Mouth in Foot Disease

Toothpicks are commonly used household items that rarely cause serious injury or infection. Toothpick-related injuries often occur due to ingestion with subsequent trauma/infection at distal sites within the gastrointestinal tract; however, cardiovascular, pleural, and soft tissue infections have been reported. Eikenella corrodens is a gram-negative, facultative anaerobic bacillus found in oral flora associated with bite wound infections. A few case reports describe E. corrodens osteomyelitis from toothpick puncture wounds. We report a case of foot cellulitis and abscess in an elderly diabetic after toothpick puncture injury that was unresponsive to empiric antibiotics. Wound cultures grew E. corrodens and rare Peptostreptococcus species. E. corrodens is resistant to first-generation cephalosporins, macrolides, aminoglycosides, clindamycin, and metronidazole. This case highlights the insidious nature of E. corrodens infections and the need to tailor empiric antibiotics for skin and soft tissue infections based on the mechanism of injury. In addition, this case stresses the importance of protective footwear in diabetics and serves as a cautionary tale regarding the use of seemingly innocuous toothpicks.

Eikenella corrodens in head and neck infections

BACKGROUND

Eikenella corrodens (E. corrodens) is a Gram-negative facultative anaerobic bacillus that originally was thought to be an attenuated and indigenous bacterium. In recent years, a number of reports have documented that E. corrodens can be a potential pathogen not only in immunocompromised patients but also in hosts with normal immunity. We herein study E. corrodens infections of the head and neck encountered in our department.

METHODS

Twenty-two consecutive patients treated in our department for E. corrodens infections of the head and neck were retrospectively analyzed. Microbial specimens were subjected to light microscopic examination, aerobic culture using chocolate and sheep blood agar media, and anaerobic culture using Brucella HK agar medium. Cultured bacteria were subjected to antimicrobial susceptibility tests by means of the broth microdilution method.

RESULTS

There were 16 males and 6 females with an average age of 29.9 years. Two patients had malignancy, while the other patients had no particular risk factors or underlying diseases. Infected sites were the ear in 6 cases, pharynx in 12 cases (tonsil in 10 cases), paranasal sinuses in 3 cases, and salivary gland in 1 case. Seventeen patients suffered polymicrobial infections. Staphylococcus and Streptococcus were the most frequently detected pathogens coexisting with E. corrodens, and mixed infections of E. corrodens and Streptococcus milleri group bacteria were prone to form abscesses. Isolated E. corrodens was susceptible to third-generation cephems (MIC90 = 0.15-0.25 microg/ml), carbapenems (MIC90 < or = 0.15 microg/ml), and new quinolones (MIC90 < or = 0.15 microg/ml), and resistant to oxacillin (MIC90 > 8 microg/ml), cefazolin (MIC90 > 4 microg/ml), macrolides (MIC90 = 4-8 microg/ml), and clindamycin (MIC90 > 4 microg/ml).

CONCLUSIONS

E. corrodens infections of the head and neck occur most frequently in the tonsil even in hosts with normal immunity. Coexistence with Streptococcus milleri group bacteria and the use of ineffective antibiotics can be exacerbating factors. First-choice drugs for E. corrodens infections should be third-generation cephems, carbapenems, or new quinolones.

Plasmid-mediated genomic recombination at the pilin gene locus enhances the N-acetyl-d-galactosamine-specific haemagglutination activity and the growth rate of Eikenella corrodens

Eikenella corrodens belongs to a group of periodontopathogenic bacteria and forms unique corroding colonies on solid medium due to twitching motility. It is believed that an N-acetyl-d-galactosamine (GalNAc)-specific lectin on the cell surface contributes significantly to its pathogenicity and can be estimated by its haemagglutination (HA) activity. Recently, a plasmid, pMU1, from strain 1073 has been found; this plasmid affects pilus formation and colony morphology. To identify the gene involved in these phenomena, ORF 4 and ORFs 5–6 on pMU1 were separately subcloned into a shuttle vector, and the resultant plasmids were introduced into E. corrodens 23834. Transformants with the ORF 4 gene, which is identified to be a homologous gene of the type IV pilin gene-specific recombinase, lost their pilus structure and formed non-corroding colonies on a solid medium, whereas transformants with ORFs 5–6 exhibited the same phenotype as the host strain 23834. Southern analysis showed that the introduction of the ORF 4 gene into strain 23834 resulted in genomic recombination at the type IV pilin gene locus. The hybridization pattern of these transformants was similar to that of strain 1073. These results suggest that ORF 4 on pMU1 encodes a site-specific recombinase and causes genomic recombination of the type IV pilin gene locus. Furthermore, the introduction of ORF 4 into strain 23834 increased GalNAc-specific HA activity to a level equivalent to that of strain 1073. Although the morphological colony changes and loss of pilus structure are also observed in phase variation, genomic recombination of the type IV pilin gene locus did not occur in these variants. Moreover, an increase was not observed in the GalNAc-specific HA activity of these variants. These results suggested that the loss of pilus structure, the morphological change in colonies and the increase in HA activity due to plasmid pMU1 might be caused by a mechanism that differs from phase variation, such as a genomic recombination of the type IV pilin gene locus.

