Oritavancin as sequential therapy for Gram-positive bloodstream infections.

BACKGROUND: Oritavancin, a long-acting lipoglycopeptide approved for use in acute bacterial skin and skin structure infections, has limited data evaluating use in serious infections due to Gram-positive organisms. We aimed to assess the effectiveness and safety of oritavancin for consolidative treatment of Gram-positive bloodstream infections (BSI), including infective endocarditis (IE). METHODS: We conducted a retrospective cohort study evaluating adult patients admitted to University of Colorado Hospital from March 2016 to January 2022 who received ≥ 1 oritavancin dose for treatment of Gram-positive BSI. Patients were excluded if the index culture was drawn at an outside facility or were > 89 years of age. The primary outcome was a 90-day composite failure (clinical or microbiological failure) in those with 90-day follow-up. Secondary outcomes included individual components of the primary outcome, acute kidney injury (AKI), infusion-related reactions (IRR), and institutional cost avoidance. RESULTS: Overall, 72 patients were included. Mean ± SD age was 54 ± 16 years, 61% were male, and 10% had IE. Organisms most commonly causing BSI were Staphylococcus aureus (68%, 17% methicillin-resistant), followed by Streptococcus spp. (26%), and Enterococcus spp. (10%). Patients received standard-of-care antibiotics before oritavancin for a median (IQR) of 11 (5-17) days. Composite failure in the clinically evaluable population (n = 64) at 90-days occurred in 14% and was composed of clinical and microbiological failure, which occurred in 14% and 5% of patients, respectively. Three patients (4%) experienced AKI after oritavancin, and two (3%) experienced an IRR. Oritavancin utilization resulted in earlier discharge for 94% of patients corresponding to an institutional cost-avoidance of $3,055,804 (mean $44,938/patient) from 1,102 hospital days saved (mean 16 days/patient). CONCLUSIONS: The use of oritavancin may be an effective sequential therapy for Gram-positive BSI to facilitate early discharge resulting in institutional cost avoidance.

Vancomycin-resistant enterococcus bloodstream infection successfully managed with oritavancin and fosfomycin as sequential treatment.

Bloodstream infections caused by vancomycin-resistant enterococci are increasingly reported and a consensus therapy does not exist. Oritavancin has shown good antimicrobial activity against VRE, but its use is mainly limited to skin, soft tissue, and/or bone infections. Fosfomycin is increasingly used for enterococcal infections (including bloodstream infections and endocarditis) as a partner drug given its anti-biofilm and synergistic properties. Recently in vitro and in vivo synergism between oritavancin and fosfomycin against VRE isolates has been demonstrated. Herein we report the case of a hematologic patient with a VRE bloodstream infection successfully treated with oritavancin and fosfomycin as sequential treatment.

The efficacy of telavancin in comparison with linezolid on endotracheal tube biofilm in pigs with methicillin-resistant Staphylococcus aureus pneumonia.

BACKGROUND: The effect of systemic treatment of ventilator-associated pneumonia (VAP) with telavancin, a semisynthetic lipoglycopeptide with good penetration in vitro biofilms, has not been tested in vivo during mechanical ventilation. This study examined the efficacy of telavancin compared with linezolid against endotracheal tube (ETT) biofilms in a porcine model of methicillin-resistant Staphylococcus aureus (MRSA) VAP. METHODS: VAP was induced in 18 pigs by instilling 107 colony-forming units (CFU/mL) of an MRSA strain susceptible to telavancin and linezolid into each pulmonary lobe. Randomization into three groups was done at pneumonia diagnosis: control (IV glucose 0.5% solution q24); linezolid (10 mg/kg q12) and telavancin groups (22.5 mg/kg q24). After 72 h of MV, data regarding bronchoalveolar lavage (BAL), tracheal aspirate (TA), ETT MRSA biofilm load and thickness measured by scanning electron microscopy were obtained. RESULTS: All 18 pigs completed the study. MRSA was isolated in 100% of ETTs from the control and linezolid groups and in 67% from the telavancin group. Telavancin treatment presented a lower MRSA load compared to the control and linezolid treatments (telavancin median [interquartile range (IQR)] = 1.94 [0.00-5.45], linezolid 3.99 [3.22-4.68] and control 4.93 [4.41-5.15], P = 0.236). Telavancin treatment also resulted in the lowest biofilm thickness according to the SEM (4.04 [2.09-6.00], P < 0.001). We found a positive correlation between ETT and BAL load (rho = 0.511, P = 0.045). CONCLUSIONS: In our VAP model, systemic telavancin treatment reduced ETT MRSA occurrence, load, and biofilm thickness. Our findings may have a bearing on ICU patients' clinical outcomes.

