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Sexually Transmitted Diseases

Sexually Transmitted Diseases

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Sexually Transmitted Diseases

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  1. Sexually Transmitted Diseases Dr Syed Suhail Ahmed

  2. Incidence and spread of STD are greatly influenced by numerous factors- • Multiple sexual partners • Increasing density and frequent movement of people within population • Absence of vaccines for most STD s. • Asymptomatic infection – a pt with an STD may be free of symptoms especially females. They may serve as reservoir of infection and unknowingly spread the pathogen.

  3. Bacterial agents - • Chlamydia tracomatis (D - K serotypes & L1 L2 L3 Serotypes) • Neisseria gonorrhoeae • Treponema pallidium • Haemophilus ducreyi • Gardnerella vaginalis • Calymmatobacterium granulomatis • Mycoplasma, Ureaplasma( t strains).

  4. Viral agents - • Human papilloma virus • Herpes simplex virus types 1 &2. • HIV • Hepatitis B virus • Molluscum Contagiosum Protozal agents- Trichomonas vaginalis, Giardia lamblia Fungal agents – Candida albicans Ectoparasites- Phthirus pubis, Sarcoptes scabiei

  5. Neisseria gonorrhoeae : Gonococcus was first described in gonorrheal pus by Neisser. Morphology- Size - 0.6- 0.8 Microns Shape - adjacent sides concave, kidney shape Arrangement - pairs(diplococci) Nonmotile ,Nonsporing Staining reaction – Gram staining : Gram negative oval or spherical cocci.

  6. Gram stained smear of urethral discharge showing; Gm-ve diplococci intra- & extra-cellularly in pus cells (diagnostic)

  7. Gram stained film of Neisseria gonorrhoeae culture on Chocolate agar showing; Gram-ve diplococci (kidney shaped)

  8. Cultural characteristic : Facultative intracellular parasite. Aerobes but may grow anaerobically Temperature- 35-37 c Grows best in 5-10% CO2 Growth - 24- 48 Hrs Media- Enriched media – Chocolate Agar(sterile site) Selective media- Thayer Martin medium, New york city media.

  9. colonies (T1-T5) are small round, transparent or opaque and easily emulsifiable. Transport media- Stuarts or Amies Transport media Biochemical Reaction : Several biochemical test like N.gonorrhoeae ferment only glucose with production of acid. Catalase - Positive Neisseria are oxidase positive key test for identifying them.

  10. Antigenic structure : (VIRULENCE FACTOR) Neisseriagonorrhoeae is antigenicallyheterogenous and capable of changing its surface structure to avoid host defenses. Surface structures include the following • Pili – Hair like appendages that enhance attachment to host cells and resistance to phagocytosis. • OPA- this protein function's in adhesion of gonococci within colonies and in attachment of gonococci to host cells.

  11. C. lipooligosaccharides(LOS) – In contrast to GNR gonococci have LOS. Toxicity in gonococal infection is largely due to endotoxin effect. The LOS structurally resemble Human cell membrane glycospingolipids ( molecular mimicry),this helps gonococci evade immune regulation. D.IgA1 protease- splits and inactivate IgA1.

  12. Pathogenesis – Mode of infection : The disease is acquired by sexual contact with an infected partner. Incubation period - 2-8 days Mechanism : 1.Extracellular multiplication : Upon gaining access to the cervix or urethra by sexual contact, these organism subvert the humoral immune response by antigenic variation of surface molecules or by production of IgA1 protease. 2. Attachment – Attach to nonciliated ,low coloumnar epithelial cell that is mediated by Pili or OPA.

  13. 3. Endocytosis – Followed by penetration of the organism between and through epithelium of the submucosal tissue, membrane bound endocytic vesicle is formed and host killing is inhibited by the Outer membrane protein. 4.Transport - Next the membrane bound vesicle containing multiple organism, migrate close to the basal surface of epithelial cell. 5.Exocytosis - Fusion of the basal membrane and vesicular membrane ensues, followed by exocytosis of gonococci. Host inflammatory response is mostly seen.

  14. Clinical significance - Genital infection in men- Acute Uretheritis– Mucopurulent discharge containing gonococci in large nos. the infection extends along the urethra to the prostrate, seminal vesicles and epididymis. Fibrosis occur leading to urethral stricture. The infection may spread to periurethral tissues, causing abscess and multiple discharging sinus. Genital infection in women : Primary infection is in endocervix and extends to urethra and vagina giving rise to mucopurulent discharge .It may then progress to uterine tubes, causing salpingitis , Fibrosis & obliteration of the tubes.