Caspase activation is involved in chronic periodontitis

Periodontitis, a common infectious disease, is initiated by various gram-negative bacteria and characterized by the destruction of the periodontal tissue. Here, we investigated the role of caspases, intracellular proteases that are the key mediators of apoptosis. We show that activation of caspase-3 and caspase-7 is considerably enhanced in gingival tissue from patients with periodontitis. We also demonstrate in in vitro experiments that various periodontopathic bacteria exert a direct growth-suppressing effect and, moreover, can trigger a host-mediated cytotoxic activity involving the CD95 death receptor. Our data suggest that caspase activation is a prominent feature in periodontitis-associated tissue injury.

Amniotic fluid infection syndrome and neonatal mortality caused by Eikenella corrodens

Different microorganisms not commonly found in the female genital tract have been implicated as causative agents for amniotic fluid infections. Eikenella corrodens is part of the normal flora in the human oral cavity and upper respiratory tract. It is most commonly found in the clinical setting of polymicrobial infections involving human bite wounds, head and neck infections, and periodontitis. On rare occasions, E. corrodens has been reported as a cause of gynecologic infections. There are only 3 reports of documented E. corrodens chorioamnionitis of the placenta resulting in preterm labor, one of which is associated with early neonatal demise. We report a case of preterm delivery of twin infants at 23 weeks of gestation with documented E. corrodens infection in 1 twin who was not resuscitated.

Prevalence of Periodontopathic Bacteria in Aggressive Periodontitis Patients in a Chilean Population

BACKGROUND

Actinobacillus actinomycetemcomitans is considered a major etiologic agent of aggressive periodontitis (AgP). Other periodontopathic bacteria such as Porphyromonas gingivalis are also suspected of participating in aggressive periodontitis although the evidence to support this is controversial. The aim of the present study was to determine the prevalence of eight periodontopathic bacteria in Chilean patients with AgP.

METHODS

Subgingival plaque samples were collected from 36 aggressive, 30 localized, and six generalized periodontitis patients. Samples from 17 advanced chronic periodontitis (CP) patients were taken as controls. Samples collected from the four deepest periodontal pockets in each patient were pooled in prereduced transport fluid (RTF) and cultured. Periodontal bacteria were primarily identified by colony morphology under stereoscopic microscope and rapid biochemical tests. The identity of some bacterial isolates was confirmed by colony polymerase chain reaction (PCR).

RESULTS

AgP showed a significatively higher prevalence of C. rectus than CP (P = 0.036). The only statistical difference found was for C. rectus. Patients with AgP showed a higher, but not statistically significant, prevalence of P. gingivalis, E. corrodens, P. micros, and Capnocytophaga sp. A similar prevalence in both groups of patients was observed for F. nucleatum and P. intermedia/nigrescens, and A. actinomycetemcomitans was less prevalent in AgP than CP patients. In localized AgP, P. intermedia/nigrescens, E. corrodens, F. nucleatum, and P. micros were the more prevalent pathogens in contrast to generalized AgP patients who harbored A. actinomycetemcomitans, P. gingivalis, and Capnocytophaga sp. as the most prevalent bacteria.

CONCLUSIONS

C. rectus, P. gingivalis, E. corrodens, P. micros, and Capnocytophaga sp. were the most predominant periodontopathic bacteria of AgP in this Chilean population, but the only statistical difference found here between AgP and CP was for C. rectus, suggesting that the differences in clinical appearance may be caused by factors other than the microbiological composition of the subgingival plaque of these patients. In this study, the prevalence of A. actinomycetemcomitans was much lower than that of P. gingivalis.

