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Pracser N, Zaiser A, Ying HMK, Pietzka A, Wagner M, Rychli K. Diverse Listeria monocytogenes in-house clones are present in a dynamic frozen vegetable processing environment. Int J Food Microbiol 2024; 410:110479. [PMID: 37977080 DOI: 10.1016/j.ijfoodmicro.2023.110479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023]
Abstract
Listeria (L.) monocytogenes is of global concern for food safety as the listeriosis-causing pathogen is widely distributed in the food processing environments, where it can survive for a long time. Frozen vegetables contaminated with L. monocytogenes were recently identified as the source of two large listeriosis outbreaks in the EU and US. So far, only a few studies have investigated the occurrence and behavior of Listeria in frozen vegetables and the associated processing environment. This study investigates the occurrence of L. monocytogenes and other Listeria spp. in a frozen vegetable processing environment and in frozen vegetable products. Using whole genome sequencing (WGS), the distribution of sequence types (MLST-STs) and core genome sequence types (cgMLST-CT) of L. monocytogenes were assessed, and in-house clones were identified. Comparative genomic analyses and phenotypical characterization of the different MLST-STs and isolates were performed, including growth ability under low temperatures, as well as survival of freeze-thaw cycles. Listeria were widely disseminated in the processing environment and five in-house clones namely ST451-CT4117, ST20-CT3737, ST8-CT1349, ST8-CT6243, ST224-CT5623 were identified among L. monocytogenes isolates present in environmental swab samples. Subsequently, the identified in-house clones were also detected in product samples. Conveyor belts were a major source of contamination in the processing environment. A wide repertoire of stress resistance markers supported the colonization and survival of L. monocytogenes in the frozen vegetable processing facility. The presence of ArgB was significantly associated with in-house clones. Significant differences were also observed in the growth rate between different MLST-STs at low temperatures (4 °C and 10 °C), but not between in-house and non-in-house isolates. All isolates harbored major virulence genes such as full length InlA and InlB and LIPI-1, yet there were differences between MLST-STs in the genomic content. The results of this study demonstrate that WGS is a strong tool for tracing contamination sources and transmission routes, and for identifying in-house clones. Further research targeting the co-occurring microbiota and the presence of biofilms is needed to fully understand the mechanism of colonization and persistence in a food processing environment.
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Affiliation(s)
- Nadja Pracser
- FFoQSI GmbH-Austrian Competence Centre for Feed and Food Quality, Safety and Innovation, Technopark 1D, 3430 Tulln, Austria.
| | - Andreas Zaiser
- Unit of Food Microbiology, Institute for Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Hui Min Katharina Ying
- Unit of Food Microbiology, Institute for Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria
| | - Ariane Pietzka
- Austrian National Reference Laboratory for Listeria monocytogenes, Institute of Medical Microbiology and Hygiene, Austrian Agency for Health and Food Safety, Beethovenstrasse 6, 8010 Graz, Austria.
| | - Martin Wagner
- FFoQSI GmbH-Austrian Competence Centre for Feed and Food Quality, Safety and Innovation, Technopark 1D, 3430 Tulln, Austria; Unit of Food Microbiology, Institute for Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Kathrin Rychli
- Unit of Food Microbiology, Institute for Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
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Bucur FI, Borda D, Neagu C, Grigore-Gurgu L, Nicolau AI. Deterministic Approach and Monte Carlo Simulation to Predict Listeria monocytogenes Time to Grow on Refrigerated Ham: A Study Supporting Risk-based Decisions for Consumers' Health. J Food Prot 2023; 86:100026. [PMID: 36916585 DOI: 10.1016/j.jfp.2022.100026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/02/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022]
Abstract
This study assessed the growth of Listeria monocytogenes in ready-to-eat (RTE) ham during storage under conditions simulating domestic practices with the intention to offer support in the elaboration of food safety policies that should better protect consumers against food poisoning at home. RTE ham, artificially contaminated at either medium (102-103 CFU/g) or high (104-105 CFU/g) concentration, was stored at both isothermal (4℃ in a refrigerator able to maintain a relatively constant temperature and 5℃ and 7℃ in a refrigerator with fluctuating temperature) and dynamic (5℃ and 7℃ with intermittent exposure to ambient temperature, e.g. 25℃) conditions. Under isothermal conditions, the increasing storage temperature determined a significantly increased (p < 0.05) capacity of L. monocytogenes to grow. The kinetic growth parameters were derived by fitting the Baranyi and Roberts model to the experimental data and, based on the maximum specific growth rates, it was estimated the temperature dependence of L. monocytogenes growth in RTE ham. At medium contamination level, sanitary risk time calculation revealed that, unlike storage at 5℃ and 7℃, storage at 4℃ of the RTE ham extends the time period during which the product is safe for consumption by ∼40 and 52%, respectively. However, the real temperature fluctuations included in the Monte Carlo simulations at low L. monocytogenes counts (1, 5 and 10 CFU/g) have shortened the safety margins. Stochastic models also proved to be useful tools for describing the pathogen's behavior when refrigeration of the RTE ham alternates with periods of ham being kept at room temperature, considered dynamic conditions of growth.
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Affiliation(s)
- Florentina Ionela Bucur
- Dunărea de Jos University of Galați, Faculty of Food Science and Engineering, Domnească Street 111, Galați 800201, Romania
| | - Daniela Borda
- Dunărea de Jos University of Galați, Faculty of Food Science and Engineering, Domnească Street 111, Galați 800201, Romania
| | - Corina Neagu
- Dunărea de Jos University of Galați, Faculty of Food Science and Engineering, Domnească Street 111, Galați 800201, Romania
| | - Leontina Grigore-Gurgu
- Dunărea de Jos University of Galați, Faculty of Food Science and Engineering, Domnească Street 111, Galați 800201, Romania
| | - Anca Ioana Nicolau
- Dunărea de Jos University of Galați, Faculty of Food Science and Engineering, Domnească Street 111, Galați 800201, Romania.
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Deciphering the virulence potential of Listeria monocytogenes in the Norwegian meat and salmon processing industry by combining whole genome sequencing and in vitro data. Int J Food Microbiol 2022; 383:109962. [DOI: 10.1016/j.ijfoodmicro.2022.109962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022]
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Li X, Shi X, Song Y, Yao S, Li K, Shi B, Sun J, Liu Z, Zhao W, Zhao C, Wang J. Genetic diversity, antibiotic resistance, and virulence profiles of Listeria monocytogenes from retail meat and meat processing. Food Res Int 2022; 162:112040. [DOI: 10.1016/j.foodres.2022.112040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/30/2022] [Accepted: 10/10/2022] [Indexed: 11/17/2022]
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Tîrziu E, Herman V, Nichita I, Morar A, Imre M, Ban-Cucerzan A, Bucur I, Tîrziu A, Mateiu-Petrec OC, Imre K. Diversity and Antibiotic Resistance Profiles of Listeria monocytogenes Serogroups in Different Food Products from the Transylvania Region of Central Romania. J Food Prot 2022; 85:54-59. [PMID: 34525194 DOI: 10.4315/jfp-21-172] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 09/12/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT This study used molecular serogrouping to assess the presence and antimicrobial susceptibility profile of Listeria monocytogenes isolates from food products of different animal origin, collected from a county situated in the historical region of Transylvania in central Romania. Seventeen (7.7%) of 221 screened samples were positive for L. monocytogenes; these included 8 (6.2%) of 130 ready-to-eat products (i.e., sausages, ham, and smoked specialties), 6 (12.8%) of 47 raw meat samples (i.e., minced pork, pork organs, and snails), and 3 (6.8%) of 44 dairy samples (i.e., assortment of cheeses). The identified L. monocytogenes serogroups were 1/2a-3a (47.1%), 4b-4d-4e (29.4%), 1/2c-3c (11.8%), and 4a-4c (11.8%). All isolates were resistant to benzylpenicillin and fusidic acid. Resistance was also detected toward oxacillin (88.2%), fosfomycin (82.4%), clindamycin (76.5%), imipenem (52.9%), ciprofloxacin (41.2%), rifampin (41.2%), trimethoprim-sulfamethoxazole (29.4%), and tetracycline (29.4%). On the other hand, all isolates proved susceptible to gentamicin, moxifloxacin, teicoplanin, vancomycin, tigecycline, erythromycin, and linezolid. All tested strains exhibited multidrug resistance, resulting in the expression of a total of 12 resistance profiles. These findings extend the understanding of the spread of an important pathogen in Romanian food products, highlighting a substantial public health issue and medical concern, especially for consumers with a compromised health status. HIGHLIGHTS
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Affiliation(s)
- Emil Tîrziu
- Department of Animal Production and Veterinary Public Health, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" Timişoara, 300645, Romania
| | - Viorel Herman
- Department of Infectious Diseases and Preventive Medicine, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" Timişoara, 300645, Romania
| | - Ileana Nichita
- Department of Animal Production and Veterinary Public Health, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" Timişoara, 300645, Romania
| | - Adriana Morar
- Department of Animal Production and Veterinary Public Health, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" Timişoara, 300645, Romania
| | - Mirela Imre
- Department of Parasitology and Parasitic Diseases, Faculty of Veterinary Medicine, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" Timişoara, 300645, Romania
| | - Alexandra Ban-Cucerzan
- Department of Animal Production and Veterinary Public Health, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" Timişoara, 300645, Romania
| | - Iulia Bucur
- Department of Animal Production and Veterinary Public Health, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" Timişoara, 300645, Romania
| | - Andreea Tîrziu
- Department of Ophthalmology, Municipal Emergency Clinical Hospital, Timişoara, 300011, Romania
| | - Oana Cătălina Mateiu-Petrec
- Department of Infectious Diseases and Preventive Medicine, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" Timişoara, 300645, Romania
| | - Kálmán Imre
- Department of Animal Production and Veterinary Public Health, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" Timişoara, 300645, Romania
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Morar A, Ban-Cucerzan A, Herman V, Tîrziu E, Sallam KI, Abd-Elghany SM, Imre K. Multidrug Resistant Coagulase-Positive Staphylococcus aureus and Their Enterotoxins Detection in Traditional Cheeses Marketed in Banat Region, Romania. Antibiotics (Basel) 2021; 10:antibiotics10121458. [PMID: 34943670 PMCID: PMC8698683 DOI: 10.3390/antibiotics10121458] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 11/16/2022] Open
Abstract
The main objectives of the present study were to determine the occurrence of coagulase positive staphylococci (CPS) and to assess the presence and antimicrobial susceptibility profile of Staphylococcus aureus isolates in different raw milk origin (cow and sheep) traditional cheeses marketed in Banat region, Romania. Additionally, the presence of mecA gene in S. aureus isolates and the staphylococcal enterotoxins (SEs) in cheese samples were evaluated. A total of 81.6% (138/169) of the screened samples were positive for CPS. Furthermore, 35.5% (49/138) of the investigated CPS positive cheese samples were contaminated with S. aureus, with an isolation frequency of 46.6% (14/30) in caș, 33.3% (32/96) in telemea, 25% (2/8) in burduf, and 25% (1/4) in urdă assortments, respectively. From the total number of S. aureus isolates, 6.1% (3/49) harbored the mecA gene. Detectable levels of SEs were identified in 4.3% (4/94) of cheese samples with a CPS contamination level higher than 105 log CFU g−1. The expressed antimicrobial susceptibility profile of the tested cheese-origin S. aureus isolates, with the automated Vitek 2 equipment, showed resistance towards amikacin (90.1%, 10 out from 11 tested), enrofloxacin (86.2%, 25/29), ceftiofur (72.7%, 8/11), neomycin (63.6%, 7/11), benzylpenicillin (53.1%, 26/49), kanamycin (41.4%, 12/29), rifampicin (39.5%, 15/38), tetracycline (38.8%, 19/49), tilmicosin (36.4%, 4/11), clindamycin (30.6%, 15/49), ciprofloxacin (30%, 6/20), erythromycin (22.4%, 11/49), tylosin (18.2%, 2/11), oxacillin (16.3%, 8/49), linezolid (15%, 3/20), teicoplanin (15%, 3/20), fusidic acid (13.1%), imipenem (10.5%, 4/38), vancomycin (7.9%, 3/38), ampicillin (5.5%, 1/18), mupirocin (5.5%, 1/18), fosfomycin (5%, 1/20), and gentamicin (4.1%, 2/49). Twenty-four (49%) S. aureus isolates exhibited multidrug resistance. The investigation highlighted a common occurrence of multidrug-resistant S. aureus strains in the monitored cheese assortments, which can constitute a potential risk for consumers’ health.
