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

Abstract

Listeria spp. is a diverse genus of Gram-positive bacteria commonly present in the environment while L. monocytogenes and L. ivanovii are well known human and ruminant pathogens. The aim of the present study was to reveal the prevalence and genetic diversity of L. monocytogenes and other Listeria spp. and to identify the factors related to the abundance of pathogen at cattle farms. A total of 521 animal and environmental samples from 27 meat and dairy cattle farms were investigated and the genetic diversity of L. monocytogenes isolates was studied with WGS. The prevalence of Listeria was 58.9%, while of L. monocytogenes it was −11%. The highest prevalence of L. monocytogenes was found in the environment—soil samples near to manure storage (93%), mixed feed from the feeding trough and hay (29%), water samples from farms drinking trough (28%) and cattle feces (28%). Clonal complexes (CC) of CC37 (30%), CC11 (20%) and CC18 (17%) (all IIa serogroup) were predominant L. monocytogenes clones. CC18, CC37 and CC8 were isolated from case farms and CC37, CC11 and CC18 from farms without listeriosis history. Only one hypervirulent CC4 (1%) was isolated from the case farm. Sequence types (STs) were not associated with the isolation source, except for ST7, which was significantly associated with soil (p < 0.05). The contamination of soil, feeding tables and troughs with L. monocytogenes was associated with an increased prevalence of L. monocytogenes at farms. Our study indicates the importance of hygienic practice in the prevention of the dissemination of L. monocytogenes in the cattle farm environment.

Characterization and Genetic Diversity of Listeria monocytogenes Isolated from Cattle Abortions in Latvia, 2013–2018

“…An additional factor complicating cluster analysis is the possibility of asymptomatic carrier animals or unobserved first-trimester abortions which might link together cases that otherwise seem too far apart in terms of time or allelic difference. Similarly, environmental sources could also play an important role in the spread of L. monocytogenes as supported by the overlap between the most frequent STs of this study and isolates from the farm environment [44]. It remains to be clarified whether these STs are predominant among cattle abortion cases because they are widely distributed in environmental reservoirs or because they are more infectious and/or cause more severe symptoms and are thus easily detected by surveillance that targets clinical manifestations of listeriosis.…”

“…According to a study of environmental Listeria spp. isolates at Latvian cattle farms, the predominant L. monocytogenes strains were ST37 (CC37), ST451 (CC11) and ST18 (CC18) [44], which all were among the most prevalent STs in cattle abortions. Significantly, the STs mentioned above were present in all kinds of the investigated environmental samples.…”

“…Furthermore, Terentjeva et al showed that lack of cleaning and disinfection of cattle feeding tables was associated with higher L. monocytogenes prevalence in soil samples of farms. The detection of the same STs in the environmental and clinical L. monocytogenes isolates highlights the importance of implementing and using appropriate hygiene measures to reduce contamination of the environment and prevent animal infection with L. monocytogenes [44].…”

Whole-Genome Sequencing Analysis of Listeria monocytogenes from Rural, Urban, and Farm Environments in Norway: Genetic Diversity, Persistence, and Relation to Clinical and Food Isolates

“…The occurrence of L. monocytogenes in soil varies widely, from 0.7% to 45%, depending on the geographic area, season, and humidity ( 4 – 6 ). In comparative investigations, higher frequencies of L. monocytogenes have been found after rain, flooding, and irrigation events ( 7 , 8 ).…”

“…An explanation for this could be high frequencies of L. monocytogenes in feces from farm animals, e.g., cattle, ducks, and sheep, leaking into surrounding soil and water ( 9 , 14 , 15 ). Dairy farms are, for example, known to hold an L. monocytogenes reservoir, and prevalences in environmental samples of 11 to 24% have been reported ( 6 , 15 – 17 ). However, L. monocytogenes is not particularly linked to farm animals and is frequently found in other animals and birds, such as game and urban birds, boars, garden slugs, and rodents ( 9 , 18 – 21 ).…”