Antimicrobial activity of dalbavancin against clinical isolates of coagulase-negative staphylococci from the USA and Europe stratified by species

Objectives: To evaluate the in vitro activity of dalbavancin compared with vancomycin, daptomycin and other agents against a large collection of coagulase-negative staphylococci (CoNS) isolates. Methods: A total of 5088 CoNS causing clinically significant infection were consecutively collected from 122 medical centres in the USA and Europe over 6 years (2014-2019). Isolates were tested for susceptibility by the reference broth microdilution method. Species identification was confirmed by MALDI-TOF. Most isolates were from bloodstream infections (BSIs) (53.5%) or skin/skin structure infections (28.5%). Results: Staphylococcus epidermidis was the most common species overall (54.6%) and for BSI (61.3%). The second most common species were Staphylococcus lugdunensis overall (12.3%) and Staphylococcus hominis for BSI (14.7%). Dalbavancin (MIC50/90, 0.03/0.06 mg/L) inhibited >99.9% of CoNS isolates at <0.25 mg/L (susceptible breakpoint for Staphylococcus aureus per CLSI). All species were inhibited at <= 0.25 mg/L dalbavancin, except some S. epidermidis (>99.9%) and Staphylococcus warneri (98.9%) isolates. Staphylococcus capitis and Staphylococcus simulans exhibited the lowest dalbavancin MIC50/90 values (0.015/0.03 mg/L) and Staphylococcus haemolyticus and Staphylococcus saprophyticus the highest (MIC50/90, 0.06/0.12 mg/L); 47.8% of S. epidermidis and 34.7% of S. haemolyticus exhibited decreased susceptibility to vancomycin (MIC >= 2 mg/L) and 23.2% of S. capitis and 28.4% of S. warneri showed decreased susceptibility to daptomycin (MIC >= 1 mg/L). Conclusion: Antimicrobial susceptibility varied widely among CoNS species. Dalbavancin inhibited >99.9% and 99.1% of isolates at the US-FDA and EUCAST breakpoints, respectively. Clinical studies of dalbavancin for treatment of CoNS infections should be considered based on these in vitro data. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.