Genetic diversity and virulence profiles of Listeria monocytogenes and L. innocua strains isolated in Uruguay from clinical cases in ruminants

Abstract

The development of the whole genome sequencing (WGS) has been possible characterized isolates of Listeria recovered form listeriosis cases in ruminants, in an attempt to increase the knowledge about the disease, the involved strains and also the possible relationship with isolates from listeriosis in humans. However, the information reported and collected in databases come from Europe and North America. We analyzed 16 L. monocytogenes and 4 L. innocua isolates recovered from listeriosis in cattle, sheep and a goat from Uruguay through multilocus sequence typing (MLST), core genome multilocus sequence typing (cgMLST) and virulence gene profile analysis. L. monocytogenes lineage I predominated over lineage II (14 vs 2 isolates, respectively). There were 9 different sequence types (STs), being ST1 the most common (6/16, 37.5%) and 7 different clonal complexes (CC’s), in which CC1 was the most frequent (7/16, 43.75%). cgMLST identified 15 different CT’s, showing that there was diversity of strains causing disease. All L. monocytogenes harbored the main virulence factors, 12 isolates possess also a full length LIPI-3 and, two of them LIPI-4. The four L. innocua isolates were grouped into 3 different CC’s, 29 virulence-associated genes were identified, as well as a full LIPI-4. Despite our dataset is small in comparison with other reports, it is the first that analyzed Listeria from South American ruminants, contributing to enhance the knowledge about the disease and characteristics of the involved strains.