Clonal diversity and stability of subgingival Eikenella corrodens

Eikenella corrodens is a commensal subgingival bacterium commonly found in both periodontally nondiseased and diseased subjects. The present study examined the clonal diversity and stability of subgingival E. corrodens over time. Ninety-five subjects were enrolled at the baseline examination, including 44 periodontally nondiseased subjects and 51 subjects with aggressive periodontitis. Twenty-two nondiseased subjects and 11 subjects with aggressive periodontitis were subsequently reexamined after an average interval of 14 months. Two subgingival plaque samples were obtained from each subject to determine the total cultivable bacteria. In addition, multiple E. corrodens isolates from each sample were recovered for clonal analysis by arbitrarily primed PCR. The mean numbers of distinct E. corrodens clones harbored by nondiseased subjects and subjects with aggressive periodontitis were 1.3 and 3.0, respectively. Thirty-nine percent of the nondiseased subjects and 63% of the subjects with aggressive periodontitis harbored multiple clones of E. corrodens. The numbers of distinct E. corrodens clones increased significantly (Mann-Whitney ranking test, P < 0.05) in sites from patients with aggressive periodontitis, in sites with pocket depths of 4 mm or greater, in sites with a clinical attachment loss of 2 mm or greater, and in sites coinfected with Porphyromonas gingivalis. Comparison of E. corrodens clones recovered at the baseline and those recovered at the follow-up examination showed that E. corrodens colonization was not stable. Thirty-eight of the 66 follow-up samples (58%) showed a complete change (including de novo colonization of the sites or complete elimination of the organism from the sites) of the subgingival E. corrodens clonal types between the baseline and the follow-up examinations. Our results suggest a complexity of subgingival microbiota not seen previously.

Eikenella corrodens brain abscess after repeated periodontal manipulations cured with imipenem and neurosurgery

Eikenella corrodens is a facultatively anaerobic gram-negative rod that colonizes the oral cavity and very rarely produces central nervous system (CNS) infections. Frontal lobe abscesses are occasionally associated with a dental source of infection. We report a case of an adult man with overzealous dental cleaning habits who developed a right frontal brain abscess caused by E. corrodens. He underwent neurosurgical drainage of the pus and was successfully treated with imipenem 4 g/i.v./day for 4 weeks with no complications. Repeated periodontal trauma could explain the Eikenella brain abscess in this case.

Soluble products from Eikenella corrodens stimulate oral epithelial cells to induce inflammatory mediators

In the inflammatory response elicited by bacterial colonization in periodontal pockets, pocket epithelial cells not only serve as a barrier to isolate the pocket microenvironment from external stimuli but also regulate the functions of neighboring cells including fibroblasts and inflammatory cells. To elucidate this mechanism, we characterized the effects of periodontopathic bacterium Eikenella corrodens 1073 components on the production of some inflammatory mediators in a human oral epithelial cell line (KB). In enzyme-linked immunosorbent assay (ELISA), the E. corrodens supernatant induced interleukin-6 (IL-6), IL-8 and prostaglandin E2 but not interferon-gamma (IFN-gamma) production by KB cells. After incubation with E. corrodens supernatant, KB cells showed a marked increase in the levels of IL-6, IL-8 and PG G/H synthase (cyclooxygenase)-2, but not IFN-gamma, gene expression by reverse-transcriptase polymerase chain reaction. All these E. corrodens products responsible for production of these inflammatory mediators resisted freezing and boiling and were present in a 10-kDa filtrate. These results imply that these soluble small-molecular-mass products from E. corrodens stimulate various inflammatory mediator productions by human oral epithelial cells and may play a role in the initiation of periodontal inflammation and subsequently perpetuate the inflammatory response during chronic infection.

Identification of lysine decarboxylase as a mammalian cell growth inhibitor in Eikenella corrodens: possible role in periodontal disease

The pathogenesis of inflammatory periodontal disease was studied by examining the mechanism of HeLa and HL60 cell growth inhibition by cell-free saline-soluble extracts of Eikenella corrodens and bacterial plaque. Previous studies identified a protein (p80) as causing growth inhibition by E. corrodens extracts. After purification by two-dimensional SDS-PAGE, p80 was digested with protease lysC. Amino acid sequences were obtained and backtranslated for use as PCR primers. A 5840 nucleotide sequence containing a lysine decarboxylase gene was obtained from a Sau3 A1 genomic library of E. corrodens DNA. Lysine decarboxylase activity was present at physiologic pH in the E. corrodens extracts containing p80, and also in bacterial plaque. Both extracts caused growth inhibition by depleting lysine from cell culture media through conversion to cadaverine. Adding lysine, or immune goat IgG to a peptide derived from the active site sequence of E. corrodens lysine decarboxylase, retarded lysine depletion and growth inhibition. epsilon-Amino caproic acid specifically enhanced lysine decarboxylase activity at the low lysine concentration in HL60 cell culture media, and also increased the growth inhibition. Thus, lysine decarboxylases such as p80 inhibit growth by removing lysine from mammalian cell culture media. A new role for lysine decarboxylase activity in the microbial aetiology of periodontal disease is discussed.

