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Arvaniti M, Balomenos A, Papadopoulou V, Tsakanikas P, Skandamis P. Modelling the colony growth dynamics of Listeria monocytogenes single cells after exposure to peracetic acid and acidic conditions. Food Res Int 2024; 191:114684. [PMID: 39059941 DOI: 10.1016/j.foodres.2024.114684] [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: 03/25/2024] [Revised: 05/27/2024] [Accepted: 06/26/2024] [Indexed: 07/28/2024]
Abstract
Studies of classical microbiology rely on the average behaviour of large cell populations without considering that clonal bacterial populations may bifurcate into phenotypic distinct sub-populations by random switching mechanisms.Listeria monocytogenes exposure to sublethal stresses may induce different physiological states that co-exist (i.e., sublethal injury or dormancy) and present variable resuscitation capacity. Exposures to peracetic acid (PAA; 10-30 ppm; for 3 h), acetic acid and hydrochloric acid (AA and HCl; pH 3.0-2.5; for 5 h) at 20 °C were used to induce different physiological states in L. monocytogenes, Scott A strain. After stress exposure, colony growth of single cells was monitored, on Tryptic Soy Agar supplemented with 0.6 % Yeast Extract, using time-lapse microscopy, at 37 °C. Images were acquired every 5 min and were analyzed using BaSCA framework. Most of the obtained growth curves of the colonies were fitted to the model of Baranyi and Roberts for the estimation of lag time (λ) and maximum specific growth rate (μmax), except the ones obtained after exposure to AA pH 2.7 and 2.5 that were fitted to the Trilinear model. The data of λ and μmax that followed a multivariate normal distribution were used to predict growth variability using Monte Carlo simulations. Outgrowth kinetics after treatment with AA (pH 2.7 and 2.5; for 5 h at 20 °C), PAA (30 ppm; for 3 h at 20 °C) revealed that these stress conditions increase the skewness of the variability distributions to the right, meaning that the variability in lag times increases in favour of longer outgrowth. Exposures to AA pH 2.5 and 30 ppm PAA resulted in two distinct subpopulations per generation with different growth dynamics. This switching mechanism may have evolved as a survival strategy for L. monocytogenes cells, maximizing the chances of survival. Simulation of microbial growth showed that heterogeneity in growth dynamics is increased when cells are recovering from exposure to sublethal stresses (i.e. PAA and acidic conditions) that may induce injury or dormancy.
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Affiliation(s)
- Marianna Arvaniti
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Athanasios Balomenos
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Vasiliki Papadopoulou
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Panagiotis Tsakanikas
- Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Panagiotis Skandamis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece.
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2
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Garcia-Gutierrez E, Monteoliva García G, Bodea I, Cotter PD, Iguaz A, Garre A. A secondary model for the effect of pH on the variability in growth fitness of Listeria innocua strains. Food Res Int 2024; 186:114314. [PMID: 38729708 DOI: 10.1016/j.foodres.2024.114314] [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: 03/11/2024] [Revised: 04/11/2024] [Accepted: 04/16/2024] [Indexed: 05/12/2024]
Abstract
Variability in microbial growth is a keystone of modern Quantitative Microbiological Risk Assessment (QMRA). However, there are still significant knowledge gaps on how to model variability, with the most common assumption being that variability is constant. This is implemented by an error term (with constant variance) added on top of the secondary growth model (for the square root of the growth rate). However, this may go against microbial ecology principles, where differences in growth fitness among bacterial strains would be more prominent in the vicinity of the growth limits than at optimal growth conditions. This study coins the term "secondary models for variability", evaluating whether they should be considered in QMRA instead of the constant strain variability hypothesis. For this, 21 strains of Listeria innocua were used as case study, estimating their growth rate by the two-fold dilution method at pH between 5 and 10. Estimates of between-strain variability and experimental uncertainty were obtained for each pH using mixed-effects models, showing the lowest variability at optimal growth conditions, increasing towards the growth limits. Nonetheless, the experimental uncertainty also increased towards the extremes, evidencing the need to analyze both sources of variance independently. A secondary model was thus proposed, relating strain variability and pH conditions. Although the modelling approach certainly has some limitations that would need further experimental validation, it is an important step towards improving the description of variability in QMRA, being the first model of this type in the field.
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Affiliation(s)
- Enriqueta Garcia-Gutierrez
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, ETSIA-Universidad Politécnica de Cartagena, Paseo Alfonso XIII, 48, 30203 Cartagena, Spain; Food Bioscience Department, Teagasc Food Research Centre Moorepark, P61 C996 Fermoy, County Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, County Cork, Ireland; VistaMilk SFI Research Centre, Teagasc Moorepark, P61 C996 Fermoy, County Cork, Ireland
| | - Gonzalo Monteoliva García
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo-UPM, 28223 Pozuelo de Alarcón (Madrid), Spain
| | - Ioana Bodea
- Department of Technical and Soil Sciences, Faculty of Agriculture, University of Agricultural Science and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania
| | - Paul D Cotter
- Food Bioscience Department, Teagasc Food Research Centre Moorepark, P61 C996 Fermoy, County Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, County Cork, Ireland; VistaMilk SFI Research Centre, Teagasc Moorepark, P61 C996 Fermoy, County Cork, Ireland
| | - Asunción Iguaz
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, ETSIA-Universidad Politécnica de Cartagena, Paseo Alfonso XIII, 48, 30203 Cartagena, Spain
| | - Alberto Garre
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, ETSIA-Universidad Politécnica de Cartagena, Paseo Alfonso XIII, 48, 30203 Cartagena, Spain.
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Ma X, Chen J, Zwietering MH, Abee T, Den Besten HMW. Stress resistant rpsU variants of Listeria monocytogenes can become underrepresented due to enrichment bias. Int J Food Microbiol 2024; 416:110680. [PMID: 38522149 DOI: 10.1016/j.ijfoodmicro.2024.110680] [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: 12/13/2023] [Revised: 02/21/2024] [Accepted: 03/09/2024] [Indexed: 03/26/2024]
Abstract
Population heterogeneity is an important component of the survival mechanism of Listeria monocytogenes, leading to cells in a population with diverse stress resistance levels. We previously demonstrated that several ribosomal gene rpsU mutations enhanced the stress resistance of L. monocytogenes and lowered the growth rate at 30 °C and lower temperatures. This study investigated whether these switches in phenotypes could result in a bias in strain detection when standard enrichment-based procedures are applied to a variety of strains. Detailed growth kinetics analysis of L. monocytogenes strains were performed, including the LO28 wild type (WT) and rpsU variants V14 and V15, during two commonly used enrichment-based procedures described in the ISO 11290-1:2017 and the U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM). WT had a higher growth rate than the variants during the enrichment processes. Co-culture growth kinetics predictions for WT and rpsU variants showed that the detection chances of the rpsU mutants were reduced from ∼52 % to less than ∼13 % and ∼ 3 % during ISO and BAM enrichment, respectively, which were further validated through subsequent qPCR experiments. Higher heat stress resistance of rpsU variants did not lead to faster recovery during enrichment after heat treatment, and different pre-culturing temperatures before heat treatment did not significantly affect the growth kinetics of the WT and rpsU variants. Additionally, post-enrichment isolation procedures involving streaking on selective agar plates did not show preferences for isolating WT or rpsU variants nor affect the detection chance of rpsU variants. The difference in detection chance suggests that the selective enrichment procedures inadequately represent the genotypic diversity present in a sample. Hence, the enrichment bias during the L. monocytogenes isolation procedure may contribute to the observed underrepresentation of the rpsU mutation among L. monocytogenes isolates deposited in publicly available genome databases. The underrepresentation of rpsU mutants in our findings suggests that biases introduced by standard isolation and enrichment procedures could inadvertently skew our understanding of genetic diversity when relying on public databases.
