Fibrinogenolytic and fibrinolytic activity in oral microorganisms

Microbiota of alveolar osteitis after permanent tooth extractions: A systematic review

Alveolar osteitis (AO) or dry socket after dental extractions is a common postoperative complication characterized by the presence of severe pain associated with an empty socket. Although some authors consider AO to be related to an alteration of the blood clot, the underlying etiology remains unclear, and recent reports suggest that bacteria might play an important role. A systematic review was made, compiling relevant references from PubMed, the Cochrane Library, Scopus and the Web of Science databases to determine which bacteria have been identified in AO sockets after dental extractions. Papers published between 1980-2019, identifying the bacteria present in AO sockets after tooth extractions, were included. Data were displayed in tables, and a descriptive analysis was carried out. After the screening process, four papers were analyzed, comprising a total of 138 samples from 138 patients with AO. The most commonly detected bacteria were Prevotella, Fusobacterium, Parvimonas and Peptostreptococcus. Two studies also showed the microbiota of patients that developed AO after dental extractions to be apparently different from that of patients without postoperative complications. These results indicate that bacteria may play an important role in the pathogenesis of AO, though further studies are needed to confirm these findings.

High-Throughput Sequencing Analysis of Microbial Profiles in the Dry Socket

PURPOSE

The aim of this study was to explore and describe the microbial profiles of dry socket (DS) and identify the key microbial population as a possible disease-related factor.

MATERIALS AND METHODS

Bacterial samples were collected from patients who underwent surgical mandibular third molar extraction and were divided in 3 groups: the disease (D) group composed of patients who were diagnosed with DS; the treated (T) group composed of patients from the D group who received treatment; and the control (C) group composed of patients who did not have adverse reactions after tooth extraction. Bacterial DNA was extracted and the V3 and V4 hypervariable regions of the bacterial 16S rRNA gene were amplified and subjected to sequencing. Sequence data were analyzed using alpha and beta diversity indices.

RESULTS

In total, 772,169 high-quality sequences were detected from 31 samples. Using a 97% similarity level, 531 operational taxonomic units were detected. In addition, 10 phyla, 23 classes, 38 orders, 63 families, and 116 genera were found. Composition of the microbial community in the D group differed considerably from that of the T and C groups. Furthermore, a specific microbial pattern, which included Parvimonas, Peptostreptococcus, Prevotella, Fusobacterium, Slackia, Oribacterium, and Solobacterium species, appeared abundantly in the D group compared with the T and C groups. Moreover, Parvimonas, Peptostreptococcus, Prevotella, and Fusobacterium species had important roles in discriminating the D group from the other 2 groups.

CONCLUSION

These results suggest differences in the microbial community composition among DSs, normal-healing sockets, and post-treated sockets. These results provide better insight into the development of DS and enhance the understanding of DS. Nonetheless, further studies are necessary to investigate and confirm how these differential bacteria contribute to the development of the disease.

Fibrinogen Degradation Products and Periodontitis: Deciphering the Connection

INTRODUCTION

Fibrinogen degradation products (e.g. D-dimer) arise from digested fibrin clots and fibrinogen. Elevated concentrations accompany activation of coagulation and fibrinolysis and indicate chronic inflammatory diseases. D-Dimer tests are a quick, noninvasive method to rule out abnormal clotting. Periodontitis strongly affects the haemostatic system and evokes a procoagulant state. Correlation of chronic periodontitis with early indicators of disease (biomarkers) might be useful.

AIM

The aim of the study was to examine whether the plasma D-dimer concentration reflects the progression of chronic periodontitis and the beneficial effect of periodontal therapy.

MATERIALS AND METHODS

Forty randomly selected subjects were divided into four groups, Group I: 10 healthy subjects, Group II: 10 with mild periodontitis, Group III: 10 with moderate periodontitis, Group IV: 10 with severe periodontitis. After thorough dental and periodontal examination, 3 mL of venous blood was collected for measurement of fibrinogen degradation products.

