1
|
Wu J, McAuliffe O, O'Byrne CP. A novel RofA-family transcriptional regulator, GadR, controls the development of acid resistance in Listeria monocytogenes. mBio 2023; 14:e0171623. [PMID: 37882515 PMCID: PMC10746197 DOI: 10.1128/mbio.01716-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 09/19/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The ability to survive the acidic conditions found in the stomach is crucial for the food-borne pathogen Listeria monocytogenes to gain access to the mammalian gastrointestinal tract. Little is currently known about how acid resistance is regulated in this pathogen and why this trait is highly variable between strains. Here, we used comparative genomics to identify a novel RofA-family transcriptional regulator, GadR, that controls the development of acid resistance. The RofA family of regulators was previously found only in a small group of bacterial pathogens, including streptococci, where they regulate virulence properties. We show that gadR encodes the dominant regulator of acid resistance in L. monocytogenes and that its sequence variability accounts for previously observed differences between strains in this trait. Together, these findings significantly advance our understanding of how this important pathogen copes with acid stress and suggest a potential molecular target to aid its control in the food chain.
Collapse
Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Olivia McAuliffe
- Department of Food Biosciences, Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | - Conor P. O'Byrne
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| |
Collapse
|
2
|
Schulz LM, Konrath A, Rismondo J. Characterisation of the growth behaviour of Listeria monocytogenes in Listeria synthetic media. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:669-683. [PMID: 37864319 PMCID: PMC10667646 DOI: 10.1111/1758-2229.13183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 06/05/2023] [Indexed: 10/22/2023]
Abstract
The foodborne pathogen Listeria monocytogenes can grow in a wide range of environmental conditions. For the study of the physiology of this organism, several chemically defined media have been developed over the past decades. Here, we examined the ability of L. monocytogenes wildtype strains EGD-e and 10403S to grow under salt and pH stress in Listeria synthetic medium (LSM). Furthermore, we determined that a wide range of carbon sources could support the growth of both wildtype strains in LSM. However, for hexose phosphate sugars such as glucose-1-phosphate, both L. monocytogenes strains need to be pre-grown under conditions, where the major virulence regulator PrfA is active. In addition, growth of both L. monocytogenes strains was observed when LSM was supplemented with the amino acid sugar N-acetylmannosamine (ManNAc). We were able to show that some of the proteins encoded in the operon lmo2795-nanE, such as the ManNAc-6-phosphate epimerase NanE, are required for growth in the presence of ManNAc. The first gene of the operon, lmo2795, encodes a transcriptional regulator of the RpiR family. Using electrophoretic mobility shift assays and quantitative real-time PCR analysis, we were able to show that Lmo2795 binds to the promoter region of the operon lmo2795-nanE and activates its expression.
Collapse
Affiliation(s)
- Lisa Maria Schulz
- Department of General Microbiology, Institute of Microbiology and GeneticsGZMB, Georg‐August University GöttingenGöttingenGermany
| | - Alicia Konrath
- Department of General Microbiology, Institute of Microbiology and GeneticsGZMB, Georg‐August University GöttingenGöttingenGermany
| | - Jeanine Rismondo
- Department of General Microbiology, Institute of Microbiology and GeneticsGZMB, Georg‐August University GöttingenGöttingenGermany
| |
Collapse
|
3
|
Fang X, Zhang Y, Guo Q, Yuan M, Liang X, Liu J, Fang S, Yang Y, Fang C. GadR4 mediates the acid resistance and pathogenicity of Listeria monocytogenes 10403S by negatively regulating the gadT2/gadD2 cluster. Food Microbiol 2023; 112:104248. [PMID: 36906312 DOI: 10.1016/j.fm.2023.104248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 01/29/2023] [Accepted: 02/23/2023] [Indexed: 03/06/2023]
Abstract
Listeria monocytogenes is an important foodborne pathogen that can survive under acidic conditions. The glutamate decarboxylase (GAD) system is one of the acid resistance systems of L. monocytogenes. It usually comprises two glutamate transporters (GadT1/T2) and three glutamate decarboxylases (GadD1/D2/D3). Among them, gadT2/gadD2 contributes most significantly to the acid resistance of L. monocytogenes. However, the regulation mechanisms of gadT2/gadD2 still remain unclear. The results of this study indicated that gadT2/gadD2 deletion significantly decreases the survival rate of L. monocytogenes under different acidic conditions, including brain and heart infusion (BHI) broth, with a pH of 2.5, 2% citric acid, 2% acetic acid and 2% lactic acid. Further, gadT2/gadD2 cluster was expressed in the representative strains in response to alkaline stress rather than acid stress. To explore the regulation of gadT2/gadD2, we knocked out the five transcriptional factors belonging to the Rgg family in L. monocytogenes 10403S. We found that the deletion of gadR4, which exhibits the highest homology with the gadR of Lactococcus lactis, resulted in a significant increase in the survival rate of L. monocytogenes upon acid stress. Western blot analysis showed that gadR4 deletion significantly increased the gadD2 expression of L. monocytogenes under alkaline and neutral conditions. Furthermore, the gfp reporter gene showed that gadR4 deletion significantly increased the expression of the gadT2/gadD2 cluster. Adhesion and invasion assays indicated that gadR4 deletion significantly increased the rates of adhesion and invasion of L. monocytogenes to epithelial Caco-2 cells. Virulence assays showed that gadR4 knockout significantly improved the colonization ability of L. monocytogenes in the livers and spleens of the infected mice. Taken together, our results showed that GadR4, a transcription factor belonging to the Rgg family, negatively regulates the gadT2/gadD2 cluster, thus, reducing the acid stress tolerance and pathogenicity of L. monocytogens 10403S. Our results provide a better understanding of the regulation of the GAD system of L. monocytogenes and a novel approach to potentially prevent and control listeriosis.
