Virulence factors in anaerobic bacteri

Hofstad, Tor

doi:10.1007/bf01967797

Cited by 29 publications

(16 citation statements)

References 55 publications

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“…Under normal circumstances, B. fragilis remains at low numbers in the intestine and in harmony with the host (Goldner et al , 1993). However, injuries to the gut epithelium may occur and the environment can become more oxidized, turning these bacteria into pathogenic microorganisms (Hofstad, 1992). Studies have demonstrated that alterations in the Eh can influence the pathogenic potential of B. fragilis .…”

Section: Discussionmentioning

confidence: 99%

A TonB-dependent outer membrane protein as aBacteroides fragilisfibronectin-binding molecule

Pauer¹,

Ferreira²,

Santos-Filho³

et al. 2009

FEMS Immunol Med Microbiol

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The binding of Bacteroides fragilis to plasmatic fibronectin was investigated using strains isolated from healthy subjects and from patients with bacteremia. They were cultivated in a synthetic media in which variations in cysteine concentrations determined alterations in the oxidation-reduction potential (Eh). All the strains assayed were capable of adhering to plasmatic fibronectin when cultivated under oxidizing and reducing conditions. Bacteroides fragilis 1405 showed the greatest difference when the results under these conditions were compared and it was selected for further investigations. Chemical treatments suggested the involvement of a protein in the interaction between B. fragilis and plasmatic fibronectin. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of outer membrane proteins (OMPs) revealed differences between the extracts obtained from cultures grown under the two conditions. Protein bands of c. 102, 100, 77, 73, 50 and 40 kDa were more highly expressed under oxidizing than reducing conditions. Dot blot analysis showed a stronger recognition of plasmatic fibronectin by OMPs obtained from cultures grown under higher Eh, and Western blot assays confirmed a band of c. 102 kDa as fibronectin-binding protein. This protein was sequenced and revealed to be a putative TonB-dependent OMPs. PCR analysis confirmed the presence of this gene in all the studied strains.

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Section: Discussionmentioning

confidence: 99%

A TonB-dependent outer membrane protein as aBacteroides fragilisfibronectin-binding molecule

Pauer¹,

Ferreira²,

Santos-Filho³

et al. 2009

FEMS Immunol Med Microbiol

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show abstract

“…The composition of capsular polysaccharide may vary among strains and may be composed of either carbohydrate or protein, depending on the conditions under which they were grown (Hofstad, 1992). In vitro studies have demonstrated a capsule on P. gingivalis (Listgarten & Lai, 1979;Woo et al, 1979), fusobacteria and peptostreptococci Walker, 1985, 1986).…”

Section: Capsules and Surface Layers (S-layers)mentioning

confidence: 99%

“…Although all their virulence mechanisms have not been studied in great detail, bacterial species that produce these proteases are associated with invasion of mucous membranes where IgA may be found (Hofstad, 1992). Prevotella and P. gingivalis (Table 6) each produce different antigenic forms of IgAI protease (Frandsen et al, 1987).…”

Section: Protease Productionmentioning

confidence: 99%

The Microbial Aetiology of Periodontal Diseases

Africa¹

2012

Periodontal Diseases - A Clinician's Guide

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“…An increase in the number of aerobic and facultativc bacteria when combined with three members of the B. fragilis group was illustrated in almost all instances except for the one between H. influenzae and B. fragilis group (Table 4) However, this is not surprising since this combination is rarely seen in clinical infections. Several hypotheses have been proposed to explain microbial synergy in mixed infections [21]. When this phenomenon occurs in mixtures of aerobic and anaerobic flora, it may be due to protection from phagocytosis and intracellular killing [44], production of essential growth factors [45], and lowering of oxidation-reduction potentials in host tissues [46].…”

Section: ]mentioning

confidence: 99%

“…In addition to capsule, anaerobic bacteria possess other important virulence factors. These include the production of superoxide dismutase and catalase, immunoglobulin proteases, coagulation-promoting and -spreading factors (such as hyalouronidase, collagenase, and fibrinolysin), and adherence factors [21]. Other factors that enhance the virulence of anaerobes include mucosal damage, oxidation reduction potential drop, and the presence of hemoglobin or blood in an 67 infected site.…”

Section: Introductionmentioning

confidence: 99%

The role of encapsulated anaerobic bacteria in synergistic infections

Brook¹

1994

FEMS Microbiology Reviews

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The effect of encapsulation on the virulence, survival, and protection of anaerobic bacteria from phagocytosis is reviewed. Support for the importance of encapsulated Gram-negative anaerobic rods (Bacteroides sp., Prevotella sp. and Porphyromonas sp.), anaerobic and facultative Gram-positive cocci (AFGPC) was provided by their higher recovery rate in oropharyngeal infections, abscesses and blood, compared to their number in the normal flora. The pathogenicity of Bacteroides, Fusobacterium, Clostridium, and AFGPC was studied by inoculating them into mice and observing their ability to induce subcutaneous abscesses. Encapsulated Bacteroides, Fusobacteria, and AFGPC generally induced abscesses, whereas non-encapsulated organisms did not. However, many of the strains that had only a minimal number of encapsulated organisms (< 1%) survived in the abscesses, and they became heavily encapsulated when inoculated with other viable or non-viable encapsulated bacteria. Thereafter, these strains were able to induce abscesses when injected alone. Encapsulated Gram-negative anaerobic rods and AFGPC-induced bacteraemia and translocation, and increased the mortality of the infected animals more often than did the non-encapsulated form of the same strains. As determined by using selective antimicrobial therapy and quantitative cultures of abscesses induced in mice, possession of a capsule generally made Gram-negative anaerobic rods more important than their aerobic counterparts. Synergistic potentials were seen between encapsulated Gram-negative anaerobic rods and all tested aerobic bacteria and most AFGPC, and also between most AFGPC and Pseudomonas aeruginosa or Staphylococcus aureus. These studies demonstrated the importance of encapsulated anaerobes in mixed infections.

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Virulence factors in anaerobic bacteri

Cited by 29 publications

References 55 publications

A TonB-dependent outer membrane protein as aBacteroides fragilisfibronectin-binding molecule

A TonB-dependent outer membrane protein as aBacteroides fragilisfibronectin-binding molecule

The Microbial Aetiology of Periodontal Diseases

The role of encapsulated anaerobic bacteria in synergistic infections

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