Activities of dalbavancin against a worldwide collection of 81,673 gram-positive bacterial isolates

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.

Recent Advances in the Development of Semisynthetic Glycopeptide Antibiotics: 2014-2022

The accelerated appearance of drug-resistant bacteria poses an ever-growing threat to modern medicine's capacity to fight infectious diseases. Gram-positive species such as methicillin-resistant Staphylococcus aureus (MRSA) and Streptococcus pneumoniae continue to contribute significantly to the global burden of antimicrobial resistance. For decades, the treatment of serious Gram-positive infections relied upon the glycopeptide family of antibiotics, typified by vancomycin, as a last line of defense. With the emergence of vancomycin resistance, the semisynthetic glycopeptides telavancin, dalbavancin, and oritavancin were developed. The clinical use of these compounds is somewhat limited due to toxicity concerns and their unusual pharmacokinetics, highlighting the importance of developing next-generation semisynthetic glycopeptides with enhanced antibacterial activities and improved safety profiles. This Review provides an updated overview of recent advancements made in the development of novel semisynthetic glycopeptides, spanning the period from 2014 to today. A wide range of approaches are covered, encompassing innovative strategies that have delivered semisynthetic glycopeptides with potent activities against Gram-positive bacteria, including drug-resistant strains. We also address recent efforts aimed at developing targeted therapies and advances made in extending the activity of the glycopeptides toward Gram-negative organisms.

Update on activity of dalbavancin and comparators against clinical isolates of Gram-positive pathogens from Europe and Russia (2017-2018), and on clonal distribution of MRSA

BACKGROUND

Gram-positive pathogens remain a major cause of healthcare- and community-associated infections. In particular, the dissemination of methicillin-resistant staphylococci, as methicillin-resistant S. aureus (MRSA) and vancomycin-resistant enterococci (VRE), have significantly reduced the therapeutic options, making the management of these infections even more challenging. Dalbavancin is a second-generation lipoglycopeptide approved for the treatment of moderate to severe acute bacterial skin and skin structure infections (ABSSSIs) caused by Gram-positive organisms, showing a bactericidal effect and a low propensity towards the selection of resistance over time.

AIM

This study aimed to evaluate the antimicrobial activity of dalbavancin and other comparators against recent clinical isolates of Gram-positive pathogens obtained from different sources and from several European countries, including countries of southern and eastern Europe and Russia, where resistance rates are typically high. This study also aimed to describe the clonal relationship of MRSA strains circulating in southern and eastern Europe and Russia.

RESULTS

A total of 1478 isolates were collected. Study results demonstrated the excellent and stable activity of dalbavancin against Gram-positive microorganisms, including MRSA. Interestingly, dalbavancin has retained unaltered MIC₅₀ and MIC₉₀ values over the years and seemed to have a low propensity in selecting resistance mechanisms.

CONCLUSIONS

Our data supported the potential efficacy of dalbavancin against Gram-positive bacteria and uncommon Gram-positive pathogens in patients with ABSSSIs. Of note, few CoNS isolates were resistant to dalbavancin and susceptible to vancomycin, pointing out the importance of testing the susceptibility to dalbavancin before its administration for CoNS infections.

In vitro activity of dalbavancin and other anti-staphylococcal agents against infecting isolates of methicillin-resistant coagulase-negative staphylococci

Introduction. Dalbavancin was approved in Europe in 2015 for skin and soft tissue infections.Hypothesis/Gap Statement. Data on methicillin-resistant coagulase-negative staphylococci (MR-CNS) dalbavancin susceptibility are scarce.Aim. To assess the susceptibility of MR-CNS to dalbavancin and other anti-staphylococcal agents.Methodology. A total of 443 MR-CNS clinical isolates from patients hospitalized in a Greek university hospital during a 2.5-year period (January 2018 to June 2020) were included. The MICs for vancomycin, teicoplanin, linezolid and daptomycin were investigated by Etest and the MIC for dalbavancin was determined according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines in 196 isolates. The consumption of the aforementioned antimicrobials was calculated.Results. In total, 51 isolates were resistant to teicoplanin (11.5 %) and 211 (47.6 %) to linezolid; all were susceptible to vancomycin and daptomycin. Among 196 isolates tested, 32 (16.3 %) were resistant to dalbavancin. A significant increase of MIC during the study period was found for vancomycin, teicoplanin and daptomycin, while a decrease in linezolid's MIC was observed. Dalbavancin's MIC remained stable. No difference in consumption was observed among the studied anti-staphylococcal agents.Conclusion. An increase of vancomycin, teicoplanin and daptomycin MICs among MR-CNS was observed, whereas 47.6 % of isolates were non-susceptible to linezolid. Dalbavancin retains excellent potency against MR-CNS, even in the presence of non-susceptibility to other anti-staphylococcal antibiotics.

Adaptation of the Start-Growth-Time Method for High-Throughput Biofilm Quantification

Colony forming unit (CFU) determination by agar plating is still regarded as the gold standard for biofilm quantification despite being time- and resource-consuming. Here, we propose an adaption of the high-throughput Start-Growth-Time (SGT) method from planktonic to biofilm analysis, which indirectly quantifies CFU/mL numbers by evaluating regrowth curves of detached biofilms. For validation, the effect of dalbavancin, rifampicin and gentamicin against mature biofilms of Staphylococcus aureus and Enterococcus faecium was measured by accessing different features of the viability status of the cell, i.e., the cultivability (conventional agar plating), growth behavior (SGT) and metabolic activity (resazurin assay). SGT correlated well with the resazurin assay for all tested antibiotics, but only for gentamicin and rifampicin with conventional agar plating. Dalbavancin treatment-derived growth curves showed a compared to untreated controls significantly slower increase with reduced cell doubling times and reduced metabolic rate, but no change in CFU numbers was observed by conventional agar plating. Here, unspecific binding of dalbavancin to the biofilm interfered with the SGT methodology since the renewed release of dalbavancin during detachment of the biofilms led to an unintended antimicrobial effect. The application of the SGT method for anti-biofilm testing is therefore not suited for antibiotics which stick to the biofilm and/or to the bacterial cell wall. Importantly, the same applies for the well-established resazurin method for anti-biofilm testing. However, for antibiotics which do not bind to the biofilm as seen for gentamicin and rifampicin, the SGT method presents a much less labor-intensive method suited for high-throughput screening of anti-biofilm compounds.

Determination of a Tentative Epidemiological Cut-Off Value (ECOFF) for Dalbavancin and Enterococcus faecium

Dalbavancin is a lipoglycopeptide antibiotic that shows potent activity against Gram-positive bacteria. It circumvents vanB-type glycopeptide resistance mechanisms; however, data on the in vitro activity of dalbavancin for Enterococcus faecium (E. faecium) are scarce, and thus, no breakpoints are provided. In recent years, there has been a continuing shift from vanA-type to vanB-type vancomycin-resistance in enterococci in Central Europe. Therefore, we aimed to investigate the in vitro activity of dalbavancin against different van-genotypes, with particular focus on vanB-type E. faecium. Dalbavancin susceptibility was determined for 25 van-negative, 50 vanA-positive, and 101 vanB-positive clinical E. faecium isolates (typed by cgMLST). Epidemiological Cut-Off Values (ECOFFs) were determined using ECOFFinder. For vanB-type E. faecium isolates, dalbavancin MICs were similar to those of vancomycin-susceptible isolates reaching values no higher than 0.125 mg/L. ECOFFs for van-negative and vanB-positive isolates were 0.5 mg/l and 0.25 mg/L respectively. In contrast, E. faecium possessing vanA predominantly showed dalbavancin MICs >8 mg/L, therefore preventing the determination of an ECOFF. We demonstrated the potent in vitro activity of dalbavancin against vancomycin-susceptible and vanB-type E. faecium. On the basis of the observed wildtype distribution, a dalbavancin MIC of 0.25 mg/L can be suggested as a tentative ECOFF for E. faecium.

Successful Treatment of Diabetic Foot Osteomyelitis with Dalbavancin

Introduction:

Dalbavancin is a new antibiotic against multi-drug resistant Gram (+) bacteria. Dalbavancin has an extremely long half-life. Current indication is skin and soft tissue infections (ABSSSI), but researchers have successfully administered it off-label to osteomyelitis (OM) patients.

Aim:

We present a case of successful treatment of diabetic foot (DF) OM.

Case report:

A 53-year-old male presented to our DF clinic, with recently diagnosed diabetes mellitus, with very bad glycaemic control (HbA1c=12,5%). He had diabetic neuropathy, but no peripheral arteriopathy. Two months before, because of an accident with hot water, he presented left foot ulcer, followed by ABSSSI and 1^st toe and 1^st metatarsal OM (plain x-ray findings). A multi-drug resistant Enterococcus faecium was isolated in cultures and a targeted treatment with tigecycline and daptomycin was administered. The patient also received 1,5 gr dalbavancin upon discharge. 2 weeks later, he continued treatment at home with linezolid and tedizolid. A complete medical record with patient’s history, informed consent and relative literature was sent to Greek National Health Care Organization (EOPYY), requesting administering off-label another 1,5 gr dalbavancin. In the meanwhile, he was admitted for iv tigecyclin, and continued treatment with linezolid at home. He finally received a second dose of 1,5 g dalbavancin. Patient received totally 14 weeks’ targeted therapy, mostly off-hospital. When he completed treatment, foot was in excellent condition and x-ray had significantly improved.

Conclusion:

Dalbavancin, due to its extremely long half-life, could potentially be the drug of choice for OM caused by multi-drug resistant Gram (+) cocci, in order to avoid hospitalization, especially on non-complient patients. Further research is necessary.

Dalbavancin for the Treatment of Prosthetic Joint Infections: A Narrative Review

Dalbavancin (DAL) is a lipoglycopeptide with bactericidal activity against a very wide range of Gram-positive microorganisms. It also has unique pharmacokinetic properties, namely a prolonged half-life (around 181 h), which allows a convenient weekly dosing regimen, and good diffusion in bone tissue. These features have led to off-label use of dalbavancin in the setting of bone and joint infection, including prosthetic joint infections (PJI). In this narrative review, we go over the pharmacokinetic and pharmacodynamic characteristics of DAL, along with published in vitro and in vivo experimental models evaluating its activity against biofilm-embedded bacteria. We also examine published experience of osteoarticular infection with special attention to DAL and PJI.

Anti-biofilm activity of dalbavancin against methicillin-resistant Staphylococcus aureus (MRSA) isolated from human bone infection

The presence of methicillin-resistant Staphylococcus aureus (MRSA) in bone infections difficults its treatment and is a sign of concern. The aim of this study was to evaluate in vitro activity of dalbavancin on pre-established adhered cells and 24 h old biofilms of MRSA strains isolated from a human bone infection. Thirty-three MRSA were isolated from osteomyelitis episodes. The antimicrobial susceptibility of these strains was assessed by the Kirby-Bauer disc diffusion method and the presence of resistance genes was screened by PCR. MRSA planktonic minimum inhibitory concentration and minimum bactericidal concentration were assessed. Minimum biofilm eradication concentration (MBEC) was performed by the microtiter biofilm formation assay. All 33 MRSA strains were classified as multidrug-resistant strains and susceptible to dalbavancin. Dalbavancin inhibited the growth of 54.6% and 52% of strains at the concentrations of 0.05 µg/mL and 1 µg/mL, respectively. The MBEC values up to 0.4 µg/mL demonstrated that dalbavancin was active against most strains in pre-established adhered cells and 24 h old biofilms. The current results show that dalbavancin is active against adhered cells and biofilms in vitro, suggesting that this antimicrobial agent may be an option for the treatment of bone infections caused by MRSA.

The role of dalbavancin for Gram positive infections in the COVID-19 era: state of the art and future perspectives

INTRODUCTION

The COVID-19 pandemic has dramatically challenged the national health systems worldwide in the last months. Dalbavancin is a novel antibiotic with a long plasmatic half-life and simplified weekly administration regimens, thus representing a promising option for the outpatient treatment of Gram-positive infections and the early discharge of hospitalized patients. Dalbavancin is approved for the treatment of acute bacterial skin and skin structure infections (ABSSSIs). Many preliminary data seem to support its use in other indications, such as osteomyelitis, prosthetic joint infections, and infective endocarditis.

AREAS COVERED

A search in the literature using validated keywords (dalbavancin, Gram-positive infections, Gram-positive cocci, ABSSSI, intravenous treatment, and long-acting antibiotics) was conducted on biomedical bibliographic databases (PubMed and Embase) from 2004 to 30 September 2020. Results were analyzed during two consensus conferences with the aim to review the current evidence on dalbavancin in Gram-positive infections, mainly ABSSSI, osteomyelitis, and infective endocarditis, highlight the main limitations of available studies and suggest possible advantages of the molecule.

EXPERT OPINION

The board identifies some specific subgroups of patients with ABSSSIs who could mostly benefit from a treatment with dalbavancin and agrees that the design of homogenous and robust studies would allow a broader use of dalbavancin even in other clinical settings.

Therapeutic potential of dalbavancin in a rat model of methicillin-resistant Staphylococcus aureus (MRSA)-osteomyelitis

Bacterial osteomyelitis is a major clinical challenge in human and veterinary patients. This infection is an infrequent but feared complication of orthopedic surgery and is mainly caused by methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to evaluate the efficacy of dalbavancin (dosed for either 7 or 14 days) in an MRSA-osteomyelitis tibial bone model. A total of 39 rats were included in the study. All animals received an inoculum of a clinical strain of MRSA (10⁶ colony-forming units [CFU]) injected into the proximal tibia under general anesthesia. Dalbavancin was injected intraperitoneally for 7 or 14 days in 13 animals each; the remaining 13 animals received saline solution. After treatment, the animals were sacrificed. Infected tibiae were recovered for histological evaluation and microbiological analysis (MRSA count per gram of bone). Rats that received dalbavancin showed a statistically significant reduction of MRSA counts compared with the control group: median 0 CFU/g bone (14 days of dalbavancin) vs. 70 CFU/g bone (7 days of dalbavancin) and 1600 CFU/g bone (control). Histological evaluation showed typical signs of osteomyelitis in the control group, whereas there were no signs of bone infection in 92% of the rats that received 14 days of dalbavancin. According to this model, dalbavancin seems to have good efficacy for treating serious Gram-positive bone infections, including those caused by MRSA.