Collapse
Affiliation(s)
- Xiaowei Fang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China; College of Agriculture, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Yu Zhang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Qian Guo
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Mei Yuan
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Xiongyan Liang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Jing Liu
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Shouguo Fang
- College of Agriculture, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Yuying Yang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Chun Fang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China.
| |
Collapse
|
4
|
Wu J, McAuliffe O, O'Byrne CP. Manganese uptake mediated by the NRAMP-type transporter MntH is required for acid tolerance in Listeria monocytogenes. Int J Food Microbiol 2023; 399:110238. [PMID: 37148667 DOI: 10.1016/j.ijfoodmicro.2023.110238] [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: 02/21/2023] [Revised: 04/25/2023] [Accepted: 04/27/2023] [Indexed: 05/08/2023]
Abstract
Listeria monocytogenes is a foodborne pathogen that is characterized by its ability to withstand mild stresses (i.e. cold, acid, salt) often encountered in food products or food processing environments. In the previous phenotypic and genotypic characterization of a collection of L. monocytogenes strains, we have identified one strain 1381, originally obtained from EURL-lm, as acid sensitive (reduced survival at pH 2.3) and extremely acid intolerant (no growth at pH 4.9, which supports the growth of most strains). In this study, we investigated the cause of acid intolerance in strain 1381 by isolating and sequencing reversion mutants that were capable of growth at low pH (pH 4.8) to a similar extent as another strain (1380) from the same MLST clonal complex (CC2). Whole genome sequencing showed that a truncation in mntH, which encodes a homologue of an NRAMP (Natural Resistance-Associated Macrophage Protein) type Mn2+ transporter, is responsible for the acid intolerance phenotype observed in strain 1381. However, the mntH truncation alone was not sufficient to explain the acid sensitivity of strain 1381 at lethal pH values as strain 1381R1 (a mntH+ revertant) exhibited similar acid survival to its parental strain at pH 2.3. Further growth experiments demonstrated that Mn2+ (but not Fe2+, Zn2+, Cu2+, Ca2+, or Mg2+) supplementation fully rescues the growth of strain 1381 under low pH conditions, suggesting that a Mn2+ limitation is the likely cause of growth arrest in the mntH- background. Consistent with the important role of Mn2+ in the acid stress response was the finding that mntH and mntB (both encoding Mn2+ transporters) had higher transcription levels following exposure to mild acid stress (pH 5). Taken together, these results provide evidence that MntH-mediated Mn2+ uptake is essential for the growth of L. monocytogenes under low pH conditions. Moreover, since strain 1381 was recommended for conducting food challenge studies by the European Union Reference Laboratory, the use of this strain in evaluating the growth of L. monocytogenes in low pH environments where Mn2+ is scarce should be reconsidered. Furthermore, since it is unknown when strain 1381 acquired the mntH frameshift mutation, the ability of the strains used for challenge studies to grow under food-related stresses needs to be routinely validated.
Collapse
Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland
| | | | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland..
| |
Collapse
|
5
|
Wu J, McAuliffe O, O'Byrne CP. Trehalose transport occurs via TreB in Listeria monocytogenes and it influences biofilm development and acid resistance. Int J Food Microbiol 2023; 394:110165. [PMID: 36933360 DOI: 10.1016/j.ijfoodmicro.2023.110165] [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: 12/25/2022] [Revised: 02/09/2023] [Accepted: 02/28/2023] [Indexed: 03/12/2023]
Abstract
Listeria monocytogenes is a pathogenic bacterium that can inhabit a diverse range of environmental niches. This is largely attributed to the high proportion of carbohydrate-specific phosphotransferase system (PTS) genes in its genome. Carbohydrates can be assimilated as sources of energy but additionally they can serve as niche-specific cues for L. monocytogenes to shape its global gene expression, in order to cope with anticipated stresses. To examine carbon source utilization among wild L. monocytogenes isolates and to understand underlying molecular mechanisms, a diverse collection of L. monocytogenes strains (n = 168) with whole genome sequence (WGS) data available was screened for the ability to grow in chemically defined media with different carbon sources. The majority of the strains grew in glucose, mannose, fructose, cellobiose, glycerol, trehalose, and sucrose. Maltose, lactose, and rhamnose supported slower growth while ribose did not support any growth. In contrast to other strains, strain1386, which belonged to clonal complex 5 (CC5), was unable to grow on trehalose as a sole carbon source. WGS data revealed that it carried a substitution (N352K) in a putative PTS EIIBC trehalose transporter, TreB, while this asparagine residue is conserved in other strains in this collection. Spontaneous mutants of strain 1386 that could grow in trehalose were found to harbour a reversion of the substitution in TreB. These results provide genetic evidence that TreB is responsible for trehalose uptake and that the N352 residue is essential for TreB activity. Moreover, reversion mutants also restored other unusual phenotypes that strain 1386 displayed, i.e. altered colony morphology, impaired biofilm development, and reduced acid resistance. Transcriptional analysis at stationary phase with buffered BHI media revealed that trehalose metabolism positively influences the transcription of genes encoding amino acid-based acid resistance mechanisms. In summary, our results demonstrated that N352 is key to the function of the sole trehalose transporter TreB in L. monocytogenes and suggest that trehalose metabolism alters physiology to favour biofilm development and acid stress resistance. Moreover, since strain 1386 is among the strains recommended by the European Union Reference Laboratory for conducting food challenge studies in order to determine whether or not L. monocytogenes can grow in food, these findings have important implications for food safety.
Collapse
Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland
| | | | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland.
| |
Collapse
|
6
|
Anast JM, Etter AJ, Schmitz‐Esser S. Comparative analysis of
Listeria monocytogenes
plasmid transcriptomes reveals common and plasmid‐specific gene expression patterns and high expression of noncoding RNAs. Microbiologyopen 2022; 11:e1315. [PMID: 36314750 PMCID: PMC9484302 DOI: 10.1002/mbo3.1315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/31/2022] [Accepted: 08/31/2022] [Indexed: 11/09/2022] Open
Abstract
Recent research demonstrated that some Listeria monocytogenes plasmids contribute to stress survival. However, only a few studies have analyzed gene expression patterns of L. monocytogenes plasmids. In this study, we identified four previously published stress‐response‐associated transcriptomic data sets which studied plasmid‐harboring L. monocytogenes strains but did not include an analysis of the plasmid transcriptomes. The four transcriptome data sets encompass three distinct plasmids from three different L. monocytogenes strains. Differential gene expression analysis of these plasmids revealed that the number of differentially expressed (DE) L. monocytogenes plasmid genes ranged from 30 to 45 with log2 fold changes of −2.2 to 6.8, depending on the plasmid. Genes often found to be DE included the cadmium resistance genes cadA and cadC, a gene encoding a putative NADH peroxidase, the putative ultraviolet resistance gene uvrX, and several uncharacterized noncoding RNAs (ncRNAs). Plasmid‐encoded ncRNAs were consistently among the highest expressed genes. In addition, one of the data sets utilized the same experimental conditions for two different strains harboring distinct plasmids. We found that the gene expression patterns of these two L. monocytogenes plasmids were highly divergent despite the identical treatments. These data suggest plasmid‐specific gene expression responses to environmental stimuli and differential plasmid regulation mechanisms between L. monocytogenes strains. Our findings further our understanding of the dynamic expression of L. monocytogenes plasmid‐encoded genes in diverse environmental conditions and highlight the need to expand the study of L. monocytogenes plasmid genes' functions.
