Isolation, identification and antimicrobial susceptibility profile of Salmonella spp. from chicken meat samples collected from wet markets of Dhaka City

Abstract

Raw chicken commonly carries Salmonella spp., a major source of highly predominant foodborne disease. Improper handling or undercooking increases contamination risk. This study examined isolation, molecular detection and antibiotic resistance of Salmonella spp. from Chicken meat samples to understand its spread and enhance food safety practices. 50 raw meat samples collected from local markets of Badda, Gulshan, Dhanmondi, Uttara, and Segunbagicha of Dhaka city. The samples were homogenized and diluted to four folds (10-4) and were spreaded on Xylose Lysine Deoxycholate (XLD) agar and Salmonella-Shigella (SS) agar. Presumptive Salmonella colonies, characterized by red colonies with black centers, were selected. The Polymerase Chain Reaction (PCR) was used to confirm suspected Salmonella colonies sub-cultured on Nutrient Agar. The Kirby-Bauer disc diffusion method was used to test the antibiotic susceptibility of Salmonella isolates. A total of 15 positive Salmonella samples were found, which is 30% of the total samples. Among the positive ones, 40% was obtained from gizzard, 33% from liver, and 13% from meat. 15 positive isolates and 10 antibiotics were used for the Antimicrobial Susceptibility Test (AST), Ampicillin and Tetracycline were resistant to most of the strains of Salmonella spp., which is in between 66.66% to 73.33%. Additionally, Sulfamethoxazole had the lowest moderate resistance whereas Tigecycline and Nalidixic Acid had the maximum moderate resistance which is 33.33%. In contrast, no isolates were able to develop resistance against Ciprofloxacin. Notably, only 46.77% isolates were sensitive to the antibiotics whereas 53.33% were multi-drug resistant. Salmonella spp. is a major cause of food-borne outbreaks. Most infections by Salmonella are attributed to consumption of contaminated food, especially those foods involving poultry and its products. This is a significant public health concern as it limits treatment options for Salmonella infections because of antibiotic resistance genes.