RESULTS

The patients with moderate and chronic periodontitis exhibited high concentrations of D-dimer (mean value 434.98-535.52 mcg/mL), whereas subjects with mild or no periodontitis exhibited values of 329.78-211.29 mcg/mL. Concentrations of D-dimer were significantly reduced after therapy of all classes of periodontitis.

CONCLUSION

Periodontal treatment can reduce amount of D-dimer in the plasma. A higher than normal concentration is observed in chronic periodontitis.

The streptococcal cysteine protease SpeB is not a natural immunoglobulin-cleaving enzyme

The human bacterial pathogen Streptococcus pyogenes has developed a broad variety of virulence mechanisms to evade the actions of the host immune defense. One of the best-characterized factors is the streptococcal cysteine protease SpeB, an important multifunctional protease that contributes to group A streptococcal pathogenesis in vivo. Among many suggested activities, SpeB has been described to degrade various human plasma proteins, including immunoglobulins (Igs). In this study, we show that SpeB has no Ig-cleaving activity under physiological conditions and that only Igs in a reduced state, i.e., semimonomeric molecules, are cleaved and degraded by SpeB. Since reducing conditions outside eukaryotic cells have to be considered nonphysiological and IgG in a reduced state lacks biological effector functions, we conclude that SpeB does not contribute to S. pyogenes virulence through the proteolytic degradation of Igs.

Porphyromonas gingivalis proteinases as virulence factors in the development of periodontitis

Porphyromonas gingivalis contains exceedingly high concentrations of cysteine proteinases with trypsin-like activity which have been implicated as virulence factors in adult-onset periodontitis. These enzymes, referred to as gingipains, cleave protein and peptide substrates after arginine (gingipain R) and lysine residues (gingipain K), and it has been found that neither is easily inhibited by host proteinase inhibitors. Examination of the properties of each proteinase clearly indicates a role(s) for both in the dysregulation of a number of normally tightly controlled pathways. The effects of such uncontrolled proteolysis are the development of edema (kallikrein/kinin pathway activation by gingipain R), neutrophil infiltration (complement pathway activation by gingipain R), and bleeding (degradation of fibrinogen by gingipain K). Since three of the major hallmarks of periodontitis involve increased crevicular flow, neutrophil accumulation at infected sites and bleeding on probing, it seems likely that both P. gingivalis-derived proteinases are important virulence factors in the development of periodontal disease.

The potential role of alpha 2-macroglobulin in the control of cysteine proteinases (gingipains) from Porphyromonas gingivalis

Porphyromonas gingivalis is closely associated with the development of some forms of periodontitis. The major cysteine proteinases released by this bacterium hydrolyze peptide bonds only after arginyl (gingipain R) or lysyl residues (gingipain K). No target protein inhibitors have been identified for either enzyme, leading us to investigate their inhibition by human plasma alpha 2-macroglobulin (alpha 2M). Both 50- and 95 kDa gingipain R were efficiently inhibited by alpha 2M, whereas the catalytic activity of gingipain K could not be eliminated. All 3 enzymes were, however, inhibited by a homologous macroglobulin from rat plasma, alpha 1-inhibitor-3 (alpha 1I3). alpha-Macroglobulins must be cleaved in the so-called "bait region" in order to inhibit proteinases by a mechanism involving physical entrapment of the enzyme. A comparison of the amino acid sequences of the 2 macroglobulins indicates that the lack of lysyl residues within the bait region of alpha 2M protects Lys-specific proteinases from being trapped. On this basis, other highly specific proteinases might also not be inhibited by alpha 2M, possibly explaining the inability of the inhibitor to control proteolytic activity in some bacterially induced inflammatory states, despite its abundance (2-5 mg/ml) in vascular fluids.

