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Listeria monocytogenes-How This Pathogen Uses Its Virulence Mechanisms to Infect the Hosts. Pathogens 2022; 11:pathogens11121491. [PMID: 36558825 PMCID: PMC9783847 DOI: 10.3390/pathogens11121491] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/23/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Listeriosis is a serious food-borne illness, especially in susceptible populations, including children, pregnant women, and elderlies. The disease can occur in two forms: non-invasive febrile gastroenteritis and severe invasive listeriosis with septicemia, meningoencephalitis, perinatal infections, and abortion. Expression of each symptom depends on various bacterial virulence factors, immunological status of the infected person, and the number of ingested bacteria. Internalins, mainly InlA and InlB, invasins (invasin A, LAP), and other surface adhesion proteins (InlP1, InlP4) are responsible for epithelial cell binding, whereas internalin C (InlC) and actin assembly-inducing protein (ActA) are involved in cell-to-cell bacterial spread. L. monocytogenes is able to disseminate through the blood and invade diverse host organs. In persons with impaired immunity, the elderly, and pregnant women, the pathogen can also cross the blood-brain and placental barriers, which results in the invasion of the central nervous system and fetus infection, respectively. The aim of this comprehensive review is to summarize the current knowledge on the epidemiology of listeriosis and L. monocytogenes virulence mechanisms that are involved in host infection, with a special focus on their molecular and cellular aspects. We believe that all this information is crucial for a better understanding of the pathogenesis of L. monocytogenes infection.
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Phobalysin: Fisheye View of Membrane Perforation, Repair, Chemotaxis and Adhesion. Toxins (Basel) 2019; 11:toxins11070412. [PMID: 31315179 PMCID: PMC6669599 DOI: 10.3390/toxins11070412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/04/2019] [Accepted: 07/11/2019] [Indexed: 11/30/2022] Open
Abstract
Phobalysin P (PhlyP, for photobacterial lysin encoded on a plasmid) is a recently described small β-pore forming toxin of Photobacterium damselae subsp. damselae (Pdd). This organism, belonging to the family of Vibrionaceae, is an emerging pathogen of fish and various marine animals, which occasionally causes life-threatening soft tissue infections and septicemia in humans. By using genetically modified Pdd strains, PhlyP was found to be an important virulence factor. More recently, in vitro studies with purified PhlyP elucidated some basic consequences of pore formation. Being the first bacterial small β-pore forming toxin shown to trigger calcium-influx dependent membrane repair, PhlyP has advanced to a revealing model toxin to study this important cellular function. Further, results from co-culture experiments employing various Pdd strains and epithelial cells together with data on other bacterial toxins indicate that limited membrane damage may generally enhance the association of bacteria with target cells. Thereby, remodeling of plasma membrane and cytoskeleton during membrane repair could be involved. In addition, a chemotaxis-dependent attack-and track mechanism influenced by environmental factors like salinity may contribute to PhlyP-dependent association of Pdd with cells. Obviously, a synoptic approach is required to capture the regulatory links governing the interaction of Pdd with target cells. The characterization of Pdd’s secretome may hold additional clues because it may lead to the identification of proteases activating PhlyP’s pro-form. Current findings on PhlyP support the notion that pore forming toxins are not just killer proteins but serve bacteria to fulfill more subtle functions, like accessing their host.
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von Hoven G, Neukirch C, Meyenburg M, Schmidt S, Vences A, Osorio CR, Husmann M, Rivas AJ. Cytotoxin- and Chemotaxis-Genes Cooperate to Promote Adhesion of Photobacterium damselae subsp. damselae. Front Microbiol 2019; 9:2996. [PMID: 30619115 PMCID: PMC6300472 DOI: 10.3389/fmicb.2018.02996] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 11/20/2018] [Indexed: 12/21/2022] Open
Abstract
Photobacterium damselae subsp. damselae (Pdd) is an emerging pathogen of marine animals that sometimes causes serious infections in humans. Two related pore forming toxins, phobalysins P and C, and damselysin, a phospholipase D, confer strong virulence of Pdd in mice. Because infections by Pdd are typically caused following exposure of wounds to sea water we investigated how salinity impacts toxin activity, swimming, and association of Pdd with epithelial cells. These activities were low when bacteria were pre-cultured in media with 3.5% NaCl, the global average salinity of sea water. In contrast, lower salinity increased swimming of wild type Pdd peaking at 2% NaCl, hemolysis, and association with epithelial cells peaking at 1-1.5%. Previously, we have found that hemolysin genes enhance the association of Pdd with epithelial cells, but the underlying mechanisms have remained ill-defined. We here searched for potential links between hemolysin-production, chemotaxis and association of Pdd with target cells at varying salt concentrations. Unexpectedly, disruption of chemotaxis regulator cheA not only affected bacterial swimming and association with epithelial cells at intermediate to low salinity, but also reduced the production of plasmid-encoded phobalysin (PhlyP). The results thus reveal unforeseen links between chemotaxis regulators, a pore forming toxin and the association of a marine bacterium with target cells.
