Mutants with oxazolidinone MICs, 2- to 16-fold higher than those of parents, were selected from two of five clinical isolates of Enterococcus faecalis during exposure to AZD2563, but only at frequencies of ca. 10 -8. Resistance was not selected in Enterococcus faecium, Staphylococcus aureus or coagulase-negative staphylococci (CoNS). Mutants of one E. faecalis isolate had a G2576→U 23S rRNA mutation; mutants derived from the second E. faecalis isolate lacked this mutation.
Bibliographical noteFunding Information:
We are grateful to AstraZeneca for financial support for this work, and for providing a sample of AZD2563.
- Oxazolidonone resistance