Linezolid and vancomycin, alone and in combination with rifampin, compared with moxifloxacin against a multidrug-resistant and a vancomycin-tolerant Streptococcus pneumoniae strain in an in vitro pharmacodynamic model.

Potential alternatives, including linezolid, adjunctive rifampin, and moxifloxacin, were evaluated against vancomycin-tolerant (P9802-020) and vancomycin-susceptible clinical isolates of Streptococcus pneumoniae in an in vitro pharmacodynamic model. Vancomycin exhibited maximal killing of 2-log(10) CFU/ml against P9802-020. Linezolid, moxifloxacin, and linezolid plus rifampin exhibited 99.9% killing against both isolates. These alternatives should be considered for further evaluation against vancomycin-tolerant S. pneumoniae.