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Affiliation(s)
- Xuchuan Ma
- Food Microbiology, Wageningen University & Research, Wageningen, the Netherlands
| | - Jingjie Chen
- State Key Laboratory of Conservation and Utilization of Bio-resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China
| | - Marcel H Zwietering
- Food Microbiology, Wageningen University & Research, Wageningen, the Netherlands
| | - Tjakko Abee
- Food Microbiology, Wageningen University & Research, Wageningen, the Netherlands
| | - Heidy M W Den Besten
- Food Microbiology, Wageningen University & Research, Wageningen, the Netherlands.
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4
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Koomen J, Ma X, Bombelli A, Tempelaars MH, Boeren S, Zwietering MH, den Besten HMW, Abee T. Ribosomal mutations enable a switch between high fitness and high stress resistance in Listeria monocytogenes. Front Microbiol 2024; 15:1355268. [PMID: 38605704 PMCID: PMC11006974 DOI: 10.3389/fmicb.2024.1355268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 03/08/2024] [Indexed: 04/13/2024] Open
Abstract
Multiple stress resistant variants of Listeria monocytogenes with mutations in rpsU encoding ribosomal protein RpsU have previously been isolated after a single exposure to acid stress. These variants, including L. monocytogenes LO28 variant V14 with a complete deletion of the rpsU gene, showed upregulation of the general stress sigma factor Sigma B-mediated stress resistance genes and had a lower maximum specific growth rate than the LO28 WT, signifying a trade-off between stress resistance and fitness. In the current work V14 has been subjected to an experimental evolution regime, selecting for higher fitness in two parallel evolving cultures. This resulted in two evolved variants with WT-like fitness: 14EV1 and 14EV2. Comparative analysis of growth performance, acid and heat stress resistance, in combination with proteomics and RNA-sequencing, indicated that in both lines reversion to WT-like fitness also resulted in WT-like stress sensitivity, due to lack of Sigma B-activated stress defense. Notably, genotyping of 14EV1 and 14EV2 provided evidence for unique point-mutations in the ribosomal rpsB gene causing amino acid substitutions at the same position in RpsB, resulting in RpsB22Arg-His and RpsB22Arg-Ser, respectively. Combined with data obtained with constructed RpsB22Arg-His and RpsB22Arg-Ser mutants in the V14 background, we provide evidence that loss of function of RpsU resulting in the multiple stress resistant and reduced fitness phenotype, can be reversed by single point mutations in rpsB leading to arginine substitutions in RpsB at position 22 into histidine or serine, resulting in a WT-like high fitness and low stress resistance phenotype. This demonstrates the impact of genetic changes in L. monocytogenes' ribosomes on fitness and stress resistance.
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Affiliation(s)
- Jeroen Koomen
- Food Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Xuchuan Ma
- Food Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Alberto Bombelli
- Food Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | | | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University & Research, Wageningen, Netherlands
| | | | | | - Tjakko Abee
- Food Microbiology, Wageningen University & Research, Wageningen, Netherlands
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Bumunang EW, Zaheer R, Niu D, Narvaez-Bravo C, Alexander T, McAllister TA, Stanford K. Bacteriophages for the Targeted Control of Foodborne Pathogens. Foods 2023; 12:2734. [PMID: 37509826 PMCID: PMC10379335 DOI: 10.3390/foods12142734] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/05/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
Foodborne illness is exacerbated by novel and emerging pathotypes, persistent contamination, antimicrobial resistance, an ever-changing environment, and the complexity of food production systems. Sporadic and outbreak events of common foodborne pathogens like Shiga toxigenic E. coli (STEC), Salmonella, Campylobacter, and Listeria monocytogenes are increasingly identified. Methods of controlling human infections linked with food products are essential to improve food safety and public health and to avoid economic losses associated with contaminated food product recalls and litigations. Bacteriophages (phages) are an attractive additional weapon in the ongoing search for preventative measures to improve food safety and public health. However, like all other antimicrobial interventions that are being employed in food production systems, phages are not a panacea to all food safety challenges. Therefore, while phage-based biocontrol can be promising in combating foodborne pathogens, their antibacterial spectrum is generally narrower than most antibiotics. The emergence of phage-insensitive single-cell variants and the formulation of effective cocktails are some of the challenges faced by phage-based biocontrol methods. This review examines phage-based applications at critical control points in food production systems with an emphasis on when and where they can be successfully applied at production and processing levels. Shortcomings associated with phage-based control measures are outlined together with strategies that can be applied to improve phage utility for current and future applications in food safety.
