Effect of Age and Season on Salmonella Infection in Broiler Chickens with Special Reference to Virulence and Antibiotic Resistance Genes

Roshdy, Heba; Mohamed, Sahar; Elsebaey, Hossam; El-Demerdash, Ghada

doi:10.21608/zvjz.2020.33609.1110

Effect of Age and Season on Salmonella Infection in Broiler Chickens with Special Reference to Virulence and Antibiotic Resistance Genes

Document Type : Original Article

Authors

¹ Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, Ministry of Agriculture, P.O. Box 246 – Dokki, 12618 – Giza, Egypt

² Animal Health Research Institute, Damanhur branch, Agriculture Researches, Egypt

³ Animal Health Research Institute, Fayoum branch, Agriculture Researches Center, Egypt

10.21608/zvjz.2020.33609.1110

Abstract

Salmonella species arecausing high morbidity and mortality rates in broiler chickens and other birds particularly young ages resulting in great economic losses. The present study was performed to detect the effect of age and season on isolation rates of Salmonella species from 120 examined broiler chickens with different ages (1-7 days- old and more than 7days -old) in different seasons (summer, winter, autumn and spring). The highest isolation rates of Salmonella species were obtained from broilers of 1-7 days – old in summer (40%) followed by broilers of more than 7 days old in summer (33.3%). The increased isolation rates of Salmonella species was detected from liver of broilers of both ages (1-7 and more than 7 days old). Seventeen Salmonella isolates were obtained in this study from both ages. Serotyping of these Salmonella isolates revealed S. Enteritidis (5 isolates), S. Typhimurium (3 isolates), S. Infantis, S. Bargny, S. Newport, S. Magherafelt (2 isolates) and finally S. Apeyeme in (1 isolate). The most frequent resistance phenotypes were tetracycline (70%-71.4%), from 1 -7 days - old and more than 7 days- old chicks and finally ampicillin (60%, 57.1%). From the result obtained by using VITEK2 system, the highest resistance was recorded against Tetracycline in all Salmonella species. All Salmonella isolates showed -associated genes. The invA gene was identified in all Salmonella serovars isolated from chickens of the two age groups, whereas, avrA gene was detected in all the isolates except S. Magherafelt recovered from the age group of more than 7 days-old birds . The tetracycline resistance gene (tetA) was identified in all the examined isolates.

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