20.500.12556/RUL-112702 Retrospective investigation of listeriosis outbreaks in small ruminants using different analytical approaches for whole genome sequencing-based typing of Listeria monocytogenes Listeria monocytogenes is the causative agent of listeriosis, a serious disease affecting both humans and animals. While listeriosis outbreaks in humans are commonly investigated in detail, routine typing of L. monocytogenes is generally not performed in animal outbreaks. Here, seven presumable listeriosis outbreaks in small ruminants were retrospectively identified based on the pulsed-field gel electrophoresis (PFGE) profiles. Outbreaks were further characterised using three different analytical approaches based on the whole-genome sequencing (WGS) data: core-genome multilocus sequence typing (cgMLST), whole-genome MLST (wgMLST) and whole-genome single nucleotide polymorphism (wgSNP) typing. A monoclonal pattern of all seven outbreaks was identified using all three approaches, indicating common-source outbreaks. The outbreak strains belonged to sequence types (STs) 1 (n = 3), ST18 (n = 1), ST21 (n = 2) and ST184 (n = 1). Two epidemiologically linked ST1 outbreaks with indistinguishable PFGE profiles showed a polyphyletic nature and differed in >78 SNPs; thus, they were classified as separate outbreaks according to WGS. In ST184, the outbreak strain was also found in faeces of apparently healthy ruminants, silage and water collected from the trough, which were the most likely source(s) of infection. The outbreak-associated isolates differed in 0–7 cgMLST alleles, 0–12 wgMLST alleles and 1–13 SNPs. The minimum genetic diversity between outbreak-associated isolates and epidemiologically unrelated isolates of the same ST was low in all analysed cases, approaching the maximum diversity within the outbreak cluster. The results suggest that a fixed threshold to define the outbreak cluster should only be considered as a guide and highlight the role of epidemiological data for outbreak confirmation. The identified cgMLST clusters may be further investigated by wgMLST and/or wgSNP typing to increase confidence during investigations of outbreaks caused by highly clonal L. monocytogenes groups. This study gives an overview of the inter- and intra-outbreak genetic diversity of L. monocytogenes strains involved in animal outbreaks, hence improving their investigation. epidemiology veterinary Listeria monocytogenes outbreak whole-genome sequencine single nucleotide polymorphism multilocus sequence typing sheep goats true false true Elsevier Angleški jezik Ni določen založnik Članek v reviji 2019-11-06 11:02:51 2019-11-06 11:02:51 2022-08-24 03:52:35 0000-00-00 00:00:00 2020 0 0 art. 104047, str. 1-9 Vol. 77 2020 0000-00-00 PostprintKoncna Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 2020-10-17 636.3.09:616.9:57.08 1567-1348 10.1016/j.meegid.2019.104047 4892282 2319124 RAZ_Papic_Bojan_2020.pdf RAZ_Papic_Bojan_2020.pdf 1 46D35A73F32B215F76FC6B5CD291E991 4a079ee98f06f4b88760a6f29c0df391a3437a5f789626ffb0ce5e12d98f41cf f1d5cdda-a1b7-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=124645 https://www.sciencedirect.com/science/article/pii/S1567134819302734?via%3Dihub 1 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=124644 Veterinarska fakulteta 0 0 0