CONICET | Buscador de Institutos y Recursos Humanos

Background: The pathogen Staphylococcus aureus is able to persist on biotic and abiotic surfaces through biofilm formation. Enterocin AP-CECT7121 has shown homogenous bactericidal activity in vitro against Staph. aureus of food and clinical origin. Objective: assess the eradication of biofilm-associated cells of multi-resistant clinical Staph. aureus. Methods: 7 multi-resistant Staph. aureus (HSSA32-HSSA38) isolated from blood cultures of inpatients, from Hospital Ramón Santamarina (Tandil City, Argentina) during the period January-November 2016 were studied. All included patients had hip prosthesis infections. Purified AP-CECT7121 was used. MICs determinations were done by the micro-liquid dilution method. For bactericidal activity against planktonic cells, AP-CECT7121 was added to staphylococcal cultures (108 CFU/mL), in a 96-well plate, to final concentrations of 1xMIC and 4xMIC, and incubated at 37°C. CFU counts were performed at 0, 4, 8, and 24 h. For assessing bactericidal activity against Staph. aureus biofilm cells, staphylococcal suspensions in Brain Heart Infusion broth-1% glucose were added to the wells and incubated for 24 h at 37°C. Formed biofilms were incubated with the enterocin (1XMIC and 4XMIC) for 1 and 24 h. After, CFU counts of the biofilms were done. Results: bactericidal activity of AP-CECT7121 against planktonic cell was detected between 1- 4 h of incubation. A dose-dependent effect of AP-CECT7121 against staphylococcal biofilms was observed. AP-CECT7121 (4XMIC) showed bactericidal activity against biofilm cells, but complete killing was not achieved. Conclusion: AP-CECT7121 showed a significant efficacy against staphylococcal biofilms and constitutes a candidate for future applications in the prevention and treatment of biofilm-associated infections.