  15. Infertility occurs in 20 % of women with gonococcal salpingitis. Men & Women Rectal Gonococcal infection – Proctitis occurs in both sex. It may directly spread in women but in men is the result of anal sex. Pharyngeal infection - Oral Sexual exposure. Disseminated Gonococcal infection - Gonococcal bacteremia leads to skin lesions ,arthritis and very rarely meningitis. Nonveneral infection – Gonococcal Ophthalmia in the newborn which result from direct infection through birth canal(Conjuntivitis).

  16. Lab diagnosis - 1. Microscopy – Examine Gram Stain smears of urethral discharge from men and urethral and cervical secretion from women .The observation of characteristic kidney shaped, gram negative diplococci lying within polymorphnuclearleukocytes with few extracellular organism is typical of gonococcal infection. 2. Culture – Plate out the specimen on Enriched media like chocolate agar and on selective culture media like Thayer martin media ,MTM, New York City media. Incubate at 35- 37 c in Co2 enriched atmosphere.

  17. Presumptive colonies of nesisseria can be identified by G.S and oxidase test. • RCUT OTHER biochemical test. 3. Antigen detection – ELISA,DNA Probe assay Fluorescent antibody test.

  18. CHLAMYDIA TRACOMATIS • Small Obligate intracellular parasite. • lack mechanism for production of metabolic energy and cannot synthesize ATP. • They have the typical LPS of GNB.They lack pepitodoglycan layer. • Dimorphic growth cycle. • The genus Chlamydia comprise 4 sp C. tracomatis C. pneumonia C. psittaci C. pecorum

  19. Structure – • C.tracomatis are small , nonmotile bacteria.They have the typical LPS of GNB . They exhibit dimorphic growth cycle - • Elementary bodies- EB are small electron dense structure about 300- 350 nm in diameter. They are extracellular, environmentally resistant, metabolically inert, infectious structure. • Reticulate bodies- RB are0.5- 1 micron, is devoid of any electron dense nucleoid. They are large pleomorphic structure ,metabolically active and divide by binary fission, they are non infectious.

  20. Staining – Gram Staining : Gram reaction of Chlamydia is negative and variable and is not useful in identification of these agents. Giemsa stain – ED – purple RB – blue. • Antigens- 1.LPS–common to all Chlamydia(group sp antig) 2.Outer membrane protein( sp or serovar sp) Based on OMP antigenic differences Serovars of C.tracomatis are grouped by letter. A - C tracoma D - K nongonoccal urethritis, epididymitis cervicities, L1-L3 – lympho granuloma venerum

  21. C. Trachomatis culture on McCoy cells Giemsa stained showing large chlamydial inclusions partially obscuring the nuclei

  22. Pathogenesis- Source of infection - Humans ,this organism is maintained within population largely as a consequence of asymptomatic infection of men and women. Mode of infection – Sexual contact. Mechanism – The mechanism by which C.tracomatis induces inflammation and tissue destruction are poorly understood. • On sexual exposure E.B pass from one infected individual to uninfected individual. • They quickly adsorb to the microvilli of coloumnar epithelial cells.

  23. They are endocytosed within membrane bound vesicles(inhibits fusion of infected endosome with lysosomal granules. • Within the endosome, EB converts to metabolically active RB and multiply. • this intraendosomal inclusion are referred to as inclusion bodies. • When the cellular nutrients have been depleted the RB convert to EB and are either exocytosed into the extracellular space or are liberated by cell lysis infecting adjacent cell (72 -96hrs).

  24. Damage from chlamydial infection is largely due to acute inflammatory response in the area of infection and scarring of the host tissue after infection. The acute inflammatory response may be consequence of the LPS produced by C.tracomatis.

  25. Clinical signifance-

  26. Lab diagnosis of C.tracomatis - 1. Cell culture - Mccoy cells are commonly used. After 48 -72 hrs of incubation monolayers are stained with iodine or an immunofluorescent stain and examined microscopically for inclusions. 2. Direct antigen detection – • Immunofluorescence DFA – FITC monoclonal antibody to either outer membrane protein or lipopolysaccharide of C.tracomatis in smears of samples. • ELISA.

  27. C. trachomatis immunofluorescence IF of cervical smear showing apple-green fluorescent C. trachomatis elementary bodies

  28. 3. Serologic Diagnosis - Microimmunofluorensence assay, CFT. 4. Molecular techniques- PCR, Ligase Chain reaction and Transciption mediated amplification

  29. Treponema Pallidium • Members of the genera treponema borrelia are spirochaetes belonging to the family spirochaetaceae. Treponema cause the following diseases- 1. Veneral syphilis- T. pallidium 2. Endemic syhilis - T. pallidium endemicum 3. Yaws -T.pertune 4. Pinta - T.carateum

  30. Structure- This organism are slender, tightly coiled spiral shape 5-15 nm long and 0.1-0.2 micron width. Actively motile .Non cultivable. Staining reaction - they do not stain by gram method modified staining procedure are used like silver impregnation methods or Fontana s method. They can be seen in dark field illumination. Ultrastructurally ,the cytoplasm of T.pallidium is surrounded by trilaminar cytoplasmic membrane enclosed by a cellwall containing pepitodoglycan which gives cell rigidity and shape.