The role of dalbavancin in the treatment of acute bacterial skin and skin structure infections (ABSSSIs)

Introduction: Acute bacterial skin and skin-structure infections (ABSSSI) are a subgroup of skin and soft tissue infections and are a common source of morbidity in both the community and the hospital setting. The most common cause of ABSSSI is Staphylococcus aureus, which also includes methicillin-resistant S. aureus (MRSA), together with beta-hemolytic streptococci, enterococci, and Gram-negative bacteria. Since the emergence of MRSA, the management of ABSSSI has become more challenging. Novel therapies alternative to teicoplanin and vancomycin, intravenous agents commonly used against MRSA and employed in hospitalized patients, and to other antibiotics which are used as standard of care for MRSA infection, with a higher efficacy and safer profile are worth evaluating.Areas covered: This review presents and discusses current evidence on the use of dalbavancin in the treatment of ABSSSI.Expert opinion: Dalbavancin represents a promising therapeutic choice in patients with ABSSSI, thanks to its favorable pharmacokinetic profile, valuable antimicrobial spectrum, and good safety profile.

Real-world experience with dalbavancin therapy in gram-positive skin and soft tissue infection, bone and joint infection

PURPOSE

Dalbavancin is a novel lipoglycopeptide with potent activity against several gram-positive pathogens, an excellent safety profile and a long elimination half-life.

METHODS

In this case series observed at the University Hospital of Vienna between 2015 and 2017, all adult patients with gram-positive infections who received at least one dosage of dalbavancin were screened (n = 118). A total of 72 patients were included in the final analysis. The number of included patients stratified by the source of infection was: skin and soft tissue infection (SSTI) (n = 26), osteomyelitis (n = 20), spondylodiscitis (n = 14), acute septic arthritis (n = 4) and prosthetic joint infection (n = 8).

RESULTS

In 46 patients (64%), clinical cure was detected at the end of dalbavancin therapy without additional antibiotic therapy. Of the 26 patients who received additional antibiotic therapy other than dalbavancin, 15 patients (21%) showed no clinical improvement under dalbavancin therapy, four patients (5%) had side effects (nausea n = 1, exanthema n = 2, hyperglycemia n = 1), and in seven patients (10%) clinical improvement under dalbavancin therapy was detected but antibiotic therapy was de-escalated to an oral drug.

CONCLUSION

We demonstrated high clinical effectiveness of dalbavancin for acute gram-positive infections primarily acute SSTI, acute septic arthritis, acute osteomyelitis and spondylodiscitis. In patients with biofilm-associated infection (chronic infection or joint prosthesis), source control was absolutely necessary for treatment success.

Safety and Efficacy of Prolonged Use of Dalbavancin in Bone and Joint Infections

Dalbavancin is a lipoglycopeptide with potent activity against Gram-positive microorganisms, a long half-life, a favorable safety profile, and a high concentration in bone, which makes it an interesting alternative for treatment of osteoarticular infections. We performed a multicentric retrospective study of all patients with an osteoarticular infection (septic arthritis, spondylodiscitis, osteomyelitis, or orthopedic implant-related infection) treated with at least one dose of dalbavancin between 2016 and 2017 in 30 institutions in Spain. In order to evaluate the response, patients with or without an orthopedic implant were separated. A total of 64 patients were included. Staphylococcus epidermidis and Staphylococcus aureus were the most frequent microorganisms. The reasons for switching to dalbavancin were simplification (53.1%), adverse events (25%), or failure (21.9%). There were 7 adverse events, and no patient had to discontinue dalbavancin. In 45 cases, infection was related to an orthopedic implant. The implant material was retained in 23 cases, including that in 15 (65.2%) patients that were classified as cured and 8 (34.8%) that presented improvement. In 21 cases, the implants were removed, including those in 16 (76.2%) cases that were considered successes, 4 (19%) cases were considered improved, and 1 (4.8%) case that was considered a failure. Among the 19 cases without implants, 14 (73.7%) were considered cured, 3 (15.8%) were considered improved, and 2 (10.5%) were considered failures. The results show that dalbavancin is a well-tolerated antibiotic, even when >2 doses are administered, and is associated with a high cure rate. These are preliminary data with a short follow-up; therefore, it is necessary to gain more experience and, in the future, to establish the most appropriate dose and frequency.

Comparative In Vitro Activities of New Antibiotics for the Treatment of Skin Infections

Bacterial skin infections result in significant morbidity and have contributed to enhanced health-care resource utilization. The problem is heightened by emerging antimicrobial resistance. Multiple novel agents active against resistant pathogens that cause skin infections-including dalbavancin, tedizolid phosphate, oritavancin, and delafloxacin-have been approved over the past 5 years. Common features of these agents include gram-positive activity and favorable safety. Of these agents, delafloxacin is unique in being active against both gram-positive and gram-negative pathogens that cause skin infections, including those resistant to other antimicrobial agents. It is, therefore, an effective option for the treatment of skin infections.

