-life conditions.

CONCLUSIONS

This fast and reliable dalbavancin quantitation method could improve current pediatric clinical practice by enabling data collection for future dose recommendations in special patient populations.

Dalbavancin-resistant Staphylococcus epidermidis in vivo selection following a prosthetic joint infection: phenotypic and genomic characterization

Background

Dalbavancin is a lipoglycopeptide antibiotic with a wide spectrum of activity against Gram-positive bacteria, including MDR isolates. Its pharmacokinetic properties and administration patterns could be useful for the treatment of bone and joint infections, especially prosthetic joint infections (PJIs).

Introduction

We report the case of an 80-year-old man who experienced an acute periprosthetic joint infection of his right total knee arthroplasty (TKA). A DAIR procedure was done with tissue sampling, which allowed identification of a linezolid-resistant MDR S. epidermidis (LR-MDRSE) strain. The patient was then treated with dalbavancin (four injections).

Methods

We studied the phenotypic and genomic evolution of the strains and plasma through concentrations of dalbavancin at different points in time.

Results

After four injections (1500 mg IV) of dalbavancin over a 6 month period, the dalbavancin MIC increased 4-fold. Calculated fAUC0-24/MIC ratios were 945, 1239 and 766.5, respectively, at Days 49, 71 and 106, assuming an MIC of 0.032 mg/L. The PFGE dendrogram revealed 97% similarity among all the isolates. These results suggest acquisition by the S. epidermidis strain of dalbavancin resistance when the patient underwent dalbavancin treatment. A 4-amino-acid deletion in the walK gene coinciding with the emergence of phenotypic resistance was revealed by WGS without any other relevant indels.

Conclusions

Despite dalbavancin treatment with pharmacokinetic management, emerging dalbavancin resistance in S. epidermidis was observed, resulting in treatment failure. This outcome led to a prosthesis revision and long-term suppressive antibiotic therapy, with no recurrence of PJI after an 18 month follow-up.

Population Pharmacokinetics and Pharmacodynamics of Dalbavancin and C-Reactive Protein in Patients with Staphylococcal Osteoarticular Infections

BACKGROUND AND OBJECTIVE

Dalbavancin is increasingly used for the long-term treatment of chronic osteoarticular infections. A population pharmacokinetic/pharmacodynamic (PK/PD) analysis for assessing the relationship between dalbavancin exposure and C-reactive protein (C-RP) over time was conducted.

METHODS

Non-linear mixed-effect modeling was fitted to dalbavancin and C-RP concentrations. Monte Carlo simulations assessed the weekly percentage of C-RP reduction associated with different dosing regimens, starting from baseline to < 1 mg/dL.

RESULTS

A total of 45 patients were retrospectively included in the analysis. The PK of dalbavancin was described by a two-compartment model, and the PD of C-RP was described by an indirect turnover maximum inhibition model. The total dalbavancin concentration model estimate producing 50% of maximum C-RP production inhibition (IC50) was 0.70 mg/L. Monte Carlo simulations showed that in patients with staphylococcal osteoarticular infections targeting total dalbavancin concentrations at > 14.5 mg/L at any time point may achieve C-RP production inhibition over time in > 95% of patients. Based on this, the findings showed that a cumulative dose of 3000 mg administered in the first 3 weeks may lead to a > 90% C-RP decrease versus baseline in approximately 5-6 weeks. In patients needing treatment prolongation, an additional 1500 mg dose after this period may maintain C-RP concentrations < 1 mg/dL for other 3 weeks.

CONCLUSIONS

A decrease in C-RP is related to dalbavancin exposure in osteoarticular infections. Targeting dalbavancin plasma concentrations above the efficacy threshold may be associated with effective treatment.

Dalbavancin as consolidation therapy for infective endocarditis in patients with comorbidity. A real world experience

OBJECTIVE

Infective endocarditis (IE) is a potentially life-threatening infection, the incidence of which has in creased in recent decades, particularly among elderly patients with comorbidity. The primary objective of this study was to evaluate the effectiveness of dalbavancin in the consolidation therapy of IE in patients with comorbidity six months after the end of treatment (EOT).

METHODS

An observational and retrospective study was conducted on patients with a Charlson Comorbidity Index (CCI) ≥ 3 who were diagnosed with IE and received consolidation therapy with dalbavancin.

RESULTS

Forty-eight patients were included, 58.3% were male, mean age of 76.2 years (IQR: 66-88), and a mean age adjusted CCI of 6.5 (IQR: 5-7.5). Definite IE was diagnosed in 77% of cases. The most frequently isolated microorganisms were Staphylococcus aureus (45.8%) followed by Enterococcus spp. (31.3%). Complications of IE were observed in 67.7% of cases, and cardiac surgery was performed in 27% of patients. The primary reason for using dalbavancin was outpatient parenteral antibiotic therapy in 85.4% of cases. The effectiveness at EOT was 93.8%. At six months, six IE-related deaths, four unrelated deaths, and two IE relapses were observed. The effectiveness was 77%. Adverse effects related to DBV were reported in 4.2% of cases, of which 2% were considered serious.

CONCLUSIONS

Dalbavancin has proven to be an effective alternative as consolidation antibiotherapy for IE in elderly patients with comorbidity. Moreover, a very favorable safety profile with few associated adverse effects has been observed in this population.

Off-label use of dalbavancin in children: a case series

INTRODUCTION

Dalbavancin is an antibiotic active against most Gram-positive bacteria approved for acute bacterial skin and skin structure infections (ABSSSI). Owing to its long half-life, it is being increasingly used for other indications.

PATIENTS AND METHODS

We present a case series of children and adolescents treated with dalbavancin for osteoarticular, catheter-related and other non-ABSSSI infections.

RESULTS

Dalbavancin was prescribed to 15 patients. Six (40%) were female and median age at prescription was 11.9 (IQR 1.3-18.0) years. Most of them (12/15) had significant comorbidities. Patients presented mainly with deep surgical site infections, osteoarticular infections and central-line-associated bloodstream infections. The most common isolate was Staphylococcus aureus followed by Staphylococcus epidermidis. Major reasons to prescribe dalbavancin were to ensure compliance and patients' convenience. Two patients discontinued the drug due to adverse events possibly related to it. The rest of the patients completed the treatment with dalbavancin, with a median duration of 56 days (IQR 17.5, 115.5). All achieved complete resolution and present no relapse after a median follow-up of 9.9 months (IQR 4.8, 16.6).

CONCLUSIONS

Dalbavancin was a safe, effective and convenient alternative in selected paediatric patients with complicated non-ABSSSI infections caused by Gram-positive bacteria.

Dalbavancin as suppressive therapy for implant-related infections: a case series with therapeutic drug monitoring and review of the literature

Implant-related infections may need suppressive antibiotic therapy (SAT). We describe a SAT strategy using dalbavancin with therapeutic drug monitoring (TDM). This is a retrospective bicentric study of patients with implant-related infection who received dalbavancin SAT between January 2021 and September 2023. Fifteen patients were included. Median number of injections was 4 (IQR: 2-7). Median time between two reinjections was 57 days (IQR 28-82). Dalbavancin plasma concentrations were above 4 mg/L for 97.9% of dosages (93/95) and above 8 mg/L for 85% (81/95). These results support the use of dalbavancin SAT for implant-related infections.