Collapse
Affiliation(s)
- Justin M. Anast
- Department of Animal Science Iowa State University Ames Iowa USA
- Interdepartmental Microbiology Graduate Program Iowa State University Ames Iowa USA
| | - Andrea J. Etter
- Department of Nutrition and Food Sciences The University of Vermont Burlington Vermont USA
| | - Stephan Schmitz‐Esser
- Department of Animal Science Iowa State University Ames Iowa USA
- Interdepartmental Microbiology Graduate Program Iowa State University Ames Iowa USA
| |
Collapse
|
7
|
Gu X, Zhang R, Zhao J, Li C, Guo T, Yang S, Han T, Kong J. Fast-acidification promotes GABA synthesis in response to acid stress in Streptococcus thermophilus. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.113671] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
8
|
Lakicevic BZ, Den Besten HMW, De Biase D. Landscape of Stress Response and Virulence Genes Among Listeria monocytogenes Strains. Front Microbiol 2022; 12:738470. [PMID: 35126322 PMCID: PMC8811131 DOI: 10.3389/fmicb.2021.738470] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/30/2021] [Indexed: 12/23/2022] Open
Abstract
The pathogenic microorganism Listeria monocytogenes is ubiquitous and responsible for listeriosis, a disease with a high mortality rate in susceptible people. It can persist in different habitats, including the farm environment, the food production environments, and in foods. This pathogen can grow under challenging conditions, such as low pH, low temperatures, and high salt concentrations. However, L. monocytogenes has a high degree of strain divergence regarding virulence potential, environmental adaption, and stress response. This review seeks to provide the reader with an up-to-date overview of clonal and serotype-specific differences among L. monocytogenes strains. Emphasis on the genes and genomic islands responsible for virulence and resistance to environmental stresses is given to explain the complex adaptation among L. monocytogenes strains. Moreover, we highlight the use of advanced diagnostic technologies, such as whole-genome sequencing, to fine-tune quantitative microbiological risk assessment for better control of listeriosis.
Collapse
Affiliation(s)
- Brankica Z. Lakicevic
- Institute of Meat Hygiene and Technology, Belgrade, Serbia
- *Correspondence: Brankica Z. Lakicevic,
| | | | - Daniela De Biase
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy
| |
Collapse
|
9
|
Quereda JJ, Morón-García A, Palacios-Gorba C, Dessaux C, García-del Portillo F, Pucciarelli MG, Ortega AD. Pathogenicity and virulence of Listeria monocytogenes: A trip from environmental to medical microbiology. Virulence 2021; 12:2509-2545. [PMID: 34612177 PMCID: PMC8496543 DOI: 10.1080/21505594.2021.1975526] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 01/02/2023] Open
Abstract
Listeria monocytogenes is a saprophytic gram-positive bacterium, and an opportunistic foodborne pathogen that can produce listeriosis in humans and animals. It has evolved an exceptional ability to adapt to stress conditions encountered in different environments, resulting in a ubiquitous distribution. Because some food preservation methods and disinfection protocols in food-processing environments cannot efficiently prevent contaminations, L. monocytogenes constitutes a threat to human health and a challenge to food safety. In the host, Listeria colonizes the gastrointestinal tract, crosses the intestinal barrier, and disseminates through the blood to target organs. In immunocompromised individuals, the elderly, and pregnant women, the pathogen can cross the blood-brain and placental barriers, leading to neurolisteriosis and materno-fetal listeriosis. Molecular and cell biology studies of infection have proven L. monocytogenes to be a versatile pathogen that deploys unique strategies to invade different cell types, survive and move inside the eukaryotic host cell, and spread from cell to cell. Here, we present the multifaceted Listeria life cycle from a comprehensive perspective. We discuss genetic features of pathogenic Listeria species, analyze factors involved in food contamination, and review bacterial strategies to tolerate stresses encountered both during food processing and along the host's gastrointestinal tract. Then we dissect host-pathogen interactions underlying listerial pathogenesis in mammals from a cell biology and systemic point of view. Finally, we summarize the epidemiology, pathophysiology, and clinical features of listeriosis in humans and animals. This work aims to gather information from different fields crucial for a comprehensive understanding of the pathogenesis of L. monocytogenes.
Collapse
Affiliation(s)
- Juan J. Quereda
- Departamento de Producción y Sanidad Animal, Salud Pública Veterinaria y Ciencia y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities. Valencia, Spain
| | - Alvaro Morón-García
- Departamento de Biología Celular. Facultad de Ciencias Biológicas, Universidad Complutense de Madrid. Madrid, Spain
| | - Carla Palacios-Gorba
- Departamento de Producción y Sanidad Animal, Salud Pública Veterinaria y Ciencia y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities. Valencia, Spain
| | - Charlotte Dessaux
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CNB)- Consejo Superior De Investigaciones Científicas (CSIC), Madrid, Spain
| | - Francisco García-del Portillo
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CNB)- Consejo Superior De Investigaciones Científicas (CSIC), Madrid, Spain
| | - M. Graciela Pucciarelli
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CNB)- Consejo Superior De Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Biología Molecular ‘Severo Ochoa’. Departamento de Biología Molecular, Facultad de Ciencias, Universidad Autónoma de Madrid. Madrid, Spain
| | - Alvaro D. Ortega
- Departamento de Biología Celular. Facultad de Ciencias Biológicas, Universidad Complutense de Madrid. Madrid, Spain
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CNB)- Consejo Superior De Investigaciones Científicas (CSIC), Madrid, Spain
| |
Collapse
|
10
|
Gu X, Zhao J, Zhang R, Yu R, Guo T, Kong J. Molecular Analysis of Glutamate Decarboxylases in Enterococcus avium. Front Microbiol 2021; 12:691968. [PMID: 34566904 PMCID: PMC8461050 DOI: 10.3389/fmicb.2021.691968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 08/23/2021] [Indexed: 11/13/2022] Open
Abstract
Enterococcus avium (E. avium) is a common bacterium inhabiting the intestines of humans and other animals. Most strains of this species can produce gamma-aminobutyric acid (GABA) via the glutamate decarboxylase (GAD) system, but the presence and genetic organization of their GAD systems are poorly characterized. In this study, our bioinformatics analyses showed that the GAD system in E. avium strains was generally encoded by three gadB genes (gadB1, gadB2, and gadB3), together with an antiporter gene (gadC) and regulator gene (gadR), and these genes are organized in a cluster. This finding contrasts with that for other lactic acid bacteria. E. avium SDMCC050406, a GABA producer isolated from human feces, was employed to investigate the contribution of the three gadB genes to GABA biosynthesis. The results showed that the relative expression level of gadB3 was higher than those of gadB1 and gadB2 in the exponential growth and stationary phases, and this was accompanied by the synchronous transcription of gadC. After heterologous expression of the three gadB genes in Escherichia coli BL21 (DE3), the Km value of the purified GAD3 was 4.26 ± 0.48 mM, a value lower than those of the purified GAD1 and GAD2. Moreover, gadB3 gene inactivation caused decreased GABA production, accompanied by a reduction in resistance to acid stress. These results indicated that gadB3 plays a crucial role in GABA biosynthesis and this property endowed the strain with acid tolerance. Our findings provided insights into how E. avium strains survive the acidic environments of fermented foods and throughout transit through the stomach and gut while maintaining cell viability.
Collapse
Affiliation(s)
- Xinyi Gu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Jiancun Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Rongling Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Ruohan Yu
- College of Food Science and Engineering, Shandong Agricultural University, Tai'an, China
| | - Tingting Guo
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Jian Kong
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| |
Collapse
|
11
|
Anast JM, Schmitz-Esser S. Certain Listeria monocytogenes plasmids contribute to increased UVC ultraviolet light stress. FEMS Microbiol Lett 2021; 368:6367057. [PMID: 34498664 PMCID: PMC8457643 DOI: 10.1093/femsle/fnab123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 09/07/2021] [Indexed: 01/20/2023] Open
Abstract
Listeria monocytogenes is the causative agent of the highly fatal foodborne disease listeriosis and can persist in food production environments. Recent research highlights the involvement of L. monocytogenes plasmids in different stress response mechanisms, which contribute to its survival in food production facilities. Ultraviolet (UV) light in the UVC spectrum (200–280 nm) is used in food production to control microbial contamination. Although plasmid-encoded UV resistance mechanisms have been described in other bacteria, no research indicates that L. monocytogenes plasmids contribute to the UV stress response. The plasmids of L. monocytogenes strains 6179, 4KSM and R479a are genetically distinct and were utilized to study the roles of plasmids in the UV response. Wild-type and plasmid-cured variant cells were grown to logarithmic or late-stationary phase, plated on agar plates and exposed to UVC for 60 or 90 s, and colony-forming units (CFUs) were determined. CFUs of 6179 and 4KSM, bearing pLM6179 and p4KSM, respectively, were significantly (P-value < 0.05) higher than those of the plasmid-cured strains in both logarithmic and stationary phases. No difference in survival was observed for the R479a strain. Our data show for the first time that certain L. monocytogenes plasmids contribute to the survival of UVC light stress.
Collapse
Affiliation(s)
- Justin M Anast
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA.,Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA 50011, USA
| | - Stephan Schmitz-Esser
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA.,Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA 50011, USA
| |
Collapse
|
12
|
Arcari T, Feger ML, Guerreiro DN, Wu J, O’Byrne CP. Comparative Review of the Responses of Listeria monocytogenes and Escherichia coli to Low pH Stress. Genes (Basel) 2020; 11:genes11111330. [PMID: 33187233 PMCID: PMC7698193 DOI: 10.3390/genes11111330] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/03/2020] [Accepted: 11/09/2020] [Indexed: 02/07/2023] Open
Abstract
Acidity is one of the principal physicochemical factors that influence the behavior of microorganisms in any environment, and their response to it often determines their ability to grow and survive. Preventing the growth and survival of pathogenic bacteria or, conversely, promoting the growth of bacteria that are useful (in biotechnology and food production, for example), might be improved considerably by a deeper understanding of the protective responses that these microorganisms deploy in the face of acid stress. In this review, we survey the molecular mechanisms used by two unrelated bacterial species in their response to low pH stress. We chose to focus on two well-studied bacteria, Escherichia coli (phylum Proteobacteria) and Listeria monocytogenes (phylum Firmicutes), that have both evolved to be able to survive in the mammalian gastrointestinal tract. We review the mechanisms that these species use to maintain a functional intracellular pH as well as the protective mechanisms that they deploy to prevent acid damage to macromolecules in the cells. We discuss the mechanisms used to sense acid in the environment and the regulatory processes that are activated when acid is encountered. We also highlight the specific challenges presented by organic acids. Common themes emerge from this comparison as well as unique strategies that each species uses to cope with acid stress. We highlight some of the important research questions that still need to be addressed in this fascinating field.
Collapse
|
13
|
Sulforaphane-enriched extracts from glucoraphanin-rich broccoli exert antimicrobial activity against gut pathogens in vitro and innovative cooking methods increase in vivo intestinal delivery of sulforaphane. Eur J Nutr 2020; 60:1263-1276. [PMID: 32651764 PMCID: PMC7987625 DOI: 10.1007/s00394-020-02322-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 07/01/2020] [Indexed: 12/19/2022]
Abstract
Purpose Studies on broccoli (Brassica oleracea var. italica) indicate beneficial effects against a range of chronic diseases, commonly attributed to their bioactive phytochemicals. Sulforaphane, the bioactive form of glucoraphanin, is formed by the action of the indigenous enzyme myrosinase. This study explored the role that digestion and cooking practices play in bioactivity and bioavailability, especially the rarely considered dose delivered to the colon. Methods The antimicrobial activity of sulforaphane extracts from raw, cooked broccoli and cooked broccoli plus mustard seeds (as a source myrosinase) was assessed. The persistence of broccoli phytochemicals in the upper gastrointestinal tract was analysed in the ileal fluid of 11 ileostomates fed, in a cross-over design, broccoli soup prepared with and without mustard seeds. Results The raw broccoli had no antimicrobial activity, except against Bacillus cereus, but cooked broccoli (with and without mustard seeds) showed considerable antimicrobial activity against various tested pathogens. The recovery of sulforaphane in ileal fluids post soup consumption was < 1% but the addition of mustard seeds increased colon-available sulforaphane sixfold. However, when sulforaphane was extracted from the ileal fluid with the highest sulforaphane content and tested against Escherichia coli K12, no inhibitory effects were observed. Analysis of glucosinolates composition in ileal fluids revealed noticeable inter-individual differences, with six “responding” participants showing increases in glucosinolates after broccoli soup consumption. Conclusions Sulforaphane-rich broccoli extracts caused potent antimicrobial effects in vitro, and the consumption of sulforaphane-enriched broccoli soup may inhibit bacterial growth in the stomach and upper small intestine, but not in the terminal ileum or the colon. Electronic supplementary material The online version of this article (10.1007/s00394-020-02322-0) contains supplementary material, which is available to authorized users.