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Affiliation(s)
- Adriana Morar
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania; (A.M.); (A.B.-C.); (E.T.)
| | - Alexandra Ban-Cucerzan
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania; (A.M.); (A.B.-C.); (E.T.)
| | - Viorel Herman
- Department of Infectious Diseases and Preventive Medicine, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania;
| | - Emil Tîrziu
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania; (A.M.); (A.B.-C.); (E.T.)
| | - Khalid Ibrahim Sallam
- Department of Food Hygiene and Control, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35511, Egypt; (K.I.S.); (S.M.A.-E.)
| | - Samir Mohammed Abd-Elghany
- Department of Food Hygiene and Control, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35511, Egypt; (K.I.S.); (S.M.A.-E.)
| | - Kálmán Imre
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania; (A.M.); (A.B.-C.); (E.T.)
- Correspondence:
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Wine Pomace Product Inhibit Listeria monocytogenes Invasion of Intestinal Cell Lines Caco-2 and SW-480. Foods 2021; 10:foods10071485. [PMID: 34206875 PMCID: PMC8304679 DOI: 10.3390/foods10071485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/19/2021] [Accepted: 06/22/2021] [Indexed: 11/17/2022] Open
Abstract
Red wine pomace products (WPP) have antimicrobial activities against human pathogens, and it was suggested that they have a probable anti-Listeria effect. This manuscript evaluates the intestinal cell monolayer invasive capacity of Listeria monocytogenes strains obtained from human, salmon, cheese, and L. innocua treated with two WPP (WPP-N and WPP-C) of different polyphenol contents using Caco-2 and SW480 cells. The invasion was dependent of the cell line, being higher in the SW480 than in the Caco-2 cell line. Human and salmon L. monocytogenes strains caused cell invasion in both cell lines, while cheese and L. innocua did not cause an invasion. The phenolic contents of WPP-N are characterized by high levels of anthocyanin and stilbenes and WPP-C by a high content of phenolic acids. The inhibitory effect of the WPPs was dependent of the strain and of the degree of differentiation of the intestinal cells line. The inhibition of Listeria invasion by WPPs in the SW480 cell line, especially with WPP-C, were higher than the Caco-2 cell line inhibited mainly by WPP-N. This effect is associated with the WPPs’ ability to protect the integrity of the intestinal barrier by modification of the cell–cell junction protein expression. The gene expression of E-cadherin and occludin are involved in the L. monocytogenes invasion of both the Caco-2 and SW480 cell lines, while the gene expression of claudin is only involved in the invasion of SW480. These findings suggest that WPPs have an inhibitory L. monocytogenes invasion effect in gastrointestinal cells lines.
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Duru IC, Bucur FI, Andreevskaya M, Nikparvar B, Ylinen A, Grigore-Gurgu L, Rode TM, Crauwels P, Laine P, Paulin L, Løvdal T, Riedel CU, Bar N, Borda D, Nicolau AI, Auvinen P. High-pressure processing-induced transcriptome response during recovery of Listeria monocytogenes. BMC Genomics 2021; 22:117. [PMID: 33579201 PMCID: PMC7881616 DOI: 10.1186/s12864-021-07407-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/25/2021] [Indexed: 12/18/2022] Open
Abstract
Background High-pressure processing (HPP) is a commonly used technique in the food industry to inactivate pathogens, including L. monocytogenes. It has been shown that L. monocytogenes is able to recover from HPP injuries and can start to grow again during long-term cold storage. To date, the gene expression profiling of L. monocytogenes during HPP damage recovery at cooling temperature has not been studied. In order identify key genes that play a role in recovery of the damage caused by HPP treatment, we performed RNA-sequencing (RNA-seq) for two L. monocytogenes strains (barotolerant RO15 and barosensitive ScottA) at nine selected time points (up to 48 h) after treatment with two pressure levels (200 and 400 MPa). Results The results showed that a general stress response was activated by SigB after HPP treatment. In addition, the phosphotransferase system (PTS; mostly fructose-, mannose-, galactitol-, cellobiose-, and ascorbate-specific PTS systems), protein folding, and cobalamin biosynthesis were the most upregulated genes during HPP damage recovery. We observed that cell-division-related genes (divIC, dicIVA, ftsE, and ftsX) were downregulated. By contrast, peptidoglycan-synthesis genes (murG, murC, and pbp2A) were upregulated. This indicates that cell-wall repair occurs as a part of HPP damage recovery. We also observed that prophage genes, including anti-CRISPR genes, were induced by HPP. Interestingly, a large amount of RNA-seq data (up to 85%) was mapped to Rli47, which is a non-coding RNA that is upregulated after HPP. Thus, we predicted that Rli47 plays a role in HPP damage recovery in L. monocytogenes. Moreover, gene-deletion experiments showed that amongst peptidoglycan biosynthesis genes, pbp2A mutants are more sensitive to HPP. Conclusions We identified several genes and mechanisms that may play a role in recovery from HPP damage of L. monocytogenes. Our study contributes to new information on pathogen inactivation by HPP. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07407-6.
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Affiliation(s)
- Ilhan Cem Duru
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - Florentina Ionela Bucur
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | | | - Bahareh Nikparvar
- Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Anne Ylinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Leontina Grigore-Gurgu
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Tone Mari Rode
- Department of Process Technology, Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, N-4068, Stavanger, Norway
| | - Peter Crauwels
- Institute of Microbiology and Biotechnology, Ulm, University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
| | - Pia Laine
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Lars Paulin
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Trond Løvdal
- Department of Process Technology, Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, N-4068, Stavanger, Norway
| | - Christian U Riedel
- Institute of Microbiology and Biotechnology, Ulm, University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
| | - Nadav Bar
- Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Daniela Borda
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Anca Ioana Nicolau
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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Virulence characterization and comparative genomics of Listeria monocytogenes sequence type 155 strains. BMC Genomics 2020; 21:847. [PMID: 33256601 PMCID: PMC7708227 DOI: 10.1186/s12864-020-07263-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/22/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Listeria (L.) monocytogenes strains show a high diversity regarding stress tolerance and virulence potential. Genome studies have mainly focused on specific sequence types (STs) predominantly associated with either food or human listeriosis. This study focused on the prevalent ST155, showing equal distribution among clinical and food isolates. We evaluated the virulence potential of 20 ST155 strains and performed comparative genomic analysis of 130 ST155 strains isolated from food, food processing environments and human listeriosis cases in different countries and years. RESULTS The in vitro virulence assays using human intestinal epithelial Caco2 and hepatocytic HEPG2 cells showed an impaired virulence phenotype for six of the 20 selected ST155 strains. Genome analysis revealed no distinct clustering of strains from the same source category (food, food processing environment, and clinical isolates). All strains harbored an intact inlA and inlB locus, except four strains, which had an internal deletion in the inlA gene. All strains harbored LIPI-1, but prfA was present in a longer variant in six strains, all showing impaired virulence. The longer PrfA variant resulted in lower expression of inlA, inlB, and prfA, and no expression of hly and actA. Regarding stress-related gene content, SSI-1 was present, whereas qacH was absent in all strains. 34.6% of the strains harbored a plasmid. All but one ST155 plasmids showed high conservation and harbored cadA2, bcrABC, and a triphenylmethane reductase. CONCLUSIONS This study contributes to an enhanced understanding of L. monocytogenes ST155 strains, being equally distributed among isolates from humans, food, and food processing environments. The conservation of the present genetic traits and the absence of unique inherent genetic features makes these types of STs especially interesting since they are apparently equally adapted to the conditions in food processing environments, as well as in food as to the human host environment. However, a ST155-specific mutation resulting in a longer PrfA variant impaired the virulence potential of several ST155 strains.
