Reproducibility of dalbavancin MIC test results and an updated surrogate accuracy analysis of vancomycin MIC values to infer dalbavancin susceptibility (2014)

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.

Comparison of dalbavancin to standard-of-care for outpatient treatment of invasive Gram-positive infections

OBJECTIVE

To assess the efficacy and safety of dalbavancin compared to standard-of-care (SOC) or vancomycin and daptomycin in invasive infections due to suspected or confirmed Gram-positive organisms.

METHODS

Retrospective cohort of adults who received dalbavancin or SOC on discharge or as an outpatient from 12/2016 to 11/2019. Indications were osteoarticular infection (OAI), infective endocarditis (IE), or other bloodstream infection (BSI). Primary endpoint was 90-day infection-related readmission (IRR); secondary endpoints included time-to-IRR, frequency of adverse drug events (ADEs), and all-cause readmission and mortality.

RESULTS

215 patients were included: 70 (33%) receiving dalbavancin, and 145 (67%) receiving SOC. Indications were OAI (47%), IE (27%), and other BSI (26%). OAI was more common in patients on dalbavancin compared with those receiving SOC (70% vs. 37%, P<0.001). Dalbavancin patients had shorter median (interquartile range [IQR]) length of stay (LOS) prior to drug initiation compared with those receiving SOC (10 [7-17] vs. 13 [9-19], P=0.021). IRR incidence was 17% for dalbavancin patients and 28% for SOC patients. Dalbavancin use was independently associated with lower IRR (adjusted odds ratio [adjOR], 0.10; 95% confidence interval [CI], 0.04-0.31). There was longer median (IQR) time-to-IRR in the dalbavancin group (43 [30-87] vs. 23 [11-63] days, P=0.039), but no differences in all-cause readmission or mortality. Treatment-related ADE incidence was 3% and 14% for the dalbavancin and SOC groups, respectively (P=0.013). Infusion reactions (1/2) and catheter-related complications (1/2) were the most common dalbavancin ADEs; catheter-related complications (14/21), nephrotoxicity (3/21), rhabdomyolysis (2/21), and rash (2/21) were the most common SOC ADEs.

CONCLUSIONS

Dalbavancin use was associated with lower 90-day IRR, a shorter hospital LOS prior to therapy, and longer time-to-IRR compared with SOC.

Antimicrobial Activity of Dalbavancin against Staphylococcus aureus with Decreased Susceptibility to Glycopeptides, Daptomycin, and/or Linezolid from U.S. Medical Centers

Dalbavancin activity was assessed against a large collection of Staphylococcus aureus isolates (n = 59,903), including isolates with decreased susceptibility to vancomycin (MIC, ≥2 mg/liter; n = 1,141), daptomycin (MIC, ≥2 mg/liter; n = 48), telavancin (MIC, ≥0.12 mg/liter; n = 52), teicoplanin (MIC, ≥4 mg/liter; n = 143), and/or linezolid (MIC, ≥8 mg/liter; n = 25). Dalbavancin displayed susceptibility rates ranging from 90.4% (isolates with telavancin MIC ≥0.12 mg/liter) to 100.0% (linezolid-resistant isolates) and lower MIC values than the comparators against these resistant subsets.

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.