Simulated Target Attainment of Multidose Regimens of Dalbavancin for Prolonged Durations of Therapy

Background

Dalbavancin is a long-acting lipoglycopeptide antibiotic that is increasingly utilized for infections that require prolonged treatment durations despite the lack of Food and Drug Administration approval for these indications. There is no consensus regarding optimal dosing of dalbavancin for these infections and no available pharmacokinetic studies to identify optimal dosing for long-term use.

Methods

An in silico pharmacokinetic simulation was performed to assess the predicted dalbavancin concentration resulting from commonly utilized dosing regimens, in addition to modified regimens. The primary endpoint evaluated was days of median 24-hour free area under the curve over the minimum inhibitory concentration (AUC/MIC) >27.1, the established PK target.

Results

A dosing regimen of 1500 mg on day 0 and day 7 resulted in median AUC/breakpoint value above the target for 57 days (lower 95% confidence interval [CI], 37 days). A modified regimen of 1500 mg on day 0 and day 21 resulted in an additional 11 days of median AUC/breakpoint target attainment. The other standard dosing regimen modeled was 1000 mg on day 0, then 500 mg weekly for 5 doses. This regimen achieved the AUC/breakpoint target for 76 days (lower 95% CI, 59 days). This regimen was modified to 1000 mg on day 0, then 500 mg on days 14 and 28, which shortened the median effective treatment duration by 14 days but required 3 fewer doses.

Conclusions

These simulated results, when combined with the favorable observational data, support the use of commonly reported dalbavancin regimens for prolonged therapy durations. In addition, these pharmacokinetic/pharmacodynamic data support extending the dosing interval beyond the frequently reported weekly regimens, which should be investigated further with a clinical trial.

Dalbavancin as consolidation antibiotic treatment in infective endocarditis, cardiac implantable electronic devices infection and bacteremia: Clinical experience of 7 years

INTRODUCTION

Dalbavancin (DBV), a novel lipoglycopeptide with activity against Gram-positive bacterial infections, is approved for the treatment of acute bacterial skin and skin structure infections (ABSSSIs). It has linear dose-related pharmacokinetics allowing a prolonged interval between doses. It would be a good option for the treatment of patients with Gram-positive cardiovascular infections.

METHODS

Retrospective analysis of patients with cardiovascular infection (infective endocarditis, bacteremia, implantable electronic device infection) treated with DBV at Hospital Clínico San Carlos (Madrid) for 7 years (2016-2022). Patients were divided in two study groups: 1) Infective endocarditis (IE), 2) Bacteremia. Epidemiological, clinical, microbiological and therapeutic data were analyzed.

RESULTS

A total of 25 patients were treated with DBV for cardiovascular infection. IE was the most common indication (68%), followed by bacteremia (32%) with male predominance in both groups (64% vs 62%) and median age of 67,7 and 57,5 years, respectively. 100% of blood cultures were positive to Gram-positive microorganisms (Staphylococcus spp., Streptococcus spp. or Enterococcus spp.) in both study groups. Previously to DBV, all patients received other antibiotic therapy, both in the group of IE (median: 80 days) as in bacteremia (14,8 days). The main reason for the administration of DBV was to continue intravenous antimicrobial therapy outside the hospital in both the EI group (n = 15) and the bacteremia group (n = 8). DBV was used as consolidation therapy in a once- or twice-weekly regimen. Microbiological and clinical successes were reached in 84% of cases (n = 21), 76,4% in IE group and 100% in bacteremia group. No patient documented adverse effects during long-term dalbavancin treatment.

CONCLUSION

DBV is an effective and safety treatment as consolidation antibiotic therapy in IE and bacteremia produced by Gram-positive microorganisms.

Experience with dalbavancin use in various gram-positive infections within Aberdeen Royal Infirmary OPAT service

PURPOSE

Dalbavancin, approved in 2014 for Gram-positive acute bacterial skin and skin structure infections (ABSSSI), has pharmacokinetics enabling treatment with one or two doses. Dalbavancin might be useful in outpatient parenteral antibiotic therapy (OPAT) of deep-seated infections, otherwise requiring inpatient admission. We documented our experience with pragmatic dalbavancin use to assess its effectiveness for varied indications, on- and off-label, as primary or sequential consolidation therapy.

METHODS

Patients prescribed dalbavancin between 1 December 2021 and 1 October 2022 were screened for demographics of age, sex, Charlson comorbidity index (CCI), allergies, pathogens, doses of dalbavancin, other antibiotics administered and surgery. Where available, infection markers were recorded. The primary outcome was a cure at the end of treatment. Secondary outcomes included any adverse events and for those with treatment failures, response to salvage antibiotics.

RESULTS

Sixty-seven per cent of patients were cured. Cure rates by indication were 93% for ABSSSI, 100% for bacteraemia, 90% for acute osteomyelitis, 0% for chronic osteomyelitis, 75% for native joint septic arthritis and 33% for prosthetic joint infection. Most bone and joint infections that were not cured did not have source control, and the goal of treatment was suppressive. Successful suppression rates were greater at 48% for chronic osteomyelitis and 66% for prosthetic joint infections. Adverse events occurred in 14 of 102 patients.

CONCLUSION

This report adds to clinical experience with dalbavancin for off-label indications whilst further validating its role in ABSSSI. Dalbavancin as primary therapy in deep-seated infections merits investigation in formal clinical trials.

Dalba Got Back? Use of Dalbavancin for the Treatment of Vertebral Osteomyelitis

Data evaluating dalbavancin use for vertebral osteomyelitis remain limited. In our retrospective cohort, 29 of 34 (85.3%) patients completed their dalbavancin course. Adverse reactions occurred for 6 (17.6%) and infection recurrence in 3 (8.8%) within 90 days. Dalbavancin appears to be safe and well-tolerated for vertebral osteomyelitis.

Dalbavancin Sequential Therapy for Gram-Positive Bloodstream Infection: A Multicenter Observational Study

INTRODUCTION

Long-acting lipoglycopeptides such as dalbavancin may have utility in patients with Gram-positive bloodstream infections (BSI), particularly in those with barriers to discharge or who require prolonged parenteral antibiotic courses. A retrospective cohort study was performed to provide further multicenter real-world evidence on dalbavancin use as a sequential therapy for Gram-positive BSI.

METHODS

One hundred fifteen patients received dalbavancin with Gram-positive BSI, defined as any positive blood culture or diagnosed with infective endocarditis, from 13 centers geographically spread across the United States between July 2015 and July 2021.

RESULTS

Patients had a mean (SD) age of 48.5 (17.5) years, the majority were male (54%), with many who injected drugs (40%). The most common infection sources (non-exclusive) were primary BSI (89%), skin and soft tissue infection (SSTI) (25%), infective endocarditis (19%), and bone and joint infection (17%). Staphylococcus aureus accounted for 72% of index cultures, coagulase-negative Staphylococcus accounted for 18%, and Streptococcus species in 16%. Dalbavancin started a median (Q1-Q3) of 10 (6-19) days after index culture collection. The most common regimen administered was dalbavancin 1500 mg as one dose for 50% of cases. The primary outcome of composite clinical failure occurred at 12.2%, with 90-day mortality at 7.0% and 90-day BSI recurrence at 3.5%.

CONCLUSIONS

Dalbavancin may serve as a useful tool in facilitating hospital discharge in patients with Gram-positive BSI. Randomized controlled trials are anticipated to validate dalbavancin as a surrogate to current treatment standards.

