الفهرس 
Zoonotic diseasesOnly 14 pages are availabe for public view
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Abstract
The goal of this study was to develop a collection of cocktail bacteriophages
that would be able to control different pathogens causing duckling diarrhea. In this
study, we isolated and identified different pathogenic bacteria from diarrheal
duckling and characterized their different bacteriophages to combat these resistant
bacteria.
Nine different Escherichia coli serotypes, Salmonella [S.Typhimurium, S.
Enteriditis and S.Virchow] and Pasteurella anatipestifer were isolated and identified.
All these bacteria serovars were found to be resistant to more than three of the nine
antimicrobial agents tested except Pasteurella anatipestifer was less resistant.
Bacteriophages have been isolated from wastewater samples of different stations,
purified and characterized morphologically. Bacteriophages were evaluated for their
potential to lyse environmental E.coli O168 and S.Typhimurium, S. Enteriditis and
S.Virchow strains in vitro at different pH and temperatures. In the present study six
new phages (ECa1, ECb1 and ECc1), (SEa1, STa1 and SVa1) were characterized and
their efficacy was evaluated separately and in cocktail (ECa1 \ECb1 \ ECc1),
(SEa1\STa1\ SVa1) to control Escherichia coli O168 and Salmonella spp.. The
isolated phages, ECa1, ECb1 and ECc1 belonged to the Podoviridae families, (SEa1,
STa1 and SVa1) belonged to the Myoviridea, Siphoviridea and Podoviridae families,
respectively and they are safe to be used in bacterial control. In general studying
phages were effective against wide range of pathogenic bacteria, but phages ECa1,
ECb1 (reduction of 4.2 log CFU/mL after 12 hrs. treatment) were more effective than
phage ECc1 phage (reduction of 2.4 log CFU/mL after 12 hrs. treatment). The use of
a cocktail ECa1 \ECb1 \ ECc1 was significantly more effective (reductions of 7.4 log
CFU/mL after 12 hrs. treatment) than the use single phage suspensions of ECa1,
ECb1 and ECc1. Phage cocktail (SEa1\STa1\SVa1) gave high reduction against planktonic cultures of Salmonella spp. and the reduction in CFU. was observed from
3.6x104 to 1.0x10 log. While in cocktail SEa1\STa1, SEa1\SVa1 and STa1\SVa1 the
reduction was less and observed from 1.6x102, 1.1x102 and 1.6x102 log respectively.
Moreover, the number of concentrated E. coli and other diarrheic bacteria are
decreased gradually with the use of individual phage or phage cocktails. The
introduction of wide host range bacteriophages in duckling’s flock can have a
potential impact on the dynamics of microbial communities, manifested by the
reduction or the elimination of microbial species. This study demonstrates a high
prevalence of E.coli and Salmonella in duckling and possible use of lytic phages as
bactericide for controlling such pathogenic bacteria.