Prevalence, molecular detection and antimicrobial susceptibility of Listeria monocytogenes isolated from milk, poultry meat and meat products

Listeria monocytogenes is a food borne zoonotic pathogen that causes listeriosis in people and animals. It has a low incidence but a high case fatality rate. The goal of this study was to assess the prevalence of L. monocytogenes in raw and frozen milk, raw and frozen poultry meat and meat products as well as their molecular identification and antimicrobial susceptibility. A total of 100 samples were collected from four different locations in Mymensingh town, including raw milk (n = 20), frozen milk (n = 20), raw poultry meat (n = 20), frozen poultry meat (n = 20), frozen chicken meat ball (n = 10), and chicken burger (n = 10). Listeria selective PALCAM agar was used to isolate L. monocytogenes from the samples. Listeria spp. created a black zone around the colonies on this agar. Gram staining, motility testing, Christie, Atkins, Munch-Petersen (CAMP) testing, haemolysis testing, sugar fermentation testing and other biochemical assays were used to confirm the presence of L. monocytogenes. The disc diffusion method was used to test antibiotic sensitivity against ten antibiotics: ampicillin, vancomycin, gentamycin, streptomycin, cefixime, cefalexin, norfloxacin, colistin, erythromycin, and amikacin. The prevalence of L. monocytogenes in various samples was found to be 30% in raw milk, 0% in frozen milk, 40% in raw poultry meat, 10% in frozen poultry meat and not found in meat products. Market 1 had a prevalence of 13.33%, market 2 had a prevalence of 15%, market 3 had a prevalence of 0%, and market 4 had a prevalence of 0%. The isolates of L. monocytogenes were shown to be susceptible to amikacin, gentamycin, vancomycin, streptomycin and norfloxacin but resistant to ampicillin, cefixime, cefalexin, colistin and erythromycin. According to the findings of this study, multidrug-resistant L. monocytogenes can be found in milk, poultry meat, and meat products, posing a public health risk.