Abstract
ABSTRACT An outbreak with a remarkable Listeria monocytogenes clone causing 163 cases of non-invasive listeriosis occurred in Germany in 2015. Core genome multi locus sequence typing grouped non-invasive outbreak isolates and isolates obtained from related food samples into a single cluster, but clearly separated genetically close isolates obtained from invasive listeriosis cases. A comparative genomic approach identified a premature stop codon in the chiB gene, encoding one of the two L. monocytogenes chitinases, which clustered with disease outcome. Correction of this premature stop codon in one representative gastroenteritis outbreak isolate restored chitinase production, but effects in infection experiments were not found. While the exact role of chitinases in virulence of L. monocytogenes is still not fully understood, our results now clearly show that ChiB-derived activity is not required to establish L. monocytogenes gastroenteritis in humans. This limits a possible role of ChiB in human listeriosis to later steps of the infection.
Highlights
Listeria monocytogenes is a Gram-positive intracellularly replicating bacterium widespread in the environment
As disease mechanisms in gastroenteritis due to L. monocytogenes infection are not well understood [9], this study describes the characterization of the L. monocytogenes clone, which has caused this outbreak using whole genome sequencing (WGS)-based subtyping, comparative genomics, genetic approaches and virulence studies
An outbreak of non-invasive listeriosis occurred among 163 patients, among which were 152 children (1–9 years, median 5 years) and 11 adults (17–56 years, median 38 years), that all suffered from gastrointestinal symptoms after consumption of rice pudding from a single local catering service in March 2015 in the Paderborn district in North-East North-Rhine Westfalia/Germany
Summary
Listeria monocytogenes is a Gram-positive intracellularly replicating bacterium widespread in the environment. L. monocytogenes infects humans by ingestion of contaminated food, predominately through milk, fish and meat products and vegetables. It represents an important food-borne human pathogen that can cause severe invasive disease with a high fatality rate of about 20–30% [1]. The number of human listeriosis cases has been increasing during the last years in Germany as well as in Europe [2]. L. monocytogenes may cause large outbreaks and sources of infection are difficult to identify due to the lengthy incubation time [3]. The bacterium has a considerable economic impact and requires great public health attention and action measures such as pathogen surveillance
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