Purification and characterization of a fibrinogen-degrading protease in Bacteroides fragilis strain YCH46

A novel fibrinogenolytic protease was purified from Bacteroides fragilis strain YCH46. The protease was extracted from cells by ultrasonic treatment and was purified 425-fold with a recovery of 2.1% by sequential procedures using azocasein as a substrate. The purified protease showed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an estimated molecular weight of 100 kDa, which was consistent with the value obtained by gel filtration, indicating a monomeric native structure. Its optimal pH, Km, and Vmax for azocasein were 7.5, 0.2%, and 286 U/min/mg, respectively. The protease activity was completely inhibited by addition of 1 mM Hg2+, Cu2+, Zn2+, diisopropyl fluorophosphate, N-ethylmaleimide or p-chloromercuribenzoate but not by the inhibitors of metalloprotease or aspartic protease, suggesting that the enzyme is a serine-thiol-like protease. The protease hydrolyzed azocasein, casein, fibrinogen, gelatin, and azocoll, but not bovine serum albumin, ovalbumin, fibrin, fibronectin, immunoglobulins, transferrin, hemoglobin or types I, III, and IV collagen. The enzyme also hydrolyzed the chromogenic substrates alanyl-alanine p-nitroanilide, L-valyl-alanine p-nitroanilide, alanyl-alanyl-valyl-alanine p-nitroanilide, and glycyl-proline p-nitroanilide, but was inert toward L-alanine p-nitroanilide, alanyl-alanyl-alanine p-nitroanilide, and N-alpha-benzoyl-DL-arginine p-nitroanilide. The protease completely hydrolyzed the alpha-chain of fibrinogen at 37 C within 10 hr and at the same time the time required for clotting of protease-treated fibrinogen by thrombin was prolonged. The fibrinogenolytic activity of a crude extract of B. fragilis was stronger than that of other species of the Bacteroides fragilis group tested: B. ovatus, B. distasonis, B. eggerthii, B. uniformis, and B. thetaiotaomicron. These results suggest that the fibrinogenolytic protease is an important biological factor in Bacteroides infection.

Effect of free and vesicle-bound cysteine proteinases of Porphyromonas gingivalis on plasma clot formation: implications for bleeding tendency at periodontitis sites

Infection by Porphyromonas gingivalis is strongly associated with adult periodontitis, with proteinases from this bacterium now considered to be important virulence factors. In order to investigate possible pathological functions of these enzymes, we examined the effect of both free and vesicle-bound forms of the two major cysteine proteinases (gingipains) of P. gingivalis on plasma clot formation by using thrombin time (TT) measurements. Both Lys-gingipain (gingipain-K) and Arg-gingipain (gingipain-R) prolonged plasma TT in a dose- and time-dependent manner, and this was also found with vesicles which are the biological carriers of P. gingivalis proteinases. The increase in plasma TT by vesicles could be completely reversed by treatment with nonspecific cysteine proteinase inhibitors but only partially by compounds selective for either gingipain-K or gingipain-R. Preincubation of vesicles with a gingipain-K-specific inhibitor (z-FK-ck) reduced plasma TT more than a gingipain-R-specific inhibitor (leupeptin), suggesting that under physiological conditions gingipain-K was more effective in fibrinogen destruction. Each purified enzyme also markedly increased fibrinogen TT, gingipain-R being fourfold more potent than gingipain-K. However, in plasma, gingipain-R was ineffective because of the inhibitory effect of albumin. These results imply that cysteine proteinases, especially gingipain-K, abrogate the clotting potential of fibrinogen and, therefore, may contribute to the bleeding tendency and to persistent inflammation in periodontitis sites infected with P. gingivalis.

Fibrinolytic activity of human gingiva in the presence or absence of plaque bacteria

