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The Production of Listeriolysin O and Subsequent Intracellular Infections by Listeria monocytogenes Are Regulated by Exogenous Short Chain Fatty Acid Mixtures. Toxins (Basel) 2020; 12:toxins12040218. [PMID: 32235519 PMCID: PMC7232371 DOI: 10.3390/toxins12040218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/24/2020] [Accepted: 03/26/2020] [Indexed: 12/14/2022] Open
Abstract
Listeria monocytogenes is a foodborne pathogen capable of secreting listeriolysin O (LLO), a pore-forming toxin encoded by the hly gene. While the functions of LLO have been studied extensively, how the production of LLO is modulated by the intestinal environment, devoid of oxygen and enriched in short chain fatty acids (SCFAs), is not completely understood. Using L. monocytogenes strain 10403s, we found that hly transcription was moderately decreased by aerobic SCFA exposures but significantly increased by anaerobic SCFA exposures. Moreover, aerobic, but not anaerobic, exposure to low levels of SCFAs resulted in a significantly higher LLO activity. These results demonstrated that transcriptional and post-transcriptional regulations of LLO production were separately modulated by SCFAs and were responsive to oxygen levels. Examining isogenic mutants revealed that PrfA and SigB play a role in regulating LLO production in response to SCFAs. Effects of SCFAs were also present in the cardiotropic strain 07PF0776 but distinctly different from those in strain 10403s. For both strains, prior exposures to SCFAs altered intracellular infections in Caco-2 and RAW264.7 cells and the plaque sizes in L fibroblasts, a result confirming the ability of L. monocytogenes to adapt to SCFAs in ways that impact its subsequent infection outcomes.
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Araujo V, Neves E, Silva AC, Martins APL, Brito LC. Listeria monocytogenes cells under nutrient deprivation showed reduced ability to infect the human intestinal cell line HT-29. J Med Microbiol 2017; 67:110-117. [PMID: 29185940 DOI: 10.1099/jmm.0.000648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE This study aimed to evaluate the effect of two types of stress, cold and nutritional, on the viability and the in vitro virulence of the foodborne pathogenic bacteria Listeria monocytogenes. METHODOLOGY Ten diverse isolates were kept in phosphate-buffered saline (PBS) at optimal (37 °C) or at refrigeration temperature (7 °C), for 1 and 7 days. The viability of the cells [log colony-forming units (c.f.u.)/ml] and their in vitro virulence, before and after storage in these conditions, were investigated. In vitro virulence (log PFA) was evaluated using the human intestinal epithelial cell line HT-29 in plaque-forming assays (PFAs).Results/Key findings. In general, when compared with the conditions at 37 °C, the exposure at 7 °C for 7 days seemed to increase the resistance of the isolates to nutritional stress. Nutritional stress per se acted significantly to decrease the in vitro virulence of the isolates. After 7 days of nutrient deprivation, whether at optimal or at refrigeration temperature, the majority of the isolates assumed a low-virulence phenotype. CONCLUSION Our results suggest that when L. monocytogenes are in refrigerated post-processing environments that are unable to support their growth they may increase their resistance to nutritional stress and may decrease their virulence. This should be considered when performing risk assessments for refrigerated ready-to-eat (RTE) foods.