Pharmacokinetics and safety of a single dose of telavancin in pediatric subjects 2-17 years of age.

Antimicrobial resistance increases infection morbidity in both adults and children, necessitating the development of new therapeutic options. Telavancin, an antibiotic approved in the United States for certain bacterial infections in adults, has not been examined in pediatric patients. The objectives of this study were to evaluate the short-term safety and pharmacokinetics (PK) of a single intravenous infusion of telavancin in pediatric patients. Single-dose safety and PK of 10 mg/kg telavancin was investigated in pediatric subjects >12 months to ≤17 years of age with known or suspected bacterial infection. Plasma was collected up to 24-h post-infusion and analyzed for concentrations of telavancin and its metabolite for noncompartmental PK analysis. Safety was monitored by physical exams, vital signs, laboratory values, and adverse events following telavancin administration. Twenty-two subjects were enrolled: 14 subjects in Cohort 1 (12-17 years), 7 subjects in Cohort 2 (6-11 years), and 1 subject in Cohort 3 (2-5 years). A single dose of telavancin was well-tolerated in all pediatric age cohorts without clinically significant effects. All age groups exhibited increased clearance of telavancin and reduced exposure to telavancin compared to adults, with mean peak plasma concentrations of 58.3 µg/mL (Cohort 1), 60.1 µg/mL (Cohort 2), and 53.1 µg/mL (Cohort 3). A 10 mg/kg dose of telavancin was well tolerated in pediatric subjects. Telavancin exposure was lower in pediatric subjects compared to adult subjects. Further studies are needed to determine the dose required in phase 3 clinical trials in pediatrics.

Kimyrsa and Orbactiv - A Tale of Two Formulations.

Kimyrsa is a new formulation (NF) of the original formulation of oritavancin ([OF] Orbactiv). Comparatively, the obvious benefit with this product is the shortened infusion time and flexibility with solution compatibility, but otherwise maintains a similar pharmacokinetic and microbiologic profile. At present, the NF lacks significant real-world experience relative to other available lipoglycopeptides and thus its place in therapy remains difficult to predict but would not be expected to be significantly different than its OF.

Comparative In Vitro Activity of New Lipoglycopeptides and Vancomycin Against Ocular Staphylococci and Their Toxicity on the Human Corneal Epithelium.

PURPOSE: The purpose of this study was to assess the potential of new lipoglycopeptides as novel topical therapies for improved treatment of recalcitrant ocular infections. We evaluated the in vitro antimicrobial activity of oritavancin, dalbavancin, and telavancin compared with vancomycin (VAN) against a large collection of ocular staphylococcal isolates and their cytotoxicity on human corneal epithelial cells (HCECs). METHODS: Antimicrobial susceptibility testing was performed by broth microdilution against 223 Staphylococcus spp. clinical isolates. Time-kill kinetics were determined for methicillin-resistant strains of Staphylococcus aureus (MRSA) (n = 2) and Staphylococcus epidermidis (MRSE) (n = 1). In vitro cytotoxicity assays were performed with AlamarBlue and live/dead staining on HCECs. RESULTS: All new lipoglycopeptides showed strong in vitro potency against ocular staphylococci, including multidrug-resistant MRSA strains, with dalbavancin showing a slightly higher potency overall [minimum inhibitory concentration (MIC) 90 0.06 µg/mL] compared with telavancin and oritavancin (MIC 90 0.12 µg/mL), whereas VAN had the lowest potency (MIC 90 2 µg/mL). Oritavancin exerted rapid bactericidal activity within 1 h for MRSA and 2 h for MRSE. All other drugs were bactericidal within 24 h. At a concentration commonly used for topical preparations (25 mg/mL), cytotoxicity was observed for VAN after 5 min of incubation, whereas reduction in HCEC viability was not seen for telavancin and was less affected by oritavancin and dalbavancin. Cytotoxicity at 25 mg/mL was seen for all drugs at 30 and 60 min but was significantly reduced or undetected for lower concentrations. CONCLUSIONS: Our study demonstrates that new lipoglycopeptides have substantially better in vitro antimicrobial activity against ocular staphylococcal isolates compared with VAN, with a similar or improved toxicity profile on HCECs.