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Affiliation(s)
- Emmanuel W Bumunang
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 1M4, Canada
| | - Rahat Zaheer
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB T1J 4B1, Canada
| | - Dongyan Niu
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Claudia Narvaez-Bravo
- Food and Human Nutritional Sciences, Faculty of Agricultural & Food Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Trevor Alexander
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB T1J 4B1, Canada
| | - Tim A McAllister
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB T1J 4B1, Canada
| | - Kim Stanford
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 1M4, Canada
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6
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Deciphering the induction of Listeria monocytogenes into sublethal injury using fluorescence microscopy and RT-qPCR. Int J Food Microbiol 2023; 385:109983. [DOI: 10.1016/j.ijfoodmicro.2022.109983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 10/16/2022] [Accepted: 10/17/2022] [Indexed: 11/22/2022]
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7
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Polese P, Del Torre M, Stecchini ML. Impact of multiple hurdles on Listeria monocytogenes dispersion of survivors. Food Microbiol 2022; 107:104088. [DOI: 10.1016/j.fm.2022.104088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 11/04/2022]
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8
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Arvaniti M, Skandamis PN. Defining bacterial heterogeneity and dormancy with the parallel use of single-cell and population level approaches. Curr Opin Food Sci 2022. [DOI: 10.1016/j.cofs.2022.100808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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9
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Listeria monocytogenes Sublethal Injury and Viable-but-Nonculturable State Induced by Acidic Conditions and Disinfectants. Microbiol Spectr 2021; 9:e0137721. [PMID: 34908469 PMCID: PMC8672913 DOI: 10.1128/spectrum.01377-21] [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] [Indexed: 11/20/2022] Open
Abstract
The dormancy continuum hypothesis states that in response to stress, cells enter different stages of dormancy ranging from unstressed living cells to cell death, in order to ensure their long-term survival under adverse conditions. Exposure of Listeria monocytogenes cells to sublethal stressors related to food processing may induce sublethal injury and the viable-but-nonculturable (VBNC) state. In this study, exposure to acetic acid (AA), hydrochloric acid (HCl), and two disinfectants, peracetic acid (PAA) and sodium hypochlorite (SH), at 20°C and 4°C was used to evaluate the potential induction of L. monocytogenes strain Scott A into different stages of dormancy. To differentiate the noninjured subpopulation from the total population, tryptic soy agar with 0.6% yeast extract (TSAYE), supplemented or not with 5% NaCl, was used. Sublethally injured and VBNC cells were detected by comparing plate counts obtained with fluorescence microscopy and by using combinations of carboxyfluorescein and propidium iodide (viable/dead cells). Induction of sublethal injury was more intense after PAA treatment. Two subpopulations were detected, with phenotypes of untreated cells and small colony variants (SCVs). SCVs appeared as smaller colonies of various sizes and were first observed after 5 min of exposure to 5 ppm PAA at 20°C. Increasing the stress intensity from 5 to 40 ppm PAA led to earlier detection of SCVs. L. monocytogenes remained culturable after exposure to 20 and 30 ppm PAA for 3 h. At 40 ppm, after 3 h of exposure, the whole population was considered nonculturable, while cells remained metabolically active. These results corroborate the induction of the VBNC state. IMPORTANCE Sublethally injured and VBNC cells may evade detection, resulting in underestimation of a food product's microbial load. Under favorable conditions, cells may regain their growth capacity and acquire new resistant characteristics, posing a major threat for public health. Induction of the VBNC state is crucial for foodborne pathogens, such as L. monocytogenes, the detection of which relies almost exclusively on the use of culture recovery techniques. In the present study, we confirmed that sublethal injury is an initial stage of dormancy in L. monocytogenes that is followed by the VBNC state. Our results showed that PAA induced SCVs (a phenomenon potentially triggered by external factors) and the VBNC state in L. monocytogenes, indicating that tests of lethality based only on culturability may provide false-positive results regarding the effectiveness of an inactivation treatment.
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10
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Thomassen GMB, Krych L, Knøchel S, Mehli L. ON-rep-seq as a rapid and cost-effective alternative to whole-genome sequencing for species-level identification and strain-level discrimination of Listeria monocytogenes contamination in a salmon processing plant. Microbiologyopen 2021; 10:e1246. [PMID: 34964295 PMCID: PMC8591450 DOI: 10.1002/mbo3.1246] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/19/2021] [Indexed: 12/28/2022] Open
Abstract
Identification, source tracking, and surveillance of food pathogens are crucial factors for the food-producing industry. Over the last decade, the techniques used for this have moved from conventional enrichment methods, through species-specific detection by PCR to sequencing-based methods, whole-genome sequencing (WGS) being the ultimate method. However, using WGS requires the right infrastructure, high computational power, and bioinformatics expertise. Therefore, there is a need for faster, more cost-effective, and more user-friendly methods. A newly developed method, ON-rep-seq, combines the classical rep-PCR method with nanopore sequencing, resulting in a highly discriminating set of sequences that can be used for species identification and also strain discrimination. This study is essentially a real industry case from a salmon processing plant. Twenty Listeria monocytogenes isolates were analyzed both by ON-rep-seq and WGS to identify and differentiate putative L. monocytogenes from a routine sampling of processing equipment and products, and finally, compare the strain-level discriminatory power of ON-rep-seq to different analyzing levels delivered from the WGS data. The analyses revealed that among the isolates tested there were three different strains. The isolates of the most frequently detected strain (n = 15) were all detected in the problematic area in the processing plant. The strain level discrimination done by ON-rep-seq was in full accordance with the interpretation of WGS data. Our findings also demonstrate that ON-rep-seq may serve as a primary screening method alternative to WGS for identification and strain-level differentiation for surveillance of potential pathogens in a food-producing environment.
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Affiliation(s)
| | - Lukasz Krych
- Department of Food ScienceUniversity of CopenhagenFrederiksbergDenmark
| | - Susanne Knøchel
- Department of Food ScienceUniversity of CopenhagenFrederiksbergDenmark
| | - Lisbeth Mehli
- Department of Biotechnology and Food ScienceNorwegian University of Science and Technology (NTNU)TrondheimNorway
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11
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Koomen J, Huijboom L, Ma X, Tempelaars MH, Boeren S, Zwietering MH, den Besten HMW, Abee T. Amino acid substitutions in ribosomal protein RpsU enable switching between high fitness and multiple-stress resistance in Listeria monocytogenes. Int J Food Microbiol 2021; 351:109269. [PMID: 34102570 DOI: 10.1016/j.ijfoodmicro.2021.109269] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 11/28/2022]
Abstract
Microbial population heterogeneity contributes to differences in stress response between individual cells in a population, and can lead to the selection of genetically stable variants with increased stress resistance. We previously provided evidence that the multiple-stress resistant Listeria monocytogenes LO28 variant 15, carries a point mutation in the rpsU gene, resulting in an arginine-proline substitution in ribosomal protein RpsU (RpsU17Arg-Pro). Here, we investigated the trade-off between general stress sigma factor SigB-mediated stress resistance and fitness in variant 15 using experimental evolution. By selecting for higher fitness in two parallel evolving cultures, we identified two evolved variants: 15EV1 and 15EV2. Whole genome sequencing and SNP analysis showed that both parallel lines mutated in the same codon in rpsU as the original mutation resulting in RpsU17Pro-His (15EV1) and RpsU17Pro-Thr (15EV2). Using a combined phenotyping and proteomics approach, we assessed the resistance of the evolved variants to both heat and acid stress, and found that in both lines reversion to WT-like fitness also resulted in WT-like stress sensitivity. Proteome analysis of L. monocytogenes LO28 WT, variant 15, 15EV1, and 15EV2 revealed high level expression of SigB regulon members only in variant 15, whereas protein profiles of both evolved variants were highly similar to that of the LO28 WT. Experiments with constructed RpsU17Arg-Pro mutants in L. monocytogenes LO28 and EGDe, and RpsU17Arg-His and RpsU17Arg-Thr in LO28, confirmed that single amino acid substitutions in RpsU enable switching between multiple-stress resistant and high fitness states in L. monocytogenes.
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Affiliation(s)
- Jeroen Koomen
- Food Microbiology, Wageningen University and Research, the Netherlands, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Linda Huijboom
- Food Microbiology, Wageningen University and Research, the Netherlands, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Xuchuan Ma
- Food Microbiology, Wageningen University and Research, the Netherlands, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Marcel H Tempelaars
- Food Microbiology, Wageningen University and Research, the Netherlands, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University and Research, the Netherlands
| | - Marcel H Zwietering
- Food Microbiology, Wageningen University and Research, the Netherlands, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Heidy M W den Besten
- Food Microbiology, Wageningen University and Research, the Netherlands, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Tjakko Abee
- Food Microbiology, Wageningen University and Research, the Netherlands, P.O. Box 17, 6700 AA Wageningen, the Netherlands.
