Retrospective Analysis of Antimicrobial Susceptibility Profiles of Nocardia Species from a Tertiary Hospital and Reference Laboratory, 2011 to 2017.

Nocardia species are found worldwide and are opportunistic pathogens of both immunocompromised and immunocompetent hosts. Recent updates to the taxonomy of this genus have indicated that there are more than 90 recognized species of Nocardia with 54 species reported to be clinically relevant. In this paper, we report the species distribution, specimen source distribution, and antimicrobial susceptibility profiles of 2,091 clinical isolates recovered for the years 2011 to 2017 using the updated taxonomy. The most commonly isolated species included Nocardia nova complex, Nocardia cyriacigeorgica, and Nocardia farcinica complex, with an additional 25 species or species complexes recovered from clinical specimens. The antimicrobial susceptibility profile was highly variable between the species, but in general, amikacin, linezolid, and trimethoprim-sulfamethoxazole demonstrated good in vitro activity against most species.