Environmental dissemination of pathogenic Listeria monocytogenes in flowing surface waters in Switzerland

Abstract

Listeria monocytogenes is an opportunistic pathogen that is widely distributed in the environment. The aquatic environment may represent a potential source for the transmission of L. monocytogenes to animals and the food chain. The present study assessed the occurrence of L. monocytogenes in 191 surface water samples from rivers, streams and inland canals throughout Switzerland. Twenty-five (13%) of the surface water samples contained L. monocytogenes. Whole genome sequence (WGS) data were used to characterize the 25 isolates. The isolates belonged to major lineages I and II, with the majority assigned to either serotype 1/2a (48%), or 4b (44%). The predominant CCs identified were the hypervirulent serotype 4b clones CC1 and CC4, and the serotype CC412; all three have been implicated in listeriosis outbreaks and sporadic cases of human and animal infection worldwide. Two (8%) of the isolates belonged to CC6 which is an emerging hypervirulent clone. All isolates contained intact genes associated with invasion and infection, including inlA/B and prfA. The four CC4 isolates all harbored Listeria pathogenicity island 4 (LIPI-4), which confers hypervirulence. The occurrence of L. monocytogenes in river ecosystems may contribute to the dissemination and introduction of clinically highly relevant strains to the food chain.

Occurrence of Multidrug-Resistant Listeria monocytogenes in Environmental Waters: A Menace of Environmental and Public Health Concern

“…Serotype 1/2a was the most prevalent (78.95%) compared to serotype 4b (21.05%). Our findings corroborated a similar report of Lm isolates recovered from surface water samples in Canada and Switzerland where strains were either serotype 1/2a or 4b (Lyautey et al, 2007;Raschle et al, 2021). By contrast, another study carried out on a municipal water supply watershed in Nova Scotia, Canada, found serotypes 4b/4d/4e as the most prevalent strains recovered from water (Stea et al, 2015).…”

“…By contrast, another study carried out on a municipal water supply watershed in Nova Scotia, Canada, found serotypes 4b/4d/4e as the most prevalent strains recovered from water (Stea et al, 2015). Our study is in support of previous studies stating that Lm serotypes usually found in various cases of human listeriosis were also found in environmental waters (Raschle et al, 2021). Notably, about 95% of Lm isolated in clinical samples belongs to serotypes 1/2a, 1/2b, 1/ 2c, and 4b (Doumith et al, 2004;Pontello et al, 2012).…”

“…tetA-tetM-sul1-sul2-bla TEM -strA-aadA (73.68%) varied among the isolates. Similarly, the presence of inlA and B among all Lm isolates recovered from water in Switzerland was reported (Raschle et al, 2021). A higher rate (100%) of the internalin C and J genes were recovered from irrigation water (Iwu and Okoh, 2020).…”

“…Multiple virulence factors enhance Lm cellular invasion and survival considering its survival in the gastrointestinal tract (Raschle et al, 2021). Virulence determinants including the plcA, inlA, and inlB were detected in all environmental water isolates; the prevalence of inlC (85.97%), inlJ (80.70%), actA (59.65%), prfA (92.98%), plcB (89.47%), hly (80.70%), and mpl…”

Prevalence, Genetic Diversity and Factors Associated with Distribution of Listeria monocytogenes and Other Listeria spp. in Cattle Farms in Latvia

“…The widespread distribution of L. monocytogenes CC18 and CC37 in control and case farms without significant differences in their prevalence (p > 0.05) may be associated with their environmental origin. In previous studies, ST37 (CC37) was associated with ruminants, ruminant farms and wildlife environments [21,39]. CC37 was prevalent among clinical isolates from ruminant farms [40].…”