Degradation of methicillin-resistant <i>Staphylococcus aureus</i> biofilms using a chimeric lysin

<div><p>Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) is responsible for a large number of chronic infections due to its ability to form robust biofilms. Herein, the authors evaluated the anti-biofilm activity of a <i>Staphylococcus</i> specific chimeric lysin ClyH on MRSA biofilms. ClyH is known to be active against planktonic MRSA cells <i>in vitro</i> and <i>in vivo</i>. The minimum concentrations for biofilm eradication (MCBE) of ClyH were 6.2–50 mg l⁻¹, much lower than those of antibiotics. Scanning electron microscope (SEM) analysis revealed that ClyH eliminated MRSA biofilms through cell lytic activity in a time-dependent manner. Viable plate counts and kinetic analysis demonstrated that biofilms of different ages displayed varying susceptibility to ClyH. Together with previously demonstrated <i>in vivo</i> efficacy of ClyH against MRSA, the degradation efficacy against biofilms of different ages indicates that ClyH could be used to remove MRSA biofilms <i>in vivo</i>.</p></div