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Bustamante F, Maury-Sintjago E, Leal FC, Acuña S, Aguirre J, Troncoso M, Figueroa G, Parra-Flores J. Presence of Listeria monocytogenes in Ready-to-Eat Artisanal Chilean Foods. Microorganisms 2020; 8:microorganisms8111669. [PMID: 33121209 PMCID: PMC7694154 DOI: 10.3390/microorganisms8111669] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 11/16/2022] Open
Abstract
Ready-to-eat (RTE) artisanal foods are very popular, but they can be contaminated by Listeria monocytogenes. The aim was to determine the presence of L. monocytogenes in artisanal RTE foods and evaluate its food safety risk. We analyzed 400 RTE artisanal food samples requiring minimal (fresh products manufactured by a primary producer) or moderate processing (culinary products for sale from the home, restaurants such as small cafés, or on the street). Listeria monocytogenes was isolated according to the ISO 11290-1:2017 standard, detected with VIDAS equipment, and identified by real-time polymerase chain reaction (PCR). A small subset (n = 8) of the strains were further characterized for evaluation. The antibiotic resistance profile was determined by the CLSI methodology, and the virulence genes hlyA, prfA, and inlA were detected by PCR. Genotyping was performed by pulsed-field gel electrophoresis (PFGE). Listeria monocytogenes was detected in 7.5% of RTE artisanal foods. On the basis of food type, positivity in minimally processed artisanal foods was 11.6%, significantly different from moderately processed foods with 6.2% positivity (p > 0.05). All the L. monocytogenes strains (n = 8) amplified the three virulence genes, while six strains exhibited premature stop codons (PMSC) in the inlA gene; two strains were resistant to ampicillin and one strain was resistant to sulfamethoxazole-trimethoprim. Seven strains were 1/2a serotype and one was a 4b strain. The sampled RTE artisanal foods did not meet the microbiological criteria for L. monocytogenes according to the Chilean Food Sanitary Regulations. The presence of virulence factors and antibiotic-resistant strains make the consumption of RTE artisanal foods a risk for the hypersensitive population that consumes them.
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Affiliation(s)
- Fernanda Bustamante
- Environmental and Public Health Laboratory, Universidad del Bío-Bío, Regional Secreatariat of the Ministry of Health in Maule, Talca 3461637, Chile;
| | - Eduard Maury-Sintjago
- Department of Nutrition and Public Health, Universidad del Bío-Bío, Chillán 3800708, Chile;
| | - Fabiola Cerda Leal
- Department of Food Engineering, Universidad del Bío-Bío, Chillán 3800708, Chile; (F.C.L.); (S.A.)
| | - Sergio Acuña
- Department of Food Engineering, Universidad del Bío-Bío, Chillán 3800708, Chile; (F.C.L.); (S.A.)
| | - Juan Aguirre
- Department of Agricultural Industry and Enology, Universidad de Chile, Santiago 8820808, Chile;
| | - Miriam Troncoso
- Microbiology and Probiotics Laboratory, Institute of Nutrition and Food Technology, Universidad de Chile, Santiago 7830490, Chile; (M.T.); (G.F.)
| | - Guillermo Figueroa
- Microbiology and Probiotics Laboratory, Institute of Nutrition and Food Technology, Universidad de Chile, Santiago 7830490, Chile; (M.T.); (G.F.)
| | - Julio Parra-Flores
- Department of Nutrition and Public Health, Universidad del Bío-Bío, Chillán 3800708, Chile;
- Correspondence:
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Duru IC, Andreevskaya M, Laine P, Rode TM, Ylinen A, Løvdal T, Bar N, Crauwels P, Riedel CU, Bucur FI, Nicolau AI, Auvinen P. Genomic characterization of the most barotolerant Listeria monocytogenes RO15 strain compared to reference strains used to evaluate food high pressure processing. BMC Genomics 2020; 21:455. [PMID: 32615922 PMCID: PMC7331262 DOI: 10.1186/s12864-020-06819-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/10/2020] [Indexed: 12/11/2022] Open
Abstract
Background High pressure processing (HPP; i.e. 100–600 MPa pressure depending on product) is a non-thermal preservation technique adopted by the food industry to decrease significantly foodborne pathogens, including Listeria monocytogenes, from food. However, susceptibility towards pressure differs among diverse strains of L. monocytogenes and it is unclear if this is due to their intrinsic characteristics related to genomic content. Here, we tested the barotolerance of 10 different L. monocytogenes strains, from food and food processing environments and widely used reference strains including clinical isolate, to pressure treatments with 400 and 600 MPa. Genome sequencing and genome comparison of the tested L. monocytogenes strains were performed to investigate the relation between genomic profile and pressure tolerance. Results None of the tested strains were tolerant to 600 MPa. A reduction of more than 5 log10 was observed for all strains after 1 min 600 MPa pressure treatment. L. monocytogenes strain RO15 showed no significant reduction in viable cell counts after 400 MPa for 1 min and was therefore defined as barotolerant. Genome analysis of so far unsequenced L. monocytogenes strain RO15, 2HF33, MB5, AB199, AB120, C7, and RO4 allowed us to compare the gene content of all strains tested. This revealed that the three most pressure tolerant strains had more than one CRISPR system with self-targeting spacers. Furthermore, several anti-CRISPR genes were detected in these strains. Pan-genome analysis showed that 10 prophage genes were significantly associated with the three most barotolerant strains. Conclusions L. monocytogenes strain RO15 was the most pressure tolerant among the selected strains. Genome comparison suggests that there might be a relationship between prophages and pressure tolerance in L. monocytogenes.
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Affiliation(s)
- Ilhan Cem Duru
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | | | - Pia Laine
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Tone Mari Rode
- Department of Process Technology, Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, N-4068, Stavanger, Norway
| | - Anne Ylinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Trond Løvdal
- Department of Process Technology, Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, N-4068, Stavanger, Norway
| | - Nadav Bar
- Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Peter Crauwels
- Institute of Microbiology and Biotechnology, Ulm, University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Christian U Riedel
- Institute of Microbiology and Biotechnology, Ulm, University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Florentina Ionela Bucur
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Anca Ioana Nicolau
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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12
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Imre K, Herman V, Morar A. Scientific Achievements in the Study of the Occurrence and Antimicrobial Susceptibility Profile of Major Foodborne Pathogenic Bacteria in Foods and Food Processing Environments in Romania: Review of the Last Decade. BIOMED RESEARCH INTERNATIONAL 2020; 2020:5134764. [PMID: 32685497 PMCID: PMC7333035 DOI: 10.1155/2020/5134764] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/15/2020] [Indexed: 01/08/2023]
Abstract
Pathogenic bacteria are recognized as a major cause of foodborne diseases in humans, globally, with negative impact on the economy of each country. The aim of the present review was to obtain a comprehensive understanding about the frequency of isolation, diversity, and antimicrobial susceptibility profile of the six major foodborne pathogenic bacteria in food matrices and food processing environment, in Romania. In this regard, results of relevant epidemiological studies, published during the last decade and retrieved from the Web of Science Core Collection database, were analyzed, with special emphasis on scientific achievements, main knowledge gaps, and future perspectives. The summarized and harmonized results offer useful insight, especially for public health authorities and researchers, having a reference effect in stimulating further opportunities for studies to be carried out to address some of the limitations of the current status.
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Affiliation(s)
- Kálmán Imre
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat's University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645, Romania
| | - Viorel Herman
- Department of Infectious Diseases and Preventive Medicine, Faculty of Veterinary Medicine, Banat's University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645, Romania
| | - Adriana Morar
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat's University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645, Romania
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13
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Maćkiw E, Stasiak M, Kowalska J, Kucharek K, Korsak D, Postupolski J. Occurrence and Characteristics of Listeria monocytogenes in Ready-to-Eat Meat Products in Poland. J Food Prot 2020; 83:1002-1009. [PMID: 32045003 DOI: 10.4315/jfp-19-525] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/06/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Listeria monocytogenes is a potential hazard for food safety and therefore for public health. The aim of the present study was to determine the prevalence and characteristics of L. monocytogenes in Polish ready-to-eat (RTE) meat products for retail sale. Among the 184,439 food samples collected within the framework of a national official control and monitoring program, only 0.3% were positive for L. monocytogenes. A significant group of products that did not meet the criteria were RTE meat products. This group accounted for 40% of all noncompliant samples. Seventy L. monocytogenes isolates from these RTE meat products (meat, sausages, and delicatessen products with meat) were examined. The majority of the tested isolates (51%) belonged to serogroup 1/2a-3a followed by 1/2c-3c (21%), 1/2b-3b-7 (14%), and 4ab-4b-4d-4e (13%). Serogroup 4a-4c was not present among the tested isolates. All L. monocytogenes isolates harbored the virulence-associated genes inlA, inlC, inlJ, and lmo2672. The llsX marker was detected in 12 (17%) of the 70 isolates. Ampicillin resistance was the most common resistance phenotype and was identified in 83% of the L. monocytogenes isolates. A low incidence of resistance to amoxicillin-clavulanic acid (6% of isolates) was also detected. All L. monocytogenes isolates were susceptible to chloramphenicol, gentamicin, ciprofloxacin, meropenem, sulfamethoxazole-trimethoprim, tetracycline, and erythromycin. This work provides useful information regarding contamination of RTE meat products with L. monocytogenes, which may have implications for food safety risks. HIGHLIGHTS
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Affiliation(s)
- Elżbieta Maćkiw
- Department of Food Safety, National Institute of Public Health-National Institute of Hygiene, 24 Chocimska Str., 00-791 Warsaw, Poland
| | - Monika Stasiak
- Department of Food Safety, National Institute of Public Health-National Institute of Hygiene, 24 Chocimska Str., 00-791 Warsaw, Poland
| | - Joanna Kowalska
- Department of Food Safety, National Institute of Public Health-National Institute of Hygiene, 24 Chocimska Str., 00-791 Warsaw, Poland
| | - Katarzyna Kucharek
- Department of Food Safety, National Institute of Public Health-National Institute of Hygiene, 24 Chocimska Str., 00-791 Warsaw, Poland
| | - Dorota Korsak
- Department of Food Safety, National Institute of Public Health-National Institute of Hygiene, 24 Chocimska Str., 00-791 Warsaw, Poland.,Department of Applied Microbiology, Faculty of Biology, University of Warsaw, 1 Miecznikowa Str., 02-096 Warsaw, Poland
| | - Jacek Postupolski
- Department of Food Safety, National Institute of Public Health-National Institute of Hygiene, 24 Chocimska Str., 00-791 Warsaw, Poland
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14
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Chen Y, Chen M, Wang J, Wu Q, Cheng J, Zhang J, Sun Q, Xue L, Zeng H, Lei T, Pang R, Ye Q, Wu S, Zhang S, Wu H, Li W, Kou X. Heterogeneity, Characteristics, and Public Health Implications of Listeria monocytogenes in Ready-to-Eat Foods and Pasteurized Milk in China. Front Microbiol 2020; 11:642. [PMID: 32351479 PMCID: PMC7174501 DOI: 10.3389/fmicb.2020.00642] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 03/20/2020] [Indexed: 12/20/2022] Open
Abstract
Listeria monocytogenes is a foodborne pathogen with a high mortality rate in humans. This study aimed to identify the pathogenic potential of L. monocytogenes isolated from ready-to-eat (RTE) foods and pasteurized milk in China on the basis of its phenotypic and genotypic characteristics. Approximately 7.7% (44/570) samples tested positive for L. monocytogenes among 10.8% (39/360) RTE and 2.4% (5/210) pasteurized milk samples, of which 77.3% (34/44) had < 10 MPN/g, 18.2% (8/44) had 10-110 MPN/g, and 4.5% (2/44) had > 110 MPN/g. A total of 48 strains (43 from RTE foods and five from milk samples) of L. monocytogenes were isolated from 44 positive samples. PCR-serogroup analysis revealed that the most prevalent serogroup was II.2 (1/2b-3b-7), accounting for 52.1% (25/48) of the total, followed by serogroup I.1 (1/2a-3a) accounting for 33.3% (16/48), serogroup I.2 (1/2c-3c) accounting for 12.5% (6/48), and serogroup II.1 (4b-4d-4e) accounting for 2.1%. All isolates were grouped into 11 sequence types (STs) belonging to 10 clonal complexes (CCs) and one singleton (ST619) via multi-locus sequence typing. The most prevalent ST was ST87 (29.2%), followed by ST8 (22.9%), and ST9 (12.5%). Virulence genes determination showed that all isolates harbored eight virulence genes belonging to Listeria pathogenicity islands 1 (LIPI-1) (prfA, actA, hly, mpl, plcA, plcB, and iap) and inlB. Approximately 85.4% isolates carried full-length inlA, whereas seven isolates had premature stop codons in inlA, six of which belonged to ST9 and one to ST5. Furthermore, LLS (encoded by llsX gene, representing LIPI-3) displays bactericidal activity and modifies the host microbiota during infection. LIPI-4 enhances neural and placental tropisms of L. monocytogenes. Results showed that six (12.5%) isolates harbored the llsX gene, and they belonged to ST1/CC1, ST3/CC3, and ST619. Approximately 31.3% (15/48) isolates (belonging to ST87/CC87 and ST619) harbored ptsA (representing LIPI-4), indicating the potential risk of this pathogen. Antimicrobial susceptibility tests revealed that > 95% isolates were susceptible to 16 antimicrobials; however, 60.4 and 22.9% isolates were intermediately resistant to streptomycin and ciprofloxacin, respectively. The results show that several isolates harbor LIPI-3 and LIPI-4 genes, which may be a possible transmission route for Listeria infections in consumers.
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Affiliation(s)
- Yuetao Chen
- College of Food Science, South China Agricultural University, Guangzhou, China
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Moutong Chen
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Juan Wang
- College of Food Science, South China Agricultural University, Guangzhou, China
| | - Qingping Wu
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Jianheng Cheng
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Jumei Zhang
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Qifan Sun
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Liang Xue
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Haiyan Zeng
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Tao Lei
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Rui Pang
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Qinghua Ye
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Shi Wu
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Shuhong Zhang
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Haoming Wu
- Guangdong Institute of Microbiology, Guangdong Academic of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Wenzhi Li
- Infinitus (China) Company, Ltd., Guangzhou, China
| | - Xiuying Kou
- Infinitus (China) Company, Ltd., Guangzhou, China
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15
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The Response to Oxidative Stress in Listeria monocytogenes Is Temperature Dependent. Microorganisms 2020; 8:microorganisms8040521. [PMID: 32260575 PMCID: PMC7232520 DOI: 10.3390/microorganisms8040521] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/30/2020] [Accepted: 04/03/2020] [Indexed: 11/24/2022] Open
Abstract
The stress response of 11 strains of Listeria monocytogenes to oxidative stress was studied. The strains included ST1, ST5, ST7, ST6, ST9, ST87, ST199 and ST321 and were isolated from diverse food processing environments (a meat factory, a dairy plant and a seafood company) and sample types (floor, wall, drain, boxes, food products and water machine). Isolates were exposed to two oxidizing agents: 13.8 mM cumene hydroperoxide (CHP) and 100 mM hydrogen peroxide (H2O2) at 10 °C and 37 °C. Temperature affected the oxidative stress response as cells treated at 10 °C survived better than those treated at 37 °C. H2O2 at 37 °C was the condition tested resulting in poorest L. monocytogenes survival. Strains belonging to STs of Lineage I (ST5, ST6, ST87, ST1) were more resistant to oxidative stress than those of Lineage II (ST7, ST9, ST199 and ST321), with the exception of ST7 that showed tolerance to H2O2 at 10 °C. Isolates of each ST5 and ST9 from different food industry origins showed differences in oxidative stress response. The gene expression of two relevant virulence (hly) and stress (clpC) genes was studied in representative isolates in the stressful conditions. hly and clpC were upregulated during oxidative stress at low temperature. Our results indicate that conditions prevalent in food industries may allow L. monocytogenes to develop survival strategies: these include activating molecular mechanisms based on cross protection that can promote virulence, possibly increasing the risk of virulent strains persisting in food processing plants.
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16
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López-Alonso V, Ortiz S, Corujo A, Martínez-Suárez JV. Analysis of Benzalkonium Chloride Resistance and Potential Virulence of Listeria monocytogenes Isolates Obtained from Different Stages of a Poultry Production Chain in Spain. J Food Prot 2020; 83:443-451. [PMID: 32053831 DOI: 10.4315/0362-028x.jfp-19-289] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 11/12/2019] [Indexed: 01/30/2023]
Abstract
ABSTRACT Listeria monocytogenes can survive in food production facilities and can be transmitted via contamination of food during the various stages of food production. This study was conducted to compile the results of three independent previous studies on the genetic diversity of L. monocytogenes in a poultry production company in Spain and to determine the potential virulence and sanitizer resistance of the strains by using both genotype and phenotype analyses. L. monocytogenes was detected at three production stages: a broiler abattoir, a processing plant, and retail stores marketing fresh poultry products from the same company. These three stages spanned three locations in three provinces of Spain. A set of 347 L. monocytogenes isolates representing 39 subtypes was obtained using pulsed-field gel electrophoresis (PFGE). A total of 28 subtypes (68%) had a full-length internalin A gene, and two subtypes had a phenotype with low potential for virulence because of a mutation in the prfA gene. A total of 32 subtypes (82%) were classified as benzalkonium chloride resistant (BAC-R) and contained the resistance determinant bcrABC (21 subtypes, 54%) or the resistance gene qacH (11 subtypes, 28%). A total of 13 persistent BAC-R subtypes (minimum of 3 months between the first and last sample from with the isolate was recovered) were identified at the abattoir and processing plant. The three production stages shared a unique subtype (PFGE type 1), which had the mutation in the prfA gene and the bcrABC resistance determinant. Whole genome sequencing revealed this subtype to be sequence type 31. Limited genetic diversity was noted in the isolates studied, including some subtypes that were persistent in the environment of the investigated facilities. Given the high prevalence of BAC-R subtypes, these results support the association between resistance to biocides and persistence of L. monocytogenes. HIGHLIGHTS
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Affiliation(s)
- Victoria López-Alonso
- Unidad de Biología Computacional, UFIEC, Instituto de Salud Carlos III, Carretera de Majadahonda a Pozuelo km 2, 28220 Majadahonda, Madrid, Spain
| | - Sagrario Ortiz
- Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Autovía A-6 km 7.5, 28040 Madrid, Spain
| | - Alfredo Corujo
- Nutreco Food Research Center, Ctra. CM 4004 km 10.5, 45950 Casarrubios del Monte, Toledo, Spain
| | - Joaquín V Martínez-Suárez
- Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Autovía A-6 km 7.5, 28040 Madrid, Spain.,(ORCID: https://orcid.org/0000-0003-4306-3223 [J.V.M.-S.])
