Emergence of dalbavancin, vancomycin, and daptomycin cross-resistance in MRSA during long-term LVAD suppression with vancomycin followed by dalbavancin: genomic insights and synergy with cefadroxil

Figures

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  Figure 1.. The timeline illustrates the therapeutic course for this patient from the initial episode of bacteremia with MRSA strain 501–20 until the emergence of the dalbavancin-, daptomycin-, and vancomycin-nonsusceptible MRSA strain (F65358). Horizontal bars represent systemic antimicrobial regimens, and vertical dashed red lines mark the timing of cultured isolates. Abbreviations: MRSA, methicillin-resistant Staphylococcus aureus; TMP-SMX, trimethoprim-sulfamethoxazole.

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  Figure 2.. Growth curves of our 6 clinical isolates in tryptic soy broth at 37°C with shaking, reported as OD600 over 30 hours. Data points represent the mean OD600 of 6 replicate cultures for strains 501–20, 1907–20, 1918–20, 1919–20, 1935–20, and F65358, with error bars indicating standard deviation.

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  Figure 3.. Time-kill curves demonstrating synergy between DAL and CFR for both susceptible (501–20) and resistant (F65358) strains. TMP was synergistic with DAL against F65358 but not 501–20. DOX was nonsynergistic with DAL against either strain. Abbreviations: CFR, cefadroxil; DAL, dalbavancin; DOX, doxycycline; TMP, trimethoprim.