In vitro activity and killing effect of temporin A on nosocomial isolates of Enterococcus faecalis and interactions with clinically used antibiotics.

ABSTRACT

OBJECTIVE: To study the in vitro activity of temporin A, a basic, highly hydrophobic, antimicrobial peptide amide derived from the skin of the European red frog Rana temporaria, alone and in combination with co-amoxiclav, imipenem, ciprofloxacin, linezolid and vancomycin, against 42 nosocomial isolates of Enterococcus faecalis. Fourteen of these were resistant to vancomycin. METHODS: Antimicrobial activity of temporin A was measured by MIC, MBC and time-kill studies and by the chequerboard titration method. RESULTS: All isolates were inhibited at concentrations of 1 to 16 mg/L. Combination studies carried out with E. faecalis ATCC 29212 and ATCC 51299 demonstrated synergy only when the peptide was combined with co-amoxiclav and imipenem. CONCLUSIONS: Our findings show that temporin A is active against E. faecalis and that its activity could be enhanced when it is combined with other antimicrobial agents.