Dalbavancin as salvage therapy in difficult-to-treat patients for diabetes-related foot osteomyelitis

OBJECTIVES

We aimed to describe the efficacy and safety of dalbavancin in treatment of patients with diabetes-related foot osteomyelitis with bone culture confirmation.

PATIENTS AND METHODS

Between January 2019 and December 2021, all consecutive patients receiving at least one 1500 mg dose of dalbavancin for diabetes-related foot osteomyelitis were included in a retrospective study. Remission was defined as absence of relapsing infection or need for surgery at the initial or a contiguous site during 6-month follow-up from the last dose of dalbavancin.

RESULTS

Thirteen patients were included. Eleven (85%) patients were surgically treated. Six (46%) patients received dalbavancin as first-line treatment and 7 (54%) as second-line treatment due to adverse events related to previous treatments. One adverse event was reported. At 6-month follow-up, 11 patients were evaluable and 9 (82%) were in remission.

CONCLUSIONS

In the study, dalbavancin was well-tolerated and showed microbiological and clinical efficacy.

Animal Models in Regulatory Breakpoint Determination: Review of New Drug Applications of Approved Antibiotics from 2014-2022

We sought to better understand the utility and role of animal models of infection for Food and Drug Administration (FDA)-approved antibiotics for the indications of community-, hospital-acquired-, and ventilator-associated bacterial pneumonia (CABP, HABP, VABP), complicated urinary tract infection (cUTI), complicated intra-abdominal infection (cIAI), and acute bacterial skin and structural infections (ABSSSIs). We reviewed relevant documents from new drug applications (NDA) of FDA-approved antibiotics from 2014-2019 for the above indications. Murine neutropenic thigh infection models supported the choice of a pharmacokinetic-pharmacodynamic (PKPD) target in 11/12 NDAs reviewed. PKPD targets associated with at least a 1-log bacterial decrease were commonly considered ideal (10/12 NDAs) to support breakpoints. Plasma PK, as opposed to organ specific PK, was generally considered most reliable for PKPD correlation. Breakpoint determination was multi-disciplinary, accounting at minimum for epidemiologic cutoffs, non-clinical PKPD, clinical exposure-response and clinical efficacy. Non-clinical PKPD targets in combination with probability of target attainment (PTA) analyses generated breakpoints that were consistent with epidemiologic cutoffs and clinically derived breakpoints. In 6/12 NDAs, there was limited data to support clinically derived breakpoints, and hence the non-clinical PKPD targets in combination with PTA analyses played a heightened role in the final breakpoint determination. Sponsor and FDA breakpoint decisions were in general agreement. Disagreement may have arisen from differences in the definition of the optimal PKPD index or the ability to extrapolate protein binding from animals to humans. Overall, murine neutropenic thigh infection models supported the reviewed NDAs by providing evidence of pre-clinical efficacy and PKPD target determination, and played, in combination with PTA analysis, a significant role in breakpoint determination for labeling purposes.

Implementation and validation of a Bayesian method for accurately forecasting duration of optimal pharmacodynamic target attainment with dalbavancin during long-term use for subacute and chronic staphylococcal infections

Dalbavancin is increasingly being used for long-term treatment of subacute and chronic staphylococcal infections. In this study, a new Bayesian model was implemented and validated using MwPharm software for accurately forecasting the duration of pharmacodynamic target attainment above the efficacy thresholds of 4.02 mg/L or 8.04 mg/L against staphylococci. Forecasting accuracy improved substantially with the a posteriori approach compared with the a priori approach, particularly when two measured concentrations were used. This strategy may help clinicians to estimate the duration of optimal exposure with dalbavancin in the context of long-term treatment.

Substance use disorder-associated infections' treatment with dalbavancin enabling outpatient transition (SUDDEN OUT) - an investigator-initiated single-arm unblinded prospective cohort study

Background

Severe gram-positive infections are frequent in people who inject drugs, and successful completion of treatment presents unique challenges in this population.

Objectives

We aimed to evaluate the feasibility of a long-acting antibiotic, dalbavancin, as an alternative to standard-of-care antibiotics for severe infections due to vancomycin-susceptible pathogens requiring ⩾2 weeks of therapy.

Design

We designed an investigator-initiated single-arm unblinded prospective cohort study to evaluate the safety and efficacy of an early switch to dalbavancin in two doses administered 1 week apart.

Methods

We screened patients admitted with bloodstream infection, osteomyelitis, septic arthritis, infective endocarditis or deep abscesses, and comorbid substance use disorder (SUD) for eligibility. Consenting patients were switched to dalbavancin within 7 days from their index culture. They were monitored in the hospital for efficacy and safety of the treatment until the second dose of dalbavancin 7 days later and then discharged if stable. Study participants were evaluated with a decision support engine for a hypothetical appropriate level of care regarding their SUD after discharge. Their follow-up was planned for 12 months from the index culture, either in-person or via telehealth/telephone.

Results

The enrollment was terminated early due to significant loss-to-follow-up. In all, 11 patients were enrolled, 4 completed 12 months of follow-up, 2 completed 8 months of follow-up, and 1 was seen once after discharge. The remaining five patients were lost to follow-up immediately after discharge. All 11 patients continued to improve after switching to dalbavancin between the first and second doses. There were two per-protocol failures of treatment. Dalbavancin was well tolerated, though some adverse events were reported.

Conclusion

Dalbavancin may be a safe and effective alternative for an early switch in treating severe gram-positive infections.

Trial registration

The trial was registered as NCT04847921 with clinicaltrials.gov.

Dalbavancin as an alternative to traditional outpatient parenteral antimicrobial therapy for deep gram-positive infections - an observational, retrospective review

Background

Treatment of invasive gram-positive infections in complex patient populations is challenging. Dalbavancin, approved for skin and soft tissue infections, offers advantages in this setting due to its long half-life and infrequent dosing. However, less is known about the outcomes of off-label dalbavancin for deeper infections.

Objectives

The objective of this study is to examine the feasibility and outcomes of patients with complex gram-positive infections treated with dalbavancin as an alternative to standard outpatient parenteral antimicrobial therapy (OPAT).

Methods

We conducted a multicenter, retrospective review of adult patients managed within an OPAT program with intravenous dalbavancin for off-label indications. Adult patients were included if they had treatment details and follow-up documented between January 2020 and June 2023. Details of dalbavancin use including indications for prescription were captured. Outcomes of interest included 90-day infection recurrence, prosthesis retention rates, 90-day mortality, and adverse medication events.

Results

In all, 61 patients received dalbavancin, mostly as sequential therapy. Twenty-three percent received dalbavancin strictly in the outpatient setting. Dalbavancin was used primarily for hardware (fracture, spine, or joint), native bone or joint, and complicated soft tissue infections. The predominant pathogen was Staphylococcus aureus (61%). Dalbavancin was frequently prescribed as a two-dose 1500 mg regimen (49%) due to persistent infection (23%), difficult line access (30%), difficulty achieving therapeutic vancomycin levels (18%), or substance abuse history (18%). Overall, six patients (10%) had infection recurrence and no patients died during the follow-up period. Three of eight patients with hardware retention had infection recurrence. Adverse effects were minimal and mostly self-limiting.

