Detection of Virulence Genes in Salmonella Serovars Isolated from Broilers

This study was conducted to determine the prevalence of Salmonellae in broilers farms in Dakahlia Governorate, Egypt. A total of 1000 samples were collected from 200 broiler chickens (40 apparently healthy, 80 diseased chickens and 80 freshly dead broiler chickens).The samples were liver, caecum, heart blood, spleen & kidney. The colonial morphology, microscopical and biochemical identifications of the isolates revealed the presence of 37 out of 200 chickens (18.5%) salmonella species isolates, representing: 3 from apparently healthy chicken (7.5%), 21 from diseased chickens (26.25%) and 13 from freshly dead broiler chickens (16.25%).The rate of recovery of Salmonellae from the different internal organs showed that high recovery rate was from liver, caecum, spleen, heart then kidney as the follow (9.5%), (5.5%), (4.5%), (3%) and (2%), respectively. The serotyping of the isolated salmonellae from chickens were eight S. enteritidis , one S. maccles Field , two S. wingrove , one S. eingedi , three S. rissen ,two S. derby , two S. vejle , one S. magherafelt , two S. berta , two S. enterica sub.spp salamae , one S. gueuletapee , one S. blegdam , five S. kentucky , two S. newport , two S. agona and two S. virchow were isolated from broilers. PCR assay was carried out for six serovars (S. enteritidis, S. maccles Field, S. rissen, S. derby, S. magherafelt and S. enterica sub.spp salamae ) to detect the presence of invA , sopB and stn gene, All serovars had the three genes. Gentamycin, ciprofloxacin, colistin sulphate and enrofloxacin were found to be the most effective antimicrobials against the tested isolates; while a high resistance to erythromycin and flumequine were shown. High prevalence of Salmonella in broilers and multidrug resistance, constituting a major concern for public health. Further surveillance programs and research are a necessity to understand their epidemiology and to limit the spread of multidrug-resistant Salmonella spp.