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17
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Taylor AJ, Stasiewicz MJ. Persistent and sporadic Listeria monocytogenes strains do not differ when growing at 37 °C, in planktonic state, under different food associated stresses or energy sources. BMC Microbiol 2019; 19:257. [PMID: 31744459 PMCID: PMC6862832 DOI: 10.1186/s12866-019-1631-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 10/29/2019] [Indexed: 02/06/2023] Open
Abstract
Background The foodborne pathogen Listeria monocytogenes causes the potentially lethal disease listeriosis. Within food-associated environments, L. monocytogenes can persist for long periods and increase the risk of contamination by continued presence in processing facilities or other food-associated environments. Most research on phenotyping of persistent L. monocytogenes’ has explored biofilm formation and sanitizer resistance, with less data examining persistent L. monocytogenes’ phenotypic responses to extrinsic factors, such as variations in osmotic pressure, pH, and energy source availability. It was hypothesized that isolates of persistent strains are able to grow, and grow faster, under a broader range of intrinsic and extrinsic factors compared to closely related isolates of sporadic strains. Results To test this hypothesis, 95 isolates (representing 74 isolates of 20 persistent strains and 21 isolates of sporadic strains) from a series of previous studies in retail delis, were grown at 37 °C, in (i) stress conditions: salt (0, 5, and 10% NaCl), pH (5.2, 7.2, and 9.2), and sanitizer (benzalkonium chloride, 0, 2, and 5 μg/mL) and (ii) energy sources: 25 mM glucose, cellobiose, glycogen, fructose, lactose, and sucrose; the original goal was to follow up with low temperature experiments for treatments where significant differences were observed. Growth rate and the ability to grow of 95 isolates were determined using high-throughput, OD600, growth curves. All stress conditions reduced growth rates in isolates compared to control (p < 0.05). In addition, growth varied by the tested energy sources. In chemically defined, minimal media there was a trend toward more isolates showing growth in all replicates using cellobiose (p = 0.052) compared to the control (glucose) and fewer isolates able to grow in glycogen (p = 0.02), lactose (p = 2.2 × 10− 16), and sucrose (p = 2.2 × 10− 16). Still, at least one isolate was able to consistently grow in every replicate for each energy source. Conclusions The central hypothesis was rejected, as there was not a significant difference in growth rate or ability to grow for retail deli isolates of persistent strains compared to sporadic strains for any treatments at 37 °C. Therefore, these data suggest that persistence is likely not determined by a phenotype unique to persistent strains grown at 37 °C and exposed to extrinsic stresses or variation in energy sources.
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Affiliation(s)
- Alexander J Taylor
- Department of Food Science and Human Nutrition, College of Agricultural, Consumer, and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Matthew J Stasiewicz
- Department of Food Science and Human Nutrition, College of Agricultural, Consumer, and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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18
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Capita R, Felices-Mercado A, García-Fernández C, Alonso-Calleja C. Characterization of Listeria Monocytogenes Originating from the Spanish Meat-Processing Chain. Foods 2019; 8:E542. [PMID: 31684121 PMCID: PMC6915328 DOI: 10.3390/foods8110542] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/16/2022] Open
Abstract
Using agglutination techniques, 118 Listeria monocytogenes isolates from red meat and poultry were serotyped. Strains were ascribed to the serotypes 4b/4e (44.1% of the strains), 1/2 (a, b or c; 28.0%), 4c (6.8%), 4d/4e (5.9%) and 3 (a, b or c; 2.5%). Among these are the serotypes most frequently involved in cases of human listeriosis. The susceptibility of 72 strains to 26 antibiotics of clinical importance was determined by disc diffusion (Clinical and Laboratory Standards Institute; CLSI). High levels of resistance were observed to cefoxitin (77.8% of the strains showed resistance), cefotaxime (62.5%), cefepime (73.6%), and nalidixic acid (97.2%), nitrofurantoin (51.4%) and oxacillin (93.1%). Less than 3% of the strains showed resistance to the antibiotic classes used in human listeriosis therapy (i.e., ampicillin, gentamicin, rifampicin, chloramphenicol, enrofloxacin, vancomycin, trimethoprim-sulfamethoxazole, erythromycin, and tetracycline). The influence of species and serotype on the growth kinetics (modified Gompertz equation) and on the adhesion ability (crystal violet staining) of nine isolates of L. monocytogenes (serotypes 1/2a, 1/2b, 1/2c, 3a, 3b, 3c, 4a, 4b, and 4d), and one strain of Listeria ivanovii were investigated. The maximum growth rate (ΔOD420-580/h) varied between 0.073 ± 0.018 (L. monocytogenes 1/2a) and 0.396 ± 0.026 (L. monocytogenes 4b). The isolates of L. monocytogenes belonging to serotypes 3a and 4a, as well as L. ivanovii, showed a greater (p < 0.05) biofilm-forming ability than did the remaining strains, including those that belong to the serotypes commonly implied in human listeriosis (1/2a, 1/2b, 1/2c and 4b). The need for training in good hygiene practices during the handling of meat and poultry is highlighted to reduce the risk of human listeriosis.
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Affiliation(s)
- Rosa Capita
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, León E-24071, Spain.
- Institute of Food Science and Technology, University of León, León E-24071, Spain.
| | - Amanda Felices-Mercado
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, León E-24071, Spain.
| | - Camino García-Fernández
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, León E-24071, Spain.
- Institute of Food Science and Technology, University of León, León E-24071, Spain.
| | - Carlos Alonso-Calleja
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, León E-24071, Spain.
- Institute of Food Science and Technology, University of León, León E-24071, Spain.
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19
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Manso B, Melero B, Stessl B, Fernández-Natal I, Jaime I, Hernández M, Wagner M, Rovira J, Rodríguez-Lázaro D. Characterization of Virulence and Persistence Abilities of Listeria monocytogenes Strains Isolated from Food Processing Premises. J Food Prot 2019; 82:1922-1930. [PMID: 31633423 DOI: 10.4315/0362-028x.jfp-19-109] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We report the characterization of 15 Listeria monocytogenes strains isolated from various food processing plants by multivirulence locus sequence typing to determine virulence types (VTs) and epidemic clones. Molecular mechanisms involved in adaptation to food processing environments and related to virulence were also studied. Phenotypic behaviors associated with various antimicrobials, biofilm formations, and invasiveness were assessed. There were 11 VTs among the 15 L. monocytogenes strains. Strains belonging to six VTs were stress survival islet 1 (SSI-1) and one strain of VT94 was SSI-2. Tn6188 was found in VT6 and VT94 strains, and bcrABC cassette genes were identified in VT21, VT60, and VT63 strains. Only one strain, in VT20, showed llxS, whereas a full-size inlA was detected in strains belonging to VT8, VT20, VT21, and VT63. VT10, VT20, VT21, VT60, and VT63 strains were the most tolerant to studied disinfectants. A VT6 strain showed the strongest biofilm formation ability in polyvinyl chloride, and strains belonging to VT10, VT11, VT20, and VT94 had moderate abilities. Antimicrobial sensitivity tests showed that all the L. monocytogenes strains were multidrug resistant. F tests revealed that only strains of VT10, VT60, and VT94 were significantly noninvasive (P < 0.05) in Caco-2 cells. Our findings illustrate how L. monocytogenes isolates exploit diverse mechanisms to adapt to adverse conditions. Consequently, detailed characterization of L. monocytogenes isolates is required for comprehensive elimination of this pathogenic bacterium in food processing environments.
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Affiliation(s)
- Beatriz Manso
- Department of Biotechnology and Food Science, Faculty of Sciences, University of Burgos, Burgos, Spain (ORCID. https://orcid.org/0000-0002-8795-854X [D.R.-L.])
| | - Beatriz Melero
- Department of Biotechnology and Food Science, Faculty of Sciences, University of Burgos, Burgos, Spain (ORCID. https://orcid.org/0000-0002-8795-854X [D.R.-L.])
| | - Beatrix Stessl
- Institute of Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.,Christian Doppler Laboratory for Molecular Food Analytics, University of Veterinary Medicine, Vienna, Austria
| | - Isabel Fernández-Natal
- Complejo Asistencial, University of León, Leon, Spain.,Institute of Biomedicine (IBIOMED), University of León, Leon, Spain
| | - Isabel Jaime
- Department of Biotechnology and Food Science, Faculty of Sciences, University of Burgos, Burgos, Spain (ORCID. https://orcid.org/0000-0002-8795-854X [D.R.-L.])
| | - Marta Hernández
- Department of Biotechnology and Food Science, Faculty of Sciences, University of Burgos, Burgos, Spain (ORCID. https://orcid.org/0000-0002-8795-854X [D.R.-L.]).,Laboratory of Molecular Biology and Microbiology, Instituto Tecnológico Agrario de Castilla y León (ITACyL), Valladolid, Spain
| | - Martin Wagner
- Institute of Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.,Christian Doppler Laboratory for Molecular Food Analytics, University of Veterinary Medicine, Vienna, Austria
| | - Jordi Rovira
- Department of Biotechnology and Food Science, Faculty of Sciences, University of Burgos, Burgos, Spain (ORCID. https://orcid.org/0000-0002-8795-854X [D.R.-L.])
| | - David Rodríguez-Lázaro
- Department of Biotechnology and Food Science, Faculty of Sciences, University of Burgos, Burgos, Spain (ORCID. https://orcid.org/0000-0002-8795-854X [D.R.-L.])