Conclusion

Dalbavancin is an efficacious and safe alternative to standard OPAT, especially in those with barriers to traditional long-term intravenous antibiotics. Improved outcomes may be achieved with hardware removal. Dalbavancin may facilitate early discharge or prevent hospitalizations. Comparative studies of standard OPAT regimens versus dalbavancin are needed.

Efficacy of ceftaroline and rifampin, alone or combined, in a rat model of methicillin-resistant Staphylococcus epidermidis osteomyelitis without implant

IMPORTANCE

Methicillin-resistant Staphylococcus epidermidis (MRSE) contributes to a high percentage of orthopedic infections, and their treatment represents a huge challenge. The present study aimed to evaluate the efficacy of ceftaroline alone or combined with rifampin in a rat MRSE osteomyelitis model and the bone penetration of ceftaroline. A ceftaroline monotherapy showed a significant bacterial reduction in infected bones after a 7-day period of treatment. The combination ceftaroline plus rifampin leveraged rifampin's bactericidal activity, shortening the duration of positive culture in infected animals. These results suggest that ceftaroline and rifampin combination therapy could represent a valuable therapeutic option for human MRSE osteomyelitis and deserves further preclinical and clinical evaluation.

Effective use of a two-dose regimen of dalbavancin to treat prosthetic joint infections and spinal hardware infections

PURPOSE

Dalbavancin is an attractive antibiotic for the treatment of Gram-positive musculoskeletal infections given its long half-life and prolonged duration in cortical bones. For certain patient populations compliance with antibiotic regimens can be problematic. Therefore, the purpose of this study was to assess the effectiveness, tolerance, and compliance of treating prosthetic joint and spinal hardware infections with a unique two-dose regimen of dalbavancin.

METHODS

Identification of patients that had prosthetic joint infections and spinal hardware infections from January 1, 2017, through December 31, 2021, that had received a two-dose regimen of dalbavancin for these infections was conducted. Patient demographics, infection recurrence, compliance and adverse drug reactions to the two-dose regimen of dalbavancin were recorded. Furthermore, preserved clinical isolates from these infections were assessed for susceptibility to dalbavancin with microbroth dilutions.

RESULTS

All patients were fully compliant with the two dose dalbavancin regimen and no patient had any adverse reactions to the two-dose dalbavancin regimen. Thirteen of fifteen patients (85.7%) have not had any recurrence of their infections and all preserved clinical isolates showed susceptibility to dalbavancin.

DISCUSSION

The two-dose regimen of dalbavancin is an effective and attractive option in treating prosthetic joint and spinal hardware infections to forgo long term central venous access and ensure compliance. However, the use of rifampin and suppression antibiotics still needs to be considered when treating these infections. Nonetheless this study supports that a two-dose dalbavancin regimen is a viable alternative in certain clinical settings and consideration for a randomized controlled clinical trial should be entertained to prove its non-inferiority to conventional treatments.

Dalbavancin plasma concentrations in 133 patients: a PK/PD observational study

OBJECTIVES

Limited pharmacokinetics data support dalbavancin long-term use in off-label indications and the optimal dosing regimen is debated. We aimed to describe dalbavancin concentrations in an observational retrospective multicentre study.

METHODS

Patients from 13 French hospitals, treated with 1500 mg doses of dalbavancin and for whom therapeutic drug monitoring was performed from June 2018 to March 2021 were included. Dalbavancin plasma concentrations were described at peak and 1, 2, 3, 4, 6 and 8 weeks after the last 1500 mg dose. Concentrations in patients weighing more or less than 75 kg and with a GFR greater or less than 60 mL/min were compared. Microbiological data were collected and dalbavancin MIC was measured when possible.

RESULTS

One hundred and thirty-three patients were included (69% treated for bone and joint infections, 16% for endocarditis). Thirty-five patients received a single dose of dalbavancin and 98 received several administrations. Two, 3 and 4 weeks after the last dose, median plasma concentrations were respectively 25.00, 14.80 and 9.24 mg/L for the first doses and 34.55, 22.60 and 19.20 mg/L for the second or subsequent doses. Weight and renal function had an impact on pharmacokinetics. Infection was documented in 105 patients (Staphylococcus spp. in 68% of cases). Staphylococcus aureus was isolated in 32.5% of cases (median MIC: 0.047 mg/L) and Staphylococcus epidermidis in 27% of cases (median MIC of 0.047 mg/L).

CONCLUSIONS

Plasma concentrations of dalbavancin were consistent with those described in clinical trials and those sought during the industrial development of the molecule.

Contemporary Management of Staphylococcus aureus Bacteremia-Controversies in Clinical Practice

Staphylococcus aureus bacteremia (SAB) carries a high risk for excess morbidity and mortality. Despite its prevalence, significant practice variation continues to permeate clinical management of this syndrome. Since the publication of the 2011 Infectious Diseases Society of America (IDSA) guidelines on management of methicillin-resistant Staphylococcus aureus infections, the field of SAB has evolved with the emergence of newer diagnostic strategies and therapeutic options. In this review, we seek to provide a comprehensive overview of the evaluation and management of SAB, with special focus on areas where the highest level of evidence is lacking to inform best practices.

Long-Term Suppressive Therapeutic-Drug-Monitoring-Guided Dalbavancin Therapy for Cardiovascular Prosthetic Infections

Dalbavancin represents a promising treatment for cardiovascular prosthetic infections due to its prolonged half-life, bactericidal activity, large spectrum of activity, and excellent biofilm penetration. However, the use of dalbavancin in this setting is limited, and only a few cases have performed therapeutic drug monitoring (TDM) analysis to optimize dosage in suppressive treatments longer than 4 weeks. Our retrospective case series reports the use of dalbavancin in a small cohort of patients with cardiovascular prosthetic infections (cardiac implantable electronic device infections (CEDIs), prosthetic valve endocarditis (PVE), prosthetic vascular graft infections (PVGIs)) treated with dalbavancin as sequential therapy. From May 2019 to May 2023, 14 patients were included: eight cases of PVE (57.1%), seven cases of PVGI (50%), three cases of CEDI (21.4%), and four cases with overlap of infection sites (28.6%). The main pathogen was Staphylococcus aureus (35.7%). Prosthesis replacement was obtained in four patients (28.6%). The median time between symptom onset and the end of treatment was 15 weeks (IQR 7-53), with a median duration of dalbavancin therapy of 8 weeks (IQR 1 to 45 weeks) and 3.5 doses per patient. Among patients managed with TDM-guided strategy, dalbavancin infusion intervals ranged from 4 to 9 weeks. The median length of follow-up was 65 weeks (IQR 23 to 144 weeks). Clinical success was achieved in 10 cases (76.9%); all clinical failures occurred in patients with the implant retained. Among patients monitored by TDM, clinical success was 87.5% vs. 60% in patients treated without TDM. Because of pharmacokinetic individual variability, dalbavancin TDM-guided administration could improve clinical outcomes by individualizing dosing and selecting dosing intervals. This case series seems to suggest a promising role of long-term suppressive dalbavancin treatment for difficult-to-treat cardiovascular prosthesis infection, also with limited surgical indications.

Expert Opinion on Dose Regimen and Therapeutic Drug Monitoring for Long-Term Use of Dalbavancin: Expert Review Panel

BACKGROUND

Dalbavancin is a lipoglycopeptide with a long elimination half-life and is currently licensed for the treatment of acute bacterial skin and skin structure infections in adults. Dalbavancin's potential in treating off-label complex Gram-positive infections is promising and real-world experience in treating such infections is growing. However, clear guidance on extended dosing regimens is lacking.