Activators of fibrinolysis are found in the gingival connective tissue and in the sulcular epithelium. The influence of plaque bacteria and the related inflammatory reaction on the fibrinolytic activity has been evaluated in the human gingiva. An autohistographic technique was applied to sections taken from three groups of 6 specimens each: group A from clinically healthy sites with plaque index = 1 and no bleeding on probing; group B from areas with unambiguous visual signs of gingivitis, with plaque index = 2-3 and bleeding on probing; group C from sites previously treated with professional toothcleaning twice a week for 3 months and with chlorhexidine mouthrinses twice a day for the final 3 wk, in order to obtain a virtually complete elimination of the plaque bacteria. In group C the plaque index was 0 and there was no bleeding on probing. Connective tissue fibrinolytic activity was present in all the sections from the three groups. The sulcular fibrinolytic activity was observed in all the sections taken from the specimens of groups A and B. In contrast, no fibrinolytic activity was observed over the sulcular area in any section taken from the specimens of group C. Therefore, this study does not support previous claims that healthy sulcular epithelium is capable of releasing activators of fibrinolysis. It can be concluded that the presence of any amount of plaque bacteria is associated with sulcular fibrinolytic activity. Contrarily, the elimination of plaque bacteria is associated with the absence of any detectable sign of fibrinolytic activity in the gingival sulcus.

Factors in virulence expression and their role in periodontal disease pathogenesis

The classic progression of the development of periodontitis with its associated formation of an inflammatory lesion is characterized by a highly reproducible microbiological progression of a Gram-positive microbiota to a highly pathogenic Gram-negative one. While this Gram-negative microbiota is estimated to consist of at least 300 different microbial species, it appears to consist of a very limited number of microbial species that are involved in the destruction of periodontal diseases. Among these "putative periodontopathic species" are members of the genera Porphyromonas, Bacteroides, Fusobacterium, Wolinella, Actinobacillus, Capnocytophaga, and Eikenella. While members of the genera Actinomyces and Streptococcus may not be directly involved in the microbial progression, these species do appear to be essential to the construction of the network of microbial species that comprise both the subgingival plaque matrix. The temporal fluctuation (emergence/disappearance) of members of this microbiota from the developing lesion appears to depend upon the physical interaction of the periodontal pocket inhabitants, as well as the utilization of the metabolic end-products of the respective species intimately involved in the disease progression. A concerted action of the end-products of prokaryotic metabolism and the destruction of host tissues through the action of a large number of excreted proteolytic enzymes from several of these periodontopathogens contribute directly to the periodontal disease process.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and characterization of a 65-kilodalton diisopropylfluorophosphate-binding protein in the outer membrane of Fusobacterium nucleatum Fev1

A 65-kilodalton protein was identified in the outer membrane of Fusobacterium nucleatum Fev1 by SDS-PAGE. The relative amount of the protein varied during growth, being greatest in stationary phase. The protein was radio-labeled by [125I]-lactoperoxidase treatment of live cells and was only partially extractable with 2% sodium dodecylsulfate (SDS) at room temperature, and therefore assumed to be both exposed to the cell surface and peptidoglycan associated. In intact cells the protein bound diisopropylfluorophosphate (DFP), indicating that it may be a serine protease. DFP-binding activity depended apparently on proper localization of the proteins in the membrane. Several methods were tried in attempts to purify the 65-kilodalton protein; the method that gave best results was preparative SDS-polyacrylamide gel electrophoresis. The isoelectric point was determined to about pH 5. Amino acid composition analysis showed that the 65-kilodalton protein possesses an excess of hydrophilic over hydrophobic residues, polarity index 52%. The N-terminal end of the protein was apparently blocked.

Specific cell components of Bacteroides gingivalis mediate binding and degradation of human fibrinogen

Bacteroides (Porphyromonas) gingivalis, which has been implicated as an etiologic agent in human periodontal diseases, has been shown to bind and degrade human fibrinogen. B. gingivalis strains bind fibrinogen reversibly and with high affinity and bind to a specific region of the fibrinogen molecule that appears to be located between the D and E domains (M. S. Lantz, R. D. Allen, P. Bounelis, L. M. Switalski, and M. Hook, J. Bacteriol. 172:716-726, 1990). We now report that human fibrinogen is bound and then degraded by specific B. gingivalis components that appear to be localized at the cell surface. Fibrinogen binding to bacterial cells occurred at 4, 22, and 37 degrees C. A functional fibrinogen-binding component (Mr, 150,000) was identified when sodium dodecyl sulfate-solubilized bacteria were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose membranes, and probed with 125I-fibrinogen. Fibrinogen degradation did not occur at 4 degrees C but did occur at 22 and 37 degrees C. When bacteria and iodinated fibrinogen were incubated at 37 degrees C, two major fibrinogen fragments (Mr, 97,000 and 50,000) accumulated in incubation mixture supernatant fractions. Two major fibrinogen-degrading components (Mr, 120,000 and 150,000) have been identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in substrate-containing gels. Fibrinogen degradation by the Mr-120,000 and -150,000 proteases was enhanced by reducing agents, completely inhibited by N-alpha-p-tosyl-L-lysyl chloromethyl ketone, and partially inhibited by n-ethyl maleimide, suggesting that these enzymes are thiol-dependent proteases with trypsinlike substrate specificity. The fibrinogen-binding component could be separated from the fibrinogen-degrading components by selective solubilization of bacteria in sodium deoxycholate.