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Affiliation(s)
- Gisela von Hoven
- Institute of Medical Microbiology and Hygiene, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Claudia Neukirch
- Institute of Medical Microbiology and Hygiene, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Martina Meyenburg
- Institute of Medical Microbiology and Hygiene, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Sabine Schmidt
- Institute of Medical Microbiology and Hygiene, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Ana Vences
- Departamento de Microbioloxìa e Parasitoloxìa, Instituto de Acuicultura, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Carlos R Osorio
- Departamento de Microbioloxìa e Parasitoloxìa, Instituto de Acuicultura, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Matthias Husmann
- Institute of Medical Microbiology and Hygiene, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Amable J Rivas
- Institute of Medical Microbiology and Hygiene, University Medical Center, Johannes Gutenberg University, Mainz, Germany
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Solanki V, Tiwari M, Tiwari V. Host-bacteria interaction and adhesin study for development of therapeutics. Int J Biol Macromol 2018; 112:54-64. [PMID: 29414732 DOI: 10.1016/j.ijbiomac.2018.01.151] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/17/2018] [Accepted: 01/21/2018] [Indexed: 12/15/2022]
Abstract
Host-pathogen interaction is one of the most important areas of study to understand the adhesion of the pathogen to the host organisms. To adhere on the host cell surface, bacteria assemble the diverse adhesive structures on its surface, which play a foremost role in targeting to the host cell. We have highlighted different bacterial adhesins which are either protein mediated or glycan mediated. The present article listed examples of different bacterial adhesin proteins involved in the interactions with their host, types and subtypes of the fimbriae and non-fimbriae bacterial adhesins. Different bacterial surface adhesin subunits interact with host via different host surface biomolecules. We have also discussed the interactome of some of the pathogens with their host. Therefore, the present study will help researchers to have a detailed understanding of different interacting bacterial adhesins and henceforth, develop new therapies, adhesin specific antibodies and vaccines, which can effectively control pathogenicity of the pathogens.
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Affiliation(s)
- Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India.
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Krawczyk-Balska A, Markiewicz Z. The intrinsic cephalosporin resistome of Listeria monocytogenes in the context of stress response, gene regulation, pathogenesis and therapeutics. J Appl Microbiol 2015; 120:251-65. [PMID: 26509460 DOI: 10.1111/jam.12989] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/18/2015] [Accepted: 08/28/2015] [Indexed: 12/22/2022]
Abstract
Intrinsic resistance to antibiotics is a serious therapeutic problem in the case of many bacterial species. The Gram-positive human pathogen Listeria monocytogenes is intrinsically resistant to broad spectrum cephalosporin antibiotics, which are commonly used in therapy of bacterial infections. Besides three penicillin-binding proteins the intrinsic cephalosporin resistome of L. monocytogenes includes multidrug resistance transporter transporters, proteins involved in peptidoglycan biosynthesis and modification, cell envelope proteins with structural or general detoxification function, cytoplasmic proteins with unknown function and regulatory proteins. Analysis of the regulation of the expression of genes involved in the intrinsic resistance of L. monocytogenes to cephalosporins highlights the high complexity of control of the intrinsic resistance phenotype. The regulation of the transcription of the intrinsic resistome determinants involves the activity of eight regulators, namely LisR, CesR, LiaR, VirR, σ(B) , σ(H) , σ(L) and PrfA, of which the most prominent role play LisR, CesR and σ(B) . Furthermore, the vast majority of the intrinsic resistome determinants contribute to the tolerance of different stress conditions and virulence. A study indicates that O-acetyltransferase OatA is the most promising candidate for co-drug development since an agent targeting OatA should sensitize L. monocytogenes to certain antibiotics, therefore improving the efficacy of listeriosis treatment as well as food preservation measures.
