Introduction
The term " Treponema" indicates a genus of bacteria to which two different pathogenic species belong, Treponema pallidum and Treponema carateum, microorganisms involved respectively in the onset of syphilis and pint. Although most of the species belonging to the genus Treponema establish a form of commensal symbiosis with the host (resulting non-pathogenic), Treponema pallidum is distinguished by its characteristic virulence.
Let's take a closer look at the distinctive features of Treponema pallidum .
Microbiological analysis of Treponema pallidum
Exponent of the phylum Spirochaetes and of the family Spirochaetaceae, Treponema pallidum is a gram negative bacterium, vector of diseases called trepomatosis, among which the lue or syphilis stands out.
Treponema pallidum is a bacterium sensitive to heat and dry temperatures. In reference to the very poor ability to survive in an oxygen-rich environment, a "microaerophilic" bacterium is defined.
Although it has flagella, Treponema pallidum differs from other flagellated microorganisms: in fact, these cellular appendages used for motility and called endoflagels, are located inside the bacterial cell (NOT outside, like most pathogens). The presence of endoflagels gives Treponema pallidum a marked ability to move so-called "spring"; thanks to these particular appendices, the microorganism is able to perform contractions, rotations, circular movements or "corkscrews". Even the bacterial wall that covers it is particularly elastic.
Treponema pallidum CANNOT be grown on liquid or solid soils: only specific serological tests can verify the presence of the bacterium.
The virulence factors associated with Treponema pallidum include:
- hyaluronidase (hydrolytic enzyme): favors the penetration of the bacterium into the host
- fibronectin (dimeric glycoprotein): protects the same Treponema pallidum from phagocytosis.
- hemolysins: toxic substances produced by the bacterium
Transmission of infections
Being sensitive to external temperatures, the bacteria of the species Treponema pallidum can be transmitted exclusively by direct contact.
As mentioned above, Treponema pallidum is the etiological agent of syphilis, a widespread venereal disease. In addition to sexual transmission, Treponema pallidum can infect the fetus by placenta during the last stages of pregnancy: in this case, the disease transmitted by the mother and acquired by the unborn child is called "congenital syphilis".
The particular helical structure of Treponema allows it to move even in a viscous medium such as mucus. Arrived later in the blood and lymph, the bacterium infects tissues and mucous membranes.
In some cases, Treponema pallidum is transmitted by transfusion of infected blood.
The period of incubation of syphilis varies from 2 to 10 weeks.
Deepening: clinical stages of syphilis
- primary phase: it is characterized by the presence of sifiloma, a highly contagious lesion that occurs at the site of inoculation, often at the level of the external genitalia. The papule soon evolves into a rigid and painful ulcer. These clinical signs are evident after 3-4 weeks after infection
- secondary phase (disseminated syphilis): 6-12 weeks after the disappearance of the primary syphiloma, the second phase of syphilis begins. At this stage, Treponema pallidum has spread and replicated in the liver, lymph nodes, joints, muscles, skin and mucous membranes. The characteristic signs of this phase are: papules spread on the trunk, arms and legs, and skin sores (erosions, erythematous plaques). The affected patient often complains of fever, alopecia, thinning of the eyebrows, headache, loss of appetite. This phase lasts about 8 weeks, at the end of which the patient can enter the latent phase (asymptomatic) or the late stage (tertiary).
- tertiary phase: appears many years after infection, with lesions in the cardiovascular system and CNS, associated with skin sores or internal organs.
Treponema pallidum infection is ascertained by a fluid sample extracted from a suspected ulcer. The liquid will then be evaluated under a microscope.
The doctor can also subject the patient to blood tests, looking for any specific antibodies (present in all subjects affected by syphilis).
Medical statistics show that a large proportion of syphilis sufferers have a high risk of contracting HIV: for this reason, syphilitics are advised to undergo all relevant tests to test for a possible concomitant HIV infection.
Prevention and treatment of infections
Since there is no vaccine for syphilis, it is good to refrain from unprotected sexual intercourse with subjects at risk; otherwise, regularly carry out blood tests, in addition to alerting all persons with whom you have consumed risky reports, up to a year before the onset of syphilis symptoms.
Treponema pallidum infections can be treated with antibiotics such as penicillin (a drug of choice), procaine, erythromycin, doxycycline and tetracycline. Prevention is the best weapon to escape Treponema pallidum infections.