Expression of matrix metalloproteinases in healthy and diseased human gingiva

BACKGROUND, AIMS

The aim of our study was to investigate the patterns of several metalloproteinases (MMP-1, MMP-2 and MT1-MMP) mRNAs expression using a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and to correlate them with clinical parameters and bacteriological diagnosis in healthy versus diseased human gingiva.

METHODS

To identify the cell origin of MMP production, in situ hybridization (ISH) was also performed for the MMPs on the same samples. 17 gingival biopsies were collected (13 affected by advanced periodontitis and 4 healthy used as controls) and plaque index, gingival index, pocket depth and bleeding on probing were measured. Subgingival microbial samples were also collected to be analysed by a DNA probe technique. The biopsies were processed both for RT-PCR and ISH. We also investigated a model for bacterial induced MMP expression in human gingival fibroblasts (HGF) infected by Eikenella corrodens.

RESULTS

We found an expression of the mRNA encoding MMP-1 only in diseased gingiva but at low levels relative to beta-actin (mean+/-SD: diseased versus healthy: 0.013+/-0.024 versus 0). Although the frequencies and levels of mRNA encoding for MMP-2 or MT1-MMP are not significantly different between each group (mean+/-SD: 0.329+/-0.344 versus 0.137+/-0.219 for MMP-2; 0.485+/-0.374 versus 0.466+/-0.296 for MT1-MMP), using ISH, we observed an expression of both mRNAs in fibroblasts of pathological specimens at sites that histologically showed signs of chronic inflammation and connective tissue remodelling. In vitro infection of HGF by Eikenella corrodens stimulated 3-fold the production of the mRNA encoding MMP-2 while other mRNAs remained unchanged.

CONCLUSION

Our results did not reveal significant differences in the expression of mRNAs encoding for the MMPs between healthy and periodontitis-affected patients, reflecting the great heterogeneity in the periodontal status of individuals. However, they indicate that gingival fibroblasts are an active source of MMP-2 production in response to a periopathogen.

[Bacterial virulence in the etiology of periodontal diseases]

Strong relationships have been very often described between various form of periodontal disease (PD) and certain bacterial species, so that nowadays periodontal disease is recognized as an infectious disease. Destruction of periodontal supporting tissues happens as a response to very intricate host-parasite interactions. When the clinician will be able to fully understand and identify such phenomena it would be possible to succeed in a properly diagnosis and control of the active phase of periodontal disease. The first step in such a direction would be to analyze the common characteristic of some bacterial species, the so called suspected periodontopathogens. Such species namely Gram-negative, associated with the outbreak of periodontal disease have in common the capacity to disrupt the integrity of the host defences by means of the so called virulence factors. These factors may enhance the bacterial colonization or may interfere with the host response that ultimately results in periodontal support breakdown. The present review focuses on the virulence factors of the main suspected periodontopathogens evaluating the effects on the host immune response and directly on the periodontal tissues.

Clonal diversity of oral Eikenella corrodens within individual subjects by arbitrarily primed PCR

The genetic diversity of 205 Eikenella corrodens isolates recovered from dental plaque, mucosal surfaces, and saliva of 24 subjects was examined by arbitrarily primed PCR. Twenty-two subjects were colonized by multiple clones (range, two to eight; mean, 3.7). This study demonstrates the utility of arbitrarily primed PCR for clonal analysis of E. corrodens and the multiclonal colonization of E. corrodens in the oral cavity.