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Affiliation(s)
- A Krawczyk-Balska
- Department of Applied Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Z Markiewicz
- Department of Applied Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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Phobalysin, a Small β-Pore-Forming Toxin of Photobacterium damselae subsp. damselae. Infect Immun 2015; 83:4335-48. [PMID: 26303391 DOI: 10.1128/iai.00277-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 08/15/2015] [Indexed: 12/16/2022] Open
Abstract
Photobacterium damselae subsp. damselae, an important pathogen of marine animals, may also cause septicemia or hyperaggressive necrotizing fasciitis in humans. We previously showed that hemolysin genes are critical for virulence of this organism in mice and fish. In the present study, we characterized the hlyA gene product, a putative small β-pore-forming toxin, and termed it phobalysin P (PhlyP), for "photobacterial lysin encoded on a plasmid." PhlyP formed stable oligomers and small membrane pores, causing efflux of K(+), with no significant leakage of lactate dehydrogenase but entry of vital dyes. The latter feature distinguished PhlyP from the related Vibrio cholerae cytolysin. Attack by PhlyP provoked a loss of cellular ATP, attenuated translation, and caused profound morphological changes in epithelial cells. In coculture experiments with epithelial cells, Photobacterium damselae subsp. damselae led to rapid hemolysin-dependent membrane permeabilization. Unexpectedly, hemolysins also promoted the association of P. damselae subsp. damselae with epithelial cells. The collective observations of this study suggest that membrane-damaging toxins commonly enhance bacterial adherence.
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Intracellular Listeria monocytogenes comprises a minimal but vital fraction of the intestinal burden following foodborne infection. Infect Immun 2015; 83:3146-56. [PMID: 26015479 DOI: 10.1128/iai.00503-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 05/18/2015] [Indexed: 12/29/2022] Open
Abstract
Listeria monocytogenes is a highly adaptive bacterium that replicates as a free-living saprophyte in the environment as well as a facultative intracellular pathogen that causes invasive foodborne infections. The intracellular life cycle of L. monocytogenes is considered to be its primary virulence determinant during mammalian infection; however, the proportion of L. monocytogenes that is intracellular in vivo has not been studied extensively. In this report, we demonstrate that the majority of wild-type (strain EGDe) and mouse-adapted (InlA(m)-expressing) L. monocytogenes recovered from the mesenteric lymph nodes (MLN) was extracellular within the first few days after foodborne infection. In addition, significantly lower burdens of L. monocytogenes were recovered from the colon, spleen, and liver of gentamicin-treated mice than of control mice. This led us to investigate whether intracellular replication of L. monocytogenes was essential during the intestinal phase of infection. We found that lipoate protein ligase-deficient L. monocytogenes (ΔlplA1) mutants, which display impaired intracellular growth, were able to colonize the colon but did not persist efficiently and had a significant defect in spreading to the MLN, spleen, and liver. Together, these data indicate that the majority of the L. monocytogenes burden in the gastrointestinal tract is extracellular, but the small proportion of intracellular L. monocytogenes is essential for dissemination to the MLN and systemic organs.
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Lechowicz J, Krawczyk-Balska A. An update on the transport and metabolism of iron in Listeria monocytogenes: the role of proteins involved in pathogenicity. Biometals 2015; 28:587-603. [PMID: 25820385 PMCID: PMC4481299 DOI: 10.1007/s10534-015-9849-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 03/17/2015] [Indexed: 12/21/2022]
Abstract
Listeria monocytogenes is a Gram-positive bacterium that causes a rare but severe human disease with high mortality rate. The microorganism is widespread in the natural environment where it shows a saprophytic lifestyle. In the human body it infects many different cell types, where it lives intracellularly, however it may also temporarily live extracellularly. The ability to survive and grow in such diverse niches suggests that this bacterium has a wide range of mechanisms for both the acquisition of various sources of iron and effective management of this microelement. In this review, data about the mechanisms of transport, metabolism and regulation of iron, including recent findings in these areas, are summarized with focus on the importance of these mechanisms for the virulence of L. monocytogenes. These data indicate the key role of haem transport and maintenance of intracellular iron homeostasis for the pathogenesis of L. monocytogenes. Furthermore, some of the proteins involved in iron homeostasis like Fri and FrvA seem to deserve special attention due to their potential use in the development of new therapeutic antilisterial strategies.
