Linezolid-Resistant Coagulase-Negative Staphylococci in a Tertiary Hospital: Molecular Epidemiology, Clinical Characteristics, and Outcomes

We report linezolid-resistant coagulase-negative Staphylococcus (LRCoNS) bacteremia at a tertiary hospital. LRCoNS with linezolid and tedizolid minimum inhibitory concentrations of >32 and 4-32 mg/L, respectively, were isolated from blood cultures of seven elderly patients who died post-bacteremia detection. Linezolid was administered to six of these patients at the time of LRCoNS isolation. Linezolid-resistant S. epidermidis ST5 isolates (LRSE) harboring mecA were isolated in seven of the nine episodes. Linezolid resistance is associated with mutations in the 23S rRNA, L3 and L4 ribosomal proteins, indigenous methyltransferases RlmN, and the presence of the cfr gene. All LRSE-ST5 genomes formed a single phylogenetic cluster.