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Subject: Veterinary Public Health × Author: Gunjiyal, Harshita × End date: 2024 × Start date: 2020 × Type: Thesis ×
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    ThesisItemOpen Access
    Isolation, identification and molecular characterization of nontyphoidal Salmonella and listeria SPP. from foods of animal origin
    (G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2022-07) Gunjiyal, Harshita; Maansi
    Non-Typhoidal Salmonella and Listeria are the two bacterial food-borne organisms that pose a major impact to the food sector worldwide. In addition, the emergence of multi-drug resistant organisms makes food-borne illnesses more severe. In view of this, the present study aims to ascertain the occurrence of non-typhoidal Salmonella and Listeria organisms in foods and their antimicrobial resistance profiles isolated from animal origin foods of four districts belonging to Kumaon region of Uttarakhand. A total of 250 samples comprising raw milk (n=141), milk products (n=59) and poultry meat (n=50) were collected randomly from multiple vendors, dairy farms, locality, butcher shops and screened for the presence of non-typhoidal Salmonella and Listeria organisms. The bacteria were isolated using culture method and biochemical identification was performed as per conventional method. Further, molecular characterization was done for confirmation. Antibiotic susceptibility testing was performed for the obtained isolates against a set of 12 antibiotics belonging to 9 different classes for Salmonella spp. and 8 different classes for Listeria spp. using the standard Kirby Bauer disc diffusion method. Salmonella spp. was detected in 7.2%; 18/250 and Listeria spp. in 2.4%; 6/250 of the 250 food samples studied. None of the Listeria isolates was found to be belonging to L. monocytogenes. Serotyping of Salmonella isolates revealed that S. Typhimurium and S. Weltevreden correspond to the dominant serotypes recording (4/18; 22.22%) higher serovar occurrence than S. Kentucky (2/18; 11.11%), S. Infantis (2/18; 11.11%). Rest were untypable (6/18; 33.33%). U.S Nagar harbored more Salmonella spp. (12.5%) followed by Nainital district (3.90%). On the other hand, Nainital district (3.12%) was found to harbor more Listeria spp. than U.S Nagar (1.9%). On subjection to antimicrobial susceptibility testing, Salmonella isolates showed varying degree of sensitivity to Co-trimoxazole (55.55%), co-resistance to Gentamicin and Chloramphenicol (44.44%). Complete phenotypic resistance (100%) was found for Cefotaxime and Erythromycin followed by Nalidixic acid (72.22%). Out of 18 obtained Salmonella isolates, 14 isolates (77.77%) were multi-drug resistant. A total of 12 different antimicrobial resistance patterns were observed. On the other hand, Listeria spp. were completely susceptible (100%) to Vancomycin, Chloramphenicol and Ampicillin. Complete resistance (100%) was found for Kanamycin and Tetracycline followed by Amikacin (83.33%). Out of six obtained isolates for Listeria spp. five isolates (5/6; 83.3%) were multi-drug resistant. A total of 5 different antimicrobial resistance patterns were observed which can be related to the non-judicious administration of antibiotics during both prophylaxis and treatment. Therefore, this study warrants careful consideration towards adopting hygienic measures and consumption of properly cooked food along with judicious use of antibiotics.