RESUMEN
Spirochaetes, a phylum that includes medically important pathogens such as the causative agents of Lyme disease, syphilis, and leptospirosis, are in many ways highly unique bacteria. Their cell morphology, subcellular organization, and metabolism reveal atypical features. Spirochetal motility is also singular, dependent on the presence of periplasmic flagella or endoflagella, inserted subterminally at cell poles and not penetrating the outer membrane and elongating outside the cell as in enterobacteria. In this review we present a comprehensive comparative genomics analysis of endoflagellar systems in spirochetes, highlighting recent findings on the flagellar basal body and filament. Continued progress in understanding the function and architecture of spirochetal flagella is uncovering paradigm-shifting mechanisms of bacterial motility.
Asunto(s)
Enfermedad de Lyme , Spirochaetales , Humanos , Spirochaetales/ultraestructura , Enfermedad de Lyme/microbiología , Flagelos/ultraestructura , Proteínas Bacterianas/metabolismoAsunto(s)
Bacterias/metabolismo , Proteínas Bacterianas/metabolismo , Flagelos/metabolismo , Bacterias/ultraestructura , Infecciones Bacterianas/microbiología , Proteínas Bacterianas/ultraestructura , Microscopía por Crioelectrón , Flagelos/ultraestructura , Flagelina/metabolismo , Flagelina/ultraestructura , Humanos , Spirochaetales/metabolismo , Spirochaetales/ultraestructuraAsunto(s)
Ciego/microbiología , Color , Intestinos/microbiología , Membrana Mucosa/microbiología , Infecciones por Spirochaetales/diagnóstico , Adulto , Biopsia , Ciego/patología , Colonoscopía , Diarrea/microbiología , Heterosexualidad , Humanos , Inmunocompetencia , Intestinos/patología , Masculino , Membrana Mucosa/patología , Membrana Mucosa/ultraestructura , Reacción del Ácido Peryódico de Schiff , Spirochaetales/aislamiento & purificación , Spirochaetales/ultraestructura , Infecciones por Spirochaetales/tratamiento farmacológico , Infecciones por Spirochaetales/microbiología , Coloración y EtiquetadoRESUMEN
Two-thirds of all bacterial genomes sequenced to-date possess an organelle for locomotion, referred to as flagella, periplasmic flagella or type IV pili. These genomes may also contain a chemotaxis-signaling system which governs flagellar rotation, thus leading a coordinated function for motility. Motility and chemotaxis are often crucial for infection or disease process caused by pathogenic bacteria. Although motility-associated genes are well-characterized in some organisms, the highly orchestrated synthesis, regulation, and assembly of periplasmic flagella in spirochetes are just being delineated. Recent advances were fostered by development of unique genetic manipulations in spirochetes coupled with cutting-edge imaging techniques. These contemporary advances in understanding the role of spirochetal motility and chemotaxis in host persistence and disease development are highlighted in this review.
Asunto(s)
Borrelia burgdorferi/fisiología , Quimiotaxis , Flagelos/fisiología , Enfermedad de Lyme/microbiología , Spirochaetales/fisiología , Animales , Vectores Arácnidos/microbiología , Borrelia burgdorferi/ultraestructura , Quimiotaxis/genética , Flagelos/genética , Enfermedad de Lyme/transmisión , Ratones , Movimiento , Spirochaetales/genética , Spirochaetales/patogenicidad , Spirochaetales/ultraestructura , Garrapatas/microbiologíaRESUMEN
Spirochetes have flagella within the cell body and swim by wriggling the spiral cell body. Besides they have been known to be critical agents causing various infectious diseases, their eccentric appearances and motilities have been attracting many scientists in a wide variety of fields other than bacteriologists. Unlike externally flagellated bacteria that swim by using flagella as a screw propeller, spirochetes progress in a liquid by changing their cell shapes. To understand the unique motion mechanism of spirochetes, many experiments and theoretical studies are being carried out. In this review, I will summarize morphological and motile properties of various species of spirochete, such as Borrelia, Treponema and Brachyspira. I will also expound on the motion mechanism of Leptospira with our latest results obtained by high-resolution optical photometry.
