bacterial sexually transmitted diseases in the tropics

STIS

1. Bacterial STDs. Brian S N MBChