Isolation, serotyping and antibiotic-resistance pattern of isolated Salmonella from chicken of Arak

Salmonella serotypes are important zoonotic pathogens in humans and animals. Most Salmonella infection in humans result from the ingestion of contaminated food. Resistance of Salmonella to commonly used antimicrobials is increasing and has emerged as a global problem. The main objective of this study was determine the frequency of serotypes of salmonella and antibiotic resistance of isolated Salmonella from poultry in Arak. A total of 245 samples were collected from poultry in Arak، and 75 Salmonella (30. 61%) were isolated. The result of Serotyping was Enteritidis (45. 33%)، Infantis (44%)، Typhimurium (5. 33%)، Bardo (2. 67%) and Bacongo (2. 67%). The prevalent Salmonella strains isolated in this study belonged to serotype Enteritidis and Infantis. The results of antibiogram test that was performed by the Kirby-Bauer disk diffusion method according to Clinical Laboratory Standards Institute (CLSI) showed that all isolated (100%) were sensitive to enrofloxacin، gentamicin، imipenem and ceftriaxone and the highest resistance were observed against nalidixic acid and nitrofuratoin. In addition، 63 isolates (84%) out of 75 had multi drug resistance to three or more antibiotics.