51
|
Regulation of Listeria virulence: PrfA master and commander. Curr Opin Microbiol 2011; 14:118-27. [DOI: 10.1016/j.mib.2011.01.005] [Citation(s) in RCA: 202] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 01/21/2011] [Accepted: 01/24/2011] [Indexed: 11/19/2022]
|
52
|
Gorski L, Duhé JM, Flaherty D. The Sigma B operon is a determinant of fitness for a Listeria monocytogenes serotype 4b strain in soil. Foodborne Pathog Dis 2011; 8:699-704. [PMID: 21381923 DOI: 10.1089/fpd.2010.0752] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In nature the foodborne pathogen Listeria monocytogenes lives as a saprophyte where it can contaminate preharvest produce. This environment can present many stresses such as ultraviolet light, variations in temperature and humidity, and oxidative stress from growing plant matter in the soil. The alternative sigma factor Sigma B, encoded by sigB, controls the response to most stresses in L. monocytogenes. Fitness in soil and on radishes sown and grown in contaminated soil was measured in a wild-type and an isogenic sigB operon mutant strain to determine if the sigma factor was necessary for life in these niches. Levels of wild-type and mutant strains were monitored in contaminated soil over the course of radish gestation from seed to mature tuber, and levels on mature radishes were determined. The wild-type strain was able to survive in soil over the 4 weeks of the experiment at levels of 4-7 log CFU/g soil, and the levels of the sigB mutant were reduced by 1-2 log from the wild type. The mutant showed reduced levels in soil by 6 h after inoculation, which was partially recovered when the mutant was complemented, and stayed at a reduced level over the next 4 weeks. Upon harvest, 3-4 log CFU/g of wild-type L. monocytogenes was detected on radish surfaces, and the bacteria could not be washed off under running water. On mature radishes populations of the mutant strain were 1-2 log CFU/g lower than the wild type. The levels on mature radishes reflected the levels in the soil at 4 weeks. The conclusions are that the Sigma B operon is necessary for initial adaptation to the soil environment, and plays a role in maintaining the population, but does not play a role in attachment or colonization of the radish.
Collapse
Affiliation(s)
- Lisa Gorski
- Produce Safety and Microbiology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710, USA.
| | | | | |
Collapse
|
53
|
Maddocks L, Khanna P, Reay-Jones N. A complicated case of cholecystitis, listeriosis and HIV/AIDS. BMJ Case Rep 2011; 2011:2011/jan20_1/bcr0820103292. [PMID: 22715268 DOI: 10.1136/bcr.08.2010.3292] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
A 37-year-old woman of Tanzanian origin presented with symptoms of cholecystitis, sepsis and oral candidiasis. Subsequent investigation found listeriosis and HIV infection. Effective use of the appropriate antibiotics and surgical management to remove the source of sepsis lead to a good recovery from the acute illness. The patient was subsequently transferred to a tertiary centre for specialist care of her underlying chronic condition of HIV/AIDS. Her case demonstrates a previously unreported association of HIV, Listeria and cholecystitis.
Collapse
Affiliation(s)
- L Maddocks
- Barnet and Chase Farm NHS Trust, Chase Farm Hospital, The Ridgeway, Enfield, Middlesex, UK.
| | | | | |
Collapse
|
54
|
Blue and red light modulates SigB-dependent gene transcription, swimming motility and invasiveness in Listeria monocytogenes. PLoS One 2011; 6:e16151. [PMID: 21264304 PMCID: PMC3019169 DOI: 10.1371/journal.pone.0016151] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 12/14/2010] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. METHODOLOGY/PRINCIPAL FINDINGS By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. CONCLUSIONS/SIGNIFICANCE Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat.
Collapse
|
55
|
Bruno JC, Freitag NE. Constitutive activation of PrfA tilts the balance of Listeria monocytogenes fitness towards life within the host versus environmental survival. PLoS One 2010; 5:e15138. [PMID: 21151923 PMCID: PMC2998416 DOI: 10.1371/journal.pone.0015138] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2010] [Accepted: 10/25/2010] [Indexed: 01/21/2023] Open
Abstract
PrfA is a key regulator of Listeria monocytogenes pathogenesis and induces the expression of multiple virulence factors within the infected host. PrfA is post-translationally regulated such that the protein becomes activated upon bacterial entry into the cell cytosol. The signal that triggers PrfA activation remains unknown, however mutations have been identified (prfA* mutations) that lock the protein into a high activity state. In this report we examine the consequences of constitutive PrfA activation on L. monocytogenes fitness both in vitro and in vivo. Whereas prfA* mutants were hyper-virulent during animal infection, the mutants were compromised for fitness in broth culture and under conditions of stress. Broth culture prfA*-associated fitness defects were alleviated when glycerol was provided as the principal carbon source; under these conditions prfA* mutants exhibited a competitive advantage over wild type strains. Glycerol and other three carbon sugars have been reported to serve as primary carbon sources for L. monocytogenes during cytosolic growth, thus prfA* mutants are metabolically-primed for replication within eukaryotic cells. These results indicate the critical need for environment-appropriate regulation of PrfA activity to enable L. monocytogenes to optimize bacterial fitness inside and outside of host cells.
Collapse
Affiliation(s)
- Joseph C. Bruno
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Nancy E. Freitag
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, Illinois, United States of America
| |
Collapse
|
56
|
Listeria monocytogenes uses Listeria adhesion protein (LAP) to promote bacterial transepithelial translocation and induces expression of LAP receptor Hsp60. Infect Immun 2010; 78:5062-73. [PMID: 20876294 DOI: 10.1128/iai.00516-10] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Listeria monocytogenes interaction with the intestinal epithelium is a key step in the infection process. We demonstrated that Listeria adhesion protein (LAP) promotes adhesion to intestinal epithelial cells and facilitates extraintestinal dissemination in vivo. The LAP receptor is a stress response protein, Hsp60, but the precise role for the LAP-Hsp60 interaction during Listeria infection is unknown. Here we investigated the influence of physiological stressors and Listeria infection on host Hsp60 expression and LAP-mediated bacterial adhesion, invasion, and transepithelial translocation in an enterocyte-like Caco-2 cell model. Stressors such as heat (41°C), tumor necrosis factor alpha (TNF-α) (100 U), and L. monocytogenes infection (10(4) to 10(6) CFU/ml) significantly (P < 0.05) increased plasma membrane and intracellular Hsp60 levels in Caco-2 cells and consequently enhanced LAP-mediated L. monocytogenes adhesion but not invasion of Caco-2 cells. In transepithelial translocation experiments, the wild type (WT) exhibited 2.7-fold more translocation through Caco-2 monolayers than a lap mutant, suggesting that LAP is involved in transepithelial translocation, potentially via a paracellular route. Short hairpin RNA (shRNA) suppression of Hsp60 in Caco-2 cells reduced WT adhesion and translocation 4.5- and 3-fold, respectively, while adhesion remained unchanged for the lap mutant. Conversely, overexpression of Hsp60 in Caco-2 cells enhanced WT adhesion and transepithelial translocation, but not those of the lap mutant. Furthermore, initial infection with a low dosage (10(6) CFU/ml) of L. monocytogenes increased plasma membrane and intracellular expression of Hsp60 significantly, which rendered Caco-2 cells more susceptible to subsequent LAP-mediated adhesion and translocation. These data provide insight into the role of LAP as a virulence factor during intestinal epithelial infection and pose new questions regarding the dynamics between the host stress response and pathogen infection.
