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Saturation reassociation assays with 125I-labeled treponemal DNAs show that Treponema hyodysenteriae is genetically unrelated to T. pallidum (Nichols), T. phagedenis biotype Reiter, and T. refringens biotype Noguchi. Pathogenic and nonpathogenic isolates of T. hyodysenteriae exhibited 28% sequence homology and had an extremely low guanine-plus-cytosine content (25.8%).
The main problems in identifying Treponema pallidum in tissues are optical definition contrast, and specificity. In general, fluorochrome staining provides optical definition and contrast superior to that obtained by ordinary tinctorial staining, and in theory improved resolution. Specificity is lacking however, as with other stains. In contrast, immunofluorescence should combine the optical advantages of fluorochrome staining with the immunological advantages of specificity. Since the validity of such staining depends in part upon the integrity of the antigenic components of the micro-organisms, it is customary to avoid such drastic procedures as are involved in routine fixation and paraffin embedding. The manipulation, however, of unfixed cryostat material, in contrast with that of paraffin sections suffers from two disadvantages--namely, friability and infectivity. Published and unpublished work has shown antigenic stability in T. pallidum to a variety of procedures, both physical and chemical. Consideration of these facts led in this work to successful immunofluorescent staining after routine formalin fixation and paraffin embedding of tissues infected with T. pallidum or Treponema pertenue. Optical definition and contrast, were superior to that obtained with silver methods, but it was not possible to differentiate between these two organisms. Nevertheless immunofluorescence applied as described to paraffin sections should supply a convenient safe, and sensitive means of reappraising the histopathology of treponemal disease in patients, necropsy material, and experimental animals.
The in vitro response of peripheral blood lymphocytes from rabbit infected with Treponema pallidum was examined using various mitogens and avirulent Treponema reiteri. For the first 4 weeks after treponemal infection, the response of lymphocytes from syphilitic rabbits to phytohemagglutinin and pokeweed mitogen was markedly reduced in comparison to uninfected controls. Lymphocytes from both groups of rabbits responded normally to class-specific immunoglobulin anti-sera (anti-immunoglobulin M and anti-immunoglobulin G) and T. reiteri.
Two strains of virulent Treponema pallidum and two of virulent T. pertenue were investigated for their ability to attach to and survive in gradient cultures of five different mammalian cells under aerobic conditions. The strains of T. pallidum studied were the high-rabbit-passage Nichols and the low-rabbit-passage KKJ. The former was known to readily attach to cottontail rabbit epithelial cells (Sf1Ep) and to survive in the virulent state for up to 21 days. We therefore compared attachment of the other virulent treponemes with that of T. pallidum (Nichols). The KKJ strain of T. pallidum behaved in a fashion similar to T. pallidum (Nichols) in all of the cultures. Both strains exhibited preferential attachment to cells of Sf1Ep and those derived from the ear of a nude athymic (nu/nu) mouse. In these cultures, we observed a consistent three- to fivefold increase in attached treponemes up to 12 days after initial inoculation. The strains of T. pertenue were the human-derived Gauthier and cynocephalus-derived FB. These two strains of T. pertenue also attached to cells of all five types of cultures, but in smaller numbers than were seen with T. pallidum and equally to all of the cultures. Neither preferential attachment to Sf1Ep and nude mouse ear cells nor increased attachment with time was seen.
Three genetically distinct groups of treponemes have been identified by saturation reassociation assays using 125I-labeled treponemal DNAs. The three groups are (i) virulent Treponema pallidum (Nichols strain), (ii) T. phagedenis and its biotypes Reiter and Kazan 5, and (iii) T. refringens biotypes Nichols and Noguchi. There is no detectable DNA sequence homology (less than 5%) among the three groups. The groups have distinct guanine + cytosine contents: 52.4 to 53.7% for T. pallidum, 41.5% for T. refringens, and 38 to 39% for T. phagedenis.