Dalbavancin in the treatment of acute bacterial skin and skin structure and other infections: a safety evaluation.

INTRODUCTION: Dalbavancin is a second-generation lipoglycopeptide approved since 2014 to treat acute bacterial skin and skin-structure infections (ABSSSI). Dalbavancin is characterized by Gram-positive activity and novel pharmacokinetic properties allowing prolonged terminal half-life andonce weekly dosing . A good safety profile was reported in clinical trials . AREAS COVERED: Dalbavancin safety and tolerability from trials and post-marketing studies were reviewed. While most reports included predominantly ABSSSI, two clinical trials and recent observational studies have explored the use of dalbavancin for off-label indications, mainly including bloodstream and osteoarticular infections. EXPERT OPINION: The occurrence of drug-related adverse effects (AE) was similar between dalbavancin and comparators in clinical trials enrolling patients with ABSSSI. Most common AE included gastrointestinal symptoms, infusion reaction, and hypersensitivity. Low rates of drug discontinuation and serious AE were reported across studies. In the past 5 years, several observational studies have reported safety data on the use of dalbavancin, confirming its favorable safety profile. Nevertheless, data from dalbavancin off-label use, often derived from prolonged (>2 weeks) treatments with variable dosing regimens, were mainly retrospective and lacked comparators. Further research is required to allow a reliable analysis of short- and long-term dalbavancin-related AE in non-ABSSSI.

A lipoglycopeptide antibiotic for Gram-positive biofilm-related infections.

Drug-resistant Gram-positive bacterial infections are still a substantial burden on the public health system, with two bacteria (Staphylococcus aureus and Streptococcus pneumoniae) accounting for over 1.5 million drug-resistant infections in the United States alone in 2017. In 2019, 250,000 deaths were attributed to these pathogens globally. We have developed a preclinical glycopeptide antibiotic, MCC5145, that has excellent potency (MIC90 ≤ 0.06 µg/ml) against hundreds of isolates of methicillin-resistant S. aureus (MRSA) and other Gram-positive bacteria, with a greater than 1000-fold margin over mammalian cell cytotoxicity values. The antibiotic has therapeutic in vivo efficacy when dosed subcutaneously in multiple murine models of established bacterial infections, including thigh infection with MRSA and blood septicemia with S. pneumoniae, as well as when dosed orally in an antibiotic-induced Clostridioides difficile infection model. MCC5145 exhibited reduced nephrotoxicity at microbiologically active doses in mice compared to vancomycin. MCC5145 also showed improved activity against biofilms compared to vancomycin, both in vitro and in vivo, and a low propensity to select for drug resistance. Characterization of drug action using a transposon library bioinformatic platform showed a mechanistic distinction from other glycopeptide antibiotics.

Structure and Biosynthesis of Desmamides A-C, Lipoglycopeptides from the Endophytic Cyanobacterium Desmonostoc muscorum LEGE 12446.

Certain cyanobacteria of the secondary metabolite-rich order Nostocales can establish permanent symbioses with a large number of cycads, by accumulating in their coralloid roots and shifting their metabolism to dinitrogen fixation. Here, we report the discovery of two new lipoglycopeptides, desmamides A (1) and B (2), together with their aglycone desmamide C (3), from the nostocalean cyanobacterium Desmonostoc muscorum LEGE 12446 isolated from a cycad (Cycas revoluta) coralloid root. The chemical structures of the compounds were elucidated using a combination of 1D and 2D NMR spectroscopy and mass spectrometry. The desmamides are decapeptides featuring O-glycosylation of tyrosine (in 1 and 2) and an unusual 3,5-dihydroxy-2-methyldecanoic acid residue. The biosynthesis of the desmamides was studied by substrate incubation experiments and bioinformatics. We describe herein the dsm biosynthetic gene cluster and propose it to be associated with desmamide production. The discovery of this class of very abundant (>1.5% d.w.) bacterial lipoglycopeptides paves the way for exploration of their potential role in root endosymbiosis.

Global trends of dalbavancin: A bibliometric analysis.