Collapse
|
57
|
Deng X, Phillippy AM, Li Z, Salzberg SL, Zhang W. Probing the pan-genome of Listeria monocytogenes: new insights into intraspecific niche expansion and genomic diversification. BMC Genomics 2010; 11:500. [PMID: 20846431 PMCID: PMC2996996 DOI: 10.1186/1471-2164-11-500] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 09/16/2010] [Indexed: 11/25/2022] Open
Abstract
Background Bacterial pathogens often show significant intraspecific variations in ecological fitness, host preference and pathogenic potential to cause infectious disease. The species of Listeria monocytogenes, a facultative intracellular pathogen and the causative agent of human listeriosis, consists of at least three distinct genetic lineages. Two of these lineages predominantly cause human sporadic and epidemic infections, whereas the third lineage has never been implicated in human disease outbreaks despite its overall conservation of many known virulence factors. Results Here we compare the genomes of 26 L. monocytogenes strains representing the three lineages based on both in silico comparative genomic analysis and high-density, pan-genomic DNA array hybridizations. We uncover 86 genes and 8 small regulatory RNAs that likely make L. monocytogenes lineages differ in carbohydrate utilization and stress resistance during their residence in natural habitats and passage through the host gastrointestinal tract. We also identify 2,330 to 2,456 core genes that define this species along with an open pan-genome pool that contains more than 4,052 genes. Phylogenomic reconstructions based on 3,560 homologous groups allowed robust estimation of phylogenetic relatedness among L. monocytogenes strains. Conclusions Our pan-genome approach enables accurate co-analysis of DNA sequence and hybridization array data for both core gene estimation and phylogenomics. Application of our method to the pan-genome of L. monocytogenes sheds new insights into the intraspecific niche expansion and evolution of this important foodborne pathogen.
Collapse
Affiliation(s)
- Xiangyu Deng
- National Center for Food Safety and Technology, Illinois Institute of Technology, Summit, Illinois 60501, USA
| | | | | | | | | |
Collapse
|
58
|
Jagadeesan B, Koo OK, Kim KP, Burkholder KM, Mishra KK, Aroonnual A, Bhunia AK. LAP, an alcohol acetaldehyde dehydrogenase enzyme in Listeria, promotes bacterial adhesion to enterocyte-like Caco-2 cells only in pathogenic species. Microbiology (Reading) 2010; 156:2782-2795. [PMID: 20507888 DOI: 10.1099/mic.0.036509-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Listeria adhesion protein (LAP), an alcohol acetaldehyde dehydrogenase (lmo1634), interacts with host-cell receptor Hsp60 to promote bacterial adhesion during the intestinal phase of Listeria monocytogenes infection. The LAP homologue is present in pathogens (L. monocytogenes, L. ivanovii) and non-pathogens (L. innocua, L. welshimeri, L. seeligeri); however, its role in non-pathogens is unknown. Sequence analysis revealed 98 % amino acid similarity in LAP from all Listeria species. The N-terminus contains acetaldehyde dehydrogenase (ALDH) and the C-terminus an alcohol dehydrogenase (ADH). Recombinant LAP from L. monocytogenes, L. ivanovii, L. innocua and L. welshimeri exhibited ALDH and ADH activities, and displayed strong binding affinity (K
D 2–31 nM) towards Hsp60. Flow cytometry, ELISA and immunoelectron microscopy revealed more surface-associated LAP in pathogens than non-pathogens. Pathogens exhibited significantly higher adhesion (P<0.05) to Caco-2 cells than non-pathogens; however, pretreatment of bacteria with Hsp60 caused 47–92 % reduction in adhesion only in pathogens. These data suggest that biochemical properties of LAP from pathogenic Listeria are similar to those of the protein from non-pathogens in many respects, such as substrate specificity, immunogenicity, and binding affinity to Hsp60. However, protein fractionation analysis of extracts from pathogenic and non-pathogenic Listeria species revealed that LAP was greatly reduced in intracellular and cell-surface protein fractions, and undetectable in the extracellular milieu of non-pathogens even though the lap transcript levels were similar for both. Furthermore, a LAP preparation from L. monocytogenes restored adhesion in a lap mutant (KB208) of L. monocytogenes but not in L. innocua, indicating possible lack of surface reassociation of LAP molecules in this bacterium. Taken together, these data suggest that LAP expression level, cell-surface localization, secretion and reassociation are responsible for LAP-mediated pathogenicity and possibly evolved to adapt to a parasitic life cycle in the host.
Collapse
Affiliation(s)
- Balamurugan Jagadeesan
- Molecular Food Microbiology Laboratory, Department of Food Science, 745 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907, USA
| | - Ok Kyung Koo
- Molecular Food Microbiology Laboratory, Department of Food Science, 745 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907, USA
| | - Kwang-Pyo Kim
- Molecular Food Microbiology Laboratory, Department of Food Science, 745 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907, USA
| | - Kristin M. Burkholder
- Molecular Food Microbiology Laboratory, Department of Food Science, 745 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907, USA
| | - Krishna K. Mishra
- Molecular Food Microbiology Laboratory, Department of Food Science, 745 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907, USA
| | - Amornrat Aroonnual
- Molecular Food Microbiology Laboratory, Department of Food Science, 745 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907, USA
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, 745 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907, USA
| |
Collapse
|
59
|
Schuppler M, Loessner MJ. The Opportunistic Pathogen Listeria monocytogenes: Pathogenicity and Interaction with the Mucosal Immune System. Int J Inflam 2010; 2010:704321. [PMID: 21188219 PMCID: PMC3003996 DOI: 10.4061/2010/704321] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 06/01/2010] [Indexed: 12/22/2022] Open
Abstract
Listeria monocytogenes is an opportunistic foodborne pathogen causing listeriosis, an often fatal infection leading to meningitis, sepsis, or infection of the fetus and abortion in susceptible individuals. It was recently found that the bacterium can also cause acute, self-limiting febrile gastroenteritis in healthy individuals. In the intestinal tract, L. monocytogenes penetrates the mucosa directly via enterocytes, or indirectly via invasion of Peyer's patches. Animal models for L. monocytogenes infection have provided many insights into the mechanisms of pathogenesis, and the development of new model systems has allowed the investigation of factors that influence adaptation to the gastrointestinal environment as well as adhesion to and invasion of the intestinal mucosa. The mucosal surfaces of the gastrointestinal tract are permanently exposed to an enormous antigenic load derived from the gastrointestinal microbiota present in the human bowel. The integrity of the important epithelial barrier is maintained by the mucosal immune system and its interaction with the commensal flora via pattern recognition receptors (PRRs). Here, we discuss recent advances in our understanding of the interaction of L. monocytogenes with the host immune system that triggers the antibacterial immune responses on the mucosal surfaces of the human gastrointestinal tract.
