Carbapenem Susceptibility Discords among Acinetobacter Isolates

Abstract

SIR— We read with great interest the case report of a fatal Acinetobacter baumannii infection with discordant carbapenem susceptibility by Lesho et al. [1]. This report implies that such cases are uncommon events and that, in fact, it was “the first report of clinically relevant discordant carbapenem susceptibilities” [1, p. 759]. We have 6 years of surveillance experience with the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program (USA) and have consistently documented the greater potency and high susceptibility rates for imipenem, compared with those for meropenem, when Acinetobacter species are being tested [2,3,4–5]. The results in the United States were further validated by reports from other surveillance programs [6] and several MYSTIC Program publications summarizing findings of Acinetobacter species, especially in Europe [7].