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Jansen W, Müller A, Grabowski NT, Kehrenberg C, Muylkens B, Al Dahouk S. Foodborne diseases do not respect borders: Zoonotic pathogens and antimicrobial resistant bacteria in food products of animal origin illegally imported into the European Union. Vet J 2019; 244:75-82. [DOI: 10.1016/j.tvjl.2018.12.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 08/14/2018] [Accepted: 12/07/2018] [Indexed: 12/17/2022]
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22
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Chen M, Cheng J, Wu Q, Zhang J, Chen Y, Xue L, Lei T, Zeng H, Wu S, Ye Q, Bai J, Wang J. Occurrence, Antibiotic Resistance, and Population Diversity of Listeria monocytogenes Isolated From Fresh Aquatic Products in China. Front Microbiol 2018; 9:2215. [PMID: 30283429 PMCID: PMC6157410 DOI: 10.3389/fmicb.2018.02215] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/30/2018] [Indexed: 12/14/2022] Open
Abstract
Listeria monocytogenes is an important Gram-positive foodborne pathogen. However, limited information is available on the comprehensive investigation and potential risk of L. monocytogenes in fresh aquatic products, which are popular to consumers in China. This study aimed to determine the occurrence, virulence profiles, and population diversity of L. monocytogenes isolated from aquatic products in China. In total, 846 aquatic product samples were collected between July 2011 and April 2016 from 43 cities in China. Approximately 7.92% (67/846) aquatic product samples were positive for L. monocytogenes, 86.57% positive samples ranged from 0.3 to 10 MPN/g, whereas 5.97% showed over 110 MPN/g by the Most Probable Number method, which included two samples of products intended to be eaten raw. Serogroups I.1 (serotype 1/2a), I.2 (serotype 1/2b), and III (serotype 4c) were the predominant serogroups isolated, whereas serogroup II.1 (serotype 4b) was detected at much lower frequencies. Examination of antibacterial resistance showed that nine antibacterial resistance profiles were exhibited in 72 isolates, a high level susceptibility of 16 tested antibiotics against L. monocytogenes were observed, indicating these common antibacterial agents are still effective for treating L. monocytogenes infection. Multilocus sequence typing revealed that ST299, ST87, and ST8 are predominant in aquatic products, indicating that the rare ST299 (serotype 4c) may have a special ecological niche in aquatic products and associated environments. Except llsX and ptsA, the 72 isolates harbor nine virulence genes (prfA, actA, hly, plcA, plcB, iap, mpl, inlA, and inlB), premature stop codons (PMSCs) in inlA were found in four isolates, three of which belonged to ST9. A novel PMSC was found in 2929-1LM with a nonsense mutation at position 1605 (TGG→TGA). All ST87 isolates harbored the ptsA gene, whereas 8 isolates (11.11%) carried the llsX gene, and mainly belonged to ST1, ST3, ST308, ST323, ST330, and ST619. Taken together, these results first reported potential virulent L. monocytogenes isolates (ST8 and ST87) were predominant in aquatic products which may have implications for public health in China. It is thus necessary to perform continuous surveillance for L. monocytogenes in aquatic products in China.
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Affiliation(s)
- Moutong Chen
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Jianheng Cheng
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Jumei Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Yuetao Chen
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
- College of Food Science, South China Agricultural University, Guangzhou, China
| | - Liang Xue
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Tao Lei
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Haiyan Zeng
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Shi Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Qinghua Ye
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Jianling Bai
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Juan Wang
- College of Food Science, South China Agricultural University, Guangzhou, China
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23
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Rychli K, Stessl B, Szakmary-Brändle K, Strauß A, Wagner M, Schoder D. Listeria monocytogenes Isolated from Illegally Imported Food Products into the European Union Harbor Different Virulence Factor Variants. Genes (Basel) 2018; 9:E428. [PMID: 30142903 PMCID: PMC6162745 DOI: 10.3390/genes9090428] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/13/2018] [Accepted: 08/20/2018] [Indexed: 12/11/2022] Open
Abstract
Unregulated international flow of foods poses a danger to human health, as it may be contaminated with pathogens. Recent studies have investigated neglected routes of pathogen transmission and reported the occurrence of Listeria monocytogenes in food illegally imported into the European Union (EU), either confiscated at four international airports or sold illegally on the Romanian black market. In this study we investigated the genotype diversity and the amino acid sequence variability of three main virulence factors of 57 L. monocytogenes isolates. These isolates were derived from 1474 food samples illegally imported into the EU and originated from 17 different countries. Multilocus sequence typing revealed 16 different sequence types (STs) indicating moderate genotype diversity. The most prevalent STs were ST2, ST9, and ST121. The pulsed-field gel electrophoresis (PFGE) analysis resulted in 34 unique pulsotypes. PFGE types assigned to the most prevalent STs (ST2, ST9, and ST121) were highly related in their genetic fingerprint. Internalin A (InlA) was present in 20 variants, including six truncated InlA variants, all harbored by isolates of ST9 and ST121. We detected eight ST-specific listeriolysin O (LLO) variants, and among them, one truncated form. The actin-assembly-inducing protein ActA was present in 15 different ST-specific variants, including four ActA variants with an internal truncation. In conclusion, this study shows that L. monocytogenes, isolated from illegally imported food, have moderate genotype diversity, but diverse virulence factors variants, mainly of InlA.
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Affiliation(s)
- Kathrin Rychli
- Institute of Milk Hygiene, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
| | - Beatrix Stessl
- Institute of Milk Hygiene, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
| | - Kati Szakmary-Brändle
- Institute of Milk Hygiene, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
| | - Anja Strauß
- Institute of Milk Hygiene, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
| | - Martin Wagner
- Institute of Milk Hygiene, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
| | - Dagmar Schoder
- Institute of Milk Hygiene, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
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24
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Muhterem-Uyar M, Ciolacu L, Wagner KH, Wagner M, Schmitz-Esser S, Stessl B. New Aspects on Listeria monocytogenes ST5-ECVI Predominance in a Heavily Contaminated Cheese Processing Environment. Front Microbiol 2018; 9:64. [PMID: 29472901 PMCID: PMC5810274 DOI: 10.3389/fmicb.2018.00064] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/10/2018] [Indexed: 01/25/2023] Open
Abstract
The eradication of Listeria monocytogenes from food chains is still a great challenge for the food industry and control authorities since some clonal complexes (CCs) are either better adapted to food processing environments (FPEs) or are globally widespread. In this work, we focus on the in-house evolution of L. monocytogenes genotypes collected from a heavily contaminated FPE whose contamination pattern underwent a massive and yet unexplained change. At the beginning of the sampling in 2010, a high variety of most likely transient L. monocytogenes genotypes was detected belonging to sequence type (ST) 1, ST7, ST21, ST37. After several efforts to intensify the hygiene measures, the variability was reduced to L. monocytogenes ST5 that was dominant in the following years 2011 and 2012. We aimed to elucidate possible genetic mechanisms responsible for the high abundance and persistence of ST5 strains in this FPE. Therefore, we compared the genomes of six L. monocytogenes ST5 strains to the less frequently occurring transient L. monocytogenes ST37 and ST204 from the same FPE as well as the highly abundant ST1 and ST21 isolated in 2010. Whole genome analysis indicated a high degree of conservation among ST5 strains [average nucleotide identity (ANI) 99.93-99.99%; tetranucleotide correlation 0.99998-0.99999]. Slight differences in pulsed field gel electrophoresis (PFGE) patterns of two ST5 isolates could be explained by genetic changes in the tRNA-Arg-TCT prophages. ST5 and ST204 strains harbored virtually identical 91 kbp plasmids related to plasmid group 2 (pLM80 and pLMUCDL175). Interestingly, highly abundant genotypes present in the FPE in 2010 did not harbor any plasmids. The ST5 plasmids harbored an efflux pump system (bcrABC cassette) and heavy metal resistance genes possibly providing a higher tolerance to disinfectants. The pLM80 prototype plasmids most likely provide important genetic determinants for a better survival of L. monocytogenes in the FPE. We reveal short-term evolution of L. monocytogenes strains within the same FPE over a 3 year period and our results suggest that plasmids are important for the persistence of ST5 strains in this FPE.
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Affiliation(s)
- Meryem Muhterem-Uyar
- Department for Farm Animals and Veterinary Public Health, Institute of Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria.,Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | - Luminita Ciolacu
- Department for Farm Animals and Veterinary Public Health, Institute of Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria
| | - Karl-Heinz Wagner
- Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | - Martin Wagner
- Department for Farm Animals and Veterinary Public Health, Institute of Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria
| | - Stephan Schmitz-Esser
- Department for Farm Animals and Veterinary Public Health, Institute of Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria.,Department of Animal Science, Iowa State University, Ames, IA, United States
| | - Beatrix Stessl
- Department for Farm Animals and Veterinary Public Health, Institute of Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria
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25
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Knudsen GM, Nielsen JB, Marvig RL, Ng Y, Worning P, Westh H, Gram L. Genome-wide-analyses of Listeria monocytogenes from food-processing plants reveal clonal diversity and date the emergence of persisting sequence types. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:428-440. [PMID: 28574206 DOI: 10.1111/1758-2229.12552] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 05/27/2017] [Indexed: 06/07/2023]
Abstract
Whole genome sequencing is increasing used in epidemiology, e.g. for tracing outbreaks of food-borne diseases. This requires in-depth understanding of pathogen emergence, persistence and genomic diversity along the food production chain including in food processing plants. We sequenced the genomes of 80 isolates of Listeria monocytogenes sampled from Danish food processing plants over a time-period of 20 years, and analysed the sequences together with 10 public available reference genomes to advance our understanding of interplant and intraplant genomic diversity of L. monocytogenes. Except for three persisting sequence types (ST) based on Multi Locus Sequence Typing being ST7, ST8 and ST121, long-term persistence of clonal groups was limited, and new clones were introduced continuously, potentially from raw materials. No particular gene could be linked to the persistence phenotype. Using time-based phylogenetic analyses of the persistent STs, we estimate the L. monocytogenes evolutionary rate to be 0.18-0.35 single nucleotide polymorphisms/year, suggesting that the persistent STs emerged approximately 100 years ago, which correlates with the onset of industrialization and globalization of the food market.
