title: D-Amino acids inhibit biofilm formation in Staphylococcus epidermidis strains from ocular infections.
abstract: Biofilm formation on medical and surgical devices is a major virulence determinant for Staphylococcus epidermidis. The bacterium S. epidermidis is able to produce biofilms on biotic and abiotic surfaces and is the cause of ocular infection (OI). Recent studies have shown that d-amino acids inhibit and disrupt biofilm formation in the prototype strains Bacillus subtilis NCBI3610 and Staphylococcus aureus SCO1. The effect of d-amino acids on S. epidermidis biofilm formation has yet to be tested for clinical or commensal isolates. S. epidermidis strains isolated from healthy skin (n = 3), conjunctiva (n = 9) and OI (n = 19) were treated with d-Leu, d-Tyr, d-Pro, d-Phe, d-Met or d-Ala and tested for biofilm formation. The presence of d-amino acids during biofilm formation resulted in a variety of patterns. Some strains were sensitive to all amino acids tested, while others were sensitive to one or more, and one strain was resistant to all of them when added individually; in this way d-Met inhibited most of the strains (26/31), followed by d-Phe (21/31). Additionally, the use of d-Met inhibited biofilm formation on a contact lens. The use of l-isomers caused no defect in biofilm formation in all strains tested. In contrast, when biofilms were already formed d-Met, d-Phe and d-Pro were able to disrupt it. In summary, here we demonstrated the inhibitory effect of d-amino acids on biofilm formation in S. epidermidis. Moreover, we showed, for the first time, that S. epidermidis clinical strains have a different sensitivity to these compounds during biofilm formation.
authors.affiliation: Departments of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. C.P. 11340 Mexico City, Mexico.
authors.forename: Miriam L
authors.initials: ML
authors.lastname: Ramón-Peréz
authors.affiliation: Organic Chemistry, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. C.P. 11340 Mexico City, Mexico.
authors.forename: Francisco
authors.initials: F
authors.lastname: Diaz-Cedillo
authors.affiliation: Departments of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. C.P. 11340 Mexico City, Mexico.
authors.forename: J Antonio
authors.initials: JA
authors.lastname: Ibarra
authors.affiliation: Immunology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. C.P. 11340 Mexico City, Mexico.
authors.forename: Azael
authors.initials: A
authors.lastname: Torales-Cardeña
authors.affiliation: Immunology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. C.P. 11340 Mexico City, Mexico.
authors.forename: Sandra
authors.initials: S
authors.lastname: Rodríguez-Martínez
authors.affiliation: Departments of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. C.P. 11340 Mexico City, Mexico.
authors.forename: Janet
authors.initials: J
authors.lastname: Jan-Roblero
authors.affiliation: Immunology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. C.P. 11340 Mexico City, Mexico.
authors.forename: Mario E
authors.initials: ME
authors.lastname: Cancino-Diaz
authors.affiliation: Departments of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. C.P. 11340 Mexico City, Mexico.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Cancino-Diaz
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D015817:Eye Infections / Q000382:microbiology*; D006801:Humans; D013203:Staphylococcal Infections / Q000382:microbiology*; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology*
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents