title: Rapid emergence of daptomycin resistance in clinical isolates of Corynebacterium striatum… a cautionary tale.
abstract: The objective of this study was to investigate the observation of daptomycin resistance in Corynebacterium striatum, both in vivo and in vitro. We describe a case of C. striatum bacteremia in a patient with a left ventricular assist device (LVAD); the initial isolate recovered was daptomycin susceptible with a minimum inhibitory concentration (MIC) of 0.125 μg/ml. Two months later, and after daptomycin therapy, the individual became bacteremic with an isolate of C. striatum with a daptomycin MIC of >256 μg/ml. To study the prevalence of daptomycin resistance in C. striatum, clinical isolates of C. striatum were grown in broth culture containing daptomycin to investigate the emergence of resistance to this antimicrobial. Molecular typing was used to evaluate serial isolates from the index patient and the clinical isolates of C. striatum we assayed. In vitro analysis of isolates from the index patient and 7 of 11 additional C. striatum isolates exhibited the emergence of high-level daptomycin resistance, despite initially demonstrating low MICs to this antimicrobial agent. This phenotype was persistent even after serial subculture in the absence of daptomycin. Together, these data demonstrate that caution should be taken when using daptomycin to treat high-inoculum infections and/or infections of indwelling medical devices with C. striatum. To our knowledge, this is the first report characterizing the emergence of daptomycin resistance in C. striatum.
authors: Department of Pathology & Immunology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8118, St. Louis, MO, 63110, USA.
authors: E
authors: E
authors: McElvania TeKippe
authors: B S
authors: BS
authors: Thomas
authors: G A
authors: GA
authors: Ewald
authors: S J
authors: SJ
authors: Lawrence
authors: C-A D
authors: CA
authors: Burnham
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology; D003352:Corynebacterium / Q000187:drug effects* / Q000302:isolation & purification; D003354:Corynebacterium Infections / Q000188:drug therapy / Q000382:microbiology*; D017576:Daptomycin / Q000494:pharmacology* / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial; D006353:Heart-Assist Devices; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000601:surgery
chemical_list: D000900:Anti-Bacterial Agents; D017576:Daptomycin