Genetic Characterization of <i>Listeria</i> from Food of Non-Animal Origin Products and from Producing and Processing Companies in Bavaria, Germany

Simone Wartha; Nancy Bretschneider; Alexandra Dangel; Bernhard Hobmaier; Stefan Hörmansdorfer; Ingrid Huber; Larissa Murr; Melanie Pavlovic; Annika Sprenger; Mareike Wenning; Thomas Alter; Ute Messelhäußer

doi:10.3390/foods12061120

Foods (Mar 2023)

Genetic Characterization of <i>Listeria</i> from Food of Non-Animal Origin Products and from Producing and Processing Companies in Bavaria, Germany

Simone Wartha,
Nancy Bretschneider,
Alexandra Dangel,
Bernhard Hobmaier,
Stefan Hörmansdorfer,
Ingrid Huber,
Larissa Murr,
Melanie Pavlovic,
Annika Sprenger,
Mareike Wenning,
Thomas Alter,
Ute Messelhäußer

Affiliations

Simone Wartha: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Nancy Bretschneider: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Alexandra Dangel: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Bernhard Hobmaier: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Stefan Hörmansdorfer: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Ingrid Huber: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Larissa Murr: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Melanie Pavlovic: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Annika Sprenger: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Mareike Wenning: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany
Thomas Alter: Institute of Food Safety and Food Hygiene, Freie Universitaet Berlin, 14195 Berlin, Germany
Ute Messelhäußer: Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany

DOI: https://doi.org/10.3390/foods12061120
Journal volume & issue: Vol. 12, no. 6
p. 1120

Abstract

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Reported cases of listeriosis from food of non-animal origin (FNAO) are increasing. In order to assess the risk of exposure to Listeria monocytogenes from FNAO, the genetic characterization of the pathogen in FNAO products and in primary production and processing plants needs to be investigated. For this, 123 samples of fresh and frozen soft fruit and 407 samples of 39 plants in Bavaria, Germany that produce and process FNAO were investigated for Listeria contamination. As a result, 64 Listeria spp. isolates were detected using ISO 11290-1:2017. Environmental swabs and water and food samples were investigated. L. seeligeri (36/64, 56.25%) was the most frequently identified species, followed by L. monocytogenes (8/64, 12.50%), L. innocua (8/64, 12.50%), L. ivanovii (6/64, 9.38%), L. newyorkensis (5/64, 7.81%), and L. grayi (1/64, 1.56%). Those isolates were subsequently sequenced by whole-genome sequencing and subjected to pangenome analysis to retrieve data on the genotype, serotype, antimicrobial resistance (AMR), and virulence markers. Eight out of sixty-four Listeria spp. isolates were identified as L. monocytogenes. The serogroup analysis detected that 62.5% of the L. monocytogenes isolates belonged to serogroup IIa (1/2a and 3a) and 37.5% to serogroup IVb (4b, 4d, and 4e). Furthermore, the MLST (multilocus sequence typing) analysis of the eight detected L. monocytogenes isolates identified seven different sequence types (STs) and clonal complexes (CCs), i.e., ST1/CC1, ST2/CC2, ST6/CC6, ST7/CC7, ST21/CC21, ST504/CC475, and ST1413/CC739. The core genome MLST analysis also showed high allelic differences and suggests plant-specific isolates. Regarding the AMR, we detected phenotypic resistance against benzylpenicillin, fosfomycin, and moxifloxacin in all eight L. monocytogenes isolates. Moreover, virulence factors, such as prfA, hly, plcA, plcB, hpt, actA, inlA, inlB, and mpl, were identified in pathogenic and nonpathogenic Listeria species. The significance of L. monocytogenes in FNAO is growing and should receive increasing levels of attention.

Published in Foods

ISSN: 2304-8158 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Chemical technology
Website: http://www.mdpi.com/journal/foods

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