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Affiliation(s)
- Vânia Araujo
- LEAF - Linking Landscape, Environment, Agriculture and Food /DRAT- Departamento dos Recursos Naturais, Ambiente e Território, Instituto Superior de Agronomia, University of Lisbon, 1349-017 Lisbon, Portugal
| | - Elsa Neves
- LEAF - Linking Landscape, Environment, Agriculture and Food /DRAT- Departamento dos Recursos Naturais, Ambiente e Território, Instituto Superior de Agronomia, University of Lisbon, 1349-017 Lisbon, Portugal.,Escola Superior de Tecnologia e Gestão Jean Piaget do Litoral Alentejano, Bairro das Flores, Apartado 38, 7500-999 Vila Nova de Santo André, Portugal
| | - Ana Carla Silva
- LEAF - Linking Landscape, Environment, Agriculture and Food /DRAT- Departamento dos Recursos Naturais, Ambiente e Território, Instituto Superior de Agronomia, University of Lisbon, 1349-017 Lisbon, Portugal
| | - António P L Martins
- Instituto Nacional de Investigação Agrária e Veterinária, IP, Av. República, Quinta do Marquês, Nova Oeiras, 2784-505 Oeiras, Portugal.,DCEB - Departamento de Ciências e Engenharia de Biossistemas, Instituto Superior de Agronomia, University of Lisbon, 1349-017 Lisbon, Portugal
| | - Luisa Castro Brito
- LEAF - Linking Landscape, Environment, Agriculture and Food /DRAT- Departamento dos Recursos Naturais, Ambiente e Território, Instituto Superior de Agronomia, University of Lisbon, 1349-017 Lisbon, Portugal
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Sansano S, Rivas A, Pina-Pérez M, Martinez A, Rodrigo D. Stevia rebaudiana Bertoni effect on the hemolytic potential of Listeria monocytogenes. Int J Food Microbiol 2017; 250:7-11. [DOI: 10.1016/j.ijfoodmicro.2017.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/07/2017] [Accepted: 03/10/2017] [Indexed: 01/13/2023]
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DYKES GARYA. IMAGE ANALYSIS OF COLONY SIZE FOR INVESTIGATING SUBLETHAL INJURY IN LISTERIA MONOCYTOGENES. ACTA ACUST UNITED AC 2011. [DOI: 10.1111/j.1745-4581.1999.tb00395.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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The role of the pH conditions of growth on the bioadhesion of individual and lawns of pathogenic Listeria monocytogenes cells. J Colloid Interface Sci 2011; 358:611-20. [PMID: 21459385 DOI: 10.1016/j.jcis.2011.03.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 03/06/2011] [Accepted: 03/08/2011] [Indexed: 11/22/2022]
Abstract
The work of adhesion that governs the interactions between pathogenic Listeria monocytogenes and silicon nitride in water was probed for individual cells using atomic force microscopy and for lawns of cells using contact angle measurements combined with a thermodynamic-based harmonic mean model. The work of adhesion was probed for cells cultured under variable pH conditions of growth that ranged from pH 5 to pH 9. Our results indicated that L. monocytogenes cells survived and adapted well to the chemical stresses applied. For all pH conditions investigated, a transition was observed in the generation time, physiochemical properties, biopolymer grafting density and bioadhesion for cells cultured in media adjusted to pH 7 of growth. In media with pH 7, the generation time for the bacterial cells was lowest, the specific growth rate constant was highest, the cells were the most polar, cells displayed the highest grafting density of surface biopolymers and the highest bioadhesion to silicon nitride in water represented in terms of the work of adhesion. When compared, the work of adhesion values quantified between silicon nitride and lawns of L. monocytogenes cells were linearly correlated with the work of adhesion values quantified between silicon nitride and individual L. monocytogenes cells.