An Eikenella corrodens toxin detected by plaque toxin-neutralizing monoclonal antibodies

Bacterial plaque from the gingival region of teeth contains cytotoxic agents which lyse undifferentiated human HL60 cells. A small panel of monoclonal antibodies (MAbs) was found to abrogate much of this activity and to detect antigens in certain strains of Streptococcus mitis and Eikenella corrodens. The aim of this study was to determine whether these bacterial antigens might be involved in HL60 cells cytolysis. Saline extracts were obtained by homogenizing washed, stationary-phase cells in 65 mM NaCl with a tight-fitting Potter-Elvehjem homogenizer. The extracts of E. corrodens were toxic to HL60 cells, whereas similar extracts of S. mitis were nontoxic. Adding plaque toxin-neutralizing MAb 3hE5 blocked the toxic effect of E. corrodens extract S. mitis extracts contained a single, strongly reactive antigen of 140 kDa (s140K antigen) detected on Western blots (immunoblots) by three MAbs from the panel. Rabbit antibodies raised to this antigen excised from the gel (anti-s140K serum) detected larger antigens in addition to s140K. E. corrodens extracts contained a number of antigens detected by the MAbs. Immunoglobulin G (IgG) was purified from anti-s140K serum by passage through DE52 cellulose. A 100-fold excess (by weight) of the purified IgG to E. corrodens protein specifically cross-precipitated an 80-kDa antigen plus a nonantigenic 16-kDa protein, presumably attached noncovalently. The remaining supernatant fraction had no toxic activity. A similar ratio of control IgG (from nonimmunized rabbits) did not precipitate these proteins, and the supernatant fraction had the same activity as the extract not treated with IgG. The proteins of 80 and 16 kDa were also detected in the anti-s140K immunoprecipitate by rabbit IgG antibodies to E. corrodens whole cells. The 80-kDa antigen, alone or complexed with the 16-kDa protein, may be involved in mediating the toxic activity in E. corrodens and plaque extracts.

Comparison of the osteolytic activity of surface-associated proteins of bacteria implicated in periodontal disease

OBJECTIVES

To compare the osteolytic activity of surface-associated material (SAM) and lipid A-associated proteins (LAPs) from periodontopathogenic bacteria.

MATERIALS AND METHODS

Surface-associated material was extracted from the surface and LAPs from the cell walls of a range of periodontopathic bacteria including Actinobacillus actinomycetemcomitans and Eikenella corrodens. These bacterial fractions were assayed to determine their composition and their capacity to induce bone resorption was determined by use of the neonatal murine calvarial bone resorption assay.

RESULTS

The SAMs from E. corrodens and A. actinomycetemcomitans demonstrated bone-resorbing capacity at concentrations as low as 1 ng ml-1 which, given the molecular weights of the active components, is in the picomolar range of activity. In contrast, the SAMs from the other three bacteria were significantly less potent and showed a lower efficacy. The LAPs all showed significant, and similar, capacities to induce bone breakdown.

CONCLUSIONS

This is the first demonstration that LAP from periodontopathic bacteria can stimulate bone degradation. The LAPs from diverse bacteria all produced similar levels of bone-resorbing activity. In contrast, the SAM showed significant differences in potency and in efficacy (maximal stimulation). This may mean that in vivo certain periodontopathic bacteria have significantly more bone-resorbing capacity than others and should be therapeutic targets.

The gingival immune response to periodontal pathogens in juvenile periodontitis

A gingival explant culture system was utilized to evaluate the reactivity of local immunoglobulins produced by juvenile periodontitis tissue. Gingival explant culture supernatant fluids were screened, via a standardized dot-immunobinding assay, for antibodies reactive to: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Campylobacter rectus, Eikenella corrodens, Peptostreptococcus micros, Peptostreptococcus anaerobius, Capnocytophaga ochracea, Eubacterium nodatum and Fusobacterium nucleatum and one nonoral microorganism, Porphyromonas asaccharolytica. Of the 75 juvenile periodontitis supernatant fluids tested, the organisms that reacted with the highest numbers of supernatant fluids were E. nodatum (72%) and A. actinomycetemcomitans (49%). More juvenile periodontitis than healthy tissue samples showed supernatant fluid reactivity to P. intermedia, C. ochracea, E. nodatum and P. micros. No significant difference was observed between the juvenile periodontitis group supernatant fluids reactivity and the supernatant fluids of the other periodontal disease groups tested. Cluster analysis revealed the association, as determined by supernatant fluid reactivity, of P. micros and C. ochracea in the juvenile periodontitis group. The data from this investigation are consistent with a hypothesis of multiple possible etiologies of periodontal destruction in juvenile periodontitis and other forms of periodontal diseases.

Scanning electron microscopy of Eikenella corrodens colony morphology variants

Eikenella corrodens is a gram-negative, human pathogen which exhibits colony morphology variation. Scanning electron microscopy (SEM) was used to examine large (non-corroding) and small (corroding) colony variants from the type strain (ATCC 23834) and two clinical isolates (strains VA1 and CM1). Large colonies were large, flatter, and appeared relatively featureless compared to small colonies and had even, smooth colony margins. Small colonies were more raised from the medium surface, and often had a central raised region surrounded by flatter border. Cells on the surface of large colonies were more regularly arranged at the colony edge, and end-to-end rows of cells around the colony were seen in some strains. Cells in the center of the upper surface of small colonies were usually randomly arranged. Within cross sections of small colonies, cells were arranged randomly or perpendicular to the medium; in large colonies, cells were random or arranged horizontally. Amorphous, "slime" material was often seen covering groups of cells in large and small variants. An unusual variant, possibly a mutant, which combined features of both colony types was isolated.

Mitogenic stimulation of murine B lymphocytes by the N-acetyl-D-galactosamine specific bacterial lectin-like substance from Eikenella corrodens

A N-acetyl-D-galactosamine (GalNAc) specific bacterial lectin-like substance from Eikenella corrodens 1073 (EcLS) was found to have potent mitogenic activity when cultured with splenocytes from BALB/c mice. The results indicated that B lymphocytes are the major cell type responding to EcLS. The mitogenic activity of EcLS was dose-dependent, and the optimal concentration was around 5 micrograms/ml. The mitogenic activity did not appear to be due to a bacterial endotoxin, as GalNAc inhibited the mitogenic activity of EcLS, but did not inhibit the activity of lipopolysaccharide isolated from E. corrodens. EcLS stimulated murine B lymphocytes not only to proliferate, but also to differentiate into antibody-secreting cells, as demonstrated by the production of immunoglobulin by B lymphocytes stimulated with EcLS. These findings suggest that EcLS is a novel lectin that not only induces B lymphocyte proliferation, but also differentiation.

Isolation of Actinomyces species and Eikenella corrodens from patients with chronic diffuse sclerosing osteomyelitis

Cultures from 26 patients with chronic diffuse sclerosing osteomyelitis of the mandible were studied. In most cases there was a mutualistic infection involving any one of the known human Actinomyces species together with Eikenella corrodens. In a few cases, Arachnia species were substituted for Actinomyces and gram-negative anaerobes for E corrodens. The specific culture protocol used to identify these organisms from clinical specimens is described. Taxonomic and experimental evidence that supports an infectious etiology are presented.

Development of a genetic system for Eikenella corrodens: transfer of plasmids pFM739 and pLES2

Eikenella corrodens is a Gram-negative microaerophilic rod which is emerging as an important human pathogen. Elucidation of the mechanisms by which it causes disease require efficient methods for the transfer of DNA to E. corrodens. Plasmids pFM739 and pLES2 have been transferred by conjugation from Escherichia coli S17-1 to E. corrodens ATCC 23834 at frequencies of 2.5 x 10(-7) and 2.42 x 10(-7), respectively. In addition, both plasmids could be transferred to four additional, clinical strains of E. corrodens at a similar frequency. The use of bacteriophage T4 as a counterselecting agent is also described.

An in vitro study of polymorphonuclear leucocyte-mediated injury to human gingival keratinocytes by periodontopathic bacterial extracts

Human gingival keratinocytes were cultured and, after the first passage, subjected to cell detachment assays with polymorphonuclear leucocytes (PMNs) and/or sonic extracts from Actinobacillus actinomycetemcomitans Y4, and Eikenella corrodens 1073. The effector-to-target cell ratio was 30:1. Bacterial extracts alone caused no disruption of keratinocyte monolayers. PMNs alone also caused only minimal detachment after 14 h incubation. Adding A. actinomycetemcomitans to the PMN-keratinocyte co-cultures at the concentration of 100 micrograms/ml caused dramatic cell detachment. The effect of A. actinomycetemcomitans was heat labile and not inhibited by polymyxin B. Cell detachment was inhibited by alpha 1-antitrypsin, whereas catalase and superoxide dismutase could not prevent it. No lysis of keratinocytes was observed after incubation, as judged by 51Cr release. E. corrodens had little effect even at the concentration of 1000 micrograms/ml. H2O2 and partially purified PMN elastase also caused detachment of keratinocytes. These data indicate that PMNs can cause non-lytic detachment of keratinocytes when interacting with certain bacteria.