Optimal culture conditions in artificial nutritive media were determined for a defined avirulent strain of Treponema hyodysenteriae and for four field strains of treponemas in pigs with clinical dysentery. The treponemas were isolated with the use of milliporous filters with pores of 0.3 micrometer in diameter, which were located on the surface of blood agar. No significant difference in the influence of equine, bovine or sheep blood on the growth of treponemas was determined. The commercial amount of glucose in the used media, 2.0 to 2.5 g per 1,000 ml, was quite sufficient for the growth of the treponemas and it was not necessary to increase the amount. After reaching the optimal rate of growth the oxidoreduction potential was diminished by adding cystein or cystein hydrochloride and placing the Petri dishes with the media, prior to inoculation, into an anaerobic medium filled with hydrogen. The suitable composition of the culture atmosphere created in a special anaerostat comprised 0.4 to 1.0% carbon dioxide and the rest being hydrogen. Treponemas grew on the blood agar in zones with very slight hemolysis without forming separated colonies.
The results of electroimmunodiffusion investigations with Reiter treponema antigen and syphilitic subject sera are presented. Counter-immunoelectrophoresis, rocked electrophoresis and crossed-electrophoresis studies have been performed. The test positivity is shown by the appearance of one ore two precipitates. No aspecificities were remarked with the latter two techniques: particular attention was devoted to the preparation of the treponema antigen in the attempt to eliminate the aspecificity which, sometimes, occurs above all with counter immuno-electrophoresis. Immuno-sorbents were also prepared to isolate IgG involved in this reaction: the latter turned out to be slow-migration IgG. Agarose-agar electroimmunoprecipitation between treponema antigens and sera of syphilitic subjects supplies possibilities for diagnosis and research in the field of treponema antigens and in the formation of antibodies in the syphilitic disease.
The present paper reports on two methods for extraction of the protein antigen from Treponema Reiter and shows the chemical and immunochemical characteristics of the extracts. Serologic testing of 1810 sera from syphilitic patients in various stages of the disease, from healthy subjects and from subjects with a false positive reaction to lipoid antigens, showed the value of the Reiter antigen to be equal to the cardiolipin antigens and those prepared from pathogenic Treponema. It is recommended to associate this antigen, in view of its qualities, to the cardiolipin tests used in the serodiagnosis of syphilis, especially in the laboratories that do not currently apply other treponema tests.
Cells of Treponema pertenue Gauthier obtained by elution from skin lesions and lymph nodes of experimentally infected hamsters were studied in the electron microscope by means of negative staining. The cells were also examined in thin secions of skin biopsies and lymph nodes. Fimbriae were observed on the negatively stained cells. Until now fimbriae have not been demonstrated on negatively stained cells of other species of Treponema, but at present only one straon of T. pertenue has been studied in our laboratory. Otherwise, the ultrastructure of the T. pertenue cells was found to be very similar, if not identical to, the substructural details observed in cells of T. pallidum and T. cuniculi. In thin sections of skin biopsies, treponemes were observed in the intercellular spaces between cells of the stratum basale and the stratum spinosum layers of the epidermis.
The morphology, the general physiological characteristics, and the energy-yielding metabolism of an obligately anaerobic spirochete isolated from the colon of a swine were studied. Electron microscopy showed that the helical spirochetal cells possessed an outer sheath, a protoplasmic cylinder, and 4 periplasmic fibrils in a 2-4-2 arrangement. The spirochete grew in an atmosphere of N2 in prereduced media containing a carbohydrate, NaHCO3, rumen fluid, yeast extract, peptone, L-cysteine, and inorganic salts. The spirochete fermented carbohydrates and required substrate amounts of CO2 (HCO3-) for growth. Amino acids were not fermented. Major fermentation products of cells growing with glucose as the substrate and in the presence of CO2 were acetate, formate, succinate, and lactate. Small amounts of 2,3-butanediol, pyruvate, and acetoin were also formed. Determinations of enzymatic activities in cell extracts, and of radioactivity in products formed by growing cells from [1-14C]glucose, indicated that this sugar was dissimilated to pyruvate via the Embden-Meyerhof pathway. The spirochetes used a coliform-type clastic reaction to metabolize pyruvate. Determinations of radioactivity in products formed from [14C]NaHCO3 indicated that CO2 was assimilated and used in succinate production. The guainine + cytosine content of the DNA was 36 mol %. This study indicates that this intestinal spirochete represents a new species of Treponema. It is proposed that the new species be named Treponema succinifaciens.
