Occurrence and antimicrobial resistance profile of Listeria monocytogenes isolated from chilled processed meat products in the Metropolitan Region of Recife, Brazil

The presence of Listeria monocytogenes in food represents a major challenge to food safety, especially in ready-to-eat products stored under refrigeration. This risk is associated with the ability of the pathogen to survive and multiply during prolonged refrigerated storage, making these foods potential sources of infection and a relevant public health concern. In this context, the aim of this study was to investigate the presence of Listeria monocytogenes in chilled processed meat products sold in bulk in the Metropolitan Region of Recife, PE, Brazil, as well as to evaluate the antimicrobial susceptibility profile of the isolates. A total of 48 samples of sausages and ham from different brands were analyzed, obtained from public markets and supermarkets in the region. Detection of Listeria spp. was performed using conventional methods recommended by the Ministry of Agriculture and Livestock, and antimicrobial susceptibility was assessed by the disk diffusion method. Of the analyzed products, 27/48 (56.25%) samples were positive for Listeria spp. by bacterial isolation. Among these, 15/48 (31.25%) were confirmed as L. monocytogenes. In the disk diffusion assay, one L. monocytogenes isolate showed a multidrug-resistant profile to vancomycin, amoxicillin, ampicillin, and ciprofloxacin. Additionally, among the Listeria spp. isolates, 6/27 (22.22%) showed resistance to at least one of the tested antimicrobials, with emphasis on ciprofloxacin (11.1%). These results demonstrate the presence of Listeria spp. and L. monocytogenes in commercially available chilled processed meat products, highlighting the importance of microbiological monitoring of these foods and surveillance of antimicrobial resistance profiles.