OBJECTIVES

This study aimed to provide clear expert opinion based on recent pharmacokinetic literature and expert and real-world experience in infection areas that require > 2 weeks of treatment.

METHODS

A single face-to-face meeting was held in September 2022 to collate expert opinion and present safety data of dalbavancin use in these clinical indications. A survey was completed by all authors on their individual experience with dalbavancin, which highlighted the heterogeneity in the regimens that were used.

RESULTS

After review of the survey data and recent literature, this study presents expert panel proposals that accommodate different healthcare settings and resource availability, and centre around the length of treatment duration including up to or exceeding 6 weeks. To achieve adequate dalbavancin concentrations for up to 6 weeks, 3000 mg of dalbavancin should be given over 4 weeks for the agreed complex infections requiring > 2 weeks of treatment. Therapeutic drug monitoring (TDM) is advised for longer treatment durations and in cases of renal failure. Specific dosing recommendations for other special populations require further investigation.

CONCLUSIONS

These proposals based on expert opinion have been defined to encourage best practice with dalbavancin, to optimise its administration beyond the current approved licenced dose across different healthcare settings.

A Narrative Review on the Role of Dalbavancin in the Treatment of Bone and Joint Infections

Bone and joint infections (BJI) require prolonged antimicrobial treatment, leading to lengthy hospitalizations, high costs, the risk of nosocomial infections, and the development of antimicrobial resistance. Dalbavancin is a novel semisynthetic lipoglycopeptide approved for the treatment of adults and children with acute bacterial skin and skin structure infections. This narrative review aims to summarize the characteristics of dalbavancin and the current scientific evidence regarding its clinical efficacy and safety in the treatment of BJI. A literature search until June 2023 was performed to identify all published research about the role of dalbavancin in the management of BJI. Due to its unique pharmacokinetics characterized by prolonged half-life, high bactericidal activity against most Gram-positive bacteria, a good safety profile, and high tissue penetration, dalbavancin can be a valuable alternative to the treatment of BJI. Clinical studies have shown its non-inferiority compared to conventional therapies in BJI, offering potent activity against key pathogens and an extended dosing interval that may shorten hospitalization. In conclusion, dalbavancin represents a promising treatment option for BJI with a favorable safety profile, but further research in both adults and particularly children, who are ideal candidates for long-acting antibiotics, is necessary to evaluate the role of dalbavancin in BJI.

New Antimicrobials for Gram-Positive Sustained Infections: A Comprehensive Guide for Clinicians

Antibiotic resistance is a public health problem with increasingly alarming data being reported. Gram-positive bacteria are among the protagonists of severe nosocomial and community infections. The objective of this review is to conduct an extensive examination of emerging treatments for Gram-positive infections including ceftobiprole, ceftaroline, dalbavancin, oritavancin, omadacycline, tedizolid, and delafloxacin. From a methodological standpoint, a comprehensive analysis on clinical trials, molecular structure, mechanism of action, microbiological targeting, clinical use, pharmacokinetic/pharmacodynamic features, and potential for therapeutic drug monitoring will be addressed. Each antibiotic paragraph is divided into specialized microbiological, clinical, and pharmacological sections, including detailed and appropriate tables. A better understanding of the latest promising advances in the field of therapeutic options could lead to the development of a better approach in managing antimicrobial therapy for multidrug-resistant Gram-positive pathogens, which increasingly needs to be better stratified and targeted.

In Vitro Efficacy of Dalbavancin as a Long-Acting Anti-Biofilm Agent Loaded in Bone Cement

Based on previous studies by our group in which we demonstrated that dalbavancin loaded in bone cement had good elution capacity for the treatment of biofilm-related periprosthetic infections, we now assess the anti-biofilm activity of dalbavancin and compare it with that of vancomycin over a 3-month period. We designed an in vitro model in which we calculated the percentage reduction in log cfu/mL counts of sonicated steel discs contaminated with staphylococci and further exposed to bone cement discs loaded with 2.5% or 5% vancomycin and dalbavancin at various timepoints (24 h, 48 h, 1 week, 2 weeks, 6 weeks, and 3 months). In addition, we tested the anti-biofilm activity of eluted vancomycin and dalbavancin at each timepoint based on a 96-well plate model in which we assessed the percentage reduction in metabolic activity. We observed a significant decrease in the dalbavancin concentration from 2 weeks of incubation, with sustained anti-biofilm activity up to 3 months. In the case of vancomycin, we observed a significant decrease at 1 week. The concentration gradually increased, leading to significantly lower anti-biofilm activity. The percentage reduction in cfu/mL counts was higher for dalbavancin than for vancomycin at both the 2.5% and the 5% concentrations. The reduction in log cfu/mL counts was higher for S. epidermidis than for S. aureus and was particularly more notable for 5% dalbavancin at 3 months. In addition, the percentage reduction in metabolic activity also decreased at 3 months in 5% dalbavancin and 5% vancomycin, with more notable values recorded for the latter.

Real-World Data Regarding Dalbavancin Use before and during the COVID-19 Pandemic-A Single-Center Retrospective Study

Dalbavancin is a semisynthetic lipoglycopeptide, which possesses great potential for bactericidal activity similar to antimicrobials with the same mechanism of action, such as vancomycin and teicoplanin. Due to its very prolonged half-life, it can be used in a single or two-dose regimen to treat infections by Gram-positive microorganisms, even resistant ones, such as methicillin-resistant Staphylococcus aureus (MRSA). Currently, it is approved only for the treatment of acute bacterial skin and skin structure infections (ABSSSIs). The aim of this study was to investigate the clinical and microbiological characteristics of patients to whom dalbavancin was administered at the University Hospital of Heraklion and evaluate its use in regard to the COVID-19 pandemic. In total, 146 patients were included in this retrospective cohort study evaluating the use of dalbavancin from the first time it was used in 2017 until the end of 2022. The median age was 68 years (range: 21-96 years), and 86 (59%) patients were male. The most common indications for dalbavancin use were osteoarticular infections in 43%, followed by ABSSSIs in 37%, and cardiovascular infections in 10%. Dalbavancin was used empirically in one out of three patients, most commonly with the indication of ABSSSIs, and most commonly in the post-COVID-19 era. The most frequently isolated pathogens were coagulase-negative staphylococci in 70%, S. aureus in 27%, Enterococcus spp. in 22%, and Streptococcus spp. in 8%, while one out of three infections were polymicrobial. In 12% of patients, the infection was not cured, but no patients died. For patients with ABSSSIs, endocarditis and vascular infections, and bacteremia, the cure rates were more than 90%, and in osteoarticular infections, the cure rate was 76%. Thus, dalbavancin has great potential for use in complicated and invasive infections that may require prolonged intravenous antimicrobial treatment. However, further studies are required to formally investigate its role in such infections.

Dalbavancin in Bone and Joint Infections: A Systematic Review

BACKGROUND

Approved for acute bacterial skin and skin structure infections, dalbavancin (DBV) has gradually acquired over the years a role as an off-label treatment for several infections caused by Gram-positive bacteria even in other anatomical sites. Osteoarticular (OA) infections are one of the most difficult-to-treat infections and, since the absence of recommendations, clinicians use different and heterogenic DBV dosing schedule regimens for the off-label treatment of osteomyelitis, spondylodiscitis, and septic arthritis. Our aim is to systematically review the current literature to describe DBV administration schedules and their outcome in OA infections.