WHAT IS KNOWN AND OBJECTIVE?: Dalbavancin is used against gram-positive pathogens such as Staphylococcus aureus in acute bacterial skin and skin-structure infections. METHODS: Our main goal was to identify the key articles sustaining the current knowledge of this drug's therapeutic possibilities through a bibliometric analysis of the available literature. RESULTS AND DISCUSSION: On 15 March 2021, we searched the Web of Science electronically for documents that contain within its title the term "dalbavancin." We found a total of 675 documents that average 20.23 citations/publication with a density of 682.60 citations per/year, yielding an h-index of 58. After ranking them by the number of times cited, we extracted the top 100 most-cited records (T100). Number of citations/publication ranged from 13 to 231, publication years were 2002-2019, with the top-cited article published in 2014. All T100 publications were written in English. JMI Laboratories was the institution with the most articles in the T100 (22 documents), and the United States was the top country (75 documents). Five authors participated in at least five of the T100, led by Jones RN with 20 articles. Positions #1, #2, #5, and #9 were clinical trials for acute bacterial skin and skin structure infections (ABSSSI), the on-label indication for dalbavancin. Only one article in the top 10 (T10) was an off-label indication that was published in 2005 with 186 citations, and occupied the third position among the T100. Using the VOSviewer© programme, we observed that the most used keywords were: dalbavancin, lipoglycopeptide, gram-positive, osteomyelitis, vancomycin, and MRSA. WHAT IS NEW AND CONCLUSIONS?: Our study identifies the most significant research on dalbavancin, including the highest impact publications, and highlights the recent trend of dalbavancin in new therapies. The T10 articles include the most important dalbavancin clinical trials, along with other studies and reviews that support the growing role of this antibiotic in clinical use. Emphasis has been on the favourable pharmacokinetic profile that allows administration once-weekly, with minimal risk of severe adverse events.

Antimicrobial Susceptibility Testing for Enterococci.

Enterococci are major, recalcitrant nosocomial pathogens with a wide repertoire of intrinsic and acquired resistance determinants and the potential of developing resistance to all clinically available antimicrobials. As such, multidrug-resistant enterococci are considered a serious public health threat. Due to limited treatment options and rapid emergence of resistance to all novel agents, the clinical microbiology laboratory plays a critical role in deploying accurate, reproducible, and feasible antimicrobial susceptibility testing methods to guide appropriate treatment of patients with deep-seated enterococcal infections. In this review, we provide an overview of the advantages and disadvantages of existing manual and automated methods that test susceptibility of Enterococcus faecium and Enterococcus faecalis to ß-lactams, aminoglycosides, vancomycin, lipoglycopeptides, oxazolidinones, novel tetracycline-derivatives, and daptomycin. We also identify unique problems and gaps with the performance and clinical utility of antimicrobial susceptibility testing for enterococci, provide recommendations for clinical laboratories to circumvent select problems, and address potential future innovations that can bridge major gaps in susceptibility testing.

New Perspectives on Antimicrobial Agents: Long-Acting Lipoglycopeptides.

The long-acting lipoglycopeptides (LGPs) dalbavancin and oritavancin are semisynthetic antimicrobials with broad and potent activity against Gram-positive bacterial pathogens. While they are approved by the Food and Drug Administration for acute bacterial skin and soft tissue infections, their pharmacological properties suggest a potential role of these agents for the treatment of deep-seated and severe infections, such as bloodstream and bone and joint infections. The use of these antimicrobials is particularly appealing when prolonged therapy, early discharge, and avoidance of long-term intravascular catheter access are desirable or when multidrug-resistant bacteria are suspected. This review describes the current evidence for the use of oritavancin and dalbavancin in the treatment of invasive infections, as well as the hurdles that are preventing their optimal use. Moreover, this review discusses the current knowledge gaps that need to be filled to understand the potential role of LGPs in highly needed clinical scenarios and the ongoing clinical studies that aim to address these voids in the upcoming years.

Cost-minimisation analysis of oritavancin for the treatment of acute bacterial skin and skin structure infections from a United Kingdom perspective.