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Affiliation(s)
- Justyna Lechowicz
- Department of Applied Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
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Seitz M, Baums C, Neis C, Benga L, Fulde M, Rohde M, Goethe R, Valentin-Weigand P. Subcytolytic effects of suilysin on interaction of Streptococcus suis with epithelial cells. Vet Microbiol 2013; 167:584-91. [DOI: 10.1016/j.vetmic.2013.09.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 08/26/2013] [Accepted: 09/06/2013] [Indexed: 10/26/2022]
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Krawczyk-Balska A, Marchlewicz J, Dudek D, Wasiak K, Samluk A. Identification of a ferritin-like protein of Listeria monocytogenes as a mediator of β-lactam tolerance and innate resistance to cephalosporins. BMC Microbiol 2012; 12:278. [PMID: 23176286 PMCID: PMC3534079 DOI: 10.1186/1471-2180-12-278] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/20/2012] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND The food-borne pathogen Listeria monocytogenes is the causative agent of listeriosis. The β-lactam antibiotics penicillin G and ampicillin are the current drugs of choice for the treatment of listerial infections. While isolates of L. monocytogenes are susceptible to these antibiotics, their action is only bacteriostatic and consequently, this bacterium is regarded as tolerant to β-lactams. In addition, L. monocytogenes has a high level of innate resistance to the cephalosporin family of β-lactams frequently used to treat sepsis of unknown etiology. Given the high mortality rate of listeriosis despite rational antibiotic therapy, it is important to identify genes that play a role in the susceptibility and tolerance of L. monocytogenes to β-lactams. RESULTS The hly-based promoter trap system was applied to identify penicillin G-inducible genes of L. monocytogenes. The results of reporter system studies, verified by transcriptional analysis, identified ten penicillin G-inducible genes. The contribution of three of these genes, encoding a ferritin-like protein (fri), a two-component phosphate-response regulator (phoP) and an AraC/XylS family transcriptional regulator (axyR), to the susceptibility and tolerance of L. monocytogenes to β-lactams was examined by analysis of nonpolar deletion mutants. The absence of PhoP or AxyR resulted in more rapid growth of the strains in the presence of sublethal concentration of β-lactams, but had no effect on the MIC values or the ability to survive a lethal dose of these antibiotics. However, the Δfri strain showed impaired growth in the presence of sublethal concentrations of penicillin G and ampicillin and a significantly reduced ability to survive lethal concentrations of these β-lactams. A lack of Fri also caused a 2-fold increase in the sensitivity of L. monocytogenes to cefalotin and cephradine. CONCLUSIONS The present study has identified Fri as an important mediator of β-lactam tolerance and innate resistance to cephalosporins in L. monocytogenes. PhoP and AxyR are probably involved in transmitting signals to adjust the rate of growth of L. monocytogenes under β-lactam pressure, but these regulators do not play a significant role in susceptibility and tolerance to this class of antibiotics.
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Affiliation(s)
- Agata Krawczyk-Balska
- Department of Applied Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
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Pizarro-Cerdá J, Kühbacher A, Cossart P. Entry of Listeria monocytogenes in mammalian epithelial cells: an updated view. Cold Spring Harb Perspect Med 2012; 2:2/11/a010009. [PMID: 23125201 DOI: 10.1101/cshperspect.a010009] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Listeria monocytogenes is a bacterial pathogen that promotes its internalization into host epithelial cells. Interaction between the bacterial surface molecules InlA and InlB and their cellular receptors E-cadherin and Met, respectively, triggers the recruitment of endocytic effectors, the subversion of the phosphoinositide metabolism, and the remodeling of the actin cytoskeleton that lead to bacterial engulfment. Additional bacterial surface and secreted virulence factors also contribute to entry, albeit to a lesser extent. Here we review the increasing number of signaling effectors that are reported as being subverted by L. monocytogenes during invasion of cultured cell lines. We also update the current knowledge of the early steps of in vivo cellular infection, which, as shown recently, challenges previous concepts generated from in vitro data.