Asunto(s)
Movimiento , Spirochaetales/citología , Spirochaetales/fisiología , Borrelia , Brachyspira , Flagelos/fisiología , Leptospira , Microscopía , Spirochaetales/patogenicidad , Spirochaetales/ultraestructura , TreponemaRESUMEN
There are limited reports on the ultrastructure of syphilis skin lesions. The aim of this study has been to perform an electron microscopic investigation of the morphology and the tissue distribution of treponemes in primary and secondary cutaneous lesions. Three cases of primary syphilitic chancre and one case of secondary syphilis were included. Prominent epidermal abnormalities in the primary chancre and a perivascular inflammatory infiltrate in the secondary lesion were found by light microscopy. Ultrastructurally, spirochetes were located mainly in the blood vessel walls and dermal tissue of the chancre lesions. In the secondary syphilis case, spirochetes were more abundant between epidermal keratinocytes. Most of them adjusted to the intercellular spaces. Occasionally, the electron microscopy images were highly suggestive of an intracellular location. Both the ultrastructural and immunohistochemical examination of the primary and secondary syphilis lesions showed a paradoxical distribution of the causative microorganisms compared to the light microscopic changes. In addition, the ultrastructural findings strongly suggest that Treponema pallidum subspecies pallidum invades tissues, not only through an intercellular, but also through a transcellular pathway.
Asunto(s)
Chancro/patología , Microscopía Electrónica , Piel/ultraestructura , Sífilis Cutánea/patología , Sífilis/patología , Treponema pallidum/ultraestructura , Adulto , Chancro/microbiología , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Piel/irrigación sanguínea , Piel/microbiología , Spirochaetales/ultraestructura , Sífilis/microbiología , Sífilis Cutánea/microbiología , Treponema pallidum/patogenicidad , Adulto JovenRESUMEN
The expression of flagellin genes in most bacteria is typically regulated by the flagellum-specific sigma(28) factor FliA, and an anti-sigma(28) factor, FlgM. However, the regulatory hierarchy in several bacteria that have multiple flagellins is more complex. In these bacteria, the flagellin genes are often transcribed by at least two different sigma factors. The flagellar filament in spirochetes consists of one to three FlaB core proteins and at least one FlaA sheath protein. Here, the genetically amenable bacterium Brachyspira hyodysenteriae was used as a model spirochete to investigate the regulation of its four flagellin genes, flaA, flaB1, flaB2, and flaB3. We found that the flaB1 and flaB2 genes are regulated by sigma(28), whereas the flaA and flaB3 genes are controlled by sigma(70). The analysis of a flagellar motor switch fliG mutant further supported this proposition; in the mutant, the transcription of flaB1 and flaB2 was inhibited, but that of flaA and flaB3 was not. In addition, the continued expression of flaA and flaB3 in the mutant resulted in the formation of incomplete flagellar filaments that were hollow tubes and consisted primarily of FlaA. Finally, our recent studies have shown that each flagellin unit contributes to the stiffness of the periplasmic flagella, and this stiffness directly correlates with motility. The regulatory mechanism identified here should allow spirochetes to change the relative ratio of these flagellin proteins and, concomitantly, vary the stiffness of their flagellar filament.
Asunto(s)
Proteínas Bacterianas/metabolismo , Brachyspira hyodysenteriae/metabolismo , Flagelina/metabolismo , Spirochaetales/metabolismo , Proteínas Bacterianas/genética , Western Blotting , Brachyspira hyodysenteriae/genética , Brachyspira hyodysenteriae/ultraestructura , Electroforesis , Flagelos/metabolismo , Flagelos/ultraestructura , Flagelina/genética , Microscopía Electrónica de Transmisión , Datos de Secuencia Molecular , Regiones Promotoras Genéticas/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Spirochaetales/genética , Spirochaetales/ultraestructuraRESUMEN
The fine structure of spirochete attachments to the plasma membrane of anaerobic protists displays variations here interpreted as legacies of an evolutionary sequence analogous to that from free-living spirochetes to undulipodia (eukaryotic "flagella" and homologous structures). Attached spirochetes form a vestment, a wriggling fringe of motile cells at the edge of the plasma membrane of unidentified cellulolytic protist cells in the hypertrophied hindgut of the digestive system of Mastotermes darwiniensis, the large wood-feeding termite from northern Australia. From the membrane extend both undulipodia and a complex of comparably sized (10-12 microm x 0.2-0.3 microm) ectosymbiotic spirochetes that resembles unruly ciliated epithelium. In the intestines are helical (swimming) and round-body morphotypes. Round bodies (RBs) are slow or immotile spirochetes, propagules known to revert to typical swimming helices under culture conditions favorable for growth. The surfaces of both the spirochete gram-negative eubacteria and the parabasalid protists display distinctive attachment structures. The attached hypertrophied structures, some of which resemble ciliate kinetids, are found consistently at sites where the spirochete termini contact the protist plasma membranes.
