Imipenem-Relebactam Susceptibility and Genotypic Characteristics of Carbapenem-Resistant Enterobacterales (CRE) Identified during Population-Based Surveillance.

Laboratories submit all carbapenem-resistant Enterobacter, Escherichia coli, and Klebsiella species to the Alameda County Public Health Department (ACPHD). ACPHD evaluated 75 isolates submitted during nine months for susceptibility to imipenem-relebactam (I-R) and identified β-lactamase genes using whole genome sequencing. Of 60 (80%) isolates susceptible to I-R, 8 (13%) had detectable carbapenemase genes, including four KPC, two NDM, and two OXA-48-like; we described the relationship between the presence of β-lactamase resistance genes and susceptibility to I-R.