Extensive bone loss associated with periapical infection with Bacteroides gingivalis: a case report

A case is presented in which rapid and extensive bone loss occurred around a maxillary molar with periapical infection by Bacteroides gingivalis (Porphyromonas gingivalis). The lesion failed to respond to conventional endodontic therapy. An adjacent vital molar was extracted and an unfavourable periodontal condition occurred despite microbiological investigation and surgery.

The role of Bacteroides gingivalis in periodontal disease

The microbial flora in adult advanced periodontitis lesions is comprised of Gram-negative rods, with Bacteroides gingivalis as one of the major representatives. This review deals with biological properties of surface antigens, hemagglutinin (attachment factor), and capsular structure of B. gingivalis. Sera containing high IgG antibody levels to B. gingivalis enhanced the complement-mediated bactericidal activity in vitro, although the susceptibility to complement-mediated lysis differed among B. gingivalis strains. The protective effect of immunization against B. gingival is infection was examined in hamsters in which cotton threads had been tied to the gingival margins of the mandibular first molar. Repeated oral topical application of hyper-immune sera against B. gingivalis resulted in effective elimination of the organisms from the periodontal lesions in the experimental animals.

The role of black-pigmented Bacteroides in human oral infections

Today, 10 black-pigmented Bacteroides (BPB) species are recognized. The majority of these species can be isolated from the oral cavity. BPB species are involved in anaerobic infections of oral and non-oral sites. In the oral cavity, BPB species are associated with gingivitis, periodontitis, endodontal infections and odontogenic abscesses. Cultural studies suggest a specific role of the various BPB species in the different types of infection. Bacteroides gingivalis is closely correlated with destructive periodontitis in adults as well as in juveniles. Bacteroides intermedius seems to be less specific since it is found in gingivitis, periodontitis, endodontal infections and odontogenic abscesses. The recently described Bacteroides endodontalis is closely associated with endodontal infections and odontogenic abscesses of endodontal origin. There are indications that these periodontopathic BPB species are only present in the oral cavity of subjects suffering from periodontal breakdown, being absent on the mucosal surfaces of subjects without periodontal breakdown. BPB species associated with healthy oral conditions are Bacteroides melaninogenicus, Bacteroides denticola and Bacteroides loescheii. There are indications that these BPB species are part of the normal indigenous oral microflora. Many studies in the past have documented the pathogenic potential and virulence of BPB species. This virulence can be explained by the large numbers of virulence factors demonstrated in this group of micro-organisms. Among others, the proteolytic activity seems to be one of the most important features. Several artificial substrates as well as numerous biological proteins are degraded. These include anti-inflammatory proteins such as alpha-2-macroglobulin, alpha-1-antitrypsin, C3 and C5 complement factors and immunoglobulins. B. gingivalis is by far the most proteolytic species, followed by B. endodontalis. Like other bacteria, the lipopolysaccharide of B. gingivalis has shown to be active in bone resorption in vitro and is capable in stimulating interleukin-1 production in human peripheral monocytes. Based on the well documented association with periodontal disease and the possession of relevant virulence factors, BPB species must be considered as important micro-organisms in the etiology of oral infections. B. gingivalis seems to be the most pathogenic and virulent species.