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Vadia S, Arnett E, Haghighat AC, Wilson-Kubalek EM, Tweten RK, Seveau S. The pore-forming toxin listeriolysin O mediates a novel entry pathway of L. monocytogenes into human hepatocytes. PLoS Pathog 2011; 7:e1002356. [PMID: 22072970 PMCID: PMC3207921 DOI: 10.1371/journal.ppat.1002356] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 09/20/2011] [Indexed: 01/18/2023] Open
Abstract
Intracellular pathogens have evolved diverse strategies to invade and survive within host cells. Among the most studied facultative intracellular pathogens, Listeria monocytogenes is known to express two invasins-InlA and InlB-that induce bacterial internalization into nonphagocytic cells. The pore-forming toxin listeriolysin O (LLO) facilitates bacterial escape from the internalization vesicle into the cytoplasm, where bacteria divide and undergo cell-to-cell spreading via actin-based motility. In the present study we demonstrate that in addition to InlA and InlB, LLO is required for efficient internalization of L. monocytogenes into human hepatocytes (HepG2). Surprisingly, LLO is an invasion factor sufficient to induce the internalization of noninvasive Listeria innocua or polystyrene beads into host cells in a dose-dependent fashion and at the concentrations produced by L. monocytogenes. To elucidate the mechanisms underlying LLO-induced bacterial entry, we constructed novel LLO derivatives locked at different stages of the toxin assembly on host membranes. We found that LLO-induced bacterial or bead entry only occurs upon LLO pore formation. Scanning electron and fluorescence microscopy studies show that LLO-coated beads stimulate the formation of membrane extensions that ingest the beads into an early endosomal compartment. This LLO-induced internalization pathway is dynamin-and F-actin-dependent, and clathrin-independent. Interestingly, further linking pore formation to bacteria/bead uptake, LLO induces F-actin polymerization in a tyrosine kinase-and pore-dependent fashion. In conclusion, we demonstrate for the first time that a bacterial pathogen perforates the host cell plasma membrane as a strategy to activate the endocytic machinery and gain entry into the host cell.
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Affiliation(s)
- Stephen Vadia
- Departments of Microbiology and Internal Medicine, Center for Microbial Interface Biology, Ohio State University, Columbus, Ohio, United States of America
| | - Eusondia Arnett
- Departments of Microbiology and Internal Medicine, Center for Microbial Interface Biology, Ohio State University, Columbus, Ohio, United States of America
| | - Anne-Cécile Haghighat
- Departments of Microbiology and Internal Medicine, Center for Microbial Interface Biology, Ohio State University, Columbus, Ohio, United States of America
| | | | - Rodney K. Tweten
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Stephanie Seveau
- Departments of Microbiology and Internal Medicine, Center for Microbial Interface Biology, Ohio State University, Columbus, Ohio, United States of America
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Stachowiak R, Wiśniewski J, Osińska O, Bielecki J. Contribution of cysteine residue to the properties of Listeria monocytogenes listeriolysin O. Can J Microbiol 2010; 55:1153-9. [PMID: 19935887 DOI: 10.1139/w09-070] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Listeriolysin (LLO) is the key virulence factor critical for Listeria monocytogenes pathogenesis. Listerial cytolysin belongs to the family of cholesterol-dependent cytolysins (CDCs), a group of pore-forming toxins produced by related gram-positive bacteria. Most CDCs contain a cysteine residue in the conserved undecapeptide - a sequence that is highly preserved among this group of proteins. Substitutions of cysteine do not always lead to loss of hemolytic activity, questioning the purpose of such strong conservation of this amino acid in the sequence of CDC. The properties of 3 L. monocytogenes strains, a wild type and 2 mutants expressing modified LLO within the cysteine residue, were analyzed in this work. The first of these mutants producing a toxin with cysteine to alanine substitution showed similar features to the wild type except that a thiol-reducing agent was not necessary for hemolytic activity. Another strain secreting LLO containing serine instead of cysteine exhibited strikingly different properties than the wild type. Modified toxin is independent of the reducing reagents, less stable, and shows accelerated kinetics of cytolysis in comparison with the unchanged protein. However, both mutant strains are less invasive in the cell culture model showing the important role of cysteine in L. monocytogenes virulence.
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Affiliation(s)
- Radosław Stachowiak
- Department of Applied Microbiology, Institute of Microbiology, University of Warsaw, Miecznikowa 1, Warsaw 02-096, Poland.
