RESUMEN
Staphylococci are a major health threat because of increasing resistance to antibiotics. An alternative to antibiotic treatment is preventing virulence by inhibition of bacterial cell-to-cell communication using the quorum-sensing inhibitor RNAIII-inhibiting peptide (RIP). In this work, we identified 2',5-di-O-galloyl-d-hamamelose (hamamelitannin) as a nonpeptide analog of RIP by virtual screening of a RIP-based pharmacophore against a database of commercially available small-molecule compounds. Hamamelitannin is a natural product found in the bark of Hamamelis virginiana (witch hazel), and it has no effect on staphylococcal growth in vitro; but like RIP, it does inhibit the quorum-sensing regulator RNAIII. In a rat graft model, hamamelitannin prevented device-associated infections in vivo, including infections caused by methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis strains. These findings suggest that hamamelitannin may be used as a suppressor to staphylococcal infections.
Asunto(s)
Farmacorresistencia Bacteriana/efectos de los fármacos , Ácido Gálico/análogos & derivados , Hexosas/química , Hexosas/farmacología , Oligopéptidos/química , Percepción de Quorum/efectos de los fármacos , Infecciones Estafilocócicas/microbiología , Animales , Adhesión Bacteriana/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Ácido Gálico/química , Ácido Gálico/farmacología , Proteínas Hemolisinas/metabolismo , Masculino , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Infecciones Relacionadas con Prótesis/microbiología , ARN Bacteriano/biosíntesis , Ratas , Ratas Wistar , Staphylococcus/citología , Staphylococcus/efectos de los fármacos , Staphylococcus/crecimiento & desarrolloAsunto(s)
Bacterias/citología , Pared Celular/metabolismo , Bacillus subtilis/citología , Radioisótopos de Carbono , Membrana Celular/análisis , Membrana Celular/enzimología , Cromatografía DEAE-Celulosa , Cromatografía por Intercambio Iónico , Medios de Cultivo , Glicerofosfatos , Azúcares de Nucleósido Difosfato , Pentosiltransferasa/metabolismo , Peptidoglicano/metabolismo , Fósforo/metabolismo , Radioisótopos de Fósforo , Fosfotransferasas/metabolismo , Polisacáridos Bacterianos/biosíntesis , Staphylococcus/citología , Ácidos Teicoicos/análisis , Ácidos Teicoicos/metabolismo , TritioAsunto(s)
Membrana Celular/efectos de los fármacos , Staphylococcus/citología , Tensoactivos/farmacología , Fraccionamiento Celular , Membrana Celular/análisis , Separación Celular , Ácido Edético , Microscopía Electrónica , Fosfolípidos/análisis , Fósforo/análisis , Ácido Fosfotúngstico , Coloración y EtiquetadoRESUMEN
The mesosomes of log-phase Staphylococcus aureus ATCC 6538P and Staphylococcus aureus phage-type 80/81, as seen in situ in ultrathin sections, were of the vesicular type. The constituent vesicles ranged from 35 to 50 nm in diameter when the glutaraldehyde-osmium-uranium-lead sequence of fixation and staining was used. During protoplasting in hypertonic buffer containing a muralytic enzyme, vesicles of the same size were extruded and required magnesium ion to maintain structural integrity. The vesicles, purified from the protoplasting supernatant medium by density gradient centrifugation, maintained size and configuration in a homogeneous preparation. Cytoplasmic membranes, produced by osmotic shock and nuclease treatment of protoplasts, were similarly concentrated in gradients. However, they were not free of membrane-associated ribosomes nor of mesosomal vesicles except when prepared in the absence of magnesium.