Asunto(s)
Adhesión Bacteriana , Cilios/ultraestructura , Spirochaetales/fisiología , Spirochaetales/ultraestructura , Animales , Australia , Evolución Biológica , Membrana Celular/microbiología , Tracto Gastrointestinal/microbiología , Tracto Gastrointestinal/parasitología , Isópteros/microbiología , Isópteros/parasitología , Isópteros/fisiología , Parásitos/microbiología , SimbiosisRESUMEN
We show that plane parabolic flow in a microfluidic channel causes nonmotile, helically shaped bacteria to drift perpendicular to the shear plane. Net drift results from the preferential alignment of helices with streamlines, with a direction that depends on the chirality of the helix and the sign of the shear rate. The drift is in good agreement with a model based on resistive force theory, and separation is efficient (>80%) and fast (<2 s). We estimate the effect of Brownian rotational diffusion on chiral separation and show how this method can be extended to separate chiral molecules.
Asunto(s)
Microfluídica , Spirochaetales/citología , Isomerismo , Mutación/genética , Resistencia al Corte , Spirochaetales/ultraestructuraRESUMEN
To study the different patterns of Treponema pallidum distribution in primary and secondary syphilis, 34 biopsy specimens of 8 patients with primary and 26 with secondary syphilis were assessed. Histopathological features, silver stain, and immunohistochemical T pallidum polyclonal antibody expression were investigated. The number and distribution of spirochetes were evaluated, and ultrastructural studies were performed. Spirochetes were identified with Warthin-Starry stain in 17 specimens (4/8 primary and 13/26 secondary syphilis), whereas immunohistochemical analysis disclosed spirochetes in 29 (8/8 primary and 21/26 secondary syphilis). In secondary syphilis, an epitheliotropic pattern characterized by abundant spirochetes in the lower mucosa/epidermis in an intercellular distribution was observed. In contrast, primary syphilis exhibited a mixed epitheliotropic and vasculotropic pattern further manifested by treponemes surrounding the vascular walls. These differences were statistically significant. Ultrastructural examination confirmed these results. Immunohistochemistry shows greater sensitivity when compared with Warthin-Starry staining. The immunohistochemical pattern of T pallidum distribution may permit the diagnostic differentiation of primary from secondary syphilis.
Asunto(s)
Sífilis/microbiología , Infecciones por Treponema/microbiología , Adulto , Femenino , Humanos , Inmunohistoquímica , Masculino , Membrana Mucosa/microbiología , Membrana Mucosa/ultraestructura , Spirochaetales/ultraestructura , Sífilis/patología , Sífilis Cutánea/microbiología , Sífilis Cutánea/patología , Treponema pallidum , Infecciones por Treponema/patologíaRESUMEN
BACKGROUND: Spirochaetes are well known causative agents of diarrhoea in veterinary medicine. However, there is no agreement as to whether or not they have any clinical significance in humans. AIMS: To assess the symptoms associated with intestinal spirochaetosis, their response to treatment and the natural history of untreated cases. METHODS: A retrospective review of all cases of intestinal spirochaetosis identified within an eight year period in a single university teaching hospital was performed. A chart review and follow up telephone interview was performed to assess the indications for colonoscopy that led to the diagnosis, treatment received, and duration and nature of symptoms. RESULTS: 18 cases were identified. The indications for colonoscopy were diarrhoea in 50% and rectal bleeding in 16.7%; also investigation of constipation, anaemia and abdominal pain, and in two cases reassessment of chronic proctitis. Two subjects were treated with metronidazole and two were treated with aminosalicylates. 69% had complete resolution of symptoms at follow-up, 15% had persistent symptoms and 15% had intermittent symptoms. Of the two patients treated with metronidazole, one had resolution of symptoms and one has persistent abdominal pain. CONCLUSION: Symptoms do not appear to parallel spirochaete persistence or eradication and therefore it seems appropriate to adopt a wait and see approach to treatment of patients in whom spirochaetes are identified, giving a trial of antimicrobial treatment only in those who have severe or persistent symptoms. Careful consideration of both host and pathogen should be undertaken.
Asunto(s)
Diarrea/microbiología , Mucosa Intestinal/microbiología , Infecciones por Spirochaetales/diagnóstico , Spirochaetales/patogenicidad , Dolor Abdominal/microbiología , Ácido Aminosalicílico/uso terapéutico , Colon , Diarrea/tratamiento farmacológico , Femenino , Humanos , Íleon , Mucosa Intestinal/ultraestructura , Masculino , Metronidazol/uso terapéutico , Microscopía Electrónica , Spirochaetales/ultraestructura , Infecciones por Spirochaetales/tratamiento farmacológicoRESUMEN
Electron cryotromography, a relatively new methodology in the field of microbiology, has been exploited by Murphy et al. (in this issue of Molecular Microbiology) in their analysis of the recently isolated termite gut spirochete Treponema primitia. Unique structures (bowls, arcades of hooks, cones at the cell ends, two layers of wall material) were evident from the analysis of its surface and internal constituents. These results, coupled to video microscopy analysis of swimming cells, allowed the authors to propose a model of cell motility. This highly significant paper highlights the importance of electron cryotomography to the field of microbiology. It also illustrates that newly cultured recalcitrant bacteria from complex environments are likely to possess novel structures not previously seen in other species.
Asunto(s)
Isópteros/microbiología , Microscopía Electrónica/métodos , Spirochaetales/ultraestructura , Animales , Sistema Digestivo/microbiología , Spirochaetales/citología , Spirochaetales/fisiología , Tomografía Computarizada por Rayos X/métodos , Treponema/citología , Treponema/fisiología , Treponema/ultraestructuraRESUMEN
AIM: Our study reports the detection and identification of intestinal spirochetosis in patients with colonic diseases in a tertiary-care hospital over a 12-year period, and includes a description of all cases we diagnosed. METHODS: Our patients (8323) underwent colonoscopy and histopathological examinations including transmission electron microscopy (TEM) and light microscopy. Specimens from patients suspected of intestinal spirochetosis at histopathology (17 patients) underwent microbiological investigation performed by culture and molecular methods (16S restriction fragment length polymorphism-polymerase chain reaction [RFLP-PCR], nox RFLP-PCR assays). RESULTS: Seventeen cases were diagnosed: seven patients were infected by B. aalborgi, one by B. pilosicoli, two by both species and four by Brachyspira spp. diagnosed both histopathology and microbiology (culture and molecular methods: 16S RFLP-PCR and nox RFLP-PCR assays). Three cases were referred to as Brachyspira spp. infections using only histopathology, including TEM. CONCLUSIONS: Our results demonstrated that intestinal spirochetosis, although rarely occurring, might play a role in chronic diarrhea and suggested a pathogenetic mechanism of intestinal spirochetosis based on the destruction of colonic microvilli and colitis histologically documented, providing additional clinical and pathological information on this entity. This study suggests that metronidazole seems to be the drug of choice for the eradication of intestinal spirochetosis.
Asunto(s)
Brachyspira , Colitis/microbiología , Colon/microbiología , Infecciones por Spirochaetales/complicaciones , Spirochaetales , Adulto , Anciano , Antibacterianos/uso terapéutico , Brachyspira/genética , Brachyspira/ultraestructura , Preescolar , Colitis/patología , Colon/ultraestructura , Colonoscopía , ADN Bacteriano/análisis , Femenino , Humanos , Mucosa Intestinal/microbiología , Masculino , Metronidazol/uso terapéutico , Microscopía Electrónica de Transmisión , Microvellosidades/microbiología , Persona de Mediana Edad , Ribotipificación , Spirochaetales/genética , Spirochaetales/ultraestructura , Infecciones por Spirochaetales/microbiología , Infecciones por Spirochaetales/patología , Resultado del TratamientoRESUMEN
The phylogenetic relationships of symbiotic spirochetes from five dry-wood feeding lower termites (Cryptotermes cavifrons, Heterotermes tenuis, Kalotermes flavicollis, Neotermes mona, and Reticulitermes grassei) was compared to those described in previous reports. The 16S rDNA bacterial genes were PCR-amplified from DNA isolated from intestinal samples using a spirochete-selective primer, and the 16S amplicons were cloned into Escherichia coli. Sequences of the cloned inserts were then used to determine closest relatives by comparison with published sequences. Clones sharing more than 97% sequence identity were grouped into the same phylotype. Forty-three new phylotypes were identified. These termite whole-gut-spirochetes fell into two previous defined clusters, designated as Treponema Clusters I and II, and one new Cluster III. Thirty-seven phylotypes were grouped in Cluster I. Cluster II comprised three phylotypes, two from Reticulitermes grassei (LJ029 and LJ012) and one from Heterotermes tenuis (LQ016). Three phylotypes, LK057, LK050 and LK028, were affiliated to Cluster III. Members of Cluster I showed the following characteristics: (i) spirochete phylotypes from a particular species of termite were more closely related to each other than to phylotypes of other termite species; (ii) spirochetes obtained from different genera of the same family, such as Cryptotermes sp., Kalotermes sp., and Neotermes sp., all from the family Kalotermitidae, were also related to each other. It was therefore concluded that spirochetes are specific symbionts that have coevolved with their respective species of termites, are stably harbored, and are closely related to members of the same termite family.
Asunto(s)
Evolución Biológica , Isópteros/microbiología , Spirochaetales/clasificación , Simbiosis , Animales , Secuencia de Bases , Variación Genética , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Ribotipificación , Spirochaetales/aislamiento & purificación , Spirochaetales/ultraestructuraRESUMEN
The recent discoveries of prokaryotic homologs of all three major eukaryotic cytoskeletal proteins (actin, tubulin, intermediate filaments) have spurred a resurgence of activity in the field of bacterial morphology. In spirochetes, however, it has long been known that the flagellar filaments act as a cytoskeletal protein structure, contributing to their shape and conferring motility on this unique phylum of bacteria. Therefore, revisiting the spirochete cytoskeleton may lead to new paradigms for exploring general features of prokaryotic morphology. This review discusses the role that the periplasmic flagella in spirochetes play in maintaining shape and producing motility. We focus on four species of spirochetes: Borrelia burgdorferi, Treponema denticola, Treponema phagedenis and Leptonema (formerly Leptospira) illini. In spirochetes, the flagella reside in the periplasmic space. Rotation of the flagella in the above species by a flagellar motor induces changes in the cell morphology that drives motility. Mutants that do not produce flagella have a markedly different shape than wild-type cells.
Asunto(s)
Citoesqueleto/fisiología , Flagelos/fisiología , Spirochaetales/fisiología , Borrelia burgdorferi/fisiología , Borrelia burgdorferi/ultraestructura , Citoesqueleto/ultraestructura , Flagelos/ultraestructura , Leptospiraceae/fisiología , Leptospiraceae/ultraestructura , Periplasma/fisiología , Spirochaetales/ultraestructura , Treponema/fisiología , Treponema/ultraestructuraRESUMEN
Here is proposed a hypothesis that a completely unsuspected biology exists for pathogenic spirochetes, namely that the cystic spirochetal forms (long thought to be static and resting or just a dormant cohort) actually are capable of killing mammalian host cells. At least two "lethal" scenarios are proposed; first, the host cell destruction from the "inside out" by small caliber cystic forms invading the host cell cytoplasm, and second host cell destruction by engulfment of entire host cells by large caliber cystic spirochetal forms. Conventional thinking about spirochetal cyst forms is divided between two polar spheres of influence; one a majority community that completely denies the existence of spirochetal cyst forms, and a second group of academically persecuted individuals who accepts the precepts of such antebellum scientists as Schaudinn, Hoffman, Dutton, Levaditi, Balfour, Fantham, Noguchi, McDonough, Hindle, Steiner, Ingraham, Coutts, Hampp, Warthin, Ovcinnikov, and Delamater. Microscopic images of cystic spirochetes are difficult to ignore, but as has been the case in this century, academic "endowments" have nearly expunged all cystic spirochetal image data from the current textbook versions of what is the truth about the spirochetaceae. If the image database from the last century is obliterated; many opportunities to diagnose will be lost. Variously sized cystic spirochetal profiles within diseased nerve cells explain the following structures: Lewy body of Parkinson's disease, Pick body, ALS spherical body, Alzheimer plaque. Borrelia infection is therefore a unifying concept to explain diverse neurodegenerative diseases, based not entirely on a corkscrew shaped profile in diseased tissue, but based on small, medium and large caliber rounded cystic profiles derived from pathogenic spirochetes which are..."hiding in plain sight".