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Protease treatment affects both invasion ability and biofilm formation in Listeria monocytogenes. Microb Pathog 2008; 45:45-52. [PMID: 18479885 DOI: 10.1016/j.micpath.2008.01.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 01/23/2008] [Accepted: 01/25/2008] [Indexed: 11/24/2022]
Abstract
Listeria monocytogenes is a notably invasive bacterium associated with life-threatening food-borne disease in humans. Several surface proteins have been shown to be essential in the adhesion of L. monocytogenes, and in the subsequent invasion of phagocytes. Because the control of the invasion of host cells by Listeria could potentially hinder its spread in the infected host, we have examined the effects of a protease treatment on the ability of L. monocytogenes to form biofilms and to invade tissues. We have chosen serratiopeptidase (SPEP), an extracellular metalloprotease produced by Serratia marcescens that is already widely used as an anti-inflammatory agent, and has been shown to modulate adhesin expression and to induce antibiotic sensitivity in other bacteria. Treatment of L. monocytogenes with sublethal concentrations of SPEP reduced their ability to form biofilms and to invade host cells. Zymograms of the treated cells revealed that Ami4b autolysin, internalinB, and ActA were sharply reduced. These cell-surface proteins are known to function as ligands in the interaction between these bacteria and their host cells, and our data suggest that treatment with this natural enzyme may provide a useful tool in the prevention of the initial adhesion of L. monocytogenes to the human gut.
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Burlak C, Hammer CH, Robinson MA, Whitney AR, McGavin MJ, Kreiswirth BN, DeLeo FR. Global analysis of community-associated methicillin-resistant Staphylococcus aureus exoproteins reveals molecules produced in vitro and during infection. Cell Microbiol 2007; 9:1172-90. [PMID: 17217429 PMCID: PMC2064037 DOI: 10.1111/j.1462-5822.2006.00858.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a threat to human health worldwide. Although progress has been made, mechanisms of CA-MRSA pathogenesis are poorly understood and a comprehensive analysis of CA-MRSA exoproteins has not been conducted. To address that deficiency, we used proteomics to identify exoproteins made by MW2 (USA400) and LAC (USA300) during growth in vitro. Two hundred and fifty unique exoproteins were identified by 2-dimensional gel electrophoresis coupled with automated direct infusion-tandem mass spectrometry (ADI-MS/MS) analysis. Eleven known virulence-related exoproteins differed in abundance between the strains, including alpha-haemolysin (Hla), collagen adhesin (Cna), staphylokinase (Sak), coagulase (Coa), lipase (Lip), enterotoxin C3 (Sec3), enterotoxin Q (Seq), V8 protease (SspA) and cysteine protease (SspB). Mice infected with MW2 or LAC produced antibodies specific for known or putative virulence factors, such as autolysin (Atl), Cna, Ear, ferritin (Ftn), Lip, 1-phosphatidylinositol phosphodiesterase (Plc), Sak, Sec3 and SspB, indicating the exoproteins are made during infection in vivo. We used confocal microscopy to demonstrate aureolysin (Aur), Hla, SspA and SspB are produced following phagocytosis by human neutrophils, thereby linking exoprotein production in vitro with that during host-pathogen interaction. We conclude that the exoproteins identified herein likely account in part for the success of CA-MRSA as a human pathogen.
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Affiliation(s)
- Christopher Burlak
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamilton, MT 59840, USA.
| | - Carl H Hammer
- Reseach Technologies Branch, Mass Spectrometry Laboratory, National Institute of Allergy and Infectious Diseases, National Institutes of HealthRockville, MD 20852, USA.
| | - Mary-Ann Robinson
- Reseach Technologies Branch, Mass Spectrometry Laboratory, National Institute of Allergy and Infectious Diseases, National Institutes of HealthRockville, MD 20852, USA.
| | - Adeline R Whitney
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamilton, MT 59840, USA.
| | - Martin J McGavin
- University of Toronto, Department of Laboratory Medicine and Pathobiology, and Sunnybrook Health Sciences CentreToronto, ON, Canada, M4N 3M5.
| | - Barry N Kreiswirth
- Public Health Research Institute Tuberculosis Center, International Center for Public HealthNewark, NJ 07103, USA.
| | - Frank R DeLeo
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamilton, MT 59840, USA.
- *For correspondence. E-mail ; Tel. (+1) 406 363 9448; Fax (+1) 406 363 9394
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