Characteristics of Tedizolid Non-susceptible Enterococcal Clinical Isolates

Abstract

BackgroundTedizolid is a novel oxazolidinone antibiotic with activity across a broad range of gram-positive pathogens. The aim of this study was to describe the characteristics of tedizolid (TZD) resistant enterococcal clinical isolates.MethodsTedizolid resistant isolates were recovered from patients at Westchester Medical Center, New York from 2012 to 2016. In vitrosusceptibility of tedizolid isolates was performed by broth microdilution using the Sensititre™ panel in accordance with the guidelines of the Clinical and Laboratory Standards Institute. The sequence type (ST) of enterococci was determined based on multilocus sequence typing (MLST) data derived from assembled next-generation sequencing.ResultsDuring the study period, we identified 8 clinical isolates which were resistant to Tedizolid. Clinical characteristics, genomic, treatment and outcome data are summarized in Table 1. 7/8 isolates were E. faecium belonging to a unique ST736 which predominates in our hospital. 7/8 isolates showed G2567T mutation of 23S rRNA. Only one patient had prior reciept of Linezolid. None of the patients had recieved Tedizolid in past.ConclusionThere is de-novo emergence of Tedizolid resistant enterococcal isolates. This along with higher incidence daptomycin non-susceptibility in our institution is of significant concern. This highlights the need for further improvement in infection control practices and newer options for the treatment of enterococcal infections.Disclosures A. Dhand, Merck, Pfizer, Allergan: Speaker’s Bureau, Speaker honorarium; Astellas: Consultant, Consulting feeDateSiteSequence typePrior Linezolid useMIC mg/LTreatmentOutcomeLINTZDDAPVAN62/F2012Urine736No81161NA-59/F2013Peritoneum736Yes826>16DAP x 14 dCure61/F2013BloodNANo>8242Tigecycline x 4 d + Doxycycline x 10 dCure80/M2015Urine736No1612>16DAP x 7 dCure47/F2015Urine736No814>16DAP x 21 dCure72/F2015Urine736No818>16NA-75/M2015Urine736No824>16NA-60/F2016Peritoneum736No1623>16DAP x 21 dCure