Genomic diversity of Listeria monocytogenes strains isolated in Slovakia between 2010 and 2020. Diversity of Listeria monocytogenes in Slovakia

Over the past 11 years, the Slovak National Reference Laboratory has collected a panel of 988 Listeria monocytogenes strains in Slovakia, isolated from various food sectors (61%), from food-processing environments (13.7%), from animals with listeriosis symptoms (21.2%) and from human cases (4.1%). Here, we serotyped these strains using the agglutination method. Serotype 1/2a showed the highest prevalence (61.1%) and serotype 1/2c showed the lowest prevalence, although it represented the majority of strains isolated from the meat sector. The distribution of clonal complexes (CCs) analysed on 176 strains demonstrated that CC11-ST451 (15.3%) was the most prevalent CC, particularly in food (14.8%) and animal strains (17.5%). CC11-ST451, followed by CC7, CC14 and CC37, were the most prevalent CCs in the milk sector, and CC9 and CC8 in the meat sector. CC11-ST451 is probably widely distributed in Slovakia, mainly in the milk and dairy product sectors, posing a possible threat to public health. Presumed persistence of CC9 was observed in one meat facility between 2014-2018, highlighting its general meat-related distribution and potential for persistence worldwide.