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12
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Makariti IP, Grivokostopoulos NC, Skandamis PN. Effect οf οxygen availability and pH οn adaptive acid tolerance response of immobilized Listeria monocytogenes in structured growth media. Food Microbiol 2021; 99:103826. [PMID: 34119111 DOI: 10.1016/j.fm.2021.103826] [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: 02/25/2021] [Revised: 05/01/2021] [Accepted: 05/03/2021] [Indexed: 10/21/2022]
Abstract
The aim of the present study was to evaluate the effect of oxygen availability (aerobic, hypoxic and anoxic conditions) and sub-optimal pH (6.2 and 5.5) in a structured medium (10% w/V gelatin) on the growth of two immobilized L. monocytogenes strains (C5, 6179) at 10 °C and their subsequent acid resistance (pH 2.0, e.g., gastric acidity). Anaerobic conditions resulted in lower bacterial population (P < 0.05) (7.8-8.2 log CFU/mL) at the end of storage than aerobic and hypoxic environment (8.5-9.0 log CFU/mL), a phenomenon that was intensified at lower pH (5.5), where no significant growth was observed for anaerobically grown cultures. Prolonged habituation of L. monocytogenes (15 days) at both pH increased its acid tolerance resulting in max. 10 times higher t4D (appx. 60 min). The combined effect though of oxygen availability and suboptimal pH on L. monocytogenes acid resistance was found to vary with the strain. Anoxically grown cultures at pH 5.5 exhibited the lowest tolerance towards lethal acid stress, with countable survivors occurring only until 20 min of exposure at pH 2.0. Elucidating the role of oxygen limiting conditions, often encountered in structured foods, on acid resistance of L. monocytogenes, would assist in assessing the capacity of L. monocytogenes originated from different food-related niches to withstand gastric acidity and possibly initiate infection.
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Affiliation(s)
- Ifigeneia P Makariti
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece
| | - Nikos C Grivokostopoulos
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece
| | - Panagiotis N Skandamis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
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13
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Ceylan E, Amezquita A, Anderson N, Betts R, Blayo L, Garces-Vega F, Gkogka E, Harris LJ, McClure P, Winkler A, den Besten HMW. Guidance on validation of lethal control measures for foodborne pathogens in foods. Compr Rev Food Sci Food Saf 2021; 20:2825-2881. [PMID: 33960599 DOI: 10.1111/1541-4337.12746] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 02/03/2021] [Accepted: 03/03/2021] [Indexed: 11/30/2022]
Abstract
Food manufacturers are required to obtain scientific and technical evidence that a control measure or combination of control measures is capable of reducing a significant hazard to an acceptable level that does not pose a public health risk under normal conditions of distribution and storage. A validation study provides evidence that a control measure is capable of controlling the identified hazard under a worst-case scenario for process and product parameters tested. It also defines the critical parameters that must be controlled, monitored, and verified during processing. This review document is intended as guidance for the food industry to support appropriate validation studies, and aims to limit methodological discrepancies in validation studies that can occur among food safety professionals, consultants, and third-party laboratories. The document describes product and process factors that are essential when designing a validation study, and gives selection criteria for identifying an appropriate target pathogen or surrogate organism for a food product and process validation. Guidance is provided for approaches to evaluate available microbiological data for the target pathogen or surrogate organism in the product type of interest that can serve as part of the weight of evidence to support a validation study. The document intends to help food manufacturers, processors, and food safety professionals to better understand, plan, and perform validation studies by offering an overview of the choices and key technical elements of a validation plan, the necessary preparations including assembling the validation team and establishing prerequisite programs, and the elements of a validation report.
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Affiliation(s)
- Erdogan Ceylan
- Silliker Food Science Center, Merieux NutriSciences, Crete, Illinois, USA
| | - Alejandro Amezquita
- Safety and Environmental Assurance Centre, Unilever R&D Colworth, Sharnbrook, Bedfordshire, UK
| | - Nathan Anderson
- U.S. Food and Drug Administration, Bedford Park, Illinois, USA
| | - Roy Betts
- Campden BRI, Chipping Campden, Gloucestershire, UK
| | - Laurence Blayo
- Société des Produits Nestlé S.A, Nestlé Research, Lausanne, Switzerland
| | | | - Elissavet Gkogka
- Arla R&D, Arla Innovation Centre, Aarhus N, Central Jutland Region, Denmark
| | - Linda J Harris
- Department of Food Science and Technology, University of California, Davis, Davis, California, USA
| | - Peter McClure
- Mondelēz International, Mondelēz R&D UK, Birmingham, UK
| | - Anett Winkler
- Microbiology and Food Safety CoE, Cargill Deutschland GmbH, Krefeld, Germany
| | - Heidy M W den Besten
- Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands
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14
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Eisenreich W, Rudel T, Heesemann J, Goebel W. Persistence of Intracellular Bacterial Pathogens-With a Focus on the Metabolic Perspective. Front Cell Infect Microbiol 2021; 10:615450. [PMID: 33520740 PMCID: PMC7841308 DOI: 10.3389/fcimb.2020.615450] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/30/2020] [Indexed: 12/19/2022] Open
Abstract
Persistence has evolved as a potent survival strategy to overcome adverse environmental conditions. This capability is common to almost all bacteria, including all human bacterial pathogens and likely connected to chronic infections caused by some of these pathogens. Although the majority of a bacterial cell population will be killed by the particular stressors, like antibiotics, oxygen and nitrogen radicals, nutrient starvation and others, a varying subpopulation (termed persisters) will withstand the stress situation and will be able to revive once the stress is removed. Several factors and pathways have been identified in the past that apparently favor the formation of persistence, such as various toxin/antitoxin modules or stringent response together with the alarmone (p)ppGpp. However, persistence can occur stochastically in few cells even of stress-free bacterial populations. Growth of these cells could then be induced by the stress conditions. In this review, we focus on the persister formation of human intracellular bacterial pathogens, some of which belong to the most successful persister producers but lack some or even all of the assumed persistence-triggering factors and pathways. We propose a mechanism for the persister formation of these bacterial pathogens which is based on their specific intracellular bipartite metabolism. We postulate that this mode of metabolism ultimately leads, under certain starvation conditions, to the stalling of DNA replication initiation which may be causative for the persister state.