BACKGROUND: Early discharge (ED) from hospital and outpatient parenteral antibiotic therapy (OPAT) are effective approaches for the management of a range of infections, including acute bacterial skin and skin structure infections (ABSSSI). Strategies that facilitate ED, thereby reducing complications such as healthcare-acquired infection whilst enhancing patient quality of life, are being increasingly adopted in line with good antimicrobial stewardship practice. This study presents a cost-minimisation analysis for the use of oritavancin at ED versus relevant comparators from a National Health Service (NHS) and personal and social services United Kingdom perspective. METHODS: A cost-minimisation model considering adult patients with ABSSSI with suspected or confirmed methicillin-resistant Staphylococcus aureus (MRSA) infection, was developed based on publicly available NHS costs, practice guidelines for ABSSSI and clinical expert's opinion. Cost of treatment and treatment days were compared for oritavancin at ED to dalbavancin, teicoplanin, daptomycin and linezolid. RESULTS: Following the empiric use of either flucloxacillin or vancomycin in the inpatient setting, oritavancin was compared to OPAT with dalbavancin, teicoplanin and daptomycin, and oral linezolid from day 4 of treatment. Oritavancin at ED reduced treatment duration by 0.8 days and led to cost savings of £281 in comparison to dalbavancin. In comparison to teicoplanin, daptomycin and linezolid, oritavancin reduced treatment duration by 5 days, with marginally higher costs (£446, £137, and £1,434, respectively). CONCLUSION: Oritavancin, used to support ED, is associated with lower costs compared with dalbavancin and reduced treatment duration relative to all comparators. Its use would support an ED approach in MRSA ABSSSI management.

Clinical Pharmacokinetics and Pharmacodynamics of Dalbavancin.

Dalbavancin is a synthetic lipoglycopeptide that exerts its antimicrobial activity through two distinct modes of action, inhibition of cell wall synthesis and an anchoring mechanism. Compared with previous glycopeptide antibiotics, dalbavancin demonstrates improved antibacterial potency against Gram-positive organisms and a long half-life of approximately 1 week, which is longer in tissues (e.g., skin, bone) than plasma. These factors facilitated the development of single-dose or once-weekly dosing regimens to treat acute bacterial skin and skin structure infections (ABSSSI). Dalbavancin exhibits dose-proportional pharmacokinetics and is highly protein bound (93%). Despite being highly protein bound, it has a steady-state volume of distribution >10 L and distributes widely into the skin, bone, peritoneal space, and epithelial lining fluid, but not cerebrospinal fluid. Dalbavancin elimination occurs via a combination of renal (approximately 45%) and non-renal clearance, with dose adjustments recommended only in patients with a creatinine clearance <30 mL/min not receiving any form of dialysis. The established pharmacokinetic/pharmacodynamic index associated with bacterial kill is free area under the concentration-time curve over the minimum inhibitory concentration (fAUC/MIC), with a goal 24-h fAUC/MIC of at least 27.1 for Staphylococcus aureus infections. Recent data suggest usefulness in the treatment of infections beyond ABSSSI, with convenient dosing and redosing strategies for complicated infections requiring extended treatment durations. Additional studies are needed to confirm these preliminary findings.

Evaluation of a Capped Dosing Telavancin Regimen Compared to Standard Dosing at a Large Community Teaching Hospital.

Telavancin, a lipoglycopeptide antibiotic, is traditionally dosed at 10 mg/kg based on total body weight but is associated with toxicities that limit its use. This study supports the use of a capped dosing regimen of 750 mg in obese patients, which is associated with equal efficacy and fewer adverse effects compared to traditional dosing.

Activity of Oritavancin against Gram-Positive Pathogens Causing Bloodstream Infections in the United States over 10 Years: Focus on Drug-Resistant Enterococcal Subsets (2010-2019).

Oritavancin displayed potent and stable activity (MIC90 range of 0.06 to 0.5 mg/L) over a 10-year period (2010 to 2019) against Gram-positive pathogens that cause bloodstream infections (BSI), including methicillin-resistant Staphylococcus aureus (MRSA) and resistant subsets of Enterococcus spp. Daptomycin and linezolid were also active against methicillin-resistant S. aureus and vancomycin-resistant Enterococcus (VRE). Only oritavancin and linezolid remained active against Enterococcus faecium isolates displaying an elevated daptomycin MIC (i.e., 2 to 4 mg/L). Proportions of methicillin-resistant S. aureus and vancomycin-resistant Enterococcus within the respective S. aureus and enterococcal populations decreased over this period.