ÿþ<HTML><HEAD><TITLE>25º Congresso Brasileiro de Microbiologia </TITLE><link rel=STYLESHEET type=text/css href=css.css></HEAD><BODY aLink=#ff0000 bgColor=#FFFFFF leftMargin=0 link=#000000 text=#000000 topMargin=0 vLink=#000000 marginheight=0 marginwidth=0><table align=center width=700 cellpadding=0 cellspacing=0><tr><td align=left bgcolor=#cccccc valign=top width=550><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=3><font size=1>25º Congresso Brasileiro de Microbiologia </font></font></strong><font face=Verdana size=1><b><br></b></font><font face=Verdana, Arial,Helvetica, sans-serif size=1><strong> </strong></font></font></td><td align=right bgcolor=#cccccc valign=top width=150><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=1><font size=1>ResumoID:1779-1</font></em></font></strong></font></td></tr><tr><td colspan=2><br><br><table align=center width=700><tr><td>Área: <b>Microbiologia Veterinária ( Divisão G )</b><p align=justify><strong>CHARACTERIZATION OF LYTIC BACTERIOPHAGES WITH THERAPEUTIC POTENTIAL AGAINST <SPAN STYLE="FONT-STYLE: ITALIC;">SALMONELLA</SPAN> ENTERITIDIS IN POULTRY </strong></p><p align=justify><b><u>Clarissa Silveira Luiz Vaz Vaz </u></b> (<i>CNPSA</i>); <b>Daiane Voss-rech Voss-rech </b> (<i>CNPSA</i>); <b>Luana Alves Alves </b> (<i>CNPSA</i>); <b>Diana Gritti Gritti </b> (<i>CNPSA</i>); <b>Iara Maria Trevisol Trevisol </b> (<i>CNPSA</i>)<br><br></p><b><font size=2>Resumo</font></b><p align=justify class=tres><font size=2> The oral administration of three genetically distinct lytic bacteriophages (LB) isolated from poultry feces by Embrapa Swine and Poultry has been able to reduce <span style="font-style: italic;">Salmonella</span> Enteritidis in poultry caecum. These LB, which show tailed morphology and double-strand DNA as nucleic acid, have been tested as therapeutic agent against <span style="font-style: italic;">S</span>. Enteritidis in broiler chickens. However, concerns have been raised about phage therapy safety. Bacteriophages chosen for therapeutic use need to be well characterized and the phage biology understood. The aim of the present study was improve the characterization of these LB. Analysis of the phage genome was carried out by the digestion of the extracted DNA with <span style="font-style: italic;">Eco</span>RI, <span style="font-style: italic;">Bam</span>HI and <span style="font-style: italic;">Hin</span>dIII restriction enzymes. Genomic DNA was also analyzed by random amplified polymorphic DNA (RAPD), whose typical fragments of each LB were purified and cloned for DNA sequencing. In order to assess the LB proteins patterns, SDS-PAGE was performed in proteins extracted from the LB pool containing 3X10<sup>7</sup> PFU/mL of each BL, which was administrated by drink water to 3 days-old SPF broiler chickens for 4 successive days. Following that phage administration, the dynamic in the SDS-PAGE patterns was analyzed in proteins extracted from LB isolated from cloacal swabs collected from 7, 10, 13 and 16 days-old broiler chickens. Identity of LB isolated was confirmed by amplified fragment length polymorphism (AFLP) patterns. Phages DNA were digested only by <span style="font-style: italic;">Hin</span>dIII. Sequencing of 375, 499 and 435 nucleotides from cloned DNA fragment chosen from each LB showed no significant homologies between other bacteriophages DNA sequences described, although higher similarities were identified against DNA sequences from families of tailed phages. Furthermore, all LB shared the same SDS-PAGE pattern, which displayed a major structural protein of 50kDa. On the other hand, there were no differences between the SDS-PAGE protein patterns from LB administrated to the broiler chickens and LB isolated from cloacal swabs, suggesting that these BL have not suffered protein changes into the avian gut during the period analyzed. The LB isolated from cloacal swabs showed the same AFLP pattern identified in LB before administration to the broiler chicken. More research involving the in-vivo activity of these LB might help to develop an effective phage therapeutic product against <span style="font-style: italic;">S</span>. Enteritidis. </font></p><br><b>Palavras-chave: </b>&nbsp;Salmonella Enteritidis, Bacteriophages, Poultry, Phage therapy</td></tr></table></tr></td></table></body></html>