Anti-proliferative and cytotoxic activity of surface-associated material from periodontopathogenic bacteria

The easily solubilized surface-associated material from three bacterial species associated with periodontal diseases, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Eikenella corrodens, produced dose-dependent inhibition of thymidine incorporation by human fibroblasts, the human monocytic cell line U937 and guinea pig epidermal cells. In contrast, lipopolysaccharides from A. actinomycetemcomitans and P. gingivalis were either inactive or substantially less active over the dose range tested. One of the constituents of surface-associated material from a 'non-leucotoxic' strain of A. actinomycetemcomitans was highly cytotoxic to human peripheral blood polymorphonuclear cells, with 50% killing from less than 1 ng/ml. A constituent of the surface-associated material from P. gingivalis was approximately one log order less active. The lipopolysaccharides from these bacteria were at least three log orders less active in neutrophil killing. These findings add weight to the hypothesis that easily solubilized exopolymers from periodontopathogens play a major part in the pathology of periodontal diseases.

Intrathoracic infections with bacteraemia due to Eikenella corrodens as a complication of peritonsillar abscesses: report of a case and review of the literature

A 52-year-old man, without previous disease, presented with dysphagia, dyspnoea, high fever and sore throat after peritonsillar abscesses drainage. Physical and complementary examinations were consistent with pericarditis, mediastinitis, pneumonia and pleuritis. Blood cultures grew Eikenella corrodens resistant to clindamycin and amikacin. We emphasize the pathogenic potential of Eikenella corrodens. To the best of our knowledge, this is the first reported case of this organism as a pathogen in intrathoracic infections after peritonsillar abscesses drainage.

Effect of infection with Eikenella corrodens on the progression of ligature-induced periodontitis in rats

The periodontopathic ability of Eikenella corrodens 1073-R (EcR) on ligature-induced periodontal defects in immunosuppressed and non-immunosuppressed rats was studied bacteriologically and histologically. Silk ligatures were placed around the maxillary second molars of rats, and the rats were divided into eight groups. Four groups received cyclophosphamide (CY), an immunosuppressive agent, the day after ligature placement. On days 3 and 4, the oral cavities of the rats in all four groups were inoculated with 8 x 10(8) cells of live EcR. Rats were sacrificed on d 1, 3, 5, 8, 11 and 18. Alveolar bone resorption of ligated rats was enhanced by the implantation of EcR, although the number of total cultivable bacterial cells from ligated sites was not changed by the implantation of EcR. CY suppressed the number of white blood cells, inflammatory cellular infiltrates in gingival tissue, and repair of periodontal tissue, and enhanced bone destruction. The implantation of EcR in the ligature- and CY-treated rats also enhanced osteoclastic bone resorption. Without ligatures, high doses of CY or EcR inoculum did not result in periodontal destruction. These results indicate that it is possible to establish EcR in conventional rat flora with a ligature and that EcR causes osteoclastic bone resorption in this model.

Lung abscess caused by Eikenella corrodens: report of a case

Eikenella corrodens is a slow-growing, facultatively anaerobic, gram-negative bacillus. It is part of the normal flora of the human upper respiratory tract. We report a 68-year-old man who developed lung abscesses caused by E. corrodens while on long-term corticosteroid therapy for polymyositis. It was isolated by percutaneous transthoracic aspiration of an abscess under real-time sonographic guidance. The organism has a very unusual antimicrobial susceptibility: sensitive to penicillin, ampicillin, cephapirin, chloramphenicol, minocycline and erythromycin but resistant to clindamycin, oxacillin and gentamicin. The patient was treated empirically with penicillin G and gentamicin. The latter was discontinued after the results of the bacterial culture and sensitivity test were available. He was discharged one month later with marked improvement. Our report clearly demonstrates that E. corrodens can be the sole pathogen of a respiratory tract infection.

Microbiology of subgingival plaque from children with localized prepubertal periodontitis

Localized prepubertal periodontitis has been described as a host-defect mediated form of bacterially induced periodontitis, with an early onset and rapid progression around a few teeth in children prior to puberty. To further our understanding of the etiology of this disease, we have examined the microbiological components of subgingival dental plaque in 9 children with localized prepubertal periodontitis to determine if patterns of putative pathogens existed, and have compared these results with those obtained from 4 children with no periodontitis. Subgingival plaque samples were plated onto a selective medium for Actinobacillus actinomycetemcomitans and onto a non-selective medium for anaerobes, and the predominant cultivable microbiota of 2 sites per child was determined. The subgingival microbiota of children with localized prepubertal periodontitis clearly differs from non-diseased children in the detection of high levels of several suspected pathogens, including A. actinomycetemcomitans, Bacteroides intermedius, Eikenella corrodens, and Capnocytophaga sputigena. These putative pathogens were found in various combinations. These findings suggest that localized prepubertal periodontitis is associated with specific subgingival bacteria which are generally not found in children without periodontitis.

