Activities of Fosfomycin and Rifampin on Planktonic and Adherent Enterococcus faecalis Strains in an Experimental Foreign-Body Infection Model

• DOI: 10.1128/aac.02583-12
• Publication Date: 2013-10-22T02:41:14Z
• Authors: Alessandra Oliva; Ulrika Furustrand...; Elena Maryka Maiolo; Safaa Jeddari; Bertrand Bétrisey; Andrej Trampuz
• Keywords: Fosfomycin; Enterococcus faecalis

ABSTRACT Enterococcal implant-associated infections are difficult to treat because antibiotics generally lack activity against enterococcal biofilms. We investigated fosfomycin, rifampin, and their combinations planktonic adherent Enterococcus faecalis (ATCC 19433) in vitro a foreign-body infection model. The MIC/MBC log values were 32/>512 μg/ml for 4/>64 1/2 ampicillin, 2/>256 linezolid, 16/32 gentamicin, 1/>64 vancomycin, 1/5 daptomycin. In time-kill studies, fosfomycin was bactericidal at 8× 16× MIC, but regrowth of resistant strains occurred after 24 h. With the exception no complete inhibition growth-related heat production observed with other antimicrobials on early (3 h) or mature (24 animal model, alone combination daptomycin reduced counts by ≈4 10 CFU/ml below levels before treatment. Fosfomycin cleared bacteria from 74% cage fluids (i.e., growth aspirated fluid) eradicated biofilm 43% cages removed cages). 77% cured 58% cages; 33% 18% daptomycin, 75% 17% cages. Rifampin showed E. , whereas it 25% Emergence resistance not vivo . conclusion, Its role biofilms should be further investigated, especially rifampin and/or