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Affiliation(s)
- Wolfgang Eisenreich
- Department of Chemistry, Chair of Biochemistry, Technische Universität München, Garching, Germany
| | - Thomas Rudel
- Chair of Microbiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Jürgen Heesemann
- Max von Pettenkofer-Institute, Ludwig Maximilian University of Munich, München, Germany
| | - Werner Goebel
- Max von Pettenkofer-Institute, Ludwig Maximilian University of Munich, München, Germany
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15
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Gayán E, Geens E, Berdejo D, García-Gonzalo D, Pagán R, Aertsen A, Michiels CW. Combination of mild heat and plant essential oil constituents to inactivate resistant variants of Escherichia coli in buffer and in coconut water. Food Microbiol 2020; 87:103388. [PMID: 31948629 DOI: 10.1016/j.fm.2019.103388] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 10/20/2019] [Accepted: 11/20/2019] [Indexed: 12/25/2022]
Abstract
The growing demand for minimally processed foods with clean labels has stimulated research into mild processing methods and natural antimicrobials to replace intensive heating and conventional preservatives, respectively. However, we have previously demonstrated that repetitive exposure of some bacteria to mild heat or subinhibitory concentrations of essential oil constituents (EOCs) may induce the emergence of mutants with increased resistance to these treatments. Since the combination of mild heat with some EOCs has a synergistic effect on microbial inactivation, we evaluated the potential of such combinations against our resistant E. coli mutants. While citral, carvacrol and t-cinnamaldehyde synergistically increased heat inactivation (53.0 °C, 10 min) of the wild-type MG1655 suspended in buffer, only the combination with carvacrol (200 μl/l) was able to mitigate the increased resistance of all the mutants. Moreover, the combination of heat and carvacrol acted synergistically inactivating heat-resistant variants of E. coli O157:H7 (ATCC 43888). This combined treatment could synergistically achieve more than 5 log10 reductions of the most resistant mutants in coconut water, although the temperature had to be raised to 57.0 °C. Therefore, the combination of mild heat with carvacrol appears to hold promise for mild processing, and it is expected to counteract the development of heat resistance.
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Affiliation(s)
- Elisa Gayán
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Faculty of Bioscience Engineering, Kasteelpark Arenberg 22, 3000, Leuven, Belgium; Tecnología de Los Alimentos, Departamento de Producción Animal y Ciencia de Los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Miguel Servet 177, 50013, Zaragoza, Spain
| | - Elise Geens
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Faculty of Bioscience Engineering, Kasteelpark Arenberg 22, 3000, Leuven, Belgium
| | - Daniel Berdejo
- Tecnología de Los Alimentos, Departamento de Producción Animal y Ciencia de Los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Miguel Servet 177, 50013, Zaragoza, Spain
| | - Diego García-Gonzalo
- Tecnología de Los Alimentos, Departamento de Producción Animal y Ciencia de Los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Miguel Servet 177, 50013, Zaragoza, Spain
| | - Rafael Pagán
- Tecnología de Los Alimentos, Departamento de Producción Animal y Ciencia de Los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Miguel Servet 177, 50013, Zaragoza, Spain
| | - Abram Aertsen
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Faculty of Bioscience Engineering, Kasteelpark Arenberg 22, 3000, Leuven, Belgium
| | - Chris W Michiels
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Faculty of Bioscience Engineering, Kasteelpark Arenberg 22, 3000, Leuven, Belgium.
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16
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Antunes P, Novais C, Peixe L. Food-to-Humans Bacterial Transmission. Microbiol Spectr 2020; 8:10.1128/microbiolspec.mtbp-0019-2016. [PMID: 31950894 PMCID: PMC10810214 DOI: 10.1128/microbiolspec.mtbp-0019-2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Indexed: 12/17/2022] Open
Abstract
Microorganisms vehiculated by food might benefit health, cause minimal change within the equilibrium of the host microbial community or be associated with foodborne diseases. In this chapter we will focus on human pathogenic bacteria for which food is conclusively demonstrated as their transmission mode to human. We will describe the impact of foodborne diseases in public health, the reservoirs of foodborne pathogens (the environment, human and animals), the main bacterial pathogens and food vehicles causing human diseases, and the drivers for the transmission of foodborne diseases related to the food-chain, host or bacteria features. The implication of food-chain (foodborne pathogens and commensals) in the transmission of resistance to antibiotics relevant to the treatment of human infections is also evidenced. The multiplicity and interplay of drivers related to intensification, diversification and globalization of food production, consumer health status, preferences, lifestyles or behaviors, and bacteria adaptation to different challenges (stress tolerance and antimicrobial resistance) from farm to human, make the prevention of bacteria-food-human transmission a modern and continuous challenge. A global One Health approach is mandatory to better understand and minimize the transmission pathways of human pathogens, including multidrug-resistant pathogens and commensals, through food-chain.
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Affiliation(s)
- Patrícia Antunes
- Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal
| | - Carla Novais
- Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Luísa Peixe
- Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
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17
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Unique response characteristics in persistent strains of Listeria monocytogenes exposed to low pH. Food Microbiol 2019; 86:103312. [PMID: 31703872 DOI: 10.1016/j.fm.2019.103312] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 08/08/2019] [Accepted: 08/24/2019] [Indexed: 11/20/2022]
Abstract
Some Listeria monocytogenes strains are persistent in food processing environments, where this pathogen may be subjected to various stresses. This study aimed to elucidate the response of persistent strains of L. monocytogenes to low pH and H2O2 exposure. Almost all of the persistent strains examined were highly susceptible to low pH, whereas H2O2 susceptibility was comparable to that of control strains. Two persistent strains isolated from the same sample, however, exhibited lower susceptibility to low pH. These findings suggest an acid-susceptible phenotype predominates in the habitat, indicating that environmental conditions contribute to the establishment of persistence. Representative strains exhibiting acid-susceptible and less acid-susceptible phenotypes were further investigated regarding acid response characteristics. Less acid-susceptible strains exhibited increased survival in acidified brain heart infusion (BHI) broth compared with acidified phosphate-buffered saline (PBS). These strains also exhibited increased survival in acidified PBS containing glucose and glutamate, which are involved in acid response mechanisms, compared with acidified PBS alone. However, neither acidified BHI broth nor exogenous glucose and glutamate increased survival of acid-susceptible strains. An adaptive acid tolerance response of the acid-susceptible phenotype was observed, but this was limited compared with that of the less acid-susceptible phenotype.
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18
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Dorey AL, Giovannercole F, Guerreiro D, Marinho C. Microbial stress meeting: From systems to molecules and back. N Biotechnol 2019; 49:66-70. [PMID: 30196137 DOI: 10.1016/j.nbt.2018.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/03/2018] [Accepted: 09/04/2018] [Indexed: 11/16/2022]
Abstract
The 4th Microbial Stress Meeting: from Systems to Moleculesand Back was held in April 2018 in Kinsale, Ireland. The meeting covered five main topics: 1. Stress at the systems and structural level; 2. Responses to osmotic and acid stress; 3. Stress responses in single cells; 4. Stress in host-pathogen interactions; and 5. Biotechnological optimisation of microorganisms through engineering and evolution, over three days. Almost 130 delegates, from 24 countries and both the industrial and academic sectors, attended the meeting, presenting 9 lectures, 28 short talks and 52 posters. The meeting showcased the diverse and rapid advancements in microbial stress research, from the single cell level to mixed populations. In this report, a summary of the highlights from the meeting is presented.