Eikenella corrodens

Eikenella corrodens is a microaerophilic gram-negative rod which is a normal inhabitant of human mucosal surfaces, particularly the oral cavity. Although an uncommon cause of infection, it is by no means rare. It is found most often as part of a mixed infection, particularly with streptococci, but is capable of independently causing serious infection in both normal and immunocompromised hosts. Given its slow growth, requirement for hemin when grown aerobically, and preference for CO2 enrichment, it is likely that the involvement of Eikenella in an infection is not always recognized, and it would be prudent to alert the laboratory in situations where isolation of Eikenella is likely (especially in head and neck infections or infected wounds caused by a human bite). Although mixed infections which include Eikenella may resolve with treatment directed at the other infecting organisms, treatment of such infections with antibiotics to which Eikenella is resistant may result in a pure Eikenella infection. Such an outcome may occur, for example, when a human bite wound is treated with clindamycin or metronidazole. Among the oral antibiotics, penicillin, tetracycline, and chloramphenicol are generally effective, whereas cephalexin, dicloxacillin and their relatives are not. Cefoxitin and the third-generation cephalosporins are highly effective against Eikenella.

A longitudinal microbiological investigation of Actinobacillus actinomycetemcomitans and Eikenella corrodens in juvenile periodontitis

Longitudinal clinical and microbiological monitoring of subjects with localized juvenile periodontitis indicated that Actinobacillus actinomycetemcomitans and Eikenella corrodens were significantly associated (P less than 0.05) with active tissue destruction.

Biological activities of Eikenella corrodens outer membrane and lipopolysaccharide

Highly purified preparations of the outer membrane and lipopolysaccharide (LPS) of Eikenella corrodens strain ATCC 23834 and the outer membrane fraction (OMF) of strain 470 were tested in in vitro biological assays. The OMFs of both strains were found to be mitogenic for BDF and C3H/HeJ murine splenocytes. The E. corrodens LPS was mitogenic for BDF spleen cells; however, doses of LPS as high as 50 micrograms/ml failed to stimulate C3H/HeJ cells. When incubated with T-lymphocyte-depleted C3H/HeJ splenocytes, the strain 23834 OMF demonstrated significant mitogenic activity, indicating that the OMF is a B-cell mitogen by a mechanism other than that elicited by conventional LPS. The E. corrodens 23834 OMF and LPS were stimulators of bone resorption when tested in organ cultures of fetal rat long bones. In contrast, the strain 470 OMF was only weakly stimulatory. Both OMFs and LPSs demonstrated "endotoxic" activity, since as little as 0.062 micrograms of E. corrodens LPS and 0.015 micrograms of the OMFs induced gelation in the Limulus amebocyte clotting assay. Thus, despite having a "nonclassical" LPS biochemistry, the E. corrodens LPS elicits classical endotoxic activities. These results also indicate that the surface structures of E. corrodens have significant biological activities as measured in vitro. The expression of such activities in vivo may play an important role in the pathogenesis of periodontitis as well as other E. corrodens infections.

Eikenella corrodents infection of the hand

The clinical presentation and course of two patients with Eikenella corrodens infection of the hand is recorded. This recently recognised organism must not be regarded as a harmless commensal and should be differentiated from the Bacteroides group because of its resistance to clindamycin. Radical surgical debridement is the most important aspect of therapy.

[Report of a case of subcutaneous abscess due to Eikenella corrodens in a splenectomized patient (author's transl)]

A case of subcutaneous abscess of the chest-wall due to Eikenella corrodens is reported in a patient recently splenectomized. This bacillus was grown in pure culture. Processing specimens and identification methods of this little Gram-negative bacillus are described. Eikenella corrodens is a commensal frequently encountered in mucous membrane surfaces. It is likely that this microorganism may be an "opportunist" pathogen.

Some observations on the effects produced in white mice following the injection of certain suspensions of corroding bacilli

Strictly anaerobic and facultatively anaerobic strains of "corroding bacilli" failed to produce any pathological symptoms when injected into white mice and no viable organisms could be recovered after 7 days. However, when these same strains were coupled with certain other living bacteria or certain sterile bacterial extracts, lesions developed from which corroding bacilli could be isolated even after 21 days.