Collapse
Affiliation(s)
- Markus Schuppler
- Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstraße 7, 8092 Zurich, Switzerland
| | | |
Collapse
|
60
|
Maltose and maltodextrin utilization by Listeria monocytogenes depend on an inducible ABC transporter which is repressed by glucose. PLoS One 2010; 5:e10349. [PMID: 20436965 PMCID: PMC2860498 DOI: 10.1371/journal.pone.0010349] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Accepted: 04/07/2010] [Indexed: 01/19/2023] Open
Abstract
Background In the environment as well as in the vertebrate intestine, Listeriae have access to complex carbohydrates like maltodextrins. Bacterial exploitation of such compounds requires specific uptake and utilization systems. Methodology/Principal Findings We could show that Listeria monocytogenes and other Listeria species contain genes/gene products with high homology to the maltodextrin ABC transporter and utilization system of B. subtilis. Mutant construction and growth tests revealed that the L. monocytogenes gene cluster was required for the efficient utilization of maltodextrins as well as maltose. The gene for the ATP binding protein of the transporter was located distant from the cluster. Transcription analyses demonstrated that the system was induced by maltose/maltodextrins and repressed by glucose. Its induction was dependent on a LacI type transcriptional regulator. Repression by glucose was independent of the catabolite control protein CcpA, but was relieved in a mutant defective for Hpr kinase/phosphorylase. Conclusions/Significance The data obtained show that in L. monocytogenes the uptake of maltodextrin and, in contrast to B. subtilis, also maltose is exclusively mediated by an ABC transporter. Furthermore, the results suggest that glucose repression of the uptake system possibly is by inducer exclusion, a mechanism not described so far in this organism.
Collapse
|
61
|
The stress-induced virulence protein InlH controls interleukin-6 production during murine listeriosis. Infect Immun 2010; 78:1979-89. [PMID: 20176794 DOI: 10.1128/iai.01096-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome of the pathogenic bacterium Listeria monocytogenes contains a family of genes encoding proteins with a leucine-rich repeat domain. One of these genes, inlH, is a sigma(B)-dependent virulence gene of unknown function. Previously, inlH was proposed to be coexpressed with two adjacent internalin genes, inlG and inlE. Using tiling arrays, we showed that inlH expression is monocistronic and specifically induced in stationary phase as well as in the intestinal lumen of mice, independent of inlG and inlE expression. Consistent with inlH sigma(B)-dependent regulation, surface expression of the InlH protein is induced when bacteria are subjected to thermal, acidic, osmotic, or oxidative stress. Disruption of inlH increases the amount of the invasion protein InlA without changing inlA transcript level, suggesting that there is a link between inlH expression and inlA posttranscriptional regulation. However, in contrast to InlA, InlH does not contribute to bacterial invasion of cultured cells in vitro or of intestinal cells in vivo. Strikingly, the reduced virulence of inlH-deficient L. monocytogenes strains is accompanied by enhanced production of interleukin-6 (IL-6) in infected tissues during the systemic phase of murine listeriosis but not by enhanced production of any other inflammatory cytokine tested. Since InlH does not modulate IL-6 secretion in macrophages at least in vitro, it may play a role in other immune cells or contribute to a pathway that modulates survival or activation of IL-6-secreting cells. These results strongly suggest that InlH is a stress-induced surface protein that facilitates pathogen survival in tissues by tempering the inflammatory response.
Collapse
|
62
|
Ramalheira R, Almeida M, Azeredo J, Brandão TR, Almeida G, Silva J, Teixeira P. Survival of Clinical and Food Isolates of Listeria monocytogenes Through Simulated Gastrointestinal Tract Conditions. Foodborne Pathog Dis 2010; 7:121-8. [DOI: 10.1089/fpd.2009.0319] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Rosário Ramalheira
- CBQF/Biotechnology School, Portuguese Catholic University, Oporto, Portugal
| | - Marta Almeida
- Biological Engineering Department, University of Minho, Braga, Portugal
| | - Joana Azeredo
- Biological Engineering Department, University of Minho, Braga, Portugal
| | | | - Gonçalo Almeida
- CBQF/Biotechnology School, Portuguese Catholic University, Oporto, Portugal
| | - Joana Silva
- CBQF/Biotechnology School, Portuguese Catholic University, Oporto, Portugal
| | - Paula Teixeira
- CBQF/Biotechnology School, Portuguese Catholic University, Oporto, Portugal
| |
Collapse
|
63
|
Specific osmolyte transporters mediate bile tolerance in Listeria monocytogenes. Infect Immun 2009; 77:4895-904. [PMID: 19737907 DOI: 10.1128/iai.00153-09] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The food-borne pathogenic bacterium Listeria monocytogenes has the potential to adapt to an array of suboptimal growth environments encountered within the host. The pathogen is relatively bile tolerant and has the capacity to survive and grow within both the small intestine and the gallbladder in murine models of oral infection. We have previously demonstrated a role for the principal carnitine transport system of L. monocytogenes (OpuC) in gastrointestinal survival of the pathogen (R. Sleator, J. Wouters, C. G. M. Gahan, T. Abee, and C. Hill, Appl. Environ. Microbiol. 67:2692-2698, 2001). However, the mechanisms by which OpuC, or indeed carnitine, protects the pathogen in this environment are unclear. In the current study, systematic analysis of strains with mutations in osmolyte transporters revealed a role for OpuC in resisting the acute toxicity of bile, with a minor role also played by BetL, a secondary betaine uptake system which also exhibits a low affinity for carnitine. In addition, the toxic effects of bile on wild-type L. monocytogenes cells were ameliorated when carnitine (but not betaine) was added to the medium. lux-promoter fusions to the promoters of the genes encoding the principal osmolyte uptake systems Gbu, BetL, and OpuC and the known bile tolerance system BilE were constructed. Promoter activity for all systems was significantly induced in the presence of bile, with the opuC and bilE promoters exhibiting the highest levels of bile-dependent expression in vitro and the betL and bilE promoters showing the highest expression levels in the intestines of orally inoculated mice. A direct comparison of all osmolyte transporter mutants in a murine oral infection model confirmed a major role for OpuC in intestinal persistence and systemic invasion and a minor role for the BetL transporter in fecal carriage. This study therefore demonstrates a previously unrecognized function for osmolyte uptake systems in bile tolerance in L. monocytogenes.
Collapse
|
64
|
Burkholder KM, Kim KP, Mishra KK, Medina S, Hahm BK, Kim H, Bhunia AK. Expression of LAP, a SecA2-dependent secretory protein, is induced under anaerobic environment. Microbes Infect 2009; 11:859-67. [DOI: 10.1016/j.micinf.2009.05.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 05/06/2009] [Accepted: 05/07/2009] [Indexed: 10/20/2022]
|
65
|
Freitag NE, Port GC, Miner MD. Listeria monocytogenes - from saprophyte to intracellular pathogen. Nat Rev Microbiol 2009; 7:623-8. [PMID: 19648949 DOI: 10.1038/nrmicro2171] [Citation(s) in RCA: 404] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Listeria monocytogenes is a bacterium that lives in the soil as a saprophyte but is capable of making the transition into a pathogen following its ingestion by susceptible humans or animals. Recent studies suggest that L. monocytogenes mediates its saprophyte-to-cytosolic-parasite transition through the careful modulation of the activity of a virulence regulatory protein known as PrfA, using a range of environmental cues that include available carbon sources. In this Progress article we describe the regulation of PrfA and its role in the L. monocytogenes transition from the saprophytic stage to the virulent intracellular stage.