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Affiliation(s)
- Amber L Dorey
- Bacterial Stress Response Group, Department of Microbiology, National University of Ireland, Galway, Ireland.
| | - Fabio Giovannercole
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy
| | - Duarte Guerreiro
- Bacterial Stress Response Group, Department of Microbiology, National University of Ireland, Galway, Ireland
| | - Catarina Marinho
- Bacterial Stress Response Group, Department of Microbiology, National University of Ireland, Galway, Ireland; University of Burgundy, UMR 1347 Agroecoecology, INRA, Dijon, France
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19
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Horn N, Bhunia AK. Food-Associated Stress Primes Foodborne Pathogens for the Gastrointestinal Phase of Infection. Front Microbiol 2018; 9:1962. [PMID: 30190712 PMCID: PMC6115488 DOI: 10.3389/fmicb.2018.01962] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 08/02/2018] [Indexed: 12/13/2022] Open
Abstract
The incidence of foodborne outbreaks and product recalls is on the rise. The ability of the pathogen to adapt and survive under stressful environments of food processing and the host gastrointestinal tract may contribute to increasing foodborne illnesses. In the host, multiple factors such as bacteriolytic enzymes, acidic pH, bile, resident microflora, antimicrobial peptides, and innate and adaptive immune responses are essential in eliminating pathogens. Likewise, food processing and preservation techniques are employed to eliminate or reduce human pathogens load in food. However, sub-lethal processing or preservation treatments may evoke bacterial coping mechanisms that alter gene expression, specifically and broadly, resulting in resistance to the bactericidal insults. Furthermore, environmentally cued changes in gene expression can lead to changes in bacterial adhesion, colonization, invasion, and toxin production that contribute to pathogen virulence. The shared microenvironment between the food preservation techniques and the host gastrointestinal tract drives microbes to adapt to the stressful environment, resulting in enhanced virulence and infectivity during a foodborne illness episode.
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Affiliation(s)
- Nathan Horn
- Department of Animal Sciences, Purdue University, West Lafayette, IN, United States
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, United States
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20
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Olaimat AN, Al-Holy MA, Shahbaz HM, Al-Nabulsi AA, Abu Ghoush MH, Osaili TM, Ayyash MM, Holley RA. Emergence of Antibiotic Resistance in Listeria monocytogenes Isolated from Food Products: A Comprehensive Review. Compr Rev Food Sci Food Saf 2018; 17:1277-1292. [PMID: 33350166 DOI: 10.1111/1541-4337.12387] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/07/2018] [Accepted: 06/07/2018] [Indexed: 12/12/2022]
Abstract
Listeria monocytogenes is an opportunistic pathogen that has been involved in several deadly illness outbreaks. Future outbreaks may be more difficult to manage because of the emergence of antibiotic resistance among L. monocytogenes strains isolated from food products. The present review summarizes the available evidence on the emergence of antibiotic resistance among L. monocytogenes strains isolated from food products and the possible ways this resistance has developed. Furthermore, the resistance of food L. monocytogenes isolates to antibiotics currently used in the treatment of human listeriosis such as penicillin, ampicillin, tetracycline, and gentamicin, has been documented. Acquisition of movable genetic elements is considered the major mechanism of antibiotic resistance development in L. monocytogenes. Efflux pumps have also been linked with resistance of L. monocytogenes to some antibiotics including fluoroquinolones. Some L. monocytogenes strains isolated from food products are intrinsically resistant to several antibiotics. However, factors in food processing chains and environments (from farm to table) including extensive or sub-inhibitory antibiotics use, horizontal gene transfer, exposure to environmental stresses, biofilm formation, and presence of persister cells play crucial roles in the development of antibiotic resistance by L. monocytogenes.
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Affiliation(s)
- Amin N Olaimat
- Dept. of Clinical Nutrition and Dietetics, Faculty of Allied Health Sciences, Hashemite Univ., P.O. Box 150459, Zarqa, 13115, Jordan
| | - Murad A Al-Holy
- Dept. of Clinical Nutrition and Dietetics, Faculty of Allied Health Sciences, Hashemite Univ., P.O. Box 150459, Zarqa, 13115, Jordan
| | - Hafiz M Shahbaz
- Dept. of Food Science and Human Nutrition, Univ. of Veterinary and Animal Sciences, Lahore, 54000, Pakistan
| | - Anas A Al-Nabulsi
- Dept. of Nutrition and Food Technology, Jordan Univ. of Science and Technology, P.O. Box 3030, Irbid, Jordan
| | - Mahmoud H Abu Ghoush
- Dept. of Clinical Nutrition and Dietetics, Faculty of Allied Health Sciences, Hashemite Univ., P.O. Box 150459, Zarqa, 13115, Jordan
| | - Tareq M Osaili
- Dept. of Nutrition and Food Technology, Jordan Univ. of Science and Technology, P.O. Box 3030, Irbid, Jordan.,Dept. of Clinical Nutrition and Dietetics, College of Health Sciences, Univ. of Sharjah, Sharjah, United Arab Emirates
| | - Mutamed M Ayyash
- Dept. of Food Science, United Arab Emirates Univ., Al Ain, United Arab Emirates
| | - Richard A Holley
- Dept. of Food and Human Nutritional Sciences, Faculty of Agricultural and Food Sciences, Univ. of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
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21
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den Besten HM, Wells-Bennik MH, Zwietering MH. Natural Diversity in Heat Resistance of Bacteria and Bacterial Spores: Impact on Food Safety and Quality. Annu Rev Food Sci Technol 2018; 9:383-410. [DOI: 10.1146/annurev-food-030117-012808] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Heidy M.W. den Besten
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands
- Top Institute Food and Nutrition, 6709 PA, Wageningen, The Netherlands
| | - Marjon H.J. Wells-Bennik
- NIZO Food Research B.V., 6718 ZB, Ede, The Netherlands
- Top Institute Food and Nutrition, 6709 PA, Wageningen, The Netherlands
| | - Marcel H. Zwietering
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands
- Top Institute Food and Nutrition, 6709 PA, Wageningen, The Netherlands
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22
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Mastwijk H, Timmermans R, Van Boekel M. The Gauss-Eyring model: A new thermodynamic model for biochemical and microbial inactivation kinetics. Food Chem 2017; 237:331-341. [DOI: 10.1016/j.foodchem.2017.05.070] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 04/07/2017] [Accepted: 05/15/2017] [Indexed: 10/19/2022]
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23
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Lee BH, Hébraud M, Bernardi T. Increased Adhesion of Listeria monocytogenes Strains to Abiotic Surfaces under Cold Stress. Front Microbiol 2017; 8:2221. [PMID: 29187836 PMCID: PMC5695204 DOI: 10.3389/fmicb.2017.02221] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 10/30/2017] [Indexed: 11/16/2022] Open
Abstract
Food contamination by Listeria monocytogenes remains a major concern for some food processing chains, particularly for ready-to-eat foods, including processed foods. Bacterial adhesion on both biotic and abiotic surfaces is a source of contamination by pathogens that have become more tolerant or even persistent in food processing environments, including in the presence of adverse conditions such as cold and dehydration. The most distinct challenge that bacteria confront upon entry into food processing environments is the sudden downshift in temperature, and the resulting phenotypic effects are of interest. Crystal violet staining and the BioFilm Ring Test® were applied to assess the adhesion and biofilm formation of 22 listerial strains from different serogroups and origins under cold-stressed and cold-adapted conditions. The physicochemical properties of the bacterial surface were studied using the microbial adhesion to solvent technique. Scanning electron microscopy was performed to visualize cell morphology and biofilm structure. The results showed that adhesion to stainless-steel and polystyrene was increased by cold stress, whereas cold-adapted cells remained primarily in planktonic form. Bacterial cell surfaces exhibited electron-donating properties regardless of incubation temperature and became more hydrophilic as temperature decreased from 37 to 4°C. Moreover, the adhesion of cells grown at 4°C correlated with affinity for ethyl acetate, indicating the role of cell surface properties in adhesion.