Biology of asaccharolytic black-pigmented Bacteroides species

Images

Interactions of Bacteroides gingivalis with fibrinogen

Results of previous studies from our laboratory have shown that a strain of Bacteroides intermedius isolated originally from a patient with acute necrotizing ulcerative gingivitis binds and degrades human fibrinogen (M.S. Lantz, L.M. Switalski, K.S. Kornman, and M. Hook, J. Bacteriol. 163:623-628, 1985). We report that strains of Bacteroides gingivalis, an organism implicated in the etiology of several forms of periodontitis, also bind and degrade fibrinogen. The binding is rapid, reversible, saturable, and specific. The number of fibrinogen-binding sites per cell varies from 500 to 1,500 in different batches of bacteria, and the dissociation constant for the complex is on the order of 10(-8) M. B. gingivalis possesses cell-associated fibrinogenolytic activity that is activated by dithiothreitol and blocked by thiol protease inhibitors. Interaction with fibrinogen may mediate colonization and establishment of these organisms in the periodontal microbiota.

Ability of oral bacteria to degrade fibronectin

The fibronectin-degrading ability of 116, mainly oral, strains was assayed by using plasma-derived fibronectin adsorbed to a polystyrene surface. Ability to degrade fibronectin was revealed in strains of Bacteroides gingivalis, Bacteroides intermedius, Bacteroides loeschii, Staphylococcus aureus, Staphylococcus epidermidis, Peptococcus prevotii, Clostridium sporogenes, and Propionibacterium acnes. The fibronectinolytic activity of subgingival bacteriological samples was found to be related to the presence of B. gingivalis and B. intermedius. In addition, strains of the nonoral Bacteroides species B. asaccharolyticus and B. fragilis showed fibronectin-degrading ability. No such ability was detected in the oral strains tested of Streptococcus, Veillonella, Actinomyces, Lactobacillus, Actinobacillus, Capnocytophaga, Fusobacterium, or Haemophilus species.

Bacteroides intermedius binds fibrinogen

The binding of Bacteroides intermedius VPI 8944 to human fibrinogen has been characterized. The binding is time dependent, at least partially reversible, saturable, and specific. On an average, a maximum of 3,500 fibrinogen molecules bind per bacterial cell, with a dissociation constant of 1.7 X 10(-11) M. These bacteria also exhibit a fibrinogenolytic activity which can be partially inhibited by protease inhibitors. Bacteria release fibrinogenolytic activity into the surrounding medium without loss of binding activity, but more pronounced fibrinogen breakdown occurs when 125I-labeled fibrinogen is associated with the bacteria, suggesting that fibrinogen is degraded at the cell surface. Fibrinogen binding by B. intermedius might represent a mechanism of bacterial tissue adherence.

Degradation of human immunoglobulins by proteases from Streptococcus pneumoniae obtained from various human sources

The ability of Streptococcus pneumoniae to degrade human secretory immunoglobulin A (S-IgA), IgG, and IgM was tested in 102 strains by use of the thin-layer enzyme assay cultivation technique. The strains were isolated from patients with acute phases of otitis media, meningitis, and pneumonia as well as from symptomless carriers. An ability to degrade S-IgA, IgG, and IgM was revealed in 50, 84, and 96 strains, respectively. An IgG- and IgM-degrading ability of S. pneumoniae has not previously been reported. A concurrent degradation of the three immunoglobulins was revealed in 38 strains; degradation of two of them was revealed in 54 strains, and degradation of only one of them was revealed in 9 strains. One strain failed to degrade any of the immunoglobulins. Correlations were not found between the ability of the S. pneumoniae strains to degrade S-IgA, IgG, or IgM and the serotype affiliation or between the ability to degrade IgG or IgM and the origin of strains. However, the ability to degrade S-IgA was evident more often in strains isolated from symptomless carriers and from bronchial secretions of patients with acute pneumonia than it was in strains from patients with acute meningitis or acute otitis media or from the blood of patients with acute pneumonia. These latter findings may indicate a biological significance of S-IgA-degrading ability in bacterial colonization of mucosal surfaces.