Treponema pallidum Microbiology Notes PDF

Duhok Polytechnic University Shekhan Health College Medical Laboratories Technology Dept. immunology 2nd Stage 2024-2025 Treponema pallidum Prepared by : Supervisor:  Alaa Akram...

Duhok Polytechnic University Shekhan Health College Medical Laboratories Technology Dept. immunology 2nd Stage 2024-2025 Treponema pallidum Prepared by : Supervisor:  Alaa Akram Prof.Azad M.Taher  Chinar Khudeeda Salih  Contents :  Introduction  Classification  Life cycle  Shape and morphology  Transmission and infection  diagnosis  Introduction Treponema pallidum is a spiral-shaped bacterium that causes syphilis, a sexually transmitted infection. It has a helical structure and moves through tissues, making it highly infectious. It progresses through multiple stages and, if untreated, can cause serious health complications.  Classification  Kingdom: Bacteria  Phylum: Spirochaetes  Class: Spirochaetia  Genus: Treponema  Species: Treponema pallidum  Life Cycle  Entry into the body via mucous membranes or skin abrasions  Replication and dissemination through the bloodstream  Stages of infection: primary, secondary, and tertiary syphilis  Primary Stage  Symptoms: Painless ulcer (chancre)  Appears at site of infection  Occurs 10-90 days post-exposure  Spontaneously heals  secondary Stage  Symptoms: Rashes, fever, sore throat, fatigue  Highly infectious stage  Systemic spread of bacteria  Occurs weeks to months after chancre heals  Tertiary Stage  Rare but severe stage  Gummas: soft, tumor-like growths  Cardiovascular and neurological damage  Occurs years to decades after initial infection  Shape and Morphology of Treponema pallidum 1. Shape  Spirochete : Treponema pallidum is a Long ,thin bacterium with a spiral shape. 2. Size  approximately 0.1 to 0.2 micrometers in diameter and 6 to 15 micrometers in length, making it very slender and difficult to visualize under light microscope. structure  Gram-Negative: does not retain to gram stain due to cell wall composition.  Motility: moves via periplasmic flagella located between membranes.  Transmission and Infection of Treponema pallidum Transmission pathways :  Sexual contact : the most common route of transmission.  Mother to child : vertical transmission from an infected pregnant mother to her fetus.  Blood transfusions : transmission through contaminated blood.  Diagnosis of Treponema pallidum  Clinical examination identification of characteristic symptoms (chancres , rashes ) and patient history.  Direct detection 1. dark-field microscopy : detects bacteria from lesion fluid. 2. PCR : identifies T. pallidum DNA from samples.  Serological Tests : 1. Nontreponemal tests (RPR & VDRL) 2. Treponemal tests (TPPA & FTA-ABS) Advantages and Disadvantages of Diagnostic Methods 1. Dark-Field Microscopy  Advantage: Direct detection of bacteria.  Disadvantage: Needs specialized equipment; not useful in latent stages. 2. PCR  Advantage: High sensitivity and specificity.  Disadvantage: Expensive and requires expertise. 3.Nontreponemal Tests (RPR, VDRL) Advantage: Quick, inexpensive, good for monitoring. Disadvantage: Prone to false positives; needs confirmation. 4.Treponemal Tests (TPPA, FTA-ABS) Advantage: Highly specific. Disadvantage: Can’t distinguish active from past infections; more costly.  Treatment Penicillin: The gold standard for treating syphilis, particularly benzathine penicillin Alternative treatments for those allergic to penicillin (doxycycline, tetracycline). Importance of early diagnosis and treatment to prevent progression to late-stage syphilis.  Summary Treponema pallidum is the bacterium that causes syphilis, a sexually transmitted infection progressing through multiple stages. It evades the immune system and spreads in the body, making early diagnosis and treatment with antibiotics crucial. Public health efforts focus on prevention, screening, and education.