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O'Bryan CA, Sostrin ML, Nannapaneni R, Ricke SC, Crandall PG, Johnson MG. Sensitivity of Listeria monocytogenes Scott A to Nisin and Diacetyl after Starvation in Sodium Phosphate Buffered Saline. J Food Sci 2009; 74:M493-8. [DOI: 10.1111/j.1750-3841.2009.01340.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Addition of bacteriocins to inhibitListeria monocytogenes in Toroi: a traditional food of New Zealand Mãori. ANN MICROBIOL 2008. [DOI: 10.1007/bf03175318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Olier M, Pierre F, Rousseaux S, Lemaître JP, Rousset A, Piveteau P, Guzzo J. Expression of truncated Internalin A is involved in impaired internalization of some Listeria monocytogenes isolates carried asymptomatically by humans. Infect Immun 2003; 71:1217-24. [PMID: 12595435 PMCID: PMC148840 DOI: 10.1128/iai.71.3.1217-1224.2003] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2002] [Revised: 09/24/2002] [Accepted: 11/08/2002] [Indexed: 11/20/2022] Open
Abstract
Fourteen human carriage Listeria monocytogenes isolates were compared to sporadic and epidemic-associated human strains in order to ascertain the pathogenic behavior of these unrecognized asymptomatic strains. Experimental infection of 14-day-old chick embryos revealed that the majority of the carriage strains were attenuated for virulence. Of the 10 attenuated carriage strains, 5 were affected in their invasion capacities in vitro. Western blot analysis with antibody directed against InlA, the surface protein implicated in the internalization in host cells, allowed correlation between the ability of the carriage strains to enter Caco-2 cells and InlA expression. Indeed, these five carriage strains produced truncated forms of InlA. Four of the five truncated forms of InlA had an apparent molecular mass of 47 kDa. In order to assess the existence of a genetic lineage, partial sequences of inlA gene of these four strains were compared and revealed that they had a high degree of sequence conservation at the gene (99.86%) and amino acid (100%) levels. Comparison of their nucleotide sequences with that of the corresponding segment of inlA from EGD-e and Scott A strains, taken as epidemic references, showed more divergence. Taken together, these observations suggest the presence of specific traits that characterize L. monocytogenes strains isolated during asymptomatic carriage. Some of these traits could provide some explanations about the determinants that make them unable to cause systemic human infection.
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Affiliation(s)
- Maïwenn Olier
- Laboratoire de Microbiologie Equipe PG2MA, UMR INRA 1082, ENSBANA, 21000 Dijon, France
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Buncic S, Avery SM, Rocourt J, Dimitrijevic M. Can food-related environmental factors induce different behaviour in two key serovars, 4b and 1/2a, of Listeria monocytogenes? Int J Food Microbiol 2001; 65:201-12. [PMID: 11393689 DOI: 10.1016/s0168-1605(00)00524-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Listeria monocytogenes isolates (81 in total; 42 isolated from cases of human listeriosis: 39 isolated from food), belonging to serovars 1/2a or 4b, were studied for any group differences between serovars to selected factors associated with foods (two bacteriocins and mild heat treatment), growth kinetics at 37 degrees C and pathogenicity for chick embryos. The isolates were tested for sensitivity to two bacteriocins at 4 degrees C and 37 degrees C, and were tested for the remaining parameters both before and after exposure to cold storage (4 degrees C) with starvation. In addition, the isolates were typed using pulsed field gel electrophoresis (PFGE), multilocus enzyme electrophoresis (MEE) and phage typing to find any correlation between the types and group differences in the chosen parameters. Considerable strain diversity within each L. monocytogenes serovar with respect to the chosen parameters was observed, especially after exposure to cold storage. Nevertheless, the serovar 1/2a isolates, as a group, tended to be more resistant to the two antilisterial bacteriocins at 4 degrees C than the group of serovar 4b isolates. In contrast, after cold storage at 4 degrees C, L. monocytogenes serovar 4b isolates, as a group, tended to be more resistant to heat treatment at 60 degrees C than the group of 1/2a isolates. In addition, the serovar 4b group tended to have shorter lag phases and higher pathogenicity, when transferred from cold storage to body temperature (37 degrees C), than the group of serovar 1/2a isolates. No correlation between PFGE-, MEE- and phage-types and the tested parameters was found. Although the above serovar-related differences were observed only when mean values of the groups were compared (not all isolates within each group followed the group pattern), the results indicate interesting directions for further research.
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Affiliation(s)
- S Buncic
- Division of Food Animal Science, University of Bristol, School of Veterinary Science, Langford, UK.
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Thomas C, O'Beirne D. Evaluation of the impact of short-term temperature abuse on the microbiology and shelf life of a model ready-to-use vegetable combination product. Int J Food Microbiol 2000; 59:47-57. [PMID: 10946838 DOI: 10.1016/s0168-1605(00)00290-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The growth dynamics of indigenous aerobic mesophilic populations (AMP), lactic acid bacteria (LAB) and inoculated (Listeria spp.) microbial populations on cooked and fresh vegetable products, packaged as separate entities and in combination, subjected to temperature fluctuation, were assessed. Microbial proliferation was temperature and product dependent, being most pronounced at 12 degrees C in all products with maximum growth rates of 0.140, 0.175 and 0.126 log10 CFU/g per h being identified for Listeria, aerobic mesophilic and LAB populations, respectively. Listeria spp. and AMP generally demonstrated higher rates of growth within products containing cooked vegetables. Prolonged storage at 3 degrees C resulted in a reduced ability by AMP and Listeria spp. to proliferate upon exposure to growth temperatures; this was not the case with LAB populations. Comparison of Listeria population estimates made using selective (Oxford) and non-selective (nutrient agar) identified reduced recovery on the former. The magnitude of the deviation increased with the duration of exposure of Listeria populations to 3 degrees C with recoveries on selective systems being reduced by 6.3% immediately after inoculation and 82.3% after 168 h at 3 degrees C, respectively. Growth of populations associated with exposure to abuse temperatures was not accompanied by significant changes in product colour (P < 0.05).
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Affiliation(s)
- C Thomas
- Food Science Research Centre, Department of Life Sciences, University of Limerick, Ireland.
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Dykes GA, Withers KM. Sub-lethal damage of Listeria monocytogenes after long-term chilled storage at 4 degrees C. Lett Appl Microbiol 1999; 28:45-8. [PMID: 10030031 DOI: 10.1046/j.1365-2672.1999.00472.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The possibility that long term in vitro chilled storage may result in sub-lethal damage to Listeria monocytogenes cells was investigated by comparing growth of chill-stored (starvation at 4 degrees C) and fresh cultures on selective and non-selective media. Growth of freshly grown cells was minimally (3-8%) affected by selective LSAMM agar compared with non-selective Brain Heart Infusion agar. In contrast, numbers of chill-stored strains were reduced by greater than 99% after direct plating on the same selective and non-selective media. Furthermore, chill-stored strains were able to grow in standard selective broth (Listeria Selective broth and Fraser broth) only if undiluted inocula (approximately 10(5)-10(6) cfu ml-1) were used, whereas they were capable of growth in Brain Heart Infusion broth even when the lowest dilutions were used (approximately 10(1) cfu ml-1). The potential public health consequences of this finding for the isolation of Listeria monocytogenes from foods is considered.
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Affiliation(s)
- G A Dykes
- MIRINZ Food Technology & Research Ltd, Hamilton, New Zealand.
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Buncic S, Avery SM. Relationship between variations in pathogenicity and lag phase at 37 degrees C of Listeria monocytogenes previously stored at 4 degrees C. Lett Appl Microbiol 1996; 23:18-22. [PMID: 8679139 DOI: 10.1111/j.1472-765x.1996.tb00020.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Three haemolytic, pathogenic strains of Listeria monocytogenes (a reference strain, a food-derived strain and a human strain) were held at 4 degrees C for 4 weeks in phosphate-buffered saline pH 5.5 or 7.0, with and without 0.2% potassium sorbate or 0.3% sodium acetate. The number of viable cells did not change significantly during this storage. Pathogenicity of non-growing L. monocytogenes cells for 14-d-old chick embryos was determined before and after storage. Storage at 4 degrees C resulted in decreased pathogenicity, but effects were strain-, pH-and substrate-dependent. After 4 weeks storage at 4 degrees C non-growing bacterial cells were transferred to Brain Heart Infusion broth and growth characteristics were determined during incubation at 37 degrees C. Strains that showed decreased pathogenicity had significantly longer lag phases at 37 degrees C than strains that maintained pathogenicity. It is concluded that decreased pathogenicity of L. monocytogenes stored without growth at 4 degrees C for 4 weeks and subsequent long lag phase at 37 degrees C are correlated.
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Affiliation(s)
- S Buncic
- Meat Industry Research Institute of New Zealand (Inc.), Hamilton, New Zealand.
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