Phenotypic and Genotypic Characterization of Salmonella enterica Serovars Isolated from Imported Poultry

Monitoring of imported 1-day-old poultry is mandated in Egypt to prevent the possible introduction of new Salmonella serovars into the country’s poultry industry. Such serovars are considered to be a major public health threat. We examined 391 imported poultry flocks for the presence of salmonellae (231 duckling, 84 chick, and 76 turkey poult), serotyped all isolated salmonellae, and performed antimicrobial susceptibility testing. Molecular profiles were also constructed based on results of conventional polymerase chain reaction assays to detect virulence genes (stn, avrA, and sopB) and antibiotic resistance genes (blaTEM, tetA(A), and qnrS) in the Salmonella isolates. Thirty Salmonella strains were isolated from the 391 samples (7.7%). By poultry type, salmonellae were isolated from 21 of 231 (9.1%) duckling samples, 6 of 84 (7.1%) of chick samples, and 3 of 76 (3.9%) turkey poult samples. Serotyping of the isolates identified 16 different serovars: S. Enteritidis, S. Typhimurium, S. Sinstorf, S. Muenster, S. Vejle, S. Cuckmere, S. Indiana, S. Infantis, S. Koenigstuhl, S. Macallen, S. Nchanga, S. Neftenbach, S. Newlands, S. Nigeria, S. Nyborg, and S. Regent. The isolates showed variable degrees of antibiotic resistance across species. All tested Salmonella strains harbored the virulence and antibiotic resistance genes, with the exception of qnrS, which was found in only 50% of the isolates. In conclusion, examination of imported poultry is a critical point of control to prevent poultry from becoming a reservoir for human health hazards, including salmonellae with antimicrobial resistance phenotypes.