Prevalence and tracing of persistent Listeria monocytogenes strains in meat processing facility production chain

Abstract

This work was aimed at determining the occurrence and diversity of Listeria monocytogenes in a traditional meat-processing facility to reveal persistent contamination. A total of 268 samples, including 196 environmental samples and 72 meat samples were collected during a four-year period, and 70 were found to be L. monocytogenes positive. Molecular serotyping of 77 isolates classified these strains into four serogroups, with the majority of 34 strains in serogroup IIa. To reveal the persistent contamination, subtyping by AscI/ApaI-PFGE was applied. Cluster analysis resulted in strain discrimination into 18 profiles. Strains with PFGE/MLST-ST classification as 1/ ST9, 2/ST14 and 9/ST2 were predominant and considered persistent. Based on the results of PFGE, a spatial and temporal map of persistent L. monocytogenes contamination was drawn. Subtyping by PFGE was used as a reliable tool to reveal persistent contamination and, complemented with virulence characteristics, can contribute to the improvement of L. monocytogenes control programs in food processing. Practical applicationListeria monocytogenes is a food-borne pathogen with significant public health and economic impact. This study, focused on prevalence and tracing of L. monocytogenes strains in a traditional meat-processing facility, revealed persistent contamination by the pathogen. Data of PFGE profiling from repeated samplings over a four-year period facilitated to draw a spatial and temporal map of persistent L. monocytogenes strains spreading in a meat-processing facility and, subsequently, will allow optimisation of cleaning and disinfection measures to ensure hygiene. Based on the detection of virulence factors, persistent ECIII and comK prophage-positive strains were observed, indicating a higher risk of contamination by more virulent L. monocytogenes strains. The obtained results clearly indicate, that most attention should be paid to control strategy improvement in the meat processing chain focused preferably on prevention, not only to final products.

Dynamics of mobile genetic elements of Listeria monocytogenes persisting in ready-to-eat seafood processing plants in France

“…The reasons why some clonal groups of L. monocytogenes are recurrently isolated in the FPEs is still under discussion, as well as the dynamics of genetic elements potentially enhancing their persistence. In the last decades, several studies aiming to determine the basis of persistence in RTE industry and to trace-back outbreaks-related L. monocytogenes strains have been performed based on conventional molecular typing [72][73][74][75]. However, the advantages provided by analyses of genome-scale data through comparative genomic approaches have been recently demonstrated in the context of L. monocytogenes strains persisting in FPEs [4,16,18,19,23,[76][77][78].…”

Listeria monocytogenes Sequence Types 121 and 14 Repeatedly Isolated Within One Year of Sampling in a Rabbit Meat Processing Plant: Persistence and Ecophysiology

“…Based on PFGE-Typing, persistence of L. monocytogenes in dairy, meat, fish and vegetable sectors was extensively observed ( Leong et al, 2014 ; Ortiz et al, 2015 ; Véghová et al, 2017 ). However, more recently, whole genome SNPs analysis revealed a superior discriminatory power.…”

“…In food-processing plants, L. monocytogenes has been repeatedly isolated from both food and the environment. Based on different molecular typing methods, isolates sharing the same profile have been collected over months or years in fish, meat, dairy and vegetable processing plants ( Leong et al, 2014 ; Stasiewicz et al, 2015 ; Véghová et al, 2017 ). Strains repeatedly isolated over time in the same plant are considered as persistent.…”

Whole genome sequencing for typing and characterisation of Listeria monocytogenes isolated in a rabbit meat processing plant

“…Listeria monocytogenes is a food-borne pathogen adapted to survive, grow and ultimately persist in different environments (Gray et al ., 2006 ). In food processing plants, L. monocytogenes has been repeatedly isolated from food samples as well as food processing environment for months or years (Stasiewicz et al, 2015 ; Véghová et al, 2017 ; Leong et al, 2014 ). Through the contamination of food, L. monocytogenes can be transmitted to humans where it can switch from saprophyte to intracellular pathogen associated to approximately 2000 confirmed cases of Listeriosis each year in Europe, with a fatality rate of 17 % (EFSA and ECDC, 2016 ).…”