In vitro activity of the antimicrobial peptide AP7121 against the human methicillin-resistant biofilm producers Staphylococcus aureus and Staphylococcus epidermidis

Abstract

In vitro activity against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis biofilm producers from blood cultures of patients with prosthetic hip infections was evaluated. The Minimum Inhibitory Concentration (MIC) for AP7121 was determined and the bactericidal activity of AP7121 (MICx1, MICx4) against planktonic cells was studied at 4, 8 and 24?h. The biofilms formed were incubated with AP7121 (MICx1, MICx4) for 1 and 24?h. The anti-adhesion effect of an AP7121-treated inert surface over the highest MIC isolate was studied with scanning electron microscopy (SEM). The bactericidal activity of AP7121 against all the planktonic staphylococcal cells was observed at 4?h at both peptide concentrations. Dose-dependent anti-biofilm activity was detected. AP7121 (MICx4) showed bactericidal activity at 24?h in all isolates. SEM confirmed prevention of biofilm formation. This research showed the in vitro anti-biofilm activity of AP7121 against MRSA and S. epidermidis and the prevention of biofilm formation by them on an abiotic surface.