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Affiliation(s)
- Gitte M Knudsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Jesper Boye Nielsen
- Department of Clinical Microbiology, Hvidovre Hospital, MRSA KnowledgeCenter, Hvidovre, Denmark
| | - Rasmus L Marvig
- Center for Genomic Medicine, Rigshospitalet, Copenhagen, Denmark
| | - Yin Ng
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Peder Worning
- Department of Clinical Microbiology, Hvidovre Hospital, MRSA KnowledgeCenter, Hvidovre, Denmark
| | - Henrik Westh
- Department of Clinical Microbiology, Hvidovre Hospital, MRSA KnowledgeCenter, Hvidovre, Denmark
- Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
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26
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Rychli K, Wagner EM, Ciolacu L, Zaiser A, Tasara T, Wagner M, Schmitz-Esser S. Comparative genomics of human and non-human Listeria monocytogenes sequence type 121 strains. PLoS One 2017; 12:e0176857. [PMID: 28472116 PMCID: PMC5417603 DOI: 10.1371/journal.pone.0176857] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 04/18/2017] [Indexed: 01/01/2023] Open
Abstract
The food-borne pathogen Listeria (L.) monocytogenes is able to survive for months and even years in food production environments. Strains belonging to sequence type (ST)121 are particularly found to be abundant and to persist in food and food production environments. To elucidate genetic determinants characteristic for L. monocytogenes ST121, we sequenced the genomes of 14 ST121 strains and compared them with currently available L. monocytogenes ST121 genomes. In total, we analyzed 70 ST121 genomes deriving from 16 different countries, different years of isolation, and different origins—including food, animal and human ST121 isolates. All ST121 genomes show a high degree of conservation sharing at least 99.7% average nucleotide identity. The main differences between the strains were found in prophage content and prophage conservation. We also detected distinct highly conserved subtypes of prophages inserted at the same genomic locus. While some of the prophages showed more than 99.9% similarity between strains from different sources and years, other prophages showed a higher level of diversity. 81.4% of the strains harbored virtually identical plasmids. 97.1% of the ST121 strains contain a truncated internalin A (inlA) gene. Only one of the seven human ST121 isolates encodes a full-length inlA gene, illustrating the need of better understanding their survival and virulence mechanisms.
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Affiliation(s)
- Kathrin Rychli
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Wien, Austria
| | - Eva M. Wagner
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Wien, Austria
| | - Luminita Ciolacu
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Wien, Austria
| | - Andreas Zaiser
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Wien, Austria
| | - Taurai Tasara
- Vetsuisse Faculty, Institute for Food Safety and Hygiene, University of Zurich, Zurich, Switzerland
| | - Martin Wagner
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Wien, Austria
| | - Stephan Schmitz-Esser
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Wien, Austria
- * E-mail:
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27
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Chau ML, Aung KT, Hapuarachchi HC, Lee PSV, Lim PY, Kang JSL, Ng Y, Yap HM, Yuk HG, Gutiérrez RA, Ng LC. Microbial survey of ready-to-eat salad ingredients sold at retail reveals the occurrence and the persistence of Listeria monocytogenes Sequence Types 2 and 87 in pre-packed smoked salmon. BMC Microbiol 2017; 17:46. [PMID: 28245788 PMCID: PMC5331722 DOI: 10.1186/s12866-017-0956-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 02/14/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND As the preparation of salads involves extensive handling and the use of uncooked ingredients, they are particularly vulnerable to microbial contamination. This study aimed to determine the microbial safety and quality of pre-packed salads and salad bar ingredients sold in Singapore, so as to identify public health risks that could arise from consuming salads and to determine areas for improvement in the management of food safety. RESULTS The most frequently encountered organism in pre-packed salad samples was B. cereus, particularly in pasta salads (33.3%, 10/30). The most commonly detected organism in salad bar ingredients was L. monocytogenes, in particular seafood ingredients (44.1%, 15/34), largely due to contaminated smoked salmon. Further investigation showed that 21.6% (37/171) of the pre-packed smoked salmon sold in supermarkets contained L. monocytogenes. Significantly higher prevalence of L. monocytogenes and higher Standard Plate Count were detected in smoked salmon at salad bars compared to pre-packed smoked salmon in supermarkets, which suggested multiplication of the organism as the products move down the supply chain. Further molecular analysis revealed that L. monocytogenes Sequence Type (ST) 2 and ST87 were present in a particular brand of pre-packed salmon products over a 4-year period, implying a potential persistent contamination problem at the manufacturing level. CONCLUSIONS Our findings highlighted a need to improve manufacturing and retail hygiene processes as well as to educate vulnerable populations to avoid consuming food prone to L. monocytogenes contamination.
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Affiliation(s)
- Man Ling Chau
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Kyaw Thu Aung
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | | | - Pei Sze Valarie Lee
- Department of Chemistry, Food Science and Technology Programme, National University of Singapore, 3 Science Drive 3, Singapore, 117543 Singapore
| | - Pei Ying Lim
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
| | - Joanne Su Lin Kang
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Youming Ng
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Hooi Ming Yap
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Hyun-Gyun Yuk
- Department of Chemistry, Food Science and Technology Programme, National University of Singapore, 3 Science Drive 3, Singapore, 117543 Singapore
| | - Ramona Alikiiteaga Gutiérrez
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Lee Ching Ng
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
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28
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Fagerlund A, Langsrud S, Schirmer BCT, Møretrø T, Heir E. Genome Analysis of Listeria monocytogenes Sequence Type 8 Strains Persisting in Salmon and Poultry Processing Environments and Comparison with Related Strains. PLoS One 2016; 11:e0151117. [PMID: 26953695 PMCID: PMC4783014 DOI: 10.1371/journal.pone.0151117] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/22/2016] [Indexed: 12/19/2022] Open
Abstract
Listeria monocytogenes is an important foodborne pathogen responsible for the disease listeriosis, and can be found throughout the environment, in many foods and in food processing facilities. The main cause of listeriosis is consumption of food contaminated from sources in food processing environments. Persistence in food processing facilities has previously been shown for the L. monocytogenes sequence type (ST) 8 subtype. In the current study, five ST8 strains were subjected to whole-genome sequencing and compared with five additionally available ST8 genomes, allowing comparison of strains from salmon, poultry and cheese industry, in addition to a human clinical isolate. Genome-wide analysis of single-nucleotide polymorphisms (SNPs) confirmed that almost identical strains were detected in a Danish salmon processing plant in 1996 and in a Norwegian salmon processing plant in 2001 and 2011. Furthermore, we show that L. monocytogenes ST8 was likely to have been transferred between two poultry processing plants as a result of relocation of processing equipment. The SNP data were used to infer the phylogeny of the ST8 strains, separating them into two main genetic groups. Within each group, the plasmid and prophage content was almost entirely conserved, but between groups, these sequences showed strong divergence. The accessory genome of the ST8 strains harbored genetic elements which could be involved in rendering the ST8 strains resilient to incoming mobile genetic elements. These included two restriction-modification loci, one of which was predicted to show phase variable recognition sequence specificity through site-specific domain shuffling. Analysis indicated that the ST8 strains harbor all important known L. monocytogenes virulence factors, and ST8 strains are commonly identified as the causative agents of invasive listeriosis. Therefore, the persistence of this L. monocytogenes subtype in food processing facilities poses a significant concern for food safety.
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Affiliation(s)
- Annette Fagerlund
- Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
- * E-mail:
| | - Solveig Langsrud
- Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
| | - Bjørn C. T. Schirmer
- Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
| | - Trond Møretrø
- Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
| | - Even Heir
- Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
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29
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Wu S, Wu Q, Zhang J, Chen M, Guo W. Analysis of Multilocus Sequence Typing and Virulence Characterization of Listeria monocytogenes Isolates from Chinese Retail Ready-to-Eat Food. Front Microbiol 2016; 7:168. [PMID: 26909076 PMCID: PMC4754575 DOI: 10.3389/fmicb.2016.00168] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 02/01/2016] [Indexed: 11/13/2022] Open
Abstract
Eighty Listeria monocytogenes isolates were obtained from Chinese retail ready-to-eat (RTE) food and were previously characterized with serotyping and antibiotic susceptibility tests. The aim of this study was to characterize the subtype and virulence potential of these L. monocytogenes isolates by multilocus sequence typing (MLST), virulence-associate genes, epidemic clones (ECs), and sequence analysis of the important virulence factor: internalin A (inlA). The result of MLST revealed that these L. monocytogenes isolates belonged to 14 different sequence types (STs). With the exception of four new STs (ST804, ST805, ST806, and ST807), all other STs observed in this study have been associated with human listeriosis and outbreaks to varying extents. Six virulence-associate genes (inlA, inlB, inlC, inlJ, hly, and llsX) were selected and their presence was investigated using PCR. All strains carried inlA, inlB, inlC, inlJ, and hly, whereas 38.8% (31/80) of strains harbored the listeriolysin S genes (llsX). A multiplex PCR assay was used to evaluate the presence of markers specific to epidemic clones of L. monocytogenes and identified 26.3% (21/80) of ECI in the 4b-4d-4e strains. Further study of inlA sequencing revealed that most strains contained the full-length InlA required for host cell invasion, whereas three mutations lead to premature stop codons (PMSC) within a novel PMSCs at position 326 (GAA → TAA). MLST and inlA sequence analysis results were concordant, and different virulence potentials within isolates were observed. These findings suggest that L. monocytogenes isolates from RTE food in China could be virulent and be capable of causing human illness. Furthermore, the STs and virulence profiles of L. monocytogenes isolates have significant implications for epidemiological and public health studies of this pathogen.