A low-molecular (8S) treponema-specific IgM antibody was isolated by means of Sephadex 200 G gel filtration and/or sucrose gradient ultracentrifugation in 78 of 4,120 sera of patients who had been identified to have had syphilis. The IgM specificity can be shown by indirect immunofluorescence using a mu-chain specific antiserum. The low molecular IgM (LMW-IgM) antibodies are not identical with the 19S-IgM as demonstrated in studies with gel filtration and sucrose gradient methods. They are not identical neither with 7S IgG or IgA. Neither the presence of antinuclear nor rheumatic factor could be shown in the LMW-IgM fraction. In most of the patients with LMW-IgM antibody, there existed a treponema infection of late latency.
The interaction between virulent Treponema pallidum extracted from infected rabbit testes and animal cells in culture was examined. The extent of treponemal attachment to monolayers of normal rabbit testicular and HEp-2 cells was dependent upon the incubation temperature and retained motility of the spirochetes. The specific orientation of treponemes to host cell surfaces was demonstrated by dark-field microscopic examination of wet-mount preparations and scanning and transmission electron microscopy. Once attached, T. pallidum organisms remained actively motile yet anchored in place by their terminal tapered structures. After several hours of co-incubation, maximal attachment was attained, and the degree of parasitism seemed regulated not only by available surface sites on individual host cells but also by the proposed membrane response of parasitized cells to continued exposure to treponemes. The avirulent strain, Treponema phagedenis biotype Reiter, did not adhere to monolayer cultures. Characterization of host cell determinants that permitted surface colonization by T. pallidum was attempted. Also, properties of virulent treponemes that enabled surface parasitism were monitored by measuring the effects of enzymes, detergents, and metabolic inhibitors on the host-parasite interaction. Results reinforced the specific nature of the treponemal attachment mechanism. Furthermore, the ability of convalescent rabbit sera to reduce attachment of treponemes to host cells suggested that surface structures on T. pallidum could be masked or inactivated by host components, thus providing a potentially effective research approach for investigating the pathogenesis of syphilis and screening appropriate vaccine candidates.
The lipid composition of Treponema pallidum (Nichols virulent strain) was determined after purification of the organisms from the infected testes of corticosteroid-treated rabbits by differential centrifugation, filtration through Nuclepore membranes, and sedimentation in Hypaque density gradients. The total lipids were comprised of 32.2% neutral lipids, mainly cholesterol, and 67.8% phospholipids consisting of phosphatidylcholine (32.1%), sphingomyelin (14.8%), cardiolipin (13.0%), phosphatidylethanolamine (6.2%), phosphatidylinositol-serine (1.2%), and lysophosphatidylcholine (0.4%). Monoglycosyldiglyceride, a glycolipid comprising 25 to 50% of thetotal lipid of all Treponema previously examined, was not detected. The fatty acid composition was similar but quntitatively distinct from that of the infected testes tissue.
