RESUMO
The formulation and characterization of gentamicin-loaded microspheres as a delivery system targeting enterotoxigenic Escherichia coli K88 (E. coli K88) was investigated. Glycated albumin with lactose (BSA-glucose-ß (4-1) galactose) was used as the microsphere matrix (MS-Lac) and gentamicin included as the transported antibiotic. The proposed target strategy was that exposed galactoses of MS-Lac could be specifically recognized by E. coli K88 adhesins, and the delivery of gentamicin would inhibit bacterial growth. Lactosylated microspheres (MS-Lac1, MS-Lac2 and MS-Lac3) were obtained using a water-in-oil emulsion, containing gentamicin, followed by crosslinking with different concentrations of glutaraldehyde. Electron microscopy displayed spherical particles with a mean size of 10-17 µm. In vitro release of gentamicin from MS-Lac was best fitted to a first order model, and the antibacterial activity of encapsulated and free gentamicin was comparable. MS-Lac treatments were recognized by plant galactose-specific lectins from Ricinus communis and Sophora japonica and by E. coli K88 adhesins. Results indicate MS-Lac1, produced with 4.2 mg/mL of crosslinker, as the best treatment and that lactosylated microsphere are promising platforms to obtain an active, targeted system against E. coli K88 infections.
Assuntos
Antibacterianos/administração & dosagem , Antígenos de Bactérias/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas de Fímbrias/metabolismo , Gentamicinas/administração & dosagem , Microesferas , Albuminas/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Gentamicinas/farmacologia , Lactose/química , Lectinas de Plantas/metabolismo , Ligação ProteicaRESUMO
Enterotoxigenic (ETEC) Escherichia coli (E. coli) causes traveller's diarrhoea and high mortality among baby animals. ETEC adhesion is mediated by lectins (adhesins) that bind to glycoconjugates on the surface of host cells. Glycans that compete for adhesion could be used for disease prevention. Neoglycans of porcine albumin (PSA) that were conjugated with prebiotic galactooligosaccharides (GOS) were synthesised using the Maillard reaction. PSA glycation was confirmed by a reduction in the number of available free amino groups, decreased tryptophan intrinsic fluorescence, increased molecular mass and Ricinus communis lectin recognition. The adhesion of four ETEC strains (E. coli H10407, CFA(+), K99 and K88) to PSA-GOS was examined by an enzyme-linked lectin assay. E. coli K88 bound to PSA-GOS with greater affinity (P<0.05) than did E. coli H10407, CFA(+) and K99. In addition, PSA-GOS partially inhibited the adherence of the K88 strain to intestinal mucins. Pig ETEC strain was unable to ferment galactooligosaccharide-neoglycans. These results suggest that neoglycans obtained by the Maillard reaction may serve in the prophylaxis of ETEC K88 diarrhoea.