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Affiliation(s)
- Bo-Hyung Lee
- BioFilm Control, Biopôle Clermont Limagne, Saint-Beauzire, France
- Université Clermont Auvergne, Clermont-Ferrand, France
| | - Michel Hébraud
- Institut National de la Recherche Agronomique, Université Clermont Auvergne, UMR MEDiS, Saint-Genès-Champanelle, France
| | - Thierry Bernardi
- BioFilm Control, Biopôle Clermont Limagne, Saint-Beauzire, France
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24
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Nowak J, Cruz CD, Tempelaars M, Abee T, van Vliet AHM, Fletcher GC, Hedderley D, Palmer J, Flint S. Persistent Listeria monocytogenes strains isolated from mussel production facilities form more biofilm but are not linked to specific genetic markers. Int J Food Microbiol 2017; 256:45-53. [PMID: 28599174 DOI: 10.1016/j.ijfoodmicro.2017.05.024] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 05/29/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
Abstract
Contamination of mussels with the human pathogen Listeria monocytogenes occurs during processing in the factory, possibly from bacteria persisting in the factory's indoor and outdoor areas. In this study, a selection of persistent (n=8) and sporadic (n=8) L. monocytogenes isolates associated with mussel-processing premises in New Zealand were investigated for their phenotypic and genomic characteristics. To identify traits that favour or contribute to bacterial persistence, biofilm formation, heat resistance, motility and recovery from dry surfaces were compared between persistent and sporadic isolates. All isolates exhibited low biofilm formation at 20°C, however, at 30°C persistent isolates showed significantly higher biofilm formation after 48h using cell enumeration and near significant difference using the crystal violet assay. All 16 isolates were motile at 20°C and 30°C and motility was fractionally higher for sporadic isolates, but no significant difference was observed. We found persistent isolates tend to exhibit greater recovery after incubation on dry surfaces compared to sporadic isolates. Two of the three most heat-resistant isolates were persistent, while four of five isolates lacking heat resistance were sporadic isolates. Comparison of genome sequences of persistent and sporadic isolates showed that there was no overall clustering of persistent or sporadic isolates, and that differences in prophages and plasmids were not associated with persistence. Our results suggest a link between persistence and biofilm formation, which is most likely multifactorial, combining subtle phenotypic and genotypic differences between isolates.
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Affiliation(s)
- Jessika Nowak
- The New Zealand Institute for Plant & Food Research Limited, Mt Albert, Auckland, New Zealand; Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand.
| | - Cristina D Cruz
- Division of Pharmaceutical Biosciences, Faculty of Pharmacy, Centre for Drug Research, University of Helsinki, Helsinki, Finland
| | - Marcel Tempelaars
- Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Tjakko Abee
- Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Arnoud H M van Vliet
- Department of Pathology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Graham C Fletcher
- The New Zealand Institute for Plant & Food Research Limited, Mt Albert, Auckland, New Zealand
| | - Duncan Hedderley
- The New Zealand Institute for Plant & Food Research Limited, Palmerston North, New Zealand
| | - Jon Palmer
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - Steve Flint
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
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25
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Buchanan RL, Gorris LG, Hayman MM, Jackson TC, Whiting RC. A review of Listeria monocytogenes : An update on outbreaks, virulence, dose-response, ecology, and risk assessments. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.12.016] [Citation(s) in RCA: 461] [Impact Index Per Article: 65.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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26
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Valdramidis VP, Koutsoumanis KP. Challenges and perspectives of advanced technologies in processing, distribution and storage for improving food safety. Curr Opin Food Sci 2016. [DOI: 10.1016/j.cofs.2016.08.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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27
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Stress-Induced Evolution of Heat Resistance and Resuscitation Speed in Escherichia coli O157:H7 ATCC 43888. Appl Environ Microbiol 2016; 82:6656-6663. [PMID: 27590820 DOI: 10.1128/aem.02027-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 08/27/2016] [Indexed: 11/20/2022] Open
Abstract
The development of resistance in foodborne pathogens to food preservation techniques is an issue of increasing concern, especially in minimally processed foods where safety relies on hurdle technology. In this context, mild heat can be used in combination with so-called nonthermal processes, such as high hydrostatic pressure (HHP), at lower individual intensities to better retain the quality of the food. However, mild stresses may increase the risk of (cross-)resistance development in the surviving population, which in turn might compromise food safety. In this investigation, we examined the evolution of Escherichia coli O157:H7 strain ATCC 43888 after recurrent exposure to progressively intensifying mild heat shocks (from 54.0°C to 60.0°C in 0.5°C increments) with intermittent resuscitation and growth of survivors. As such, mutant strains were obtained after 10 cycles of selection with ca. 106-fold higher heat resistance than that for the parental strain at 58.0°C, although this resistance did not extend to temperatures exceeding 60.0°C. Moreover, these mutant strains typically displayed cross-resistance against HHP shock and displayed signs of enhanced RpoS and RpoH activity. Interestingly, additional cycles of selection maintaining the intensity of the heat shock constant (58.5°C) selected for mutant strains in which resuscitation speed, rather than resistance, appeared to be increased. Therefore, it seems that resistance and resuscitation speed are rapidly evolvable traits in E. coli ATCC 43888 that can compromise food safety. IMPORTANCE In this investigation, we demonstrated that Escherichia coli O157:H7 ATCC 43888 rapidly acquires resistance to mild heat exposure, with this resistance yielding cross-protection to high hydrostatic pressure treatment. In addition, mutants of E. coli ATCC 43888 in which resuscitation speed, rather than resistance, appeared to be improved were selected. As such, both resistance and resuscitation speed seem to be rapidly evolvable traits that can compromise the control of foodborne pathogens in minimal processing strategies, which rely on the efficacy of combined mild preservation stresses for food safety.
