In Vitro Activity of Dalbavancin against Refractory Multidrug-Resistant (MDR) <i>Staphylococcus aureus</i> Isolates
The high prevalence of methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) infections, always treated with vancomycin and daptomycin, has led to the emergence of vancomycin-intermediate (VISA), heteroresistant vancomycin-intermediate (hVISA) and daptomycin non-susceptible (DNS) <...
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| Main Authors: | , , , |
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| Format: | Book |
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MDPI AG,
2020-12-01T00:00:00Z.
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| Summary: | The high prevalence of methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) infections, always treated with vancomycin and daptomycin, has led to the emergence of vancomycin-intermediate (VISA), heteroresistant vancomycin-intermediate (hVISA) and daptomycin non-susceptible (DNS) <i>S. aureus</i>. Even if glycopeptides and daptomycin remain the keystone for treatment of resistant <i>S. aureus</i>, the need for alternative therapies that target MRSA has now become imperative. The in vitro antibacterial and bactericidal activity of dalbavancin was evaluated against clinically relevant <i>S. aureus</i> showing raised antibiotic resistance levels, from methicillin-susceptible to Multidrug-Resistant (MDR) MRSA, including hVISA, DNS and rifampicin-resistant (RIF-R) strains. A total of 124 <i>S. aureus</i> strains were tested for dalbavancin susceptibility, by the broth microdilution method. Two VISA and 2 hVISA reference strains, as well as a vancomycin-resistant (VRSA) reference strain and a methicillin-susceptible <i>Staphylococcus aureus</i> (MSSA) reference strain, were included as controls. Time-kill curves were assayed to assess bactericidal activity. Dalbavancin demonstrated excellent in vitro antibacterial and bactericidal activity against all <i>S. aureus</i> resistance classes, including hVISA and DNS isolates. The RIF-R strains showed the highest percentage of isolates with non-susceptibility, reflecting the correlation between <i>rpo</i>B mutations and VISA/hVISA emergence. Our observations suggest that dalbavancin can be considered as an effective alternative for the management of severe MRSA infections also sustained by refractory phenotypes. |
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| Item Description: | 10.3390/antibiotics9120865 2079-6382 |