Whole-Genome Sequencing-Based Characterization of a Listeria monocytogenes Strain from an Aborted Water Buffalo in Southern Italy.

Rubina Paradiso,Bianca Cecere,Giovanna Fusco,Anna Cerrone,Antonietta Anzalone,Roberto Scialla,Giorgia Borriello,Marita Georgia Riccardi,Nunzia Riccone,Esterina De Carlo

doi:10.3390/microorganisms9091875

Rubina Paradiso, Bianca Cecere + Show 8 more

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https://doi.org/10.3390/microorganisms9091875

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Abstract

Listeria monocytogenes is a Gram-positive pathogen causing life-threatening infections both in humans and animals. In livestock farms, it can persist for a long time and primarily causes uterine infections and encephalitis in farmed animals. Whole genome sequencing (WGS) is currently becoming the best method for molecular typing of this pathogen due to its high discriminatory power and efficiency of characterization. This study describes the WGS-based characterization of an L. monocytogenes strain from an aborted water buffalo fetus in southern Italy. The strain under study was classified as molecular serogroup IVb, phylogenetic lineage I, MLST sequence type 6, Clonal Complex 6, and cgMLST type CT3331, sublineage 6. Molecular analysis indicated the presence of 61 virulence genes and 4 antibiotic resistance genes. Phylogenetic analysis, including all the publicly available European L. monocytogenes serogroup IVb isolates, indicated that our strain clusterized with all the other CC6 strains and that different CCs were variably distributed within countries and isolation sources. This study contributes to the current understanding of the genetic diversity of L. monocytogenes from animal sources and highlights how the WGS strategy can provide insights into the pathogenic potential of this microorganism, acting as an important tool for epidemiological studies.

Highlights

Listeria monocytogenes is a facultative intracellular pathogen ubiquitously present in natural environments with the ability to cause life-threatening infections both in humans and animals [1]
The Listeria monocytogenes strain under study was isolated from the lungs of an aborted water buffalo fetus exhibiting severe abdominal and moderate pleural serohematic effusions, with the presence of mild pericardial serohematic fluid [10]
This strain was assigned to a seven-loci multilocus sequence typing (MLST) sequence type 6 (ST6) and Clonal Complex 6 (CC6)

Summary

Introduction

Listeria monocytogenes is a facultative intracellular pathogen ubiquitously present in natural environments with the ability to cause life-threatening infections both in humans and animals [1]. L. monocytogenes primarily causes uterine infections and encephalitis. Uterine infections induce late-term abortions or septicemia in neonates, while central nervous system (CNS) infection, mainly rhombencephalitis, is the most common clinical manifestation in animals and is associated with a high mortality rate [2,3]. L. monocytogenes can cause eye infection and keratitis in ruminants. Listeriosis may occur as a large outbreak within a farm, even though it most commonly affects a single or a few animals [4]. Infected animals are generally asymptomatic carriers but can spread this pathogen by fecal shedding, disseminating the pathogen in the farm environment [5,6]

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