Multidrug resistance cases of Listeria monocytogenes isolated from fresh meats

Listeria monocytogenes is an important bacteria that can contaminate meat and meat products, having an important impact on public health, being a potential cause of foodborne diseases. The aim of this study is to provide an overview of multidrug resistance cases of L. monocytogenes isolated from fresh meat and meat products, from the North of Portugal. Samples of fresh meat preparations and meat products were undertaken from hypermarkets and small traditional local shops. Of the total samples, 20% were meat-based products, 12% were meatballs and hamburgers, 12% were meat skewers, 8% were breaded meat, 40% were minced meat and 8% were fresh sausage. Samples were transported to the laboratory in refrigeration conditions in 10 minutes. After, samples were subjected to microbiological analysis and antimicrobial resistance tests. The strains were identified using morphological and molecular methods. Antibiotic resistance was determined using the Kirby-Bauer disk diffusion method. The overall prevalence of L. monocytogenes among screened samples was 32% and 9 isolates obtained from minced meat, displayed a multidrug-resistance profile. This study showed a frequent occurrence of multidrug resistance in L. monocytogenes which represent a major concern of public health, since most antimicrobial resistances detected were against antimicrobials considered to be essential and frequently used in human medicine.