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Affiliation(s)
- Shi Wu
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
- School of Bioscience and Bioengineering, South China University of TechnologyGuangzhou, China
| | - Qingping Wu
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
| | - Jumei Zhang
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
| | - Moutong Chen
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
| | - Weipeng Guo
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
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Ciolacu L, Stessl B, Bolocan AS, Oniciuc EA, Wagner M, Rychli K, Nicolau AI. Tracking Foodborne Pathogenic Bacteria in Raw and Ready-to-Eat Food Illegally Sold at the Eastern EU Border. Foodborne Pathog Dis 2016; 13:148-55. [PMID: 26741503 DOI: 10.1089/fpd.2015.2057] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Food illegally brought into the European Union, mainly in the personal luggage of travelers, represents a potential threat to consumers' health. The aim of this study was to investigate the presence of five pathogens in food brought into the European Union by Moldavian citizens as personal goods and illegally sold in Romania in the vicinity of the border. The occurrence of Staphylococcus aureus and Listeria monocytogenes was 7.5% and 8%, while Campylobacter spp., Escherichia coli O157:H7, and Salmonella spp. were absent in all samples. L. monocytogenes sequence type 2, 9, 121, and 155, highly prevalent among foodstuffs worldwide, was also present among isolates from ready-to-eat food illegally sold in Romania, even at the same date of sampling, indicating cross-contamination during food handling. S. aureus spa types t449, t304, and t524 were most often isolated from raw-milk cheeses contaminated with 10(3)-10(5) colony-forming units per gram, evidencing a contamination at herd level or unhygienic conditions during processing. S. aureus t011 and t3625, both included in the livestock-associated CC398, were isolated from pork lard and poultry meat. This study shows that cross-border trade from nonmember states represents a neglected route of transmission of foodborne pathogens into the European Union that could lead to sporadic or family-associated cases of disease.
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Affiliation(s)
- Luminita Ciolacu
- 1 Faculty of Food Science and Engineering, Dunarea de Jos University of Galati , Galati, Romania .,2 Institute for Milk Hygiene, University of Veterinary Medicine Vienna , Vienna, Austria
| | - Beatrix Stessl
- 2 Institute for Milk Hygiene, University of Veterinary Medicine Vienna , Vienna, Austria
| | - Andrei Sorin Bolocan
- 1 Faculty of Food Science and Engineering, Dunarea de Jos University of Galati , Galati, Romania
| | - Elena Alexandra Oniciuc
- 1 Faculty of Food Science and Engineering, Dunarea de Jos University of Galati , Galati, Romania
| | - Martin Wagner
- 2 Institute for Milk Hygiene, University of Veterinary Medicine Vienna , Vienna, Austria
| | - Kathrin Rychli
- 2 Institute for Milk Hygiene, University of Veterinary Medicine Vienna , Vienna, Austria
| | - Anca Ioana Nicolau
- 1 Faculty of Food Science and Engineering, Dunarea de Jos University of Galati , Galati, Romania
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Rychli K, Grunert T, Ciolacu L, Zaiser A, Razzazi-Fazeli E, Schmitz-Esser S, Ehling-Schulz M, Wagner M. Exoproteome analysis reveals higher abundance of proteins linked to alkaline stress in persistent Listeria monocytogenes strains. Int J Food Microbiol 2015; 218:17-26. [PMID: 26594790 DOI: 10.1016/j.ijfoodmicro.2015.11.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 11/04/2015] [Accepted: 11/08/2015] [Indexed: 01/24/2023]
Abstract
The foodborne pathogen Listeria monocytogenes, responsible for listeriosis a rare but severe infection disease, can survive in the food processing environment for month or even years. So-called persistent L. monocytogenes strains greatly increase the risk of (re)contamination of food products, and are therefore a great challenge for food safety. However, our understanding of the mechanism underlying persistence is still fragmented. In this study we compared the exoproteome of three persistent strains with the reference strain EGDe under mild stress conditions using 2D differential gel electrophoresis. Principal component analysis including all differentially abundant protein spots showed that the exoproteome of strain EGDe (sequence type (ST) 35) is distinct from that of the persistent strain R479a (ST8) and the two closely related ST121 strains 4423 and 6179. Phylogenetic analyses based on multilocus ST genes showed similar grouping of the strains. Comparing the exoproteome of strain EGDe and the three persistent strains resulted in identification of 22 differentially expressed protein spots corresponding to 16 proteins. Six proteins were significantly increased in the persistent L. monocytogenes exoproteomes, among them proteins involved in alkaline stress response (e.g. the membrane anchored lipoprotein Lmo2637 and the NADPH dehydrogenase NamA). In parallel the persistent strains showed increased survival under alkaline stress, which is often provided during cleaning and disinfection in the food processing environments. In addition, gene expression of the proteins linked to stress response (Lmo2637, NamA, Fhs and QoxA) was higher in the persistent strain not only at 37 °C but also at 10 °C. Invasion efficiency of EGDe was higher in intestinal epithelial Caco2 and macrophage-like THP1 cells compared to the persistent strains. Concurrently we found higher expression of proteins involved in virulence in EGDe e.g. the actin-assembly-inducing protein ActA and the surface virulence associated protein SvpA. Furthermore proteins involved in cell wall modification, such as the lipoteichonic acid primase LtaP and the N-acetylmuramoyl-l-alanine amidase (Lmo2591) are more abundant in EGDe than in the persistent strains and could indirectly contribute to virulence. In conclusion this study provides information about a set of proteins that could potentially support survival of L. monocytogenes in abiotic niches in food processing environments. Based on these data, a more detailed analysis of the role of the identified proteins under stresses mimicking conditions in food producing environment is essential for further elucidate the mechanism of the phenomenon of persistence of L. monocytogenes.
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Affiliation(s)
- Kathrin Rychli
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Tom Grunert
- Functional Microbiology, Institute of Microbiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Luminita Ciolacu
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria; "Dunarea de Jos" University of Galaţi, 47 Domneasca St., 800008 Galaţi, Romania.
| | - Andreas Zaiser
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Ebrahim Razzazi-Fazeli
- VetCORE facility for research, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Stephan Schmitz-Esser
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute of Microbiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Martin Wagner
- Institute for Milk Hygiene, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
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The Connection between Persistent, Disinfectant-Resistant Listeria monocytogenes Strains from Two Geographically Separate Iberian Pork Processing Plants: Evidence from Comparative Genome Analysis. Appl Environ Microbiol 2015; 82:308-17. [PMID: 26497458 DOI: 10.1128/aem.02824-15] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/17/2015] [Indexed: 02/07/2023] Open
Abstract
The aim of this study was to investigate the basis of the putative persistence of Listeria monocytogenes in a new industrial facility dedicated to the processing of ready-to-eat (RTE) Iberian pork products. Quaternary ammonium compounds, which included benzalkonium chloride (BAC), were repeatedly used as surface disinfectants in the processing plant. Clean and disinfected surfaces were sampled to evaluate if resistance to disinfectants was associated with persistence. Of the 14 isolates obtained from product contact and non-product contact surfaces, only five different pulsed-field gel electrophoresis (PFGE) types were identified during the 27-month study period. Two of these PFGE types (S1 and S10-1) were previously identified to be persistent and BAC-resistant (BAC(r)) strains in a geographically separate slaughterhouse belonging to the same company. The remaining three PFGE types, which were first identified in this study, were also BAC(r). Whole-genome sequencing and in silico multilocus sequence typing (MLST) analysis of five BAC(r) isolates of the different PFGE types identified in this study showed that the isolate of the S1 PFGE type belonged to MLST sequence type 31 (ST31), a low-virulence type characterized by mutations in the inlA and prfA genes. The isolates of the remaining four PFGE types were found to belong to MLST ST121, a persistent type that has been isolated in several countries. The ST121 strains contained the BAC resistance transposon Tn6188. The disinfection-resistant L. monocytogenes population in this RTE pork product plant comprised two distinct genotypes with different multidrug resistance phenotypes. This work offers insight into the L. monocytogenes subtypes associated with persistence in food processing environments.
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Occurrence, Persistence, and Virulence Potential of Listeria ivanovii in Foods and Food Processing Environments in the Republic of Ireland. BIOMED RESEARCH INTERNATIONAL 2015; 2015:350526. [PMID: 26543856 PMCID: PMC4620271 DOI: 10.1155/2015/350526] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 02/19/2015] [Indexed: 11/18/2022]
Abstract
The aim of this study was to assess the occurrence of L. ivanovii in foods and food processing environments in Ireland, to track persistence, and to characterize the disease causing potential of the isolated strains. A total of 2,006 samples (432 food samples and 1,574 environmental swabs) were collected between March 2013 and March 2014 from 48 food business operators (FBOs) belonging to different production sectors (dairy, fish, meat, and fresh-cut vegetable). Six of the forty-eight FBOs had samples positive for L. ivanovii on at least one sampling occasion. L. ivanovii was present in fifteen samples (fourteen environmental samples and one food sample). All but one of those positive samples derived from the dairy sector, where L. ivanovii prevalence was 1.7%. Six distinguishable pulsotypes were obtained by PFGE analysis, with one pulsotype being persistent in the environment of a dairy food business. Sequence analysis of the sigB gene showed that fourteen isolates belonged to L. ivanovii subsp. londoniensis, while only one isolate was L. ivanovii subsp. ivanovii. Cell invasion assays demonstrated that the majority of L. ivanovii strains were comparable to L. monocytogenes EGDe in their ability to invade CACO-2 epithelial cells whilst four isolates had significantly higher invasion efficiencies.
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