Asunto(s)
Infecciones por Borrelia/transmisión , Quistes/patología , Enfermedades Neurodegenerativas/microbiología , Spirochaetales/patogenicidad , Quistes/ultraestructura , Modelos Biológicos , Enfermedades Neurodegenerativas/patología , Spirochaetales/ultraestructuraRESUMEN
Subsequent to Schaudinn and Hoffman's visualization of Treponema pallidum in 1905, many distinguished syphilologists proposed that spirochetes have a life cycle. What is the "essence" of a life cycle? Simply put, life cycles are diverse arrays of life forms, which emerge in an ordered sequence; which are "connected" to one another across primary and secondary hosts, and constitute a cycle with "circular" relationship between hosts. Fecal-oral life cycles and blood-to-blood life cycles are exemplary of host parasite relationships in this realm. The "blood-to-blood" begins and ends with an insect taking a blood "meal". In this operatic scenario, a "blood-less" insect functions simultaneously as a hypodermic needle and as an incubator for some of the infectious components. The initial phase is inside the body fluid compartment of an insect. The second phase is in the blood or body fluid of a warm-blooded mammal. Third, is the phase inside the cell of a mammalian host. And a final portion of the "life" marked by "death" of the parasitized mammalian cells and the release of infectious parasites which return to the "warm" blood where the "cold blooded" vector again takes a blood meal. The cycle then begins again. In each phase of a blood to blood life cycle, the infectious agent changes its shape. Blood phase "profiles" look different from "tissue phase" profiles. Some of the tissue phase profiles may be "invisible". Borrelia spirochetes offer an excellent example of a life cycle, by virtue of the insect vector to mammalian "piece", the blood and intracellular residence "pieces" and the morphologic diversity "piece". Stereotypes of what a spirochete "should " look like, have actually produced a state of "perseveration" in spirochetal pathobiology. We have been "stuck" like a broken record, on the corkscrew form, and have failed to see the rest of the life cycle. Cystic, granular, and cell wall deficient spirochetal profiles, which were well known in the 19th and 20th centuries by such titans as Schaudinn, Hoffman, Noguchi, Delamater, Steiner, and Mattman, have been repudiated by professional microbiologists, and by pathologists who practice and who confer the status of 21st century truths in microbiology matters. Proper microscopic study, as is required by Dr. Robert Koch's second postulate, for establishing links between microbes and disease, presupposes that the microscopist be aware of the complete array of morphologic repertoires of the alleged pathogen. (Morphologies, which are herein introduced.).
Asunto(s)
Borrelia/crecimiento & desarrollo , Borrelia/fisiología , Insectos/microbiología , Spirochaetales/fisiología , Animales , Borrelia/ultraestructura , Estadios del Ciclo de Vida , Modelos Biológicos , Spirochaetales/ultraestructuraRESUMEN
When cultures of Brachyspira hyodysenteriae were grown under a wide range of in vitro conditions, at least 1% of the cells formed spherical bodies different to the normal helical form. This percentage increased considerably in aging cultures or following their incubation in caramelized media. Spherical body formation was initiated from a terminal localized swelling of the outer sheath followed by a retraction of the protoplasmic cylinder into the resulting swollen vesicle. As this occurred, the periplasmic flagella seemed to unwind from the protoplasmic cylinder. Once retracted, the protoplasmic cylinder was found to be wrapped in an organized manner around the inner surface of the membrane of the swollen vesicle. Although most were 2-3 microm in diameter, some much larger spherical bodies (6-12 microm diameter) were occasionally seen, with a corresponding increase in the visible number of peripheral protoplasmic cylinder cross-sections. Spherical bodies from older cultures did not contain protoplasmic cylinders arranged around the periphery, but instead were characterized by the presence of a centrally located, electron-dense body c. 0.5-0.8 mum in diameter. Brachyspira hyodysenteriae spherical bodies differ in both their structural organization and probable method of formation from similar structures described in other spirochaete genera.