Collapse
Affiliation(s)
- Nancy E Freitag
- Department of Microbiology and Immunology (MC790), University of Illinois at Chicago, 835 South Wolcott Avenue, Chicago, Illinois 606127344, USA.
| | | | | |
Collapse
|
66
|
Rieu A, Guzzo J, Piveteau P. Sensitivity to acetic acid, ability to colonize abiotic surfaces and virulence potential of Listeria monocytogenes EGD-e after incubation on parsley leaves. J Appl Microbiol 2009; 108:560-70. [PMID: 19778346 DOI: 10.1111/j.1365-2672.2009.04463.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM To investigate how the survival of Listeria monocytogenes on parsley leaves may affect its ability to sustain process-related harsh conditions and its virulence. METHODS AND RESULTS Parsley seedlings were spot inoculated with stationary phase cells of L. monocytogenes EGD-e and incubated for 15 days. Each day, bacterial cells were harvested and enumerated, and their ability to survive acetic acid challenge (90 min, pH 4.0), to colonize abiotic surfaces and to grow as biofilms was assessed. After a 3-log decrease over the first 48 h, the population stabilized to about 10(6) CFU g(-1) until the sixth day. After the sixth day, L. monocytogenes was no longer detected, even after specific enrichment. Incubation on parsley leaves affected the ability of L. monocytogenes to survive acetic acid challenge (90 min, pH 4.0) and to adhere to stainless steel although the ability to grow as biofilm was preserved. To further investigate these physiological alterations, the mRNA levels of six target genes (bsh, clpC, groEL, inlA, opuC, prfA) was quantified using reverse transcription qPCR after 5 h of incubation on parsley leaves. A decrease was observed in all but one (bsh) target, including groEL and clpC which are involved in resistance to salt and acid. Moreover, the decrease in the levels of inlA, prfA and opuC transcripts after incubation on parsley suggested a repression of some genes involved in pathogenicity. In vitro assessment of mammalian cell adherence and invasion using Caco-2 cells confirmed the repression of the virulence factor InlA; however, the virulence potential in vivo in the chick embryo model was not affected. CONCLUSION Listeria monocytogenes did undergo rapid changes to adapt its physiology to the phyllosphere. SIGNIFICANCE AND IMPACT OF THE STUDY This study highlights the physiological changes undergone by L. monocytogenes during/after survival on parsley leaves.
Collapse
Affiliation(s)
- A Rieu
- Laboratoire de Recherche En Vigne et Vin REVV, Université de Bourgogne, IUVV, Dijon, France
| | | | | |
Collapse
|
67
|
Sleator RD, Watson D, Hill C, Gahan CGM. The interaction between Listeria monocytogenes and the host gastrointestinal tract. MICROBIOLOGY-SGM 2009; 155:2463-2475. [PMID: 19542009 DOI: 10.1099/mic.0.030205-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Listeria monocytogenes is a ubiquitous bacterium that causes significant foodborne disease with high mortality rates in immunocompromised adults. In pregnant women foodborne infection can give rise to infection of the fetus resulting in miscarriage. In addition, the bacterium has recently been demonstrated to cause localized gastrointestinal symptoms, predominantly in immunocompetent individuals. The murine model of systemic L. monocytogenes infection has provided numerous insights into the mechanisms of pathogenesis of this organism. However, recent application of transcriptomic and proteomic approaches as well as the development of new model systems has allowed a focus upon factors that influence adaptation to gastrointestinal environments and adhesion to and invasion of the gastrointestinal mucosa. In addition, the availability of a large number of complete L. monocytogenes genome sequences has permitted inter-strain comparisons and the identification of factors that may influence the emergence of 'epidemic' phenotypes. Here we review some of the exciting recent developments in the analysis of the interaction between L. monocytogenes and the host gastrointestinal tract.
Collapse
Affiliation(s)
- Roy D Sleator
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Debbie Watson
- Department of Microbiology, University College Cork, Cork, Ireland
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Colin Hill
- Department of Microbiology, University College Cork, Cork, Ireland
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Cormac G M Gahan
- School of Pharmacy, University College Cork, Cork, Ireland
- Department of Microbiology, University College Cork, Cork, Ireland
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| |
Collapse
|
68
|
Begley M, Kerr C, Hill C. Exposure to bile influences biofilm formation by Listeria monocytogenes. Gut Pathog 2009; 1:11. [PMID: 19476630 PMCID: PMC2693109 DOI: 10.1186/1757-4749-1-11] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 05/28/2009] [Indexed: 01/10/2023] Open
Abstract
In the present study we demonstrate that the initial attachment of Listeria monocytogenes cells to plastic surfaces was significantly increased by growth in the presence of bile. Improved biofilm formation was confirmed by crystal violet staining, microscopy and bioluminescence detection of a luciferase-tagged strain. Enhanced biofilm formation in response to bile may influence the ability of L. monocytogenes to form biofilms in vivo during infection and may contribute to survival of this important pathogen in the human gastrointestinal tract and gallbladder.
Collapse
Affiliation(s)
- Máire Begley
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
| | | | | |
Collapse
|
69
|
Toledo-Arana A, Dussurget O, Nikitas G, Sesto N, Guet-Revillet H, Balestrino D, Loh E, Gripenland J, Tiensuu T, Vaitkevicius K, Barthelemy M, Vergassola M, Nahori MA, Soubigou G, Régnault B, Coppée JY, Lecuit M, Johansson J, Cossart P. The Listeria transcriptional landscape from saprophytism to virulence. Nature 2009; 459:950-6. [PMID: 19448609 DOI: 10.1038/nature08080] [Citation(s) in RCA: 672] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2009] [Accepted: 04/27/2009] [Indexed: 12/12/2022]
Abstract
The bacterium Listeria monocytogenes is ubiquitous in the environment and can lead to severe food-borne infections. It has recently emerged as a multifaceted model in pathogenesis. However, how this bacterium switches from a saprophyte to a pathogen is largely unknown. Here, using tiling arrays and RNAs from wild-type and mutant bacteria grown in vitro, ex vivo and in vivo, we have analysed the transcription of its entire genome. We provide the complete Listeria operon map and have uncovered far more diverse types of RNAs than expected: in addition to 50 small RNAs (<500 nucleotides), at least two of which are involved in virulence in mice, we have identified antisense RNAs covering several open-reading frames and long overlapping 5' and 3' untranslated regions. We discovered that riboswitches can act as terminators for upstream genes. When Listeria reaches the host intestinal lumen, an extensive transcriptional reshaping occurs with a SigB-mediated activation of virulence genes. In contrast, in the blood, PrfA controls transcription of virulence genes. Remarkably, several non-coding RNAs absent in the non-pathogenic species Listeria innocua exhibit the same expression patterns as the virulence genes. Together, our data unravel successive and coordinated global transcriptional changes during infection and point to previously unknown regulatory mechanisms in bacteria.
