الفهرس 
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Abstract
In this study, a total of 400 samples were collected from ten broiler farms
showing diarrhea and depression at different intervals during the period from
Mars 2021 to December 2021.located Giza governorate , 41 isolates were taken
with prevalence(10.25%),prevalence of S. Kentucky was (34%) ( 14 isolates), S.
Enteritidis (24.4%) ( 10 isolates), S. Virchow (12.2%) ( 5 isolates ) and S.
Typhimurium (9.8 %) ( 4 isolate), S. Infantis (9.8%) ( 4 isolates ), S. Newlands
(9.8%) ( 4 isolates ) of total S.enterica isolates, Morphologically Salmonella
appeared as smooth red colonies with black center on (XLD) media,while on
macconkey agar appear as pale, colourless smooth transparent,The staining
characters appear as Gram negative , non-spore forming short rods in shape.
In vitro, the prevalence of S.enterica resistance to ceftazidime (45%), cefepime
(100%), cephaloxine (100%), ceftriaxone (45%), cephalothin (65%), ciprofloxacin
(10%), nalidixic acid (60%), colisiting (85%), chloraphenicole (90%) ,
erythromycine (100%), co-trimoxazole (60%) ,gentamycine (45%) ,
oxytetracycline (90%), doxycycline (90%), amoxycillin (90%), ampicilline (65%),
amoxycilline – clavulinic acid (50%) \ on the other hand, cefotaxime, norfloxacin
are highly effective . The prevalence of S.enterica isolates were subjected to PCR
assay for detection of virulence genes (invA,stn,hilA, and pefA ) and the obtained
results revealed that the the prevalence of S.enterica isolates were for invA gene
(5/5, 100%) and stn gene (5/5, 100%) while for hilA and pefA genes (1/5, 20%)
with specific amplicon size of 617 bp ,854 bp and 700 bp.The prevalence of
S.enterica isolates were subjected to PCR assay for detection of antibiotic
resistance genes (blaTEM , BlaCTX-M ,qnrA, AadA1 and Sul1) and the obtained
results revealed that the tested isolates for (blaTEM and blaCTX-M) were positive
(5/5, 100%) while (qnrA and Sul1) were positive (3/5,60%), and (AadA1) were
positive ( 1/5 , 20%).PCR-screening results detected class 1 integron in 5 of 20
isolates (25%); DNA-sequencing results for the inserted gene cassettes identified
5 types of class integrons. The identified antimicrobial resistance genes were
dihydrofolate reductase types : dfrA15 and dfrA12 which confer resistance to
trimethoprim; aminoglycoside adenyltransferase type aadA2 which confer
resistance to streptomycin and spectinomycin and aadA7 which resistance to
streptomycin resistance; carbenicillin hydrolyzing class A beta-lactamase CARB-2
(blaCARB) which resistance to penicillin beta-lactames ,While all isolates were
negative for class 2 integrons.