Asunto(s)
Spirochaetales/crecimiento & desarrollo , Spirochaetales/ultraestructura , Animales , Medios de Cultivo , Disentería Bacilar/microbiología , Disentería Bacilar/veterinaria , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Orgánulos/fisiología , Orgánulos/ultraestructura , Porcinos , Enfermedades de los Porcinos/microbiologíaRESUMEN
Studies of equine intestinal spirochetes have long focused on intestinal contents alone, but intestinal spirochetosis has been reported recently in a 21-month-old Thoroughbred colt in Japan. To define the clinical and pathological significances of intestinal spirochetosis in several horses, an epizootiologic survey with histologic, immunohistochemical, and ultrastructural methods was conducted for Brachyspira antigen-containing intestinal spirochetes in 12 diseased or injured Thoroughbred horses, aged from 35 days to 17 years. Brachyspira antigen-containing spirochetes were found in 7 of 12 horses (58.3%) and were more frequent in the cecum than in other parts of the bowel. It was not clear whether the infection was clinically related to diarrhea or dysentery, but histopathology revealed a close association between the bacterial infection and epithelial hyperplasia. Crypt epithelium consisted mainly of goblet cells and showed frequent mitosis throughout its length. Inflammatory cells and congestion were also present. There were numerous spirochetes in the crypts, and some invaded the cecal and colonic epithelia and underlying lamina propria. Ultrastructurally, the spirochetes were divided into 4 types. Three types were identified in degenerative epithelial cells or intracellularly. Brachyspira antigen-containing intestinal spirochetes invading the mucosa were capable of causing epithelial hyperplasia in the cecum and colon in the horses. The findings in this study will increase awareness of the importance of intestinal spirochetosis and may also be helpful for diagnosis and treatment of this condition.
Asunto(s)
Colitis/veterinaria , Enfermedades de los Caballos/diagnóstico , Intestinos/microbiología , Infecciones por Spirochaetales/veterinaria , Spirochaetales/aislamiento & purificación , Animales , Antígenos Bacterianos/análisis , Colitis/diagnóstico , Colitis/microbiología , ADN Viral/metabolismo , Femenino , Enfermedades de los Caballos/microbiología , Enfermedades de los Caballos/patología , Caballos , Inmunohistoquímica/métodos , Inmunohistoquímica/veterinaria , Intestinos/patología , Intestinos/ultraestructura , Masculino , Microscopía Electrónica/veterinaria , Spirochaetales/inmunología , Spirochaetales/ultraestructura , Infecciones por Spirochaetales/diagnóstico , Infecciones por Spirochaetales/microbiologíaRESUMEN
BACKGROUND: Details of the development of human subgingival biofilm are unknown due to the difficulties in conducting experiments and especially in obtaining undisturbed materials. METHODS: This study was performed using deposits on carbonate apatite that had been inserted into human periodontal pockets for up to three weeks. Scanning electron microscopy using the vertically sectioned method and transmission electron microscopy using the freeze-substitution method were adopted. RESULTS: The development of subgingival biofilm occurred in five sequential phases: pellicle formation, microbial adherence, initial colonization, microbial organization, and establishment. Certain species in each of the initial, secondary and tertiary colonizers were considered to have a predilection for biofilm formation. Gram-positive, bacillary initial colonizers and gram-negative, filamentous secondary colonizers organized one stable structure that served as the framework for biofilm formation, and gram-negative, rod-shaped tertiary colonizers with cell-surface vesicles showed multigeneric coaggregation. The microbiota in the tertiary colonizers underwent repeated microflora alteration. CONCLUSIONS: Subgingival biofilm is constituted by initial, secondary and tertiary colonizers. Microflora alteration which is suggested to be related to periodontal disease, frequently occurred in the tertiary colonizers.