Dalbavancin for treating prosthetic joint infections caused by Gram-positive bacteria: A proposal for a low dose strategy. A retrospective cohort study

OBJECTIVE

Gram-positive bacteria are the leading cause of prosthetic joint infection (PJI). Dalbavancin is a lipoglycopeptide with remarkable pharmacokinetic properties and high bactericidal activity against most Gram-positive bacteria. Although clear evidence regarding its effectiveness in bone and joint infections lacks, recent studies suggest a promising role of dalbavancin in PJI.

METHODS

From June 1st 2016 to May 1st 2018, all patients diagnosed of PJI and treated with DAL alone or in combination with other drugs were retrospectively evaluated. Dalbavancin susceptibility of every isolate was studied following CLSI criteria. The primary objective was to assess the clinical efficacy and tolerability of the drug in patients with PJI. A cost-analysis was performed following the DALBUSE study methodology.

RESULTS

Sixteen patients were treated with dalbavancin, eight with total hip arthroplasty infection (THAi) and eight with total knee arthroplasty infection (TKAi). Staphylococcus spp. and Enterococcus spp. were the microorganisms involved. No major side effects were detected. Infection resolved in 12 patients. In 2 patients the treatment failed, and another patient died due to unrelated causes. One patient is currently being treated for hematogenous-spread knee infection secondary to prosthetic aortic arch endocarditis. After discontinuation of dalbavancin, and excluding patients who died or with clinical failure, the median follow up of the cohort was 503 days (interquartile range IQR, 434.5 to 567 days). We calculate that US$ 264,769 were saved.

CONCLUSIONS

This study suggests that dalbavancin treatment for PJI caused by Gram-positive bacteria is a safe and effective option that reduces hospital stay and costs. Future reports are needed to confirm these findings.

Trends in NP and RN enrollment, graduation, and practice

The employment outlook for NPs is expected to continue its growth trend in the coming years. This article summarizes graduation and employment trends for nursing students and provides a synopsis of data from the Bureau of Labor Statistics about the growing demand for NPs and nurses. A brief overview of the history of recent workforce trends is also provided.

Successful treatment of Enterococcus faecalis bacteremia with dalbavancin as an outpatient in an intravenous drug user

This report describes the treatment of a 35-year-old male who presented to the emergency department with an empyema, and who had a long hospital course complicated by a catheter-related bloodstream infection and a history of intravenous drug use. Blood culture results confirmed Enterococcus faecalis. He was not a candidate for outpatient intravenous therapy and needed 14days of treatment, but was able to be discharged with a 3-day supply of oral levofloxacin to complete treatment for his empyema and 1 dose of dalbavancin at an outpatient infusion center to treat his bacteremia. Due to the unique properties of dalbavancin, off-label use in specific populations may help facilitate transitions of care. This report outlines the successful use of dalbavancin and removal of the central catheter in the treatment of E. faecalis bacteremia.

Vancomycin-resistant enterococcus infection in the hematopoietic stem cell transplant recipient: an overview of epidemiology, management, and prevention

Vancomycin-resistant enterococcus (VRE) is now one of the leading causes of nosocomial infections in the United States. Hematopoietic stem cell transplantation (HSCT) recipients are at increased risk of VRE colonization and infection. VRE has emerged as a major cause of bacteremia in this population, raising important clinical questions regarding the role and impact of VRE colonization and infection in HSCT outcomes as well as the optimal means of prevention and treatment. We review here the published literature and scientific advances addressing these thorny issues and provide a rational framework for their approach.

Dalbavancin is active in vitro against biofilms formed by dalbavancin-susceptible enterococci

We tested the in vitro activity of dalbavancin, vancomycin and daptomycin against 83 enterococcal isolates in planktonic and biofilm states. The MIC₉₀ for vancomycin-susceptible Enterococcus faecalis was 0.125 and 4μg/mL for dalbavancin and daptomycin, respectively. For vancomycin-resistant Enterococcus faecium, the MIC₉₀ was >16 and 2μg/mL for dalbavancin and daptomycin, respectively. Dalbavancin minimum biofilm inhibitory concentrations (MBICs) for vancomycin-susceptible and -resistant isolates were ≤0.25 and >16μg/mL, respectively. The daptomycin MBIC₉₀ for all isolates was 4μg/mL. For E. faecalis and E. faecium, dalbavancin minimum biofilm bactericidal concentrations (MBBCs) for vancomycin-susceptible and -resistant isolates were ≤4 and >16μg/mL, respectively, whereas vancomycin MBBCs were >128μg/mL for all isolates, and daptomycin MBBC₉₀ values for both species were 128μg/mL. In summary, dalbavancin exhibited in vitro activity against all tested isolates of vancomycin-susceptible, but not against vancomycin-resistant enterococci; activity was observed in both the planktonic and biofilm states.

Emergence of dalbavancin non-susceptible, vancomycin-intermediate Staphylococcus aureus (VISA) after treatment of MRSA central line-associated bloodstream infection with a dalbavancin- and vancomycin-containing regimen

OBJECTIVES

Dalbavancin is a long-acting lipoglycopeptide with activity against gram-positives, including methicillin-resistant Staphylococcus aureus (MRSA). The potential for lipoglycopeptides, with half-lives greater than 1 week, to select for resistance is unknown. Here we explore a case of MRSA central line-associated bloodstream infection in which dalbavancin and vancomycin non-susceptibility emerged in a urine isolate collected after the patient was treated with vancomycin and dalbavancin sequentially.

