Antibiotic resistance pattern of salmonella isolated from hamburgers and detection of their sensitivity to some essential oils

Background and purpose: Antibiotic resistance has prompted the use of medicinal plants with low side effects instead of common drugs. The aim of this study was to identify the contamination level of industrial hamburgers to salmonella, detecting their antibiotic resistance pattern, and their sensitivity to Ferula gummosa, Citrus limon, Rosmarinus officinalis, Pelargonium roseum, Zataria multiflora, Bunium persicum, Mentha piperita, Eucalyptus globulus, Lavandula angustifolia, Rosa damascene, Artemisia dracunculus, and Ocimum basilicum essential oils. Materials and methods: In a cross-sectional study, 100 samples were randomly purchased from local markets in Kashan and evaluated for occurrence of Salmonella by culture media. Antimicrobial susceptibility of the isolates was evaluated using disc diffusion. Also, susceptibility of the isolates to 12 plant essential oils was evaluated by disc diffusion and microdilution methods. Results: Two samples (2%) were contaminated with Salmonella that one was Salmonella serogroup C2 (antigen O8) and the other isolate was not in any serogroup. Disk diffusion method showed that the two isolates were 100% resistant to at least one antibiotic or more. The isolates were resistant to most of the antibiotics such as chloramphenicol, kanamycin, ceftriaxone, ceftazidime, and amoxicillin/clavulanic acid. The inhibitory effect of Zataria multiflora essential oil on growth of Salmonella was the highest with minimum inhibitory concentration and minimum bactericidal concentration of 0.39 and 0.78 mg/mL, respectively, and the mean zone of inhibition growth of 23.67±1.18 mm. Conclusion: Antibiotic resistance of Salmonella isolated from hamburgers was high. The essential oils used in this study exhibited high anti-Salmonella properties compared to common antibiotics and could be used as a beneficial medicinal plant. © 2017, Mazandaran University of Medical Sciences. All rights reserved