GROWTH INHIBITIN OF STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI STRAINS BY NEUTRALIZING IGY ANTIBODIES FROM OSTRICH EGG YOLK

Fernando Luiz Tobias (UENF); João Gatto Brom de Luna (UENF); Luize Néli Nunes Garcia (UENF); Cláudia Maria Costa de Almeida (UENF); Mosar Lemos (UENF); Romildo Rocha Azevedo Junior (UVV); Enrique Medina-acosta (UENF); Olney Vieira da Motta (UENF)

Ostriches are raised around the world, however, some key factors determining the profit of ostrich farming depend largely on information and ability of farmers to rear these animals. Staphylococcus aureus is a Gram-positive bacterium causing several types of human and animal diseases by producing virulence factors, among them enterotoxins, and toxic shock syndrome (TSST-1). Escherichia coli a Gram-negative rod-shaped bacterium lives in the intestinal tract of humans and animals, and pathogenic strains can cause several infections. To optimize the sub-products from ostriches, non fertilized egg yolks from hipper-immunized females were used for the development of IgY antibodies. Four females ostriches were primed (200 µg/animal) with purified recombinant enterotoxin C (SEC_rec) and synthetic protein RAP (RAP_rec), both derived from S. aureus, and EspB_rec and BFPA_rec involved in pathogenicity of E.coli, in Freund's complete adjuvant. Animal were boosted three weeks later at 21 days intervals in saline and Freund's incomplete adjuvant. Blood samples and eggs were collected before and during immunization, and assayed for the presence of specific IgY by ELISA. Egg yolk immunoglobulins were purified by precipitation with 19% sodium sulfate and 20% ammonium sulphate methodologies. Purified IgY 50 µL  aliquots were incubated in 850 µL BHI broth containing 100 µL  inoculums of five S. aureus (ATCC25923, SEC/SED+ LSA88, FRI100, Saost1, Saost2 and five E.coli (EPEC (E2348/69), EAEC (O42), ETEC (H10407), EIEC (EDL 1284), EHEC (EDL931) and ATCC 25922) during 16 hours at 37ºC. Growth inhibition was evaluated each four hours by photometry (DO_510nm). Egg yolk IgY preparation from hiperimmunized birds contained antibodies that inhibited significantly (p<0,05) growth of  strains tested. Potential use of ostrich IgY polyclonal antibodies as a diagnostic and therapeutic tool is proposed.