METHODS

Isolates from blood and urine underwent susceptibility testing, and whole genome sequencing (WGS). The blood isolate was subjected to successive passage in vitro in the presence of escalating dalbavancin concentrations and the emergent isolate was subjected to repeat susceptibility testing and WGS.

RESULTS

The blood isolate was fully susceptible to vancomycin; however, MICs of the urine isolate to dalbavancin, vancomycin, telavancin, and daptomycin were at least fourfold higher than the blood-derived strain. Both strains were indistinguishable by spa and variable number tandem repeat (VNTR) typing, and WGS revealed only seven variants, indicating clonality. Four variants affected genes, including a 3bp in-frame deletion in yvqF, a gene which has been implicated in glycopeptide resistance. Vancomycin and dalbavancin non-susceptibility emerged in the blood isolate after successive passage in vitro in the presence of dalbavancin, and WGS identified a single non-synonymous variant in yvqF.

CONCLUSIONS

This is the first case in which VISA has emerged in the context of a dalbavancin-containing regimen. The selection for cross-resistance to vancomycin in vitro by dalbavancin exposure alone is troubling. Clinicians should be aware of the possibility for emergence of dalbavancin non-susceptibility and glycopeptide cross-resistance arising following therapy.

Dalbavancin for outpatient parenteral antimicrobial therapy of skin and soft tissue infections in a returning traveller : Proposal for novel treatment indications

Skin and soft tissue infections (SSTIs) are among the most common health problems in travellers returning from tropical and subtropical countries. Importantly, the prevalence of Staphylococcus aureus, the most common pathogen for purulent SSTIs, with specific drug resistance, such as methicillin resistant Staphylococcus aureus (MRSA) and those expressing virulence genes, such as Panton-Valentine-leukocidin is higher in tropical regions than in most high resource settings. This poses challenges for the empirical antimicrobial treatment of SSTIs in returning travellers. This short report describes a patient with a recent travel history to Hong Kong, Singapore and the Philippines who presented with multiple mosquito bites on both upper extremities and secondary bacterial superinfection. He had previously been prescribed oral beta-lactam antimicrobial therapy but lacked adherence to this treatment. Based on the risk for MRSA infection and problems with treatment adherence to oral therapy an outpatient parenteral antimicrobial therapy with dalbavancin was administered on days 0 and 7. Microbiological culture confirmed presence of MRSA and clinical follow-up demonstrated complete remission of the SSTI within 2 weeks. Dalbavancin is a promising treatment option for empirical parenteral treatment of SSTIs in returning travellers, a population at high risk for beta-lactam resistant S. aureus skin infections.

Managing acute bacterial skin and skin structure infections: Focus on new lipoglycopeptides

Acute bacterial skin and skin structure infections (ABSSSI) are some of the most commonly encountered infections worldwide. Hospitalizations as a result of ABSSSI are associated with high mortality. This article discusses the role of oritavancin and dalbavancin, two new lipoglycopeptides, in the context of the other I.V. available standard therapy options.

Single-Dose Dalbavancin: A Review in Acute Bacterial Skin and Skin Structure Infections

Intravenous dalbavancin (Dalvance^®, Xydalba^®), first approved as a two-dose regimen for the treatment of acute bacterial skin and skin structure infections (ABSSSI), has now been additionally approved as a single-dose regimen. This narrative review discusses the pharmacological properties of intravenous dalbavancin and its clinical efficacy and tolerability as a single-dose regimen in the treatment of adult patients with ABSSSI. Single-dose dalbavancin is an effective and generally well tolerated treatment option for adults with ABSSSI, with noninferior efficacy to the two-dose dalbavancin regimen with regard to early clinical response (at 48-72 h) and low rates of adverse events. Clinical success rates at days 14 and 28 also did not significantly differ between the single- and two-dose dalbavancin regimens; neither did clinical success rates at day 14 when analysed by baseline pathogen. It has a broad spectrum of activity against common ABSSSI-related pathogens, and a favourable pharmacokinetic profile allowing for the convenience of single-dose administration. Thus, dalbavancin presents a promising alternative to conventional antibacterials for the treatment of ABSSSI in adult patients.