METHODS

According to the 2020 updated PRISMA guidelines, all peer-reviewed articles regarding the use of DBV in OA infections were included. We conducted a literature search on PubMed and Cochrane Controlled Trials.

RESULTS

A total of 23 studies and 450 patients were included, prevalently male (144/195, 73.8%) and diabetic (53/163, 32.5%). Overall, 280 (280/388, 72.2%) osteomyelitis, 79 (79/388, 20.4%) spondylodiscitis, and 29 (29/388, 7.5%) septic arthritis were considered. Staphylococcus aureus (164/243, 67.5%) was the most common pathogen isolated. A previous treatment failure (45/96, 46.9%) was the main reason for a switch to a long-acting antibiotic. Most patients were successfully cured with DBV (318/401, 79.3%). A source control was performed in most patients with a favourable outcome (80.4%), while MRSA was prevalently isolated in people with an unfavourable outcome (57%). While a higher percentage of success was found in people who received three doses of DBV 1 week apart (92.3%), a higher rate of treatment failure was recorded in cases of when the DBV cycle was composed of less than two or more than four doses (27.8%).

CONCLUSIONS

DBV has shown to be effective as a treatment for OA infections. The most favourable outcome was found in patients receiving three doses of DBV and with an adequate surgical management prior to antibiotic treatment. Although a rigorous administration schedule does not exist, DBV is a viable treatment option in the management of OA infections.

Pharmacokinetic and pharmacodynamic considerations for optimizing antimicrobial therapy used to treat bone and joint infections: an evidence-based algorithmic approach

INTRODUCTION

Bone and joint infections (BJIs) are a major health concern causing remarkable morbidity and mortality. However, which antimicrobial treatment could be the best according to specific clinical scenarios and/or to the pharmacokinetic/pharmacodynamic (PK/PD) features remains an unmet clinical need. This multidisciplinary opinion article aims to develop evidence-based algorithms for empirical and targeted antibiotic therapy of patients affected by BJIs.

AREAS COVERED

A multidisciplinary team of four experts had several rounds of assessment for developing algorithms devoted to empirical and targeted antimicrobial therapy of BJIs. A literature search was performed on PubMed-MEDLINE (until April 2023) to provide evidence for supporting therapeutic choices. Four different clinical scenarios were structured according to specific infection types (i.e. vertebral osteomyelitis, prosthetic joint infections, infected non-unions and other chronic osteomyelitis, and infectious arthritis), need or not of surgical intervention or revision, isolation or not of clinically relevant bacterial pathogens from blood and/or tissue cultures, and PK/PD features of antibiotics.

EXPERT OPINION

The proposed therapeutic algorithms were based on a multifaceted approach considering the peculiar features of each antibiotic (spectrum of activity, PK/PD properties, bone penetration rate, and anti-biofilm activity), and could be hopefully helpful in improving clinical outcome of BJIs.

Dalbavancin is thermally stable at clinically relevant temperatures against methicillin-sensitive Staphylococcus Aureus

Introduction: While the rate of orthopaedic infections has remained constant over the years, the burden on healthcare systems continues to rise with an aging population. Local antibiotic delivery via polymethyl methacrylate bone cement is a common adjunct in treating bone and joint infections. Dalbavancin is a novel lipoglycopeptide antibiotic in the same class as vancomycin that has shown efficacy against Gram-positive organisms when used systemically but has not been investigated as a local antibiotic. This study aims to identify whether dalbavancin is thermally stable at the temperatures expected during the polymerization of polymethyl methacrylate cement. Methods: Stock solutions of dalbavancin were prepared and heated using a polymerase chain reaction machine based upon previously defined models of curing temperatures in two clinically relevant models: a 10 mm polymethyl methacrylate bead and a polymethyl methacrylate articulating knee spacer model. Aliquots of heated dalbavancin were then transferred to be incubated at core body temperature (37 ∘ C) and analyzed at various time points up to 28 d. The minimum inhibitory concentration at which 90 % of colonies were inhibited (MIC90 ) for each heated sample was determined against methicillin-sensitive Staphylococcus aureus (American Type Culture Collection, ATCC, 0173K) using a standard microbroth dilution assay. Results: The average MIC90 of dalbavancin was 1.63 µ g mL - 1 ± 0.49 against 0173K S. aureus. There were no significant differences in the relative MIC90 values after heating dalbavancin in either model compared to unheated control dalbavancin. Conclusions: Dalbavancin is thermally stable at the curing temperatures of polymethyl methacrylate cement and at human core body temperature over 28 d. Future in vitro and in vivo studies are warranted to further investigate the role of dalbavancin as a local antibiotic prior to its clinical use.

Synthetic and Semisynthetic Compounds as Antibacterials Targeting Virulence Traits in Resistant Strains: A Narrative Updated Review

This narrative review paper provides an up-to-date overview of the potential of novel synthetic and semisynthetic compounds as antibacterials that target virulence traits in resistant strains. The review focused on research conducted in the last five years and investigated a range of compounds including azoles, indoles, thiophenes, glycopeptides, pleuromutilin derivatives, lactone derivatives, and chalcones. The emergence and spread of antibiotic-resistant bacterial strains is a growing public health concern, and new approaches are urgently needed to combat this threat. One promising approach is to target virulence factors, which are essential for bacterial survival and pathogenesis, but not for bacterial growth. By targeting virulence factors, it may be possible to reduce the severity of bacterial infections without promoting the development of resistance. We discuss the mechanisms of action of the various compounds investigated and their potential as antibacterials. The review highlights the potential of targeting virulence factors as a promising strategy to combat antibiotic resistance and suggests that further research is needed to identify new compounds and optimize their efficacy. The findings of this review suggest that novel synthetic and semisynthetic compounds that target virulence factors have great potential as antibacterials in the fight against antibiotic resistance.

Cost analysis of dalbavancin versus standard of care for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) in two Italian hospitals

Objectives

Thanks to its long half-life, dalbavancin qualifies as an optimal drug for saving costs. We aimed to assess the cost and effectiveness of dalbavancin versus the standard of care (SoC).

Patients and methods

We conducted a multicentre retrospective study, including all hospitalized or outpatients diagnosed with ABSSSIs at Padua University Hospital, Padua and San Paolo Hospital, Milan (1 January 2016 to 31 July 2020). We compared patients according to antibiotic treatment (dalbavancin versus SoC), the number of lines of dalbavancin treatment, and monotherapy or combination (dalbavancin in association with other antibiotics). Primary endpoints were direct medical costs and length of hospital stay (LOS) associated with ABSSSI management; Student's t-test, chi-squared test and one-way ANOVA were used.

Results

One hundred and twenty-six of 228 (55.3%) patients received SoC, while 102/228 (44.7%) received dalbavancin. Twenty-seven of the 102 (26.5%) patients received dalbavancin as first-line treatment, 46 (45.1%) as second-line, and 29 (28.4%) as third- or higher-line treatment. Most patients received dalbavancin as monotherapy (62/102; 60.8%). Compared with SoC, dalbavancin was associated with a significant reduction of LOS (5 ± 7.47 days for dalbavancin, 9.2 ± 5.59 days for SoC; P < 0.00001) and with lower mean direct medical costs (3470 ± 2768€ for dalbavancin; 3493 ± 1901€ for SoC; P = 0.9401). LOS was also reduced for first-line dalbavancin, in comparison with second-, third- or higher-line groups, and for dalbavancin monotherapy versus combination therapy. Mean direct medical costs were significantly lower in first-line dalbavancin compared with higher lines, but no cost difference was observed between monotherapy and combination therapy.