Collapse
|
14
|
Guerreiro DN, Arcari T, O'Byrne CP. The σ B-Mediated General Stress Response of Listeria monocytogenes: Life and Death Decision Making in a Pathogen. Front Microbiol 2020; 11:1505. [PMID: 32733414 PMCID: PMC7358398 DOI: 10.3389/fmicb.2020.01505] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/10/2020] [Indexed: 12/17/2022] Open
Abstract
Sensing and responding to environmental cues is critical for the adaptability and success of the food-borne bacterial pathogen Listeria monocytogenes. A supramolecular multi-protein complex known as the stressosome, which acts as a stress sensing hub, is responsible for orchestrating the activation of a signal transduction pathway resulting in the activation of σB, the sigma factor that controls the general stress response (GSR). When σB is released from the anti-sigma factor RsbW, a rapid up-regulation of the large σB regulon, comprised of ≥ 300 genes, ensures that cells respond appropriately to the new environmental conditions. A diversity of stresses including low pH, high osmolarity, and blue light are known to be sensed by the stressosome, resulting in a generalized increase in stress resistance. Appropriate activation of the stressosome and deployment of σB are critical to fitness as there is a trade-off between growth and stress protection when the GSR is deployed. We review the recent developments in this field and describe an up-to-date model of how this sensory organelle might integrate environmental signals to produce an appropriate activation of the GSR. Some of the outstanding questions and challenges in this fascinating field are also discussed.
Collapse
Affiliation(s)
- Duarte N Guerreiro
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Talia Arcari
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| |
Collapse
|
15
|
Barnes RH, Karatzas KAG. Investigation into the antimicrobial activity of fumarate against Listeria monocytogenes and its mode of action under acidic conditions. Int J Food Microbiol 2020; 324:108614. [DOI: 10.1016/j.ijfoodmicro.2020.108614] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/27/2020] [Accepted: 03/22/2020] [Indexed: 11/16/2022]
|
16
|
Matereke LT, Okoh AI. Listeria monocytogenes Virulence, Antimicrobial Resistance and Environmental Persistence: A Review. Pathogens 2020; 9:E528. [PMID: 32629911 PMCID: PMC7400505 DOI: 10.3390/pathogens9070528] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/06/2020] [Accepted: 06/20/2020] [Indexed: 12/23/2022] Open
Abstract
Listeria monocytogenes is a ubiquitous opportunistic pathogen responsible for the well-known listeriosis disease. This bacterium has become a common contaminant of food, threatening the food processing industry. Once consumed, the pathogen is capable of traversing epithelial barriers, cellular invasion, and intracellular replication through the modulation of virulence factors such as internalins and haemolysins. Mobile genetic elements (plasmids and transposons) and other sophisticated mechanisms are thought to contribute to the increasing antimicrobial resistance of L. monocytogenes. The environmental persistence of the pathogen is aided by its ability to withstand environmental stresses such as acidity, cold stress, osmotic stress, and oxidative stress. This review seeks to give an insight into L. monocytogenes biology, with emphasis on its virulence factors, antimicrobial resistance, and adaptations to environmental stresses.
Collapse
Affiliation(s)
- Lavious Tapiwa Matereke
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South Africa
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa
| | - Anthony Ifeanyi Okoh
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South Africa
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa
| |
Collapse
|
17
|
Paudyal R, O'Byrne CP, Karatzas KA. Amino acids other than glutamate affect the expression of the GAD system in Listeria monocytogenes enhancing acid resistance. Food Microbiol 2020; 90:103481. [PMID: 32336364 DOI: 10.1016/j.fm.2020.103481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 02/23/2020] [Accepted: 02/28/2020] [Indexed: 01/06/2023]
Abstract
The Glutamate Decarboxylase (GAD) system is important for survival of L. monocytogenes and other microorganisms under acidic conditions. Environmental conditions influence the function of the GAD system. Until now, the only conditions known to lead to increased transcription of the GAD system are the stationary phase in rich media and anoxic conditions. Previously, we showed that transcription of the GAD system requires unidentified compounds other than glutamate present in rich media. Following a test looking at various compounds we identified for first time that peptone, tryptone and casamino acids activate the GAD system under oxic conditions suggesting that amino acid(s) other than glutamate and/or peptides are important for the above process. The defined medium, where the GAD system is inactive, once it is supplemented with the above compounds results in an active intracellular and extracellular GAD system and increased acid resistance. Through functional genomics we show that these compounds are required for GadD2 activity and although we previously showed that GadD3 is active part of the intracellular GAD system, the supplementation did not activate this gene. The above is explained by the fact that only gadD2 transcription was upregulated by these compounds while the transcription of gadD1 and gadD3 remained unaffected. Together our results show that the L. monocytogenes GadD2 decarboxylase is activated in the presence of amino acids or peptides other than glutamate, a finding that has important implications for acid tolerance and food safety.
Collapse
Affiliation(s)
- Ranju Paudyal
- Department of Food and Nutritional Sciences, The University of Reading, PO Box 226, Whiteknights, Reading, RG6 6AP, UK
| | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Galway, Ireland
| | - Kimon Andreas Karatzas
- Department of Food and Nutritional Sciences, The University of Reading, PO Box 226, Whiteknights, Reading, RG6 6AP, UK.
| |
Collapse
|
18
|
A novel role for the glutamate decarboxylase system in Listeria monocytogenes; protection against oxidative stress. Food Microbiol 2020; 85:103284. [DOI: 10.1016/j.fm.2019.103284] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 07/30/2019] [Indexed: 12/17/2022]
|
19
|
Patange A, O’Byrne C, Boehm D, Cullen PJ, Keener K, Bourke P. The Effect of Atmospheric Cold Plasma on Bacterial Stress Responses and Virulence Using Listeria monocytogenes Knockout Mutants. Front Microbiol 2019; 10:2841. [PMID: 31921026 PMCID: PMC6918802 DOI: 10.3389/fmicb.2019.02841] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 11/22/2019] [Indexed: 12/28/2022] Open
Abstract
Listeria monocytogenes is an opportunistic intracellular pathogen commonly associated with serious infections and multiple food-borne outbreaks. In this study, we investigated the influence of atmospheric cold plasma (80 kV, 50 Hz) on L. monocytogenes (EGD-e) and its knockout mutants of sigB, rsbR, prfA, gadD, and lmo0799 genes at different treatment time intervals. Further, to ascertain if sub-lethal environmental stress conditions could influence L. monocytogenes survival and growth responses, atmospheric cold plasma (ACP) resistance was evaluated for the cultures exposed to cold (4°C) or acid (pH 4) stress for 1 h. The results demonstrate that both wild-type and knockout mutants were similarly affected after 1 min exposure to ACP (p > 0.05), with a difference in response noted only after 3 min of treatment. While all L. monocytogenes strains exposed to acid/cold stress were hypersensitive to ACP treatment and were significantly reduced or inactivated within 1 min of treatment (p < 0.05). The results indicate sigB and prfA are important for general stress resistance and biofilm, respectively, loss of these two genes significantly reduced bacterial resistance to ACP treatment. In addition, exposure to sub-lethal 1min ACP increased the gene expression of stress associated genes. SigB showed the highest gene expression, increasing by 15.60 fold, followed by gadD2 (7.19) and lmo0799 (8.6) after 1 min exposure. Overall, an increase in gene expression was seen in all stress associated genes analyzed both at 1 min treatment; while long treatment time reduced the gene expression and some cases down-regulated prfA and gadD3 gene expression. By comparing the response of mutants under ACP exposure to key processing parameters, the experimental results presented here provide a baseline for understanding the bacterial genetic response and resistance to cold plasma stress and offers promising insights for optimizing ACP applications.
Collapse
Affiliation(s)
- Apurva Patange
- School of Food Science and Environmental Health, Technological University Dublin, Dublin, Ireland
| | - Conor O’Byrne
- Bacterial Stress Response Group, School of Natural Sciences, National University of Ireland, Galway, Galway, Ireland
| | - Daniela Boehm
- School of Food Science and Environmental Health, Technological University Dublin, Dublin, Ireland
| | - P. J. Cullen
- School of Food Science and Environmental Health, Technological University Dublin, Dublin, Ireland
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, Australia
| | - Kevin Keener
- School of Food Science and Environmental Health, Technological University Dublin, Dublin, Ireland
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, United States
| | - Paula Bourke
- School of Food Science and Environmental Health, Technological University Dublin, Dublin, Ireland
- School of Biological Sciences, IGFS, Queen’s University Belfast, Belfast, United Kingdom
| |
Collapse
|
20
|
Harter E, Lassnig C, Wagner EM, Zaiser A, Wagner M, Rychli K. The Novel Internalins InlP1 and InlP4 and the Internalin-Like Protein InlP3 Enhance the Pathogenicity of Listeria monocytogenes. Front Microbiol 2019; 10:1644. [PMID: 31396177 PMCID: PMC6664051 DOI: 10.3389/fmicb.2019.01644] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/03/2019] [Indexed: 01/08/2023] Open
Abstract
The pathogenicity of the human foodborne pathogen Listeria monocytogenes relies on virulence factors such as internalins. In 2009/2010 two L. monocytogenes strains were responsible for a serious listeriosis outbreak in Austria, Germany, and the Czech Republic. One of these clones, QOC1, which caused 14 cases including five fatalities, encodes the novel internalins inlP1, inlPq and inlP4, and the novel internalin-like protein inlP3 in the genomic region of hypervariable genetic hotspot 9 in addition to the standard set of virulence genes. The in silico prevalence study revealed that these genes rarely occur in L. monocytogenes, mainly in minor clonal complexes. To obtain first insights of the role of these genes in the pathogenicity of L. monocytogenes, we studied the gene expression under conditions mimicking the ingestion in the host. Expression of inlP1, inlP3, inlPq and inlP4 was increased under gastric stress and in intracellular bacteria grown in intestinal epithelial cells. Furthermore, colonization of the liver and the spleen was slightly, but significantly reduced 72 h post infection in an oral mouse infection model when inlP1 or inlP4 was deleted. Moreover, the impact of InlP1 and InlP3 in virulence was shown in vitro in human intestinal epithelial cells. In this study we conclusively demonstrate a potential contribution of uncommon novel internalins and an internalin-like protein to the pathogenicity of L. monocytogenes.
Collapse
Affiliation(s)
- Eva Harter
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Caroline Lassnig
- Department of Biomedical Sciences, Institute of Animal Breeding and Genetics and Biomodels Austria, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Eva Maria Wagner
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
- Austrian Competence Centre for Feed and Food Quality, Safety and Innovation – FFoQSI GmbH, Tulln, Austria
| | - Andreas Zaiser
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Martin Wagner
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
- Austrian Competence Centre for Feed and Food Quality, Safety and Innovation – FFoQSI GmbH, Tulln, Austria
| | - Kathrin Rychli
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
| |
Collapse
|
21
|
Role and regulation of the stress activated sigma factor sigma B (σ B) in the saprophytic and host-associated life stages of Listeria monocytogenes. ADVANCES IN APPLIED MICROBIOLOGY 2019; 106:1-48. [PMID: 30798801 DOI: 10.1016/bs.aambs.2018.11.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The stress activated sigma factor sigma B (σB) plays a pivotal role in allowing the food-borne bacterial pathogen Listeria monocytogenes to modulate its transcriptional landscape in order to survive in a variety of harsh environments both outside and within the host. While we have a comparatively good understanding of the systems under the control of this sigma factor much less is known about how the activity of σB is controlled. In this review, we present a current model describing how this sigma factor is thought to be controlled including an overview of what is known about stress sensing and the early signal transduction events that trigger its activation. We discuss the known regulatory overlaps between σB and other protein and RNA regulators in the cell. Finally, we describe the role of σB in surviving both saprophytic and host-associated stresses. The complexity of the regulation of this sigma factor reflects the significant role that it plays in the persistence of this important pathogen in the natural environment, the food chain as well as within the host during the early stages of an infection. Understanding its regulation will be a critical step in helping to develop rational strategies to prevent its growth and survival in the food destined for human consumption and in the prevention of listeriosis.
