Adherence of Isolates of Neisseria meningitidis from Patients and Carriers to Human Buccal Epithelial Cells

Craven, D E; Peppler, M S; Frasch, Carl E.; Mocca, L F; McGrath, Philip P.; Washington, Glennelle C.

doi:10.1093/infdis/142.4.556

Cited by 93 publications

(59 citation statements)

References 44 publications

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“…Both vesiculating Neisseria meningitidis and freely diffused vesicles were detected in asymptomatic carriers and symptomatic patients, including in the cerebrospinal fluid from a patient with meningitis and blood from a patient who died from meningitis (Craven et al 1980;Stephens et al 1982;Brandtzaeg et al 1992;Bjerre et al 2000;Namork and Brandtzaeg 2002). Similarly, vesiculating Borrelia and free vesicles were detected in the urine and blood of B. burgdorferi-infected mice as well as in infected ticks (Dorward et al 1991).…”

Section: Vesicle Production During Infectionmentioning

confidence: 99%

Bacterial outer membrane vesicles and the host–pathogen interaction

Kuehn¹,

Kesty²

2005

Genes Dev.

796

725

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Extracellular secretion of products is the major mechanism by which Gram-negative pathogens communicate with and intoxicate host cells. Vesicles released from the envelope of growing bacteria serve as secretory vehicles for proteins and lipids of Gram-negative bacteria. Vesicle production occurs in infected tissues and is influenced by environmental factors. Vesicles play roles in establishing a colonization niche, carrying and transmitting virulence factors into host cells, and modulating host defense and response. Vesicle-mediated toxin delivery is a potent virulence mechanism exhibited by diverse Gram-negative pathogens. The biochemical and functional properties of pathogen-derived vesicles reveal their potential to critically impact disease.In nearly every case, virulence factors of Gram-negative pathogens are secreted products that enhance the survival of the bacteria and/or damage the host. Secretion of virulence factors by Gram-negative pathogens is complicated by the fact that the bacterial envelope consists of two lipid bilayers, the inner and outer membrane, and the periplasm in between. Gram-negative pathogens have developed many strategies, some specific to pathogens, to enable active virulence factors to gain access to the extracellular environment, typically the tissues or bloodstream of the host organism (Henderson et al. 2004). The Type II and Type V secretion systems are two-step processes in which proteins are transported first through the inner membrane (IM) and then through the outer membrane (OM). For secretion via the Type I, Type III, and Type IV secretion systems, the material is transferred directly into the extracellular milieu or into another cell. The Type III system is specific for the transport of factors by pathogenic bacteria. All of these secretion systems secrete individual proteins or small complexes. This review examines secretion via OM vesicles, a distinct "Type VI" mechanism that enables bacteria to secrete a large, complex group of proteins and lipids into the extracellular milieu.Both pathogenic and nonpathogenic species of Gram- Vesicles are a means by which bacteria interact with prokaryotic and eukaryotic cells in their environment. Some of the best-characterized vesicles are those produced by pathogens. Biochemical analysis and functional characterization of pathogen-derived outer membrane vesicles demonstrate that this secretory pathway has been usurped by pathogens for the transport of active virulence factors to host cells (Table 1). Naturally produced OM vesicles from pathogenic bacteria contain adhesins, toxins, and immunomodulatory compounds, and they directly mediate bacterial binding and invasion, cause cytotoxicity, and modulate the host immune response. By participating in such diverse aspects of the host-pathogen interaction, OM vesicles are potent bacterial virulence factors. Formation of bacterial OM vesiclesNaturally produced bacterial vesicles are discrete, closed OM blebs produced by growing cells, not products of cell lysis or cell death (Mug-Opstelte...

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Section: Vesicle Production During Infectionmentioning

confidence: 99%

Bacterial outer membrane vesicles and the host–pathogen interaction

Kuehn¹,

Kesty²

2005

Genes Dev.

796

725

View full text Add to dashboard Cite

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“…Strains recovered during carriage also have other decreased phenotypes, such as M protein production, hemolysis, and dissemination to other individuals (8)(9)(10). Unencapsulated strains of N. meningitidis have been isolated from carriers (11), suggesting that lack of capsule production is linked to carriage. Recently, a comparative genomic analysis showed that hyaluronic acid capsule biosynthesis in GAS is under strong selective pressure depending on the host environment (12).…”

mentioning

confidence: 99%

Asymptomatic Carriage of Group A Streptococcus Is Associated with Elimination of Capsule Production

et al. 2014

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cHumans commonly carry pathogenic bacteria asymptomatically, but despite decades of study, the underlying molecular contributors remain poorly understood. Here, we show that a group A streptococcus carriage strain contains a frameshift mutation in the hasA gene resulting in loss of hyaluronic acid capsule biosynthesis. This mutation was repaired by allelic replacement, resulting in restoration of capsule production in the isogenic derivative strain. The "repaired" isogenic strain was significantly more virulent than the carriage strain in a mouse model of necrotizing fasciitis and had enhanced growth ex vivo in human blood. Importantly, the repaired isogenic strain colonized the mouse oropharynx with significantly greater bacterial burden and had significantly reduced ability to internalize into cultured epithelial cells than the acapsular carriage strain. We conducted full-genome sequencing of 81 strains cultured serially from 19 epidemiologically unrelated human subjects and discovered the common theme that mutations negatively affecting capsule biosynthesis arise in vivo in the has operon. The significantly decreased capsule production is a key factor contributing to the molecular détente between pathogen and host. Our discoveries suggest a general model for bacterial pathogens in which mutations that downregulate or ablate virulence factor production contribute to carriage.

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“…There are many complicated events which occur during the attachment process and an electron microscope (EM) is useful to observe the details of the interaction between the bacteria and the host cell (4,6,7,14,17,18). EM can reveal the events more precisely than the light microscope (LM).…”

mentioning

confidence: 99%