Dalbavancin and Oritavancin: An Innovative Approach to the Treatment of Gram-Positive Infections

Health care-associated infections, especially those caused by multidrug-resistant gram-positive organisms, such as methicillin-resistant Staphylococcus aureus (MRSA), are a growing public health threat. In 2014, the U.S. Food and Drug Administration approved two new lipoglycopeptides, oritavancin and dalbavancin, for the treatment of acute bacterial skin and skin structure infections. The rationale for the development of these antimicrobials was partly to aid in the battle against vancomycin resistance in both Staphylococcus and Enterococcus. Considered a subclass of the glycopeptide antibiotics, the new lipoglycopeptides have similar mechanisms of action of binding to the carboxyl terminal d-alanyl-d-alanine residue of the growing peptide chains but differ from their parent glycopeptides by the addition of lipophilic tails. This addition allows for these agents to have prolonged half-lives, giving them unique dosing profiles. In addition, by concentrating at the site of action, they have increased potency against MRSA compared with vancomycin, the current mainstay of therapy. In this review, we focus on comparing and contrasting these two new agents with regard to their pharmacology, mechanisms of action, spectrum of activity, safety profiles, dosage and administration, and drug and laboratory interactions, and we review the clinical trials evaluating their use.

Dalbavancin Activity When Tested against Streptococcus pneumoniae Isolated in Medical Centers on Six Continents (2011 to 2014)

Dalbavancin, a novel lipoglycopeptide, was approved for use in 2014 by regulatory agencies in the United States and Europe for the treatment of skin and skin structure infections. The activity of dalbavancin was also widely assessed by determination of its activity against Streptococcus pneumoniae clinical isolates collected from patients on six continents monitored during two time intervals (2011 to 2013 and 2014). A total of 18,186 pneumococcal isolates were obtained from 49 nations and submitted to a monitoring laboratory as part of the SENTRY Antimicrobial Surveillance Program for reference susceptibility testing. The potency of dalbavancin against S. pneumoniae was consistent across the years that it was monitored, with the MIC50 and MIC90 being 0.015 and 0.03 μg/ml, respectively, and all isolates were inhibited by ≤0.12 μg/ml. The activity of dalbavancin was not adversely influenced by nonsusceptibility to β-lactams (ceftriaxone or penicillin), macrolides, clindamycin, fluoroquinolones, or tetracyclines or multidrug resistance (MDR). Regional variations in dalbavancin activity were not detected, but S. pneumoniae strains isolated in the Asia-Pacific region were more likely to be nonsusceptible to penicillin and ceftriaxone as well as to be MDR than strains isolated in North or South America and Europe. Direct comparisons of potency illustrated that dalbavancin (MIC50 and MIC90, 0.015 and 0.03 μg/ml, respectively) was 16-fold or more active than vancomycin (MIC50, 0.25 μg/ml), linezolid (MIC50, 1 μg/ml), levofloxacin (MIC50, 1 μg/ml), ceftriaxone (MIC90, 1 μg/ml), and penicillin (MIC90, 2 μg/ml). In conclusion, dalbavancin had potent and consistent activity against this contemporary (2011 to 2014) collection of S. pneumoniae isolates.

In vitro activity of dalbavancin against biofilms of staphylococci isolated from prosthetic joint infections

The in vitro activity of dalbavancin was tested against biofilms of 171 staphylococci associated with prosthetic joint infection. Dalbavancin minimum biofilm bactericidal concentration (MBBC) values were: MBBC50 for Staphylococcus aureus and Staphylococcus epidermidis, 1μg/mL; MBBC90 for S. aureus, 2μg/mL; MBBC90 for S. epidermidis, 4μg/mL.

Dalbavancin (BI-387) for the treatment of complicated skin and skin structure infection

In the era of increasing antibiotic resistance, development of new agents that could provide therapeutic options for difficult to treat pathogens is vital. Dalbavancin is a new lipoglycopeptide recently approved by the US FDA for the treatment of acute bacterial skin and skin structure infections. A derivative of the older glycopeptide class, chemical structure alterations resulted in a molecule with a similar mechanism of action, however, with a comparatively increased activity as reflected by organism MICs. These modifications also resulted in an antibiotic with distinctive properties that allow for once-weekly dosing in the treatment of Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus and drug resistant Streptococcus spp. As the first of these long acting compounds, understanding the pharmacokinetic and pharmacodynamic properties of agents like dalbavancin is essential for determining a place in therapy.

New Gram-Positive Agents: the Next Generation of Oxazolidinones and Lipoglycopeptides

The growing problem of antimicrobial resistance among bacterial pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE), has reached a critical state. Tedizolid phosphate, dalbavancin, and oritavancin have recently been approved by the U.S. Food and Drug Administration (FDA) for the treatment of acute bacterial skin and skin structure infections (ABSSSI) and represent the next generation of oxazolidinones and lipoglycopeptides. All three agents exhibit in vitro activity and clinical efficacy against MRSA. Tedizolid phosphate and oritavancin demonstrate in vitro activity against VRE. These new Gram-positive agents are reviewed here.

