In vitro activity of eravacycline and comparators against Gram-negative and Gram-positive bacterial isolates...

To evaluate eravacycline (ERV) activity against Gram-negative and Gram-positive bacteria collected between 2017 and 2020 from worldwide locations.

MIC determinations were performed using Clinical and Laboratory Standards Institute (CLSI) broth microdilution methodology. ERV and tigecycline susceptibility was interpreted using United States Food and Drug Administration (FDA) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. Comparator susceptibility was interpreted using CLSI and EUCAST breakpoints.

ERV MIC₉₀ was 0.5 µg/mL against 12 436 Enterobacteriaceae isolates, which only increased to 1 µg/mL against multidrug-resistant (MDR) isolates (n = 2931) (23.6%). Similar activity was shown against 1893 Acinetobacter baumannii (MIC₉₀ 1 µg/mL) and 356 Stenotrophomonas maltophilia (MIC₉₀ 2 µg/mL). ERV was more active against Gram-positive bacteria: 415 Streptococcus pneumoniae (MIC₉₀ 0.008 µg/mL), 273 S. anginosus group (MIC₉₀ 0.015 µg/mL), 1876 Enterococcus faecalis and 1724 E. faecium (MIC₉₀ 2 µg/mL), 2158 Staphylococcus aureus and 575 S. saprophyticus (MIC₉₀ 0.12 µg/mL), 1143 S. epidermidis and 423 S. haemolyticus (MIC₉₀ 0.25 µg/mL). ERV MIC₉₀ against methicillin-resistant staphylococci and vancomycin-resistant enterococci was similar to susceptible strains. However, ERV susceptibility varied between EUCAST or FDA against staphylococci, especially S. epidermidis (91.5% vs. 47.2%), and vancomycin-resistant E. faecalis (98.3% vs. 76.5%).

This study reaffirms ERV's consistent broad-spectrum activity, which has been evaluated since 2003. ERV remains a key agent for the treatment of bacterial infections, including resistant isolates, but urgent reassessment of clinical breakpoints is required for staphylococci and enterococci.