  31. Several flagella are attached at each pole of the cell and wraps around bacterial cell body. • The outer membrane is usually lipid rich. Pathogenesis- • Source of infection- Natural infection with T. pallidium occurs only in human beings. • Mode of infection- • Sexual contact. • Congenital syphilis occurs following vertical transmission and also during passage through infected birth canal. • Transfusion of blood.

  32. Virulence factor- • Molecular mimicry outer sheath contain glycosylaminoglycans which resemble molecules found on the surface of human cell • Hyaluronidase – breakdown of hyaluronic acid in host tissue • Mechanism- 1 . T. pallidium following deposition onto the genital mucosa, gain access to subepithelial tissue through tiny cracks in the epithelial cell space.

  33. 2. From this site T. pallidium spreads to local lymphnodes eventually to the blood over a period of 10 wks. 3. After an incubation period of 2-10 wks, a painless syphilitic chancre characteristic of primary syphilis develops at the site of infection due to inflammation and necrosis resulting from response by neutrophils, T-cells and macrophages. 4. The microorganism then disseminates in the the blood ,localized to bood vessel and spreading to skin, liver ,joints ,lymphnodes ,muscles and brain.( Secondary syphilis).

  34. 5.Following secondary syphilis ,the disease progress into a state of latency, microorganism resides within local lymphnodes and the spleen. 6.In 30-40% of latent pts,the pathogen reactivates & begins to replicate actively,spread & penetrate various tissues of the body. 7.Tertiary syphilis,gumma formation appears to be the result of Cell mediated hypersensitivity reaction to treponemal antigen.

  35. Clinical manifestation - • Primary syphilis - chancre at the site of inoculation external genitila mostly in males. • Cervix ,mouth ,perinal area and anal canal in females. • Chancer or ulcer – no exudates, painless indurated hard chancre .the chancre heals on its own within 3-6 wks leaving either no trace or a thin atrophic scar.

  36. Secondary syphilis - disseminated syphilis It is the most florid stage of infection. It results from multiplication and dissemination of the spirochaete and last until a sufficient host response to exert some immune control over the spirochaete .it usually begins 2-8 wks after the appearance of a chancre. Latent syphilis - After the secondary lesion disappear there is a period of quiescence known as latent syphilis. diagnosis during this period is possible only by serological test. In many cases, this is followed by natural cure but in some leads to manifestation of tertiary syphilis appears

  37. Manifestation of Secondary Syphilis • Manifestation of Skin Rash,Macular,Maculopapular,,papular,Pustular Pruritus Mouth and throat Mucous patches ,Erosions ,Ulcer (aphthous) Genital lesions • Chancre • Chondyloma latum Generalized lymphadenopathy

  38. Tertiary syphilis (late syphilis) these consist of cardiovascular lesions including aneurysm ,chronic granulomata and meningovascular manifestation. In few cases ,neurological manifestation such as tabes dorsalis or general paralysis of insane develops several decades. • Congenital syphilis - Transplacental transmission can take place at any stage of pregnancy .a woman with early syphilis can infect her fetus much more commonly .

  39. Lab diagnosis of T. pallidium • 1.Microscopy • A. Dark field examination- A drop of exudate is placed on a slide and preparation is examined under dark field illumination for typical motile spirochaetes. • B.DFA-TP - A drop of exudate is placed on a slide with flourescent labelled anti treponemal serum and examining by means of flourescent microscope.

  40. Serological test - This test forms the main stay of laboratory diagnosis. Various methods use to measure anti body response in treponemal infection can be divided into two types: • A: Test to measure antibodies against non specific treponemal antigen. • B:Test to measure antibody against antigens specific for pathogenic treponemes.

  41. A-Non treponemal antigen test- • Non specific test: this test use the lipoidal or cardiolipin antigen. they are commonly used test. • VDRL or RPR • Primary syphilis - 70% • Secondary syphilis - 100% • Positive VDRL revert to negative after treatment

  42. B.Specific treponemal test • 1.FTAbS(flourescent treponemal antibody absorbtion test)the serum is first absorb in the suspension of non pathogenic treponemes which removes non specific cross reactive anti bodies that may be directed against commensal spirochaetes. • Primary syphilis 80% • Secondary syphilis 100% • Late syphilis 95%

  43. TPHA (MHATP)- Antigen is coated on the surface of red cells and specific antibody in test sera causes heamagglutination. • ELISA ,Blotting etc. • 3. PCR