Treponema pallidum

Four subspecies of T. pallidum are known, all of them are pathogenic for humans:

• T. pallidum pallidum - the causative agent of syphilis , the most widely known
• T. pallidum pertenue - causative agent of frambesia ^{[2] [3]}
• T. pallidum carateum - a pint pathogen ^[4]
• T. pallidum endemicum - Begel causative agent ( endemic syphilis) ^[5]

Morphology

According to Gram, it does not stain, a long (8–20 μm) thin (0.25–0.35) spirochete, the spiral depth is 0.8–1 μm, the coil amplitude is 1 μm, and the number of curls is 8–12–14. Treponema pallidum is capable of helical, flexion and contractile movements provided by fibrils and treponema cell own contractions. There is a so-called. the axillary body , which is an intracellular flagella ^[6] .

The body of pale treponema is surrounded by a mucous, structureless capsule-like substance that performs a protective function. Due to the presence of a large number of hydrophobic components in the cytoplasm, treponema is poorly stained with aniline dyes, but stained in pale pink according to the Romanovsky – Giemsa method (for which it was called “ pale treponema”). Silver etching and impregnation methods are also applicable. Unpainted, unfixed live treponemas are not visible under a light microscope; dark-field microscopy , viewing in a phase-contrast microscope, and a more modern method of fluorescent antibodies are used to visualize them.

Cultural Properties

Hemorganorgan heterotroph , obligate anaerobic . Not cultivated on simple nutrient media. Known methods for producing so-called. “Mixed cultures” (for example, the Shereshevsky method ^[7] on half-rolled up horse serum, the Noguchi method ^[8] on a mixture of alkaline agar and ascitic fluid and the addition of a piece of a kidney or testicle of a rabbit, the method of Proca, Daniela and Stroe (Proca, Daniela, Stroe) ^{[ 9]} and others), methods for obtaining pure cultures are also known (both from mixed cultures — according to the Muels method ^[10] , and directly from the blood of patients with syphilis), methods of cultivation on solid nutrient media (on blood or serum agar under anaerobic conditions are known) ^[11] ). Cultivated spirochetes lose their pathogenicity , but antigenic properties are partially preserved ( cardiolipin extract is used to formulate the Wasserman reaction ). T. pallidum is also cultivated by infection of rabbits due to the susceptibility of the latter and is a convenient organism for modeling syphilis ^{[12] [13]} (including neurosyphilis ).

Treponema pallidum has a unique biological feature: its reproduction can only occur in a very narrow temperature range - about 37 ° C. The method of pyrotherapy of syphilis is based on this phenomenon. The bacterium multiplies by division once every 30–32 hours.

Genome

The genome of T. pallidum strain Nichols is represented by a ring double-stranded DNA molecule measuring 1138012 bp and contains 1090 genes , of which 1039 encode proteins , open reading frames comprise 92.9% of the genome, the percentage of G + C pairs is 52.77% ^[14] . T. pallidum is characterized by a strong reduction in catabolic and biosynthetic functions ^[15] , a comparison with the T. pallidum genome of strain SS14 shows 327 single nucleotide substitutions (224 transitions , 103 transversions ), 14 deletions and 18 insertions , and hypervariable regions of the T. pallidum chromosome were found ^[16] . The differences in the genomes of Treponema pallidum strain Nichols and T. paraluiscuniculi strain Cuniculi were also studied ^[17] . The tprK gene has many alleles and differs between T. pallidum strains ^[18] and is responsible for antigenic differences between different T. pallidum strains ^[19] .

T. pallidum is the causative agent of syphilis , a sexually transmitted disease . Transplacental transmission of the pathogen from mother to fetus during pregnancy is also known with consequences in the form of miscarriages or congenital syphilis ^[20] . T. pallidum gained resistance to many antibiotics , including macrolides ^{[21] [22]} , in particular, azithromycin ^[23] , a 47 kDa lipoprotein T. pallidum has the ability to bind penicillins ^[24] . T. pallidum carries binding proteins and immunogens ^{[25] [26]} on the cell surface, including proteins that bind to human fibronectin ^{[27] [28]} and laminin ^[29] . Immunization with endo-flagella of T. pallidum affects the course of experimental syphilis in rabbits ^[30] . Lipoproteins of T. pallidum in a certain way influence the course of the pathological process ^[31] , being similar to the receptor ^[32] . T. pallidum is able to invade intercellular endothelial compounds ^[33] .

• Treponema pallidum
• Treponema Schaudinn 1905
• Treponema Molecular Genetics Server
• Treponema pallidum causes syphilis
• Biological Basis for Syphilis Rebecca E. LaFond and Sheila A. Lukehart