Aims: We investigated the effectiveness in vitro of the association between norfloxacin (NOR) and ursolic acid (UA) against Staphylococcus aureus. Methods and Results: The minimal inhibitory concentrations (MICs), the minimal bactericidal concentrations, the bacterial killing and the postantibiotic effect (PAE) of NOR and UA were determined both singly and in combination. A synergistic interaction was observed against Staph. aureus ATCC 29213: the mean PAEs were 3h for NOR, -1·2h for UA (1×MIC) and 2·0h for UA (2×MIC). Synergism was observed with longer PAEs and postantibiotic sub-MIC effects after NOR/UA exposure. UA was also active against clinical isolates and methicillin-resistant Staph. aureus. Conclusions: The application of antimicrobial combinations may address the rising resistance to established classes of both systemic and topical agents. Significance and Impact of the Study: In vitro interactions between NOR and UA may contribute to the development of novel topical agents for the treatment of skin infections as well as for topical formulations.
Norfloxacin and ursolic acid: in vitro association and postantibiotic effect against Staphylococcus aureus.
FILOCAMO, ANGELA;BISIGNANO, CARLO;D'ARRIGO, Manuela;GINESTRA, GIOVANNA;MANDALARI, Giuseppina;GALATI, Enza Maria
2011-01-01
Abstract
Aims: We investigated the effectiveness in vitro of the association between norfloxacin (NOR) and ursolic acid (UA) against Staphylococcus aureus. Methods and Results: The minimal inhibitory concentrations (MICs), the minimal bactericidal concentrations, the bacterial killing and the postantibiotic effect (PAE) of NOR and UA were determined both singly and in combination. A synergistic interaction was observed against Staph. aureus ATCC 29213: the mean PAEs were 3h for NOR, -1·2h for UA (1×MIC) and 2·0h for UA (2×MIC). Synergism was observed with longer PAEs and postantibiotic sub-MIC effects after NOR/UA exposure. UA was also active against clinical isolates and methicillin-resistant Staph. aureus. Conclusions: The application of antimicrobial combinations may address the rising resistance to established classes of both systemic and topical agents. Significance and Impact of the Study: In vitro interactions between NOR and UA may contribute to the development of novel topical agents for the treatment of skin infections as well as for topical formulations.Pubblicazioni consigliate
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