Cecilia G Carvalhaes, Helio S Sader, Paul R Rhomberg, Rodrigo E Mendes

The antimicrobial activity of tedizolid and comparators was evaluated against a large worldwide collection of Staphylococcus aureus and Streptococcus pneumoniae isolates recovered from patients with pneumonia. Clinical isolates were collected from patients in 96 medical centers in the Asia-Pacific, Europe, Latin America, and United States during 2017-2019 and tested for susceptibility by reference broth microdilution. The most active agents against S. aureus (n = 4,667) were tedizolid (100.0% susceptible), linezolid (100.0% susceptible), ceftaroline (96.2% susceptible), and vancomycin (100.0% susceptible), but only tedizolid, linezolid, and vancomycin retained activity against >95% of MRSA isolates from all regions. In general, linezolid, ceftriaxone, ceftaroline, levofloxacin, penicillin, and vancomycin showed susceptibility rates >95% against S. pneumoniae (n = 3,008). However, only linezolid, ceftaroline, levofloxacin, and vancomycin remained active (>95% susceptibility) against isolates displaying penicillin-nonsusceptible or multidrug resistant phenotypes. Penicillin-nonsusceptible S. pneumoniae isolates were less frequently recovered from patients <5 years-old compared to other age groups. The in vitro data presented here confirm the high potency of tedizolid against S. aureus and S. pneumoniae causing pneumonia worldwide and support further clinical evaluations of tedizolid for treating pneumonia caused by these pathogens.