Collapse
|
70
|
Ryan S, Hill C, Gahan CGM. Acid stress responses in Listeria monocytogenes. ADVANCES IN APPLIED MICROBIOLOGY 2009; 65:67-91. [PMID: 19026862 DOI: 10.1016/s0065-2164(08)00603-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Sheila Ryan
- Department of Microbiology, University College Cork, Cork, Ireland
| | | | | |
Collapse
|
71
|
Contributions to selected phenotypic characteristics of large species- and lineage-specific genomic regions in Listeria monocytogenes. Food Microbiol 2009; 26:212-23. [DOI: 10.1016/j.fm.2008.08.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2008] [Revised: 08/12/2008] [Accepted: 08/16/2008] [Indexed: 11/20/2022]
|
72
|
Riedel CU, Monk IR, Casey PG, Waidmann MS, Gahan CGM, Hill C. AgrD-dependent quorum sensing affects biofilm formation, invasion, virulence and global gene expression profiles inListeria monocytogenes. Mol Microbiol 2009; 71:1177-89. [DOI: 10.1111/j.1365-2958.2008.06589.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
|
73
|
Ryan S, Begley M, Gahan CGM, Hill C. Molecular characterization of the arginine deiminase system inListeria monocytogenes: regulation and role in acid tolerance. Environ Microbiol 2009; 11:432-45. [DOI: 10.1111/j.1462-2920.2008.01782.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
74
|
Abstract
The bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Listeria spp. are isolated from a diversity of environmental sources, including soil, water, effluents, a large variety of foods, and the feces of humans and animals. Recent outbreaks demonstrated that L. monocytogenes can cause gastroenteritis in otherwise healthy individuals and more severe invasive disease in immunocompromised patients. Common symptoms include fever, watery diarrhea, nausea, headache, and pains in joints and muscles. The intestinal tract is the major portal of entry for L. monocytogenes, whereby strains penetrate the mucosal tissue either directly, via invasion of enterocytes, or indirectly, via active penetration of the Peyer's patches. Studies have revealed the strategy taken by the bacteria to overcome changes in oxygen tension, osmolarity, acidity, and the sterilizing effects of bile or antimicrobial peptides to adapt to conditions in the gut. In addition, L. monocytogenes has evolved species-specific strategies for intestinal entry by exploiting the interaction between the internalin protein and its receptor E-cadherin, or inducing diarrhea and an inflammatory response via the activity of its hemolytic toxin, listeriolysin. The ability of these bacteria to survive in bile-rich environments, and to induce depletion of sentinel cells such as Paneth cells that monitor the luminal burden of commensal bacteria, suggest strategies that have evolved to promote intestinal survival. Preexisting gastrointestinal disease may be a risk factor for infection of the gastrointestinal tract with L. monocytogenes. Currently, there is enough evidence to warrant consideration of L. monocytogenes as a possible etiology in outbreaks of febrile gastroenteritis, and for further studies to examine the genetic structure of Listeria strains that have a propensity to cause gastrointestinal versus systemic infections.
Collapse
|
75
|
Watson D, Sleator RD, Hill C, Gahan CGM. Enhancing bile tolerance improves survival and persistence of Bifidobacterium and Lactococcus in the murine gastrointestinal tract. BMC Microbiol 2008; 8:176. [PMID: 18844989 PMCID: PMC2577680 DOI: 10.1186/1471-2180-8-176] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 10/09/2008] [Indexed: 12/11/2022] Open
Abstract
Background The majority of commensal gastrointestinal bacteria used as probiotics are highly adapted to the specialised environment of the large bowel. However, unlike pathogenic bacteria; they are often inadequately equipped to endure the physicochemical stresses of gastrointestinal (GI) delivery in the host. Herein we outline a patho-biotechnology strategy to improve gastric delivery and host adaptation of a probiotic strain Bifidobacterium breve UCC2003 and the generally regarded as safe (GRAS) organism Lactococcus lactis NZ9000. Results In vitro bile tolerance of both strains was significantly enhanced (P < 0.001), following heterologous expression of the Listeria monocytogenes bile resistance mechanism BilE. Strains harbouring bilE were also recovered at significantly higher levels (P < 0.001), than control strains from the faeces and intestines of mice (n = 5), following oral inoculation. Furthermore, a B. breve strain expressing bilE demonstrated increased efficacy relative to the wild-type strain in reducing oral L. monocytogenes infection in mice. Conclusion Collectively the data indicates that bile tolerance can be enhanced in Bifidobacterium and Lactococcus species through rational genetic manipulation and that this can significantly improve delivery to and colonisation of the GI tract.
Collapse
Affiliation(s)
- Debbie Watson
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
| | | | | | | |
Collapse
|
76
|
Bhagwat AA, Bhagwat M. Methods and tools for comparative genomics of foodborne pathogens. Foodborne Pathog Dis 2008; 5:487-97. [PMID: 18713064 PMCID: PMC2614369 DOI: 10.1089/fpd.2008.0117] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A comparison of genome sequences and of encoded proteins with the database of existing annotated sequences is a useful approach to understand the information at the genome level. Here we demonstrate the utility of several DNA and protein sequence comparison tools to interpret the information obtained from several genome projects. Comparisons are presented between closely related strains of Escherichia coli commensal isolates, different isolates of O157:H7, and Shigella spp. It is expected that comparative genome analysis will generate a wealth of data to compare pathogenic isolates with varying levels of pathogenicity, which in turn may reveal mechanisms by which the pathogen may adapt to a particular nutrient supply in certain foods. These genome sequence analysis tools will strengthen foodborne pathogen surveillance and subsequent risk assessment to enhance the safety of the food supply.
Collapse
Affiliation(s)
- Arvind A Bhagwat
- Produce Quality and Safety Laboratory, Henry A. Wallace Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland 20705-2350, USA.
| | | |
Collapse
|
77
|
Differences in survival among 13 Listeria monocytogenes strains in a dynamic model of the stomach and small intestine. Appl Environ Microbiol 2008; 74:5563-7. [PMID: 18586963 DOI: 10.1128/aem.00319-08] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Thirteen Listeria monocytogenes strains were compared for the ability to survive in a dynamic gastrointestinal model. Strains displayed various degrees of susceptibility to gastric acidity; however, strain-to-strain variations became evident mainly after 90 min of exposure (pH 2.0). Cell levels transferred to the intestine depended on initial populations, while reductions during intestinal exposure were relatively small for all strains.
Collapse
|
78
|
Drevets DA, Bronze MS. Listeria monocytogenes: epidemiology, human disease, and mechanisms of brain invasion. ACTA ACUST UNITED AC 2008; 53:151-65. [PMID: 18462388 DOI: 10.1111/j.1574-695x.2008.00404.x] [Citation(s) in RCA: 226] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Listeria monocytogenes is a facultative intracellular bacterium that has predilection for causing central nervous systemic infections in humans and domesticated animals. This pathogen can be found worldwide in the food supply and most L. monocytogenes infections are acquired through ingestion of contaminated food. The main clinical syndromes caused by L. monocytogenes include febrile gastroenteritis, perinatal infection, and systemic infections marked by central nervous system infections with or without bacteremia. Experimental infection of mice has been used for over 50 years as a model system to study the pathogenesis of this organism including the mechanisms by which it invades the brain. Data from this model indicate that a specific subset of monocytes, distinguished in part by high expression of the Ly-6C antigen, become parasitized in the bone marrow and have a key role in transporting intracellular bacteria across the blood-brain barriers and into the central nervous system. This Minireview will summarize recent epidemiologic and clinical information regarding L. monocytogenes as a human pathogen and will discuss current in vitro and in vivo data relevant to the role of parasitized monocytes and the pathogenetic mechanisms that underlie its formidable ability to invade the central nervous system.