New developments in the treatment of acute bacterial skin and skin structure infections: considerations for the effective use of dalbavancin

Dalbavancin, an intravenous glycopeptide, was approved by the US Food and Drug Administration in May 2014 for use in adult patients with acute bacterial skin and skin structure infections. The recommended dosing regimen for effective use of dalbavancin is 1,000 mg followed by a 500 mg dose after 1 week. Two multinational, identically designed, non-inferiority trials, DISCOVER 1 and 2, demonstrated similar early clinical success with dalbavancin compared to vancomycin with an option to switch to oral linezolid. In a recently published non-inferiority trial, a single-dose regimen of dalbavancin was compared to the traditional two-dose administration and was found to have a non-inferior clinical response. In the aforementioned trials, dalbavancin was well tolerated, with patients experiencing transient adverse events of mild to moderate severity. The prolonged half-life, excellent skin and soft tissue penetration, bactericidal activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus, and convenient dosing make dalbavancin a reasonable option for the treatment of acute bacterial skin and skin structure infections in adult patients who have tried and failed other therapies.

Impact of Glycopeptide Resistance in Staphylococcus aureus on the Dalbavancin In Vivo Pharmacodynamic Target

Dalbavancin is a novel lipoglycopeptide with activity against Staphylococcus aureus, including glycopeptide-resistant isolates. The in vivo investigation reported here tested the effects of this antibiotic against seven S. aureus isolates with higher MICs, including several vancomycin-intermediate strains. Results of 1-log kill and 2-log kill were achieved against seven and six of the isolates, respectively. The mean free-drug area under the concentration-time curve (fAUC)/MIC values for net stasis, 1-log kill, and 2-log kill were 27.1, 53.3, and 111.1, respectively.

Dalbavancin for the treatment of acute bacterial skin and skin structure infections

INTRODUCTION

Acute bacterial skin and skin structure infections (ABSSSI) have increased in incidence and severity. The involvement of resistant organisms, particularly methicillin-resistant Staphylococcus aureus, presents additional challenges. The lipoglycopeptide dalbavancin has a prolonged half-life, high protein binding, and excellent tissue levels which led to its development as a once-weekly treatment for ABSSSI. In the pivotal DISCOVER 1 and DISCOVER 2 trials, dalbavancin proved non-inferior to vancomycin followed by linezolid when used sequentially for ABSSSI, forming the basis for its recent approval in the US and Europe for ABSSSI.

AREAS COVERED

A literature search of published pharmacologic and clinical data was conducted to review the chemistry, pharmacodynamics, and pharmacokinetics of dalbavancin. We also discuss its development process, highlighting efficacy and safety data from pertinent clinical trials and the role it could play in the current clinical landscape.

EXPERT OPINION

DISCOVER 1 and DISCOVER 2 demonstrated dalbavancin's non-inferiority to vancomycin followed by linezolid for ABSSSI and confirmed its safety and tolerability. They were among the first trials to use new, early primary efficacy endpoints, and dalbavancin was among the first agents designated a Qualified Infectious Disease Product for expedited review. Dalbavancin may prove to be a valuable option for ABSSSI patients in whom conventional therapy is limited.

New antibiotics against gram-positives: present and future indications

Gram-positive cocci are the most frequent aetiology of community and nosocomially bacterial acquired infections. The prevalence of multidrug-resistant gram-positive bacteria is increasing and is associated with high morbidity and mortality. New antibiotics will be available in the European market during the next months. This revision is focused on lipoglycopeptides, new cephalosporins active against methicillin-resistant Staphylococcus aureus (MRSA) and the new oxazolidinone, tedizolid. The purpose of this review is to describe their in vitro activity, pharmacokinetic and pharmacodynamic characteristics, and experience from clinical trials.

Antimicrobial Activity of Plectasin NZ2114 in Combination with Cell Wall Targeting Antibiotics Against VanA-Type Enterococcus faecalis

Antimicrobial peptide plectasin targeting bacterial cell wall precursor Lipid II has been reported to be active against benzylpenicillin-resistant Streptococcus pneumoniae but less potent against vancomycin-resistant enterococci than their susceptible counterparts. The aim of this work was to test plectasin NZ2114 in combination with cell wall targeting antibiotics on vancomycin-resistant Enterococcus faecalis. The activity of antibiotic combinations was evaluated against VanA-type vancomycin-resistant E. faecalis strain BM4110/pIP816-1 by disk agar-induction, double-disk assay, determination of fractional inhibitory concentration (FIC) index, and time-kill curve. The results indicated that plectasin NZ2114 was synergistic in combination with teicoplanin, moenomycin, and dalbavancin but not with vancomycin, telavancin, penicillin G, bacitracin, ramoplanin, daptomycin, and fosfomycin. To gain an insight into the synergism, we tested other cell wall antibiotic combinations. Interestingly, synergy was observed between teicoplanin or moenomycin and the majority of the antibiotics tested; however, vancomycin was only synergistic with penicillin G. Other cell wall active antibiotics such as ramoplanin, bacitracin, and fosfomycin did not synergize. It appeared that most of the synergies observed involved inhibition of the transglycosylation step in peptidoglycan synthesis. These results suggest that teicoplanin, dalbavancin, vancomycin, and telavancin, although they all bind to the C-terminal D-Ala-D-Ala of Lipid II, might act on different stages of cell wall synthesis.