Collapse
|
22
|
Bucur FI, Grigore-Gurgu L, Crauwels P, Riedel CU, Nicolau AI. Resistance of Listeria monocytogenes to Stress Conditions Encountered in Food and Food Processing Environments. Front Microbiol 2018; 9:2700. [PMID: 30555426 PMCID: PMC6282059 DOI: 10.3389/fmicb.2018.02700] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/23/2018] [Indexed: 12/17/2022] Open
Abstract
Listeria monocytogenes is a human food-borne facultative intracellular pathogen that is resistant to a wide range of stress conditions. As a consequence, L. monocytogenes is extremely difficult to control along the entire food chain from production to storage and consumption. Frequent and recent outbreaks of L. monocytogenes infections illustrate that current measures of decontamination and preservation are suboptimal to control L. monocytogenes in food. In order to develop efficient measures to prevent contamination during processing and control growth during storage of food it is crucial to understand the mechanisms utilized by L. monocytogenes to tolerate the stress conditions in food matrices and food processing environments. Food-related stress conditions encountered by L. monocytogenes along the food chain are acidity, oxidative and osmotic stress, low or high temperatures, presence of bacteriocins and other preserving additives, and stresses as a consequence of applying alternative decontamination and preservation technologies such high hydrostatic pressure, pulsed and continuous UV light, pulsed electric fields (PEF). This review is aimed at providing a summary of the current knowledge on the response of L. monocytogenes toward these stresses and the mechanisms of stress resistance employed by this important food-borne bacterium. Circumstances when L. monocytogenes cells become more sensitive or more resistant are mentioned and existence of a cross-resistance when multiple stresses are present is pointed out.
Collapse
Affiliation(s)
- Florentina Ionela Bucur
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Leontina Grigore-Gurgu
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Peter Crauwels
- Institute of Microbiology and Biotechnology, Ulm University, Ulm, Germany
| | | | - Anca Ioana Nicolau
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| |
Collapse
|
23
|
Pasquali F, Palma F, Guillier L, Lucchi A, De Cesare A, Manfreda G. Listeria monocytogenes Sequence Types 121 and 14 Repeatedly Isolated Within One Year of Sampling in a Rabbit Meat Processing Plant: Persistence and Ecophysiology. Front Microbiol 2018; 9:596. [PMID: 29662481 PMCID: PMC5890179 DOI: 10.3389/fmicb.2018.00596] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 03/15/2018] [Indexed: 01/15/2023] Open
Abstract
Listeria monocytogenes is a foodborne pathogen adapted to survive and persist in multiple environments. Following two previous studies on prevalence and virulence of L. monocytogenes ST121 and ST14 repeatedly collected in a the same rabbit-meat processing plant, the research questions of the present study were to: (1) assess persistence of L. monocytogenes isolates from the rabbit-plant; (2) select genes associated to physiological adaptation to the food-processing environment; (3) compare presence/absence/truncation of these genes in newly sequenced and publicly available ST121 and ST14 genomes. A total of 273 draft genomes including ST121 and ST14 newly sequenced and publicly available draft genomes were analyzed. Whole-genome Single Nucleotide Polymorfism (wgSNP) analysis was performed separately on the assemblies of ST121 and ST14 draft genomes. SNPs alignments were used to infer phylogeny. A dataset of L. monocytogenes ecophysiology genes was built based on a comprehensive literature review. The 94 selected genes were screened on the assemblies of all ST121 and ST14 draft genomes. Significant gene enrichments were evaluated by statistical analyses. A persistent ST14 clone, including 23 out of 27 newly sequenced genomes, was circulating in the rabbit-meat plant along with two not persistent clones. A significant enrichment was observed in ST121 genomes concerning stress survival islet 2 (SSI-2) (alkaline and oxidative stress), qacH gene (resistance to benzalkonium chloride), cadA1C gene cassette (resistance to 70 mg/l of cadmium chloride) and a truncated version of actA gene (biofilm formation). Conversely, ST14 draft genomes were enriched with a full-length version of actA gene along with the Listeria Genomic Island 2 (LGI 2) including the ars operon (arsenic resistance) and the cadA4C gene cassette (resistance to 35 mg/l of cadmium chloride). Phenotypic tests confirmed ST121 as a weak biofilm producer in comparison to ST14. In conclusion, ST121 carried the qacH gene and was phenotypically resistant to quaternary ammonium compounds. This property might contribute to the high prevalence of ST121 in food processing plants. ST14 showed greater ability to form biofilms, which might contribute to the occasional colonization and persistence on harborage sites where sanitizing procedures are difficult to display.
Collapse
Affiliation(s)
- Frédérique Pasquali
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum - Università di Bologna, Bologna, Italy
| | - Federica Palma
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum - Università di Bologna, Bologna, Italy
| | - Laurent Guillier
- Laboratoire de Sécurité des Aliments, Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail, Maisons-Alfort, France
| | - Alex Lucchi
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum - Università di Bologna, Bologna, Italy
| | - Alessandra De Cesare
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum - Università di Bologna, Bologna, Italy
| | - Gerardo Manfreda
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum - Università di Bologna, Bologna, Italy
| |
Collapse
|
24
|
Bergholz TM, Shah MK, Burall LS, Rakic-Martinez M, Datta AR. Genomic and phenotypic diversity of Listeria monocytogenes clonal complexes associated with human listeriosis. Appl Microbiol Biotechnol 2018; 102:3475-3485. [PMID: 29500754 DOI: 10.1007/s00253-018-8852-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/08/2018] [Accepted: 02/10/2018] [Indexed: 12/11/2022]
Abstract
Listeria monocytogenes is a pathogen of significant concern in many ready to eat foods due to its ability to survive and multiply even under significant environmental stresses. Listeriosis in humans is a concern, especially to high-risk populations such as those who are immunocompromised or pregnant, due to the high rates of morbidity and mortality. Whole genome sequencing has become a routine part of assessing L. monocytogenes isolated from patients, and the frequency of different genetic subtypes associated with listeriosis is now being reported. The recent abundance of genome sequences for L. monocytogenes has provided a wealth of information regarding the variation in core and accessory genomic elements. Newly described accessory genomic regions have been linked to greater virulence capabilities as well as greater resistance to environmental stressors such as sanitizers commonly used in food processing facilities. This review will provide a summary of our current understanding of stress response and virulence phenotypes of L. monocytogenes, within the context of the genetic diversity of the pathogen.
Collapse
Affiliation(s)
- Teresa M Bergholz
- Department of Microbiological Sciences, North Dakota State University, 130A Van Es, Fargo, ND, 58102, USA.
| | - Manoj K Shah
- Department of Microbiological Sciences, North Dakota State University, 130A Van Es, Fargo, ND, 58102, USA
| | - Laurel S Burall
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD, 20708, USA
| | - Mira Rakic-Martinez
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD, 20708, USA
| | - Atin R Datta
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD, 20708, USA
| |
Collapse
|
25
|
Götz F, Longnecker K, Kido Soule MC, Becker KW, McNichol J, Kujawinski EB, Sievert SM. Targeted metabolomics reveals proline as a major osmolyte in the chemolithoautotroph Sulfurimonas denitrificans. Microbiologyopen 2018; 7:e00586. [PMID: 29423975 PMCID: PMC6079173 DOI: 10.1002/mbo3.586] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/08/2017] [Accepted: 12/28/2017] [Indexed: 01/15/2023] Open
Abstract
Chemoautotrophic bacteria belonging to the genus Sulfurimonas in the class Campylobacteria are widespread in many marine environments characterized by redox interfaces, yet little is known about their physiological adaptations to different environmental conditions. Here, we used liquid chromatography coupled with tandem mass spectrometry (LC‐MS/MS) in a targeted metabolomics approach to study the adaptations of Sulfurimonas denitrificans to varying salt concentrations that are found in its natural habitat of tidal mudflats. Proline was identified as one of the most abundant internal metabolites and its concentration showed a strong positive correlation with ionic strength, suggesting that it acts as an important osmolyte in S. denitrificans. 2,3‐dihydroxypropane‐1‐sulfonate was also positively correlated with ionic strength, indicating it might play a previously unrecognized role in osmoregulation. Furthermore, the detection of metabolites from the reductive tricarboxylic acid cycle at high internal concentrations reinforces the importance of this pathway for carbon fixation in Campylobacteria and as a hub for biosynthesis. As the first report of metabolomic data for an campylobacterial chemolithoautotroph, this study provides data that will be useful to understand the adaptations of Campylobacteria to their natural habitat at redox interfaces.
Collapse
Affiliation(s)
- Florian Götz
- Biology DepartmentWoods Hole Oceanographic InstitutionWoods HoleMAUSA
| | - Krista Longnecker
- Department of Marine Chemistry and GeochemistryWoods Hole Oceanographic InstitutionWoods HoleMAUSA
| | - Melissa C. Kido Soule
- Department of Marine Chemistry and GeochemistryWoods Hole Oceanographic InstitutionWoods HoleMAUSA
| | - Kevin W. Becker
- Department of Marine Chemistry and GeochemistryWoods Hole Oceanographic InstitutionWoods HoleMAUSA
| | - Jesse McNichol
- Biology DepartmentWoods Hole Oceanographic InstitutionWoods HoleMAUSA
- Present address:
Department of Biological SciencesUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Elizabeth B. Kujawinski
- Department of Marine Chemistry and GeochemistryWoods Hole Oceanographic InstitutionWoods HoleMAUSA
| | - Stefan M. Sievert
- Biology DepartmentWoods Hole Oceanographic InstitutionWoods HoleMAUSA
| |
Collapse
|
26
|
Paudyal R, Barnes RH, Karatzas KAG. A novel approach in acidic disinfection through inhibition of acid resistance mechanisms; Maleic acid-mediated inhibition of glutamate decarboxylase activity enhances acid sensitivity of Listeria monocytogenes. Food Microbiol 2018; 69:96-104. [DOI: 10.1016/j.fm.2017.07.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 01/23/2023]
|
27
|
NicAogáin K, O’Byrne CP. The Role of Stress and Stress Adaptations in Determining the Fate of the Bacterial Pathogen Listeria monocytogenes in the Food Chain. Front Microbiol 2016; 7:1865. [PMID: 27933042 PMCID: PMC5120093 DOI: 10.3389/fmicb.2016.01865] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 11/04/2016] [Indexed: 12/15/2022] Open
Abstract
The foodborne pathogen Listeria monocytogenes is a highly adaptable organism that can persist in a wide range of environmental and food-related niches. The consumption of contaminated ready-to-eat foods can cause infections, termed listeriosis, in vulnerable humans, particularly those with weakened immune systems. Although these infections are comparatively rare they are associated with high mortality rates and therefore this pathogen has a significant impact on food safety. L. monocytogenes can adapt to and survive a wide range of stress conditions including low pH, low water activity, and low temperature, which makes it problematic for food producers who rely on these stresses for preservation. Stress tolerance in L. monocytogenes can be explained partially by the presence of the general stress response (GSR), a transcriptional response under the control of the alternative sigma factor sigma B (σB) that reconfigures gene transcription to provide homeostatic and protective functions to cope with the stress. Within the host σB also plays a key role in surviving the harsh conditions found in the gastrointestinal tract. As the infection progresses beyond the GI tract L. monocytogenes uses an intracellular infectious cycle to propagate, spread and remain protected from the host's humoral immunity. Many of the virulence genes that facilitate this infectious cycle are under the control of a master transcriptional regulator called PrfA. In this review we consider the environmental reservoirs that enable L. monocytogenes to gain access to the food chain and discuss the stresses that the pathogen must overcome to survive and grow in these environments. The overlap that exists between stress tolerance and virulence is described. We review the principal measures that are used to control the pathogen and point to exciting new approaches that might provide improved means of control in the future.
Collapse
Affiliation(s)
| | - Conor P. O’Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, College of Science, National University of IrelandGalway, Ireland
| |
Collapse
|
28
|
Saá Ibusquiza P, Nierop Groot M, Debán-Valles A, Abee T, den Besten HM. Impact of growth conditions and role of sigB on Listeria monocytogenes fitness in single and mixed biofilms cultured with Lactobacillus plantarum. Food Res Int 2015. [DOI: 10.1016/j.foodres.2015.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|