Establishment of epidemiological cut-off values for eravacycline, against Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Acinetobacter baumannii and Staphylococcus aureus

Abstract

Objectives: To establish the epidemiology cut-off (ECOFF) values of eravacycline against Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Acinetobacter baumannii and Staphylococcus aureus, from a multi-centre study in China.

Methods: We collected 2500 clinical isolates from five hospitals in China from 2017 to 2020. The MICs of eravacycline were determined using broth microdilution. The ECOFF values of eravacycline against the five species commonly causing cIAIs were calculated using visual estimation and ECOFFinder following the EUCAST guideline.

Results: The MICs of eravacycline against all the strains were in the range of 0.004-16 mg/L. The ECOFF values of eravacycline were 0.5 mg/L for E. coli, 2 mg/L for K. pneumonia and E. cloacae, and 0.25 mg/L for A. baumannii and S. aureus, consistent with the newest EUCAST publication of eravacycline ECOFF values for the populations. No discrepancy was found between the visually estimated and 99.00% ECOFF values calculated using ECOFFinder.

Conclusions: The determined ECOFF values of eravacycline against the five species can assist in distinguishing wild-type from non-wild-type strains. Given its promising activity, eravacycline may represent a member of the tetracycline class in treating cIAIs caused by commonly encountered Gram-negative and Gram-positive pathogens.

Figure 1.

Nonlinear regression fitting MIC distribution of eravacycline to E. coli, K. pneumoniae, E. cloacae, A. baumannii and S. aureus (red ‘Raw Count or %’ represents measured MIC data, green ‘Fitted Count or %’ represents simulated MIC data). The dotted lines represent estimated ECOFFs using ECOFFinder for these species. For E. coli and S. aureus, the dotted lines also represent the available MIC breakpoints from the newest EUCAST publication (https://mic.eucast.org/search/).