Conclusions

Monotherapy with first-line dalbavancin was confirmed as a promising strategy for ABSSSIs in real-life settings, thanks to its property in reducing LOS and saving direct medical costs.

Off-label use versus formal recommendations of conventional and novel antibiotics for the treatment of infections caused by multidrug-resistant bacteria

The infections caused by multidrug- and extensively drug-resistant (MDR, XDR) bacteria, including Gram-positive cocci (GPC, including methicillin-resistant Staphylococcus aureus, MDR-Streptococcus pneumoniae and vancomycin-resistant enterococci) and Gram-negative bacilli (GNB, including carbapenem-resistant [CR] Enterobacterales, CR-Pseudomonas aeruginosa and XDR/CR-Acinetobacter baumannii complex) can be quite challenging for physicians with respect to treatment decisions. Apart from complicated urinary tract and intra-abdominal infections (cUTIs, cIAIs), bloodstream infections and pneumonia, these difficult-to-treat bacteria also cause infections at miscellaneous sites (bones, joints, native/prosthetic valves and skin structures, etc.). Antibiotics like dalbavancin, oritavancin, telavancin and daptomycin are currently approved for the treatment of acute bacterial skin and skin structural infections (ABSSSIs) caused by GPC. Additionally, ceftaroline, linezolid and tigecycline have been formally approved for the treatment of community-acquired pneumonia and ABSSSI. Cefiderocol and meropenem-vaborbactam are currently approved for the treatment of cUTIs caused by XDR-GNB. The spectra of ceftazidime-avibactam and imipenem/cilastatin-relebactam are broader than that of ceftolozane-tazobactam, but these three antibiotics are currently approved for the treatment of hospital-acquired pneumonia, cIAIs and cUTIs caused by MDR-GNB. Clinical investigations of other novel antibiotics (including cefepime-zidebactam, aztreonam-avibactam and sulbactam-durlobactam) for the treatment of various infections are ongoing. Nevertheless, evidence for adequate antibiotic regimens against osteomyelitis, arthritis and infective endocarditis due to several GPC and MDR-GNB is still mostly lacking. A comprehensive review of PubMed publications was undertaken and the formal indications and off-label use of important conventional and novel antibiotics against MDR/XDR-GPC and GNB isolates cultured from miscellaneous sites are presented in this paper.

Evaluation of Dalbavancin Use on Clinical Outcomes, Cost-Savings, and Adherence at a Large Safety Net Hospital

Dalbavancin is a second-generation lipoglycopeptide antibiotic with activity against Gram-positive organisms. Dalbavancin is Food and Drug Administration (FDA)-approved for acute bacterial skin and soft tissue infections (ABSSTIs). There is a lack of substantial data on dalbavancin in more invasive infections, particularly in high-risk populations (patients with intravenous drug use and unstable living conditions). In this retrospective observational study, we reviewed all patients that received at least one dose of dalbavancin in an inpatient or outpatient setting at Parkland Hospital from February of 2019 to August of 2021. The demographics, type of infection, and rationale for dalbavancin were collected at the baseline. Clinical failure was measured by an avoidance of emergency department (ED) visits or hospital readmission at 30, 60, and 90 days. A separate analysis was conducted to estimate hospital, rehabilitation, or nursing facility days saved based on the projected length of treatment. 40 patients were included, and the majority were uninsured (85%), experiencing homelessness (60%), or had intravenous drug use (IDU) (57.5%). Indications for use included ABSSTIs (45%), bloodstream infection (67.5%), osteomyelitis (40%), infective endocarditis (10%), and septic arthritis (10%). Clinical failure was observed in 5 of the 40 patients (12.5%). Nonadherence to medical recommendations, a lack of source control, and ongoing IDU increased the risk of failure. Dalbavancin saved a total of 566 days of inpatient, rehabilitation, and nursing facility stays. Dalbavancin is a reasonable alternative to the standard of care in an at-risk population, offering decreased lengths of stays and cost savings. The uses of second-generation lipoglycopeptides are desirable alternatives to traditional outpatient parenteral antibiotic therapies for patients who otherwise would not qualify or for patients who desire less hospital contact in light of the COVID-19 pandemic. IMPORTANCE This study contributes additional experience to the literature of dalbavancin use in off-label indications, particularly for patients who do not qualify for outpatient parenteral antimicrobial therapy. The majority of the patient population were people who inject drugs and the uninsured. There is difficulty in tracking outcomes in this patient population, given their outpatient follow-up rates; however, we were able to track emergency room visits and readmissions throughout the majority of the local metroplex. The clinical use of dalbavancin at our institution also increased in the midst of the COVID-19 pandemic in an effort to preserve hospital resources and limit health care exposure. In addition, we are able to provide institution-specific cost-saving data with the use of dalbavancin.

Dalbavancin as sequential therapy for infective endocarditis due to Gram-positive organisms: a review

Dalbavancin is a parenteral lipoglycopeptide antibiotic derived from teicoplanin, an analogue of vancomycin. It is mainly used for skin and soft tissue infections. The sustained half-life of approximately 14 days makes dalbavancin a novel option for potential use as sequential treatment in infections such as infective endocarditis, which require prolonged antibiotic courses. However, only a few studies have been reported in the literature, and the use of dalbavancin remains limited. This article is a review of the currently available literature using dalbavancin for the treatment of infective endocarditis due to Gram-positive organisms. Almost all patients received dalbavancin as sequential therapy following standard-of-care antibiotics. The overall clinical efficacy of dalbavancin was approximately 90%, and it appeared to be well tolerated.

Current and emerging drug treatment strategies to tackle invasive community-associated methicillin-resistant Staphylococcus aureus (MRSA) infection: what are the challenges?

INTRODUCTION

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections represent a leading cause of purulent skin and soft tissue infections in some geographical regions. Traditionally, 'old antibiotics' such as trimethoprim-sulfamethoxazole, tetracyclines, clindamycin, chloramphenicol,vancomycin, and teicoplanin have been used to treat these infections, but these were often associated with low efficacy and excessive side effects and toxicity, especially nephrotoxicity. Along with the development of new compounds, the last decade has seen substantial improvements in the management of CA-MRSA infections.

AREAS COVERED

In this review, the authors discuss the current and emerging drug treatment strategies to tackle invasive CA-MRSA infections. Articles reported in this review were selected from through literature searches using the PubMed database.

EXPERT OPINION

The availability of new drugs showing a potent in vitro activity against CA-MRSA represents a unique opportunity to face the threat of resistance while potentially reducing toxicity. All these compounds represent promising options to enhance our antibiotic armamentarium. However, data regarding the use of these new drugs in real-life studies are limited and their best placement in therapy and in terms of optimization of medical resources and balance of cost-effectiveness requires further investigation.