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Minimal inhibitory concentrations of undissociated lactic, acetic, citric and propionic acid for Listeria monocytogenes under conditions relevant to cheese. Food Microbiol 2016; 58:63-7. [DOI: 10.1016/j.fm.2016.03.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 03/21/2016] [Accepted: 03/24/2016] [Indexed: 11/17/2022]
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Metselaar KI, Abee T, Zwietering MH, den Besten HMW. Modeling and Validation of the Ecological Behavior of Wild-Type Listeria monocytogenes and Stress-Resistant Variants. Appl Environ Microbiol 2016; 82:5389-401. [PMID: 27342563 PMCID: PMC4988195 DOI: 10.1128/aem.00442-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 06/21/2016] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED Listeria monocytogenes exhibits a heterogeneous response upon stress exposure which can be partially attributed to the presence of stable stress-resistant variants. This study aimed to evaluate the impact of the presence of stress-resistant variants of Listeria monocytogenes and their corresponding trade-offs on population composition under different environmental conditions. A set of stress robustness and growth parameters of the wild type (WT) and an rpsU deletion variant was obtained and used to model their growth behavior under combined mild stress conditions and to model their kinetics under single- and mixed-strain conditions in a simulated food chain. Growth predictions for the WT and the rpsU deletion variant matched the experimental data generally well, although some deviations from the predictions were observed. The data highlighted the influence of the environmental conditions on the ratio between the WT and variant. Prediction of performance in the simulated food chain proved to be challenging. The trend of faster growth and lower stress robustness for the WT than for the rpsU variant in the different steps of the chain was confirmed, but especially for the inactivation steps and the time needed to resume growth after an inactivation step, the experimental data deviated from the model predictions. This report provides insights into the conditions which can select for stress-resistant variants in industrial settings and discusses their potential persistence in food processing environments. IMPORTANCE Listeria monocytogenes exhibits a heterogeneous stress response which can partially be attributed to the presence of genetic variants. These stress-resistant variants survive better under severe conditions but have, on the other hand, a reduced growth rate. To date, the ecological behavior and potential impact of the presence of stress-resistant variants is not fully understood. In this study, we quantitatively assessed growth and inactivation behavior of wild-type L. monocytogenes and its stress-resistant variants. Predictions were validated under different conditions, as well as along a model food chain. This work illustrates the effects of environmental factors on population dynamics of L. monocytogenes and is a first step in evaluating the impact of population diversity on food safety.
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Affiliation(s)
- Karin I Metselaar
- Top Institute Food and Nutrition, Wageningen, the Netherlands Laboratory of Food Microbiology, Wageningen University, Wageningen, the Netherlands
| | - Tjakko Abee
- Top Institute Food and Nutrition, Wageningen, the Netherlands Laboratory of Food Microbiology, Wageningen University, Wageningen, the Netherlands
| | - Marcel H Zwietering
- Top Institute Food and Nutrition, Wageningen, the Netherlands Laboratory of Food Microbiology, Wageningen University, Wageningen, the Netherlands
| | - Heidy M W den Besten
- Laboratory of Food Microbiology, Wageningen University, Wageningen, the Netherlands
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Fister S, Robben C, Witte AK, Schoder D, Wagner M, Rossmanith P. Influence of Environmental Factors on Phage-Bacteria Interaction and on the Efficacy and Infectivity of Phage P100. Front Microbiol 2016; 7:1152. [PMID: 27516757 PMCID: PMC4964841 DOI: 10.3389/fmicb.2016.01152] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/11/2016] [Indexed: 11/13/2022] Open
Abstract
When using bacteriophages to control food-borne bacteria in food production plants and processed food, it is crucial to consider that environmental conditions influence their stability. These conditions can also affect the physiological state of bacteria and consequently host–virus interaction and the effectiveness of the phage ability to reduce bacteria numbers. In this study we investigated the stability, binding, and replication capability of phage P100 and its efficacy to control Listeria monocytogenes under conditions typically encountered in dairy plants. The influences of SDS, Lutensol AO 7, salt, smear water, and different temperatures were investigated. Results indicate that phage P100 is stable and able to bind to the host under most conditions tested. Replication was dependent upon the growth of L. monocytogenes and efficacy was higher when bacterial growth was reduced by certain environmental conditions. In long-term experiments at different temperatures phages were initially able to reduce bacteria up to seven log10 units after 2 weeks at 4°C. However, thereafter, re-growth and development of phage-resistant L. monocytogenes isolates were encountered.
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Affiliation(s)
- Susanne Fister
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary Medicine Vienna, Austria
| | - Christian Robben
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary Medicine Vienna, Austria
| | - Anna K Witte
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary Medicine Vienna, Austria
| | - Dagmar Schoder
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria; Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria
| | - Martin Wagner
- Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary Medicine Vienna, Austria
| | - Peter Rossmanith
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria; Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria
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González-Ramos D, Gorter de Vries AR, Grijseels SS, van Berkum MC, Swinnen S, van den Broek M, Nevoigt E, Daran JMG, Pronk JT, van Maris AJA. A new laboratory evolution approach to select for constitutive acetic acid tolerance in Saccharomyces cerevisiae and identification of causal mutations. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:173. [PMID: 27525042 PMCID: PMC4983051 DOI: 10.1186/s13068-016-0583-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/27/2016] [Indexed: 05/22/2023]
Abstract
BACKGROUND Acetic acid, released during hydrolysis of lignocellulosic feedstocks for second generation bioethanol production, inhibits yeast growth and alcoholic fermentation. Yeast biomass generated in a propagation step that precedes ethanol production should therefore express a high and constitutive level of acetic acid tolerance before introduction into lignocellulosic hydrolysates. However, earlier laboratory evolution strategies for increasing acetic acid tolerance of Saccharomyces cerevisiae, based on prolonged cultivation in the presence of acetic acid, selected for inducible rather than constitutive tolerance to this inhibitor. RESULTS Preadaptation in the presence of acetic acid was shown to strongly increase the fraction of yeast cells that could initiate growth in the presence of this inhibitor. Serial microaerobic batch cultivation, with alternating transfers to fresh medium with and without acetic acid, yielded evolved S. cerevisiae cultures with constitutive acetic acid tolerance. Single-cell lines isolated from five such evolution experiments after 50-55 transfers were selected for further study. An additional constitutively acetic acid tolerant mutant was selected after UV-mutagenesis. All six mutants showed an increased fraction of growing cells upon a transfer from a non-stressed condition to a medium containing acetic acid. Whole-genome sequencing identified six genes that contained (different) mutations in multiple acetic acid-tolerant mutants. Haploid segregation studies and expression of the mutant alleles in the unevolved ancestor strain identified causal mutations for the acquired acetic acid tolerance in four genes (ASG1, ADH3, SKS1 and GIS4). Effects of the mutations in ASG1, ADH3 and SKS1 on acetic acid tolerance were additive. CONCLUSIONS A novel laboratory evolution strategy based on alternating cultivation cycles in the presence and absence of acetic acid conferred a selective advantage to constitutively acetic acid-tolerant mutants and may be applicable for selection of constitutive tolerance to other stressors. Mutations in four genes (ASG1, ADH3, SKS1 and GIS4) were identified as causative for acetic acid tolerance. The laboratory evolution strategy as well as the identified mutations can contribute to improving acetic acid tolerance in industrial yeast strains.
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Affiliation(s)
- Daniel González-Ramos
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Arthur R. Gorter de Vries
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Sietske S. Grijseels
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Margo C. van Berkum
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Steve Swinnen
- Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Elke Nevoigt
- Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany
| | - Jean-Marc G. Daran
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Antonius J. A. van Maris
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
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