Collapse
Affiliation(s)
- Douglas A Drevets
- Department of Medicine, Oklahoma University Health Sciences Center and the Veterans Affairs Medical Center, Oklahoma City, OK, USA.
| | | |
Collapse
|
79
|
The Listeria monocytogenes virulence factor InlJ is specifically expressed in vivo and behaves as an adhesin. Infect Immun 2008; 76:1368-78. [PMID: 18227172 DOI: 10.1128/iai.01519-07] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The food-borne pathogen Listeria monocytogenes is adapted to a diversity of environments, such as soil, food, body fluids, and the cytosol of eukaryotic cells. The transition between saprophytic and pathogenic life is mediated through complex regulatory pathways that modulate the expression of virulence factors. Here we examined the expression of inlJ, a recently identified gene encoding a protein of the LPXTG-internalin family and involved in pathogenesis. We show that inlJ expression is controlled neither by the major listerial regulator of virulence genes, PrfA, nor by AxyR, a putative AraC regulator encoded by a gene adjacent to inlJ and divergently transcribed. The InlJ protein is not produced by bacteria grown in vitro in brain heart infusion medium or replicating in the cytosol of tissue-cultured cells. In contrast, it is efficiently produced and localized at the surface of bacteria present in the liver and blood of infected animals. Strikingly, the expression of inlJ by a heterologous promoter in L. monocytogenes or L. innocua promotes bacterial adherence to human cells in vitro. Taken together, these results strongly suggest that InlJ acts as a novel L. monocytogenes sortase-anchored adhesin specifically expressed during infection in vivo.
Collapse
|
80
|
Ryan E, Gahan C, Hill C. A significant role for Sigma B in the detergent stress response of Listeria monocytogenes. Lett Appl Microbiol 2007; 46:148-54. [DOI: 10.1111/j.1472-765x.2007.02280.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
81
|
Peterson LD, Faith NG, Czuprynski CJ. Resistance of Listeria monocytogenes F2365 cells to synthetic gastric fluid is greater following growth on ready-to-eat deli turkey meat than in brain heart infusion broth. J Food Prot 2007; 70:2589-95. [PMID: 18044439 DOI: 10.4315/0362-028x-70.11.2589] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ready-to-eat (RTE) deli meats have been categorized as high-risk foods for contraction of foodborne listeriosis. Several recent listeriosis outbreaks have been associated with the consumption of RTE deli turkey meat. In this study, we examined whether the growth of Listeria monocytogenes F2365 on commercially prepared RTE deli turkey meat causes listerial cells to become more resistant to inactivation by synthetic gastric fluid (SGF). Listerial cells grown on turkey meat to late logarithmic-early stationary phase were significantly more resistant to SGF at pH 7.0, 5.0, or 3.5 than listerial cells grown in brain heart infusion (BHI) broth. The pH was lower in the fluid in packages of turkey meat than in BHI broth (6.5 versus 7.5). However, listerial cells grown in BHI broth adjusted to a lower pH (6.0) did not exhibit enhanced resistance to SGF. The lesser resistance to SGF of listerial cells grown in BHI broth may be due, in part, to the presence of glucose (0.2%). This study indicates the environment presented by the growth of L. monocytogenes on deli turkey meat affects its ability to survive conditions it encounters in the gastrointestinal tract.
Collapse
Affiliation(s)
- Luke D Peterson
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | | | | |
Collapse
|
82
|
Hecker M, Pané-Farré J, Uwe V. SigB-Dependent General Stress Response inBacillus subtilisand Related Gram-Positive Bacteria. Annu Rev Microbiol 2007; 61:215-36. [DOI: 10.1146/annurev.micro.61.080706.093445] [Citation(s) in RCA: 352] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Michael Hecker
- Institut für Mikrobiologie, 2Interfakultäres Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität, Greifswald 17489, Germany; , ,
| | - Jan Pané-Farré
- Institut für Mikrobiologie, 2Interfakultäres Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität, Greifswald 17489, Germany; , ,
| | - Völker Uwe
- Institut für Mikrobiologie, 2Interfakultäres Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität, Greifswald 17489, Germany; , ,
| |
Collapse
|
83
|
Abstract
In the past decades impressive knowledge has been accumulated concerning the basic mechanisms of interactions between intracellular bacteria and their host cells. Comparatively little is known on the metabolic requirements necessary for efficient replication of these bacteria within their specific host cell compartments. Recent developments in functional genomics have led to more extensive studies of the metabolic aspects that may be crucial for understanding the pathogenesis of intracellular bacteria. Here we summarize our present knowledge on the physiology of L. monocytogenes with emphasis on those parts that seem to be important for its ability to replicate in the cytosol of mammalian host cells.
Collapse
Affiliation(s)
- Biju Joseph
- Theodor-Boveri-Institut (Biozentrum), Lehrstuhl für Mikrobiologie, Universität Würzburg, Josef-Schneider-Strasse 2, D-97074 Würzburg, Germany
| | | |
Collapse
|
84
|
Sleator RD, Clifford T, Hill C. Gut osmolarity: a key environmental cue initiating the gastrointestinal phase of Listeria monocytogenes infection? Med Hypotheses 2007; 69:1090-2. [PMID: 17433559 DOI: 10.1016/j.mehy.2007.02.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 02/25/2007] [Indexed: 01/03/2023]
Abstract
In addition to the severe invasive systemic disease of listeriosis, recent evidence suggests that the Gram-positive intracellular bacterial pathogen Listeria monocytogenes is also a causative agent of febrile gastroenteritis. We examined the listerial response to stresses normally encountered in the upper small intestine and demonstrate that osmotic stress appears to be at the top of the hierarchy of stress responses during gastrointestinal residence. Furthermore, we suggest that the increased osmolarity of the gastrointestinal lumen may be interpreted as an environmental cue signalling gut entry and that the underlying genetic element governing this response is the alternative stress sigma factor sigma(B).