Phage Therapy as an Alternative Treatment Modality for Resistant Staphylococcus aureus Infections

The production and use of antibiotics increased significantly after the Second World War due to their effectiveness against bacterial infections. However, bacterial resistance also emerged and has now become an important global issue. Those most in need are typically high-risk and include individuals who experience burns and other wounds, as well as those with pulmonary infections caused by antibiotic-resistant bacteria, such as Pseudomonas aeruginosa, Acinetobacter sp, and Staphylococci. With investment to develop new antibiotics waning, finding and developing alternative therapeutic strategies to tackle this issue is imperative. One option remerging in popularity is bacteriophage (phage) therapy. This review focuses on Staphylococcus aureus and how it has developed resistance to antibiotics. It also discusses the potential of phage therapy in this setting and its appropriateness in high-risk people, such as those with cystic fibrosis, where it typically forms a biofilm.

Partial-Oral Antibiotic Therapy for Bone and Joint Infections in People With Recent Injection Drug Use

Background

Limited outcome data exist regarding partial-oral antibiotic therapy, defined as oral antibiotics as part of a patient's treatment, for bone and joint infections (BJIs) in people who inject drugs (PWID).

Methods

We conducted a retrospective study of all PWID reporting drug use within 3 months and BJIs requiring ≥6 weeks of antibiotics in an urban safety-net hospital between February 1, 2019, and February 1, 2021. Treatment outcomes were assessed by chart review. Rates of failure, defined as death, symptoms, or signs concerning for worsening or recurrent infections, were assessed 90 and 180 days after completion of antibiotics. Univariate logistic regression was used to explore the association between covariates and failure.

Results

Of 705 patients with BJI, 88 (13%) were PWID. Eighty-six patients were included in the final cohort. Forty-four (51%) were homeless, 50 (58%) had spine infection, 68 (79%) had surgery, and 32 of 68 (47%) had postoperatively retained hardware. Twelve (14%) of 86 patients received exclusively intravenous (IV) antibiotics, and 74 (86%) received partial-oral antibiotics. Twelve (14%) of 86 patients had patient-directed discharge. In those who received partial-oral antibiotics, the failure rate was 20% at 90 days and 21% at 180 days after completion of intended treatment. Discharge to a medical respite and follow-up with infectious diseases (ID) or surgery were negatively associated with odds of failure.

Conclusions

Partial-oral treatment of BJI in PWID was a common practice and often successful when paired with medical respite and follow-up with ID or surgery.

Emerging resistance in Staphylococcus epidermidis during dalbavancin exposure: a case report and in vitro analysis of isolates from prosthetic joint infections

BACKGROUND

Dalbavancin, a semisynthetic lipoglycopeptide with exceptionally long half-life and Gram-positive spectrum, is an attractive option for infections requiring prolonged therapy, including prosthetic joint infections (PJIs).

OBJECTIVES

To investigate the prevalence of reduced susceptibility to dalbavancin in a strain collection of Staphylococcus epidermidis from PJIs, and to investigate genomic variation in isolates with reduced susceptibility selected during growth under dalbavancin exposure.

METHODS

MIC determination was performed on S. epidermidis isolates from a strain collection (n = 64) and from one patient with emerging resistance during treatment (n = 4). These isolates were subsequently cultured on dalbavancin-containing agar and evaluated at 48 h; MIC determination was repeated if phenotypical heterogeneity was detected during growth. Population analysis profile (PAP-AUC) was performed in isolates where a  ≥ 2-fold increase in MIC was detected, together with corresponding parental isolates (n = 21). Finally, WGS was performed.

RESULTS

All strains grew at 48 h on agar containing 0.125 mg/L dalbavancin. PAP-AUC demonstrated significant differences between parental and derived strains in four of the eight analysed groups. An amino acid change in the walK gene coinciding with emergence of phenotypic resistance was detected in the patient isolates, whereas no alterations were found in this region in the in vitro derived strains.

CONCLUSIONS

Exposure to dalbavancin may lead to reduced susceptibility to dalbavancin through either selection of pre-existing subpopulations, epigenetic changes or spontaneous mutations during antibiotic exposure. Source control combined with adequate antibiotic concentrations may be important to prevent emerging reduced susceptibility during dalbavancin treatment.

Off-Label Use of Dalbavancin for Sequential Treatment of Spondylodiscitis by Methicillin-Resistant Staphylococcus aureus: A Retrospective Single-Centre Experience

Background: Our aim was to describe the clinical outcome and safety of the sequential treatment with off-label dalbavancin in patients with spondylodiscitis that is caused by methicillin-resistant Staphylococcus aureus (MRSA). Methods: We retrospectively included all patients >18 years of age with spondylodiscitis that is caused by MRSA that was treated with dalbavancin from January 2018−January 2021, recording the instances of clinical cure/failure, adverse events, and the need to be re-hospitalized after the initiation of dalbavancin. In 2/15 patients, we performed therapeutic drug monitoring (TDM) for dalbavancin. Results: We included 15 patients, 53.3% of them were females, with a median age of 67.9 years (57.4−78.5); 100% patients reported back pain, while a fever was present only in 2/15 cases. The spondylodiscitis was localized in 86.6% cases at the lumbar level. A median of a 2-week in-hospital intravenous vancomycin was followed by dalbavancin with a median duration of 12 weeks (12−16). All patients reported a clinical cure, except for a woman who is still on a suppressive treatment. No patient needed to be re-hospitalized, access to emergency department, or experienced adverse events. The TDM for dalbavancin showed that more than 90% of the determinations were above the pharmacodynamic target against staphylococci. Conclusions: The results from our unique, even if it was small, cohort demonstrated that dalbavancin can be a safe/effective option as a sequential treatment in patients with serious infections requiring prolonged antibiotic therapy, such as spondylodiscitis.

Determination of the Elution Capacity of Dalbavancin in Bone Cements: New Alternative for the Treatment of Biofilm-Related Peri-Prosthetic Joint Infections Based on an In Vitro Study

Antibiotic-loaded bone cement is the most widely used approach for the treatment of biofilm-induced septic sequelae in orthopedic surgery. Dalbavancin is a lipoglycopeptide that acts against Gram-positive bacteria and has a long half-life, so we aimed to assess whether it could be a new alternative drug in antibiotic-loaded bone cement for the treatment of periprosthetic joint infections. We assessed the elution capacity of dalbavancin and compared it with that of vancomycin in bone cement. Palacos®R (Heraeus Medical GmbH, Wehrheim, Germany) bone cement was manually mixed with each of the antibiotics studied at 2.5% and 5%. Three cylinders were obtained from each of the mixtures; these were weighed and incubated in 5 mL phosphate-buffered saline at 37°C under shaking for 1 h, 2 h, 4 h, 8 h, 24 h, 48 h, 168 h, and 336 h. PBS was replenished at each time point. The samples were analyzed using high-performance liquid chromatography (vancomycin) and mass cytometry (dalbavancin). Elution was higher than the minimum inhibitory concentration (MIC)90 for both antibiotics after 14 days of study. The release of vancomycin at 14 days was higher than of dalbavancin at each concentration tested (p = 0.05, both). However, the cumulative release of 5% dalbavancin was similar to that of 2.5% vancomycin (p = 0.513). The elution capacity of dalbavancin reached a cumulative concentration similar to that of vancomycin. Moreover, considering that the MIC90 of dalbavancin is one third that of vancomycin (0.06 mg/L and 2 mg/L, respectively) and given the long half-life of dalbavancin, it may be a new alternative for the treatment of biofilm-related periprosthetic infections when loaded in bone cement.