UNLABELLED: The global resurgence of treponematoses, particularly syphilis, poses a growing public health challenge. Despite advances in sequencing technologies, obtaining complete Treponema pallidum genome sequences for epidemiological studies remains challenging due to clinical sampling and methodological constraints. There is, therefore, a need for rapid, cost-effective, and accessible typing methods. Based on the analysis of 121 T. pallidum genomes spanning all three subspecies (TPA, TPE, and TEN) from diverse regions, we selected seven highly variable genes (tp0136, tp0326, tp0548, tp0705, tp0858, tp0865, and tp1031) to form a new typing system, combined with analysis of macrolide resistance mutations in the 23S rRNA gene. The scheme was validated on 542 global T. pallidum samples, using either Sanger reads or whole genome sequence data, obtaining 82 sequence types (STs) among the 415 fully typed samples. Macrolide resistance mutations were frequently detected, highlighting the need for ongoing epidemiological surveillance. Phylogenetic analyses based on concatenated multilocus typing (MLST) loci recovered the expected subspecies and lineage structure. Consistently, almost all sequence types formed monophyletic groups, indicating strong concordance between MLST-based classification and whole-genome phylogenies. In addition, population genetic analyses revealed comparable levels of within-lineage diversity across subspecies and lineages, despite pronounced differences in geographic distribution, and identified distinct regional genetic clusters consistent with localized transmission dynamics. Importantly, the scheme employs a single-step PCR for all seven targets, facilitating implementation in standard laboratories and is publicly accessible through PubMLST. Overall, our novel MLST scheme offers a rapid, cost-effective tool to advance molecular epidemiology of T. pallidum, facilitate transmission and resistance tracking, and support global surveillance to strengthen public health interventions for syphilis and endemic treponematoses control. IMPORTANCE: We have developed a new multilocus typing (MLST) scheme useful for all Treponema pallidum lineages after the analysis of 121 complete genome sequences of this species. The new scheme can be used directly with uncultured clinical samples, thus providing an excellent contribution to the molecular surveillance of syphilis and other treponematoses. The application of this MLST scheme to over 500 samples from all lineages and main geographical regions has revealed similar levels of genetic variation within them. Furthermore, the analyses show a complex pattern of spread, with global and local contributions to the observed distribution of genetic variation in the syphilis-producing sublineages. The new scheme represents a significant improvement over previous proposals and also reveals unsuspected levels of variability in T. pallidum lineages.
Antibody titres were measured in patients with clinical syphilis, and the effect of treatment on the results of the Treponema pallidum immune adherence (TPIA) test is reported. In the Treponema pallidum haemagglutination (TPHA) test little change in antibody titre occurred after treatment while in the fluorescent treponemal antibody-absorbed (FTA-ABS) test only a slight decrease occurred. The decrease in the antibody titre in the TPIA test was similar to that in the glass plate test, but the findings were different. From the results of gel filtration of sera obtained from patients with syphilis at different intervals after treatment it was apparent that the decrease in antibody titre after treatment mainly concerned the IgM antibody; thus, because of the high sensitivity of the TPIA test to IgM antibody the test is useful in evaluating the effect of treatment.
To judge the pathogenicity of Treponema palllidum in mice, we inoculated two groups of animals. 1) One with a normal immune system : adult Swiss mice. 2) The other with an immune system presenting a defect in T cells : athymic Nude mice. No lesions appeared at the points of inoculation and the survival of these animals was not modified compared with control animals. We have also carried out a study of antitreponema antibodies in adult and new-born Swiss mice, using, for the adults, various concentrations of treponema pallidum and various routes of inoculation. In adult mice, the search for antibodies by fluorescence, showed, firstly, that the intradermal route permits a more rapid humoral response than the intraperitoneal route, with higher antibody titers. Furthermore, an inoculum of 8,6 X 10(6) per mice, gives earlier results and higher titers than those obtained with an inoculum twice lower. The earliness of the positive Nelson test is independent of the route of inoculation but related to the injected dose. On the other hand, the Kline reaction remained negative for all groups of mice throughout the whole period of our study. In new-born mice, 76% only became positive on fluorescence and Nelson test.
Pure cultures of Treponema hyodysenteriae given orally to conventional pigs resulted in the development of swine dysentery, whereas identical cultures given to gnotobiotic pigs did not produce the disease. Oral inoculation of gnotobiotic pigs with Vibrio coli and/or a peptostreptococcus in addition to T. hyodysenteriae did not result in dysentery. Neutralization of gastric secretions with NaHCO3 immediately prior to inoculation with T. hyodysenteriae increased the period during which treponemes were evident in the feces, as did the inoculation of this organism via the intracecal route. None of the gnotobiotic pigs with a persistent fecal Treponema population developed signs of dysentery. Factors other than those investigated in this work must play a part in the etiology of swine dysentery.
Levels of phospholipids, glycolipids and cardiolipin were determined in various organs of Treponema pallidum-infected rabbits. The phospholipid levels on the second week of infection decreased significantly in the spleen but remained unchanged in other organs. During the same time, glycolipids decreased significantly in both kidney and heart. 3 days after infection, a brief but significant increase of cardiolipin in the spleen was observed. Heat-killed T. pallidum but not Treponema reiteri caused a similar effect. The possible implication of these changes in the immunopathology of syphilis is discussed.