Resistance Patterns to Antibiotics in Salmonella Serovars Isolated from Broiler Flocks in Amol, Iran

The aim of this study was to determine the occurrence and the level of antibiotic resistance patterns in 62 Salmonella isolates obtained from broiler chicken farms in Amol، Iran to common antibiotics in Iranian poultry industry. Antimicroibial resistance testing was performed using 7 useful antibiotics tetracycline، flumequin، lincospectin، florfenicol، neomycin، danofloxacin and enrofluxacin Foty one isolates were belonged to serotype Salmonella enteritidis. We found 17 different patterns of resistance in 62 salmonella isolates and 16 resistance patterns in 41 serotype Salmonella enteritidis. There were 5 resistant isolates to all antibiotics and there was not any sensitive isolate to all antibiotics. The highest and lowest percentage of resistance was found to flumacoin (83. 87%) and danofluxacin (30. 64%). The most frequent pattern of multiresistant isolates was tetracycline + flumequin + lincospectin + florfenicol + enrofluxacin. Multiple resistances were observed in 60 isolates (96. 77%). All isolates were found to be resistant to one or more of the antibiotics tested. The high prevalence of resistance to antimicrobial agents found in this study might be attributed to uncontrolled use of antimicrobial agents in veterinary specially poultry industry in Iran that is serious implication for public health by transmitting resistant strains to human via food chain. Establishment of standardized monitoring systems for determining the occurrence of resistance among food animal for designing Salmonella control program in farms is needed.