الفهرس 
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Abstract
A total of 300 freshly slaughtered and dressed poultry carcasses consisted of 100 each of whole duck, pigeon, and quail carcasses, were randomly purchased from different poultry shops having different sanitation levels distributed at Mansoura city, Egypt. Serological and molecular identification verified the presence of Salmonella in only 62%, 40%, and 46% of duck, pigeon, and quail carcasses examined, consecutively. Out of the 205 biochemically suspected Salmonella isolates, 158 were serologically identified into 14 different Salmonella serovars. Overall, S. Typhimurium (22.2%), S. Kentucky (17.7%), and S. Enteritidis (16.4%) were the most prevalent serovars, followed by S. Molade (8.9%), S. Tamale (7.6%), S. Wingrove (6.3%), S. Shangani (6.3%), and S. Larochelle (5.1%), whereas the less common serovars were S. Tsevie (0.6%), S. Daula (1.3%), S. Labadi (1.3%), S. Shubra (1.3%), S. Infantis (2.5%), and S. Alfort (2.5%). All 158 serologically identified isolates were genetically confirmed as Salmonella through PCR amplification of the 275-bp DNA fragment of Salmonella marker gene; invA gene. Other virulence genes were detected in an incidence of 91.8% (145/158) for the hilA gene, 65.8% (104/158) for the stn gene, and 22.8% (36/158) for the spvC gene. All of the 158 Salmonella-verified isolates exhibited absolute resistance to clindamycin and oxacillin (100%) and higher resistance rates against streptomycin (97.5%), tetracycline (78.5%), nalidixic acid (70.9%), amikacin (57%), and sulphamethoxazole/trimethoprim (54.4%). The medium resistance rates of Salmonella isolates examined were observed against ampicillin (48.1%), kanamycin (43%), cefotaxime (39.2%), colistin (39.2%), gentamicin (30.4%), ciprofloxacin (27.8%), and chloramphenicol (21.5%), while the lower resistance rate was detected against meropenem (7.6%) and levofloxacin (5.1%). The multiple antibiotic resistance index (MAR) of Salmonella serovars isolated from duck, pigeon, and quail carcasses was 0.530, 0.528, and 0.473, respectively. In a word, 97.5% (154/158) of Salmonella isolates examined in the present study were resistant to three or more antibiotics, indicating the high prevalence of MDR pattern among Salmonella isolates from all poultry carcasses investigated. Ten (13.2%) out of the 76 ampicillin-resistant Salmonella isolates were confirmed as β-lactamase producers and had at least one β-lactamase resistance gene.