Eravacycline: In Vitro Activity and Combination Effects Against the Klebsiella pneumoniae Complex

Background. Eravacycline is a new antibiotic from the tetracycline class with broad-spectrum activity against resistant strains. The aim of this study was to assess the susceptibility of Klebsiella spp. strains to eravacycline alone and in combination with selected antibiotics. Methods. A total of 145 clinical isolates of the Klebsiella pneumoniae complex were included in the study. The strains were isolated from intra-abdominal and skin infections. Susceptibility to ERV was assessed using the gradient strip method. Of the analyzed strains, 20 (13.8%) were multidrug-susceptible, 52 (35.9%) produced extended-spectrum β-lactamases, and 73 (50.3%) produced different carbapenemases. Results. Eravacycline exhibited high activity against Klebsiella pneumoniae complex strains, with MICs ranging from 0.125 to 0.5 mg/L for multidrug-susceptible strains, from 0.094 to 2 mg/L for ESBL-producing strains, and from 0.19 to 3 mg/L for carbapenemase-producing strains. A total of 106 (73.1%) strains were susceptible to ERV, with MICs ≤ 0.5 mg/L. The MIC50 and MIC90 values for all analyzed strains were 0.5 mg/L and 1 mg/L. Conclusions. ERV demonstrated very good in vitro activity against multidrug-susceptible strains and good activity against ESBL-producing and carbapenemase-producing strains. The results of this study suggest that eravacycline may be a potentially therapeutic option, either alone or in combination with other antimicrobial agents, for the treatment of infections caused by K. pneumoniae complex strains.