Collapse
Affiliation(s)
- Roy D Sleator
- Department of Microbiology and Alimentary Pharmabiotic Centre, University College Cork, Ireland.
| | | | | |
Collapse
|
85
|
Formato G, Geornaras I, Barmpalia IM, Skandamis PN, Belk KE, Scanga JA, Kendall PA, Smith GC, Sofos JN. Effect of acid adaptation on growth during storage at 10 degrees C and resistance to simulated gastric fluid of Listeria monocytogenes inoculated onto bologna formulated with or without antimicrobials. J Food Prot 2007; 70:65-9. [PMID: 17265862 DOI: 10.4315/0362-028x-70.1.65] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The fate of acid-adapted and nonadapted Listeria monocytogenes inoculated onto bologna slices (formulated with or without antimicrobials) was examined during storage and after exposure to in vitro gastric challenge. Bologna slices formulated with no antimicrobials (control), 3% sodium lactate (SL), or 1.8% SL plus 0.25% sodium diacetate (SD) were inoculated (2 log CFU/cm2) with a 10-strain composite of acid-adapted or nonadapted L. monocytogenes strains. Growth or survival of the two inocula on bologna was evaluated during vacuum-packaged storage (10 degrees C) for up to 36 days. Survival of previously acid-adapted or nonadapted L. monocytogenes on stored bologna exposed to simulated gastric fluid (adjusted to pH 1.0 with HCl) for 20, 40, and 60 min also was determined. As expected, inclusion of antimicrobials in the product formulation inhibited growth of L. monocytogenes during storage of vacuum-packaged bologna compared with growth on control samples. Acid adaptation of L. monocytogenes prior to product inoculation did not affect subsequent survival or growth on bologna or resistance to simulated gastric fluid (P > 0.05). Survival of L. monocytogenes exposed to simulated gastric fluid during storage increased with product age, growth phase of the cells, and possibly age of the cells, particularly for control samples (no antimicrobials), in which the pathogen grew uninhibited to approximately 6 log CFU/cm2 by day 8 of storage. Inhibition of L. monocytogenes growth on product formulated with antimicrobials was associated with only sporadic and small numbers of survivors following exposure of these samples to simulated gastric fluid, especially in samples stored longer. However, cell numbers in these treatment groups before the gastric challenge did not exceed 3.8 log CFU/cm2. Inhibition of growth on product with antimicrobials precluded detection of survivors resistant to the effects of simulated gastric fluid.
Collapse
Affiliation(s)
- Giovanni Formato
- Center for Red Meat Safety, Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
86
|
Abstract
Given the increasing commercial and clinical relevance of probiotic cultures, improving their stress tolerance profile and ability to overcome the physiochemical defences of the host is an important biological goal. Pathogenic bacteria have evolved sophisticated strategies to overcome host defences, interact with the immune system and interfere with essential host systems. We coin the term 'patho-biotechnology' to describe the exploitation of these valuable traits in biotechnology and biomedicine. This approach shows promise for the design of more technologically robust and effective probiotic cultures with improved biotechnological and clinical applications as well as the development of novel vaccine and drug delivery platforms.
Collapse
|
87
|
Shaughnessy LM, Swanson JA. The role of the activated macrophage in clearing Listeria monocytogenes infection. FRONTIERS IN BIOSCIENCE : A JOURNAL AND VIRTUAL LIBRARY 2007; 12:2683-92. [PMID: 17127272 PMCID: PMC2851543 DOI: 10.2741/2364] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Macrophage activation often contributes to the strong immune response elicited upon infection. The ability of macrophages to become activated was discovered when sub-lethal primary infections of mice with the bacterium Listeria monocytogenes provided protection against secondary infections through non-humoral immunity. L. monocytogenes infect and propagate in macrophages by escaping the phagosome into the cytosol, where they avoid humoral immune mediators. Activated macrophages kill L. monocytogenes by blocking phagosomal escape. The timing of the antimicrobial activities within the phagosome is crucial to the outcome. In non-activated macrophages, bacterial factors generally prevail, and L. monocytogenes can escape from the vacuoles and grow within cytoplasm. Activated macrophages generate reactive oxygen or nitrogen intermediates early after bacterial uptake, which prevent the bacteria from escaping vacuoles into cytoplasm. The heterogeneity in the interactions between L. monocytogenes and the macrophage indicate a complex relationship between the host and the pathogen governed by chemistries that promote and inhibit escape from vacuoles. This review examines the mechanisms used by activated and non-activated macrophages to kill microbes, and how those mechanisms are employed against L. monocytogenes.
Collapse
Affiliation(s)
- Lee M Shaughnessy
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0620, USA
| | | |
Collapse
|
88
|
Zundel E, Bernard S. Listeria monocytogenes translocates throughout the digestive tract in asymptomatic sheep. J Med Microbiol 2006; 55:1717-1723. [PMID: 17108277 DOI: 10.1099/jmm.0.46709-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ruminants are fed forage which is often contaminated with Listeria, and frequently shed Listeria monocytogenes with their faeces. The present study was designed to localize the sites of infection in the digestive tract concomitant with Listeria faecal excretion in a sheep model. Ten Listeria-free sheep were inoculated per os with a dose of 10(10) c.f.u. of a pathogenic L. monocytogenes strain. Listeria received by two of the ten animals were radiolabelled with (111)indium oxine. The dissemination of the Listeria was assessed by in vivo imaging, by culture of bacteria in the faeces, organs and digesta samples taken at slaughter on days 1, 2, 6, 10 and 14 post-inoculation, and by measuring gamma radioactivity of samples on day 6. It was shown that Listeria spread through the entire volume of the forestomachs within 4 h, and through the whole gastrointestinal tract (GIT) within 24 h. Faecal shedding of Listeria lasted 10 days. Rumen, duodenum, jejunum, ileum, caecum and colon walls and digesta, mesenteric lymph nodes, liver and spleen were temporarily infected. However, Listeria persisted for at least 14 days in rumen digesta and retropharyngeal lymph nodes, and at a relatively high level (1 x 10(4) c.f.u. g(-1)) in palatine tonsils. These findings suggest that L. monocytogenes can translocate from all parts of the GIT, with the rumen digesta, but not the gallbladder, serving as a reservoir. The results indicate that brief and low-level faecal excretion of L. monocytogenes is concomitant with a transitory asymptomatic infection in sheep.
Collapse
Affiliation(s)
- Etienne Zundel
- INRA, Infectiologie Animale et Santé Publique, 37380 Nouzilly, France
| | - Serge Bernard
- INRA, Infectiologie Animale et Santé Publique, 37380 Nouzilly, France
| |
Collapse
|
89
|
Bron PA, Monk IR, Corr SC, Hill C, Gahan CGM. Novel luciferase reporter system for in vitro and organ-specific monitoring of differential gene expression in Listeria monocytogenes. Appl Environ Microbiol 2006; 72:2876-84. [PMID: 16597994 PMCID: PMC1449049 DOI: 10.1128/aem.72.4.2876-2884.2006] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In this paper we describe construction of a luciferase-based vector, pPL2lux, and use of this vector to study gene expression in Listeria monocytogenes. pPL2lux is a derivative of the listerial integration vector pPL2 and harbors a synthetic luxABCDE operon encoding a fatty acid reductase complex (LuxCDE) involved in synthesis of the fatty aldehyde substrate for the bioluminescence reaction catalyzed by the LuxAB luciferase. We constructed pPL2lux derivatives in which the secA and hlyA promoters were translationally fused to luxABCDE and integrated as a single copy into the chromosome of L. monocytogenes EGD-e. Growth experiments revealed that hlyA was expressed predominantly in the stationary phase in LB medium buffered at pH 7.4, whereas secA expression could be detected in the exponential growth phase. Moreover, the correlation between luciferase activity and transcription levels, as determined by reverse transcriptase PCR, was confirmed using conditions known to lead to repression and activation of hemolysin expression (addition of cellobiose and activated charcoal, respectively). Furthermore, hemolysin expression could be monitored in real time during invasion of an intact monolayer of C2Bbe1 (Caco-2-derived) cells. Finally, hemolysin expression could be detected in the livers, spleens, and kidneys of mice 3 days postinfection. These experiments clearly established the effectiveness of pPL2lux as a quantitative reporter system for real-time, noninvasive evaluation of gene expression in L. monocytogenes.
Collapse
Affiliation(s)
- Peter A Bron
- Alimentary Pharmabiotic Centre, University College Cork, Western Road, Cork, Ireland
| | | | | | | | | |
Collapse
|
90
|
Dimitrijevic M, Anderson RC, Callaway TR, Jung YS, Harvey RB, Ricke SC, Nisbet DJ. Inhibitory effect of select nitrocompounds on growth and survivability of Listeria monocytogenes in vitro. J Food Prot 2006; 69:1061-5. [PMID: 16715805 DOI: 10.4315/0362-028x-69.5.1061] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We report the effects of 2-nitro-1-propanol (2NPOH), 2-nitroethanol (2NEOH), and nitroethane (NE) on growth and survivability of Listeria monocytogenes. In all cases, inhibition was greatest with 2NPOH and least with NE. For example, specific growth rates of L. monocytogenes strain 18 declined (P < 0.05) 76, 60, and 29% from controls during aerobic culture at 37 degrees C in brain heart infusion broth containing 10 mM 2NPOH, 2NEOH, or NE, respectively. Mean specific growth rate for the controls incubated likewise without added nitrocompound was 0.62 +/- 0.02 h(-1). Specific growth rates of L. monocytogenes Scott A decreased (P < 0.05) 67, 45, and 11%, respectively, from controls (0.67 +/- 0.02 h(-1)) when cultured similarly. Specific growth rates for L. monocytogenes strain 18 incubated similarly except at 30 degrees C were reduced (P < 0.05) 76, 60, and 30%, respectively, and were reduced (P < 0.05) 78, 23, and 23% during anaerobic culture at 30 degrees C in brain heart infusion broth containing 15 mM 2NPOH, 2NEOH, or NE (control rates ranged from 0.37 +/- 0.07 to 0.74 +/- 0.05 h(-1)). Survivability of L. monocytogenes strain 18 was reduced (P < 0.05) during aerobic storage (4 months at 4 degrees C) in brain heart infusion broth containing 2NPOH or 2NEOH (by 7.8 and 1.9 log units, respectively) but not NE. The inhibitory effect of 2NPOH was approximately 20% greater during growth at pH 7.0 than at pH 5.6 or 8.0. These results demonstrate the differential inhibitory activity of 2NPOH, 2NEOH, and NE against L. monocytogenes in vitro.
Collapse
Affiliation(s)
- M Dimitrijevic
- Faculty of Veterinary Medicine, Department of Food Hygiene and Technology, University of Belgrade, Belgrade, Serbia-Montenegro
| | | | | | | | | | | | | |
Collapse
|
91
|
Hardy J, Margolis JJ, Contag CH. Induced biliary excretion of Listeria monocytogenes. Infect Immun 2006; 74:1819-27. [PMID: 16495556 PMCID: PMC1418634 DOI: 10.1128/iai.74.3.1819-1827.2006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 10/02/2005] [Accepted: 11/30/2005] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes is a ubiquitous gram-positive bacterium that can cause systemic and often life-threatening disease in immunocompromised hosts. This organism is largely an intracellular pathogen; however, we have determined that it can also grow extracellularly in animals, in the lumen of the gallbladder. The significance of growth in the gallbladder with respect to the pathogenesis and spread of listeriosis depends on the ability of the bacterium to leave this organ and be disseminated to other tissues and into the environment. Should this process be highly inefficient, growth in the gallbladder would have no impact on pathogenesis or spread, but if it occurs efficiently, bacterial growth in this organ may contribute to listeriosis and dissemination of this organism. Here, we use whole-body imaging to determine the efficacy and kinetics of food- and hormone-induced biliary excretion of L. monocytogenes from the murine gallbladder, demonstrating that transit through the bile duct into the intestine can occur within 5 min of induction of gallbladder contraction by food or cholecystokinin and that movement of bacteria through the intestinal lumen can occur very rapidly in the absence of fecal material. These studies demonstrate that L. monocytogenes bacteria replicating in the gallbladder can be expelled from the organ efficiently and that the released bacteria move into the intestinal tract, where they pass into the environment and may possibly reinfect the animal.
Collapse
Affiliation(s)
- Jonathan Hardy
- Department of Pediatrics, E150 Clark Center MC 5427, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | | |
Collapse
|
92
|
Garner MR, Njaa BL, Wiedmann M, Boor KJ. Sigma B contributes to Listeria monocytogenes gastrointestinal infection but not to systemic spread in the guinea pig infection model. Infect Immun 2006; 74:876-86. [PMID: 16428730 PMCID: PMC1360341 DOI: 10.1128/iai.74.2.876-886.2006] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 09/29/2005] [Accepted: 11/08/2005] [Indexed: 01/07/2023] Open
Abstract
Contributions of the alternative sigma factor sigmaB to Listeria monocytogenes infection were investigated using strains bearing null mutations in sigB, prfA, or inlA or in selected inlA or prfA promoter regions. The DeltaP4inlA strain, which has a deletion in the sigmaB-dependent P4inlA promoter, and the DeltasigB strain had significantly reduced invasion efficiencies relative to that of the wild-type strain in the Caco-2 human colorectal epithelial cell line, while the invasion efficiency of a strain bearing a deletion in the partially sigmaB dependent P2prfA promoter region did not differ from that of the wild type. The virulence of the DeltasigB and DeltaP4inlA strains was attenuated in intragastrically inoculated guinea pigs, with the DeltasigB strain showing greater attenuation, while the virulence capacity of the DeltaP2prfA strain was similar to that of the wild-type strain, suggesting that attenuation of virulence due to the DeltasigB mutation does not result from loss of sigmaB-dependent prfA transcription. Our results show that sigmaB-dependent activation of inlA is important for cell invasion and gastrointestinal infection and suggest that sigmaB-regulated genes in addition to inlA appear to contribute to gastrointestinal infection. Interestingly, the virulence of the DeltasigB strain was not attenuated in intravenously infected guinea pigs. We conclude that (i) L. monocytogenes sigmaB plays a critical role in invasion of human host cells, (ii) sigmaB-mediated contributions to invasion are, in part, due to direct effects on inlA transcription but not on prfA transcription, and (iii) sigmaB plays a critical role during the gastrointestinal stage of listeriosis in the guinea pig but is not important for systemic spread of the organism.
Collapse
Affiliation(s)
- M R Garner
- Department of Food Science, 413 Stocking Hall, Cornell University, Ithaca, NY 14853, USA
| | | | | | | |
Collapse
|
93
|
Kimura B. Recent Advances in the Study of the Genotypic Diversity and Ecology of Listeria monocytogenes. Microbes Environ 2006. [DOI: 10.1264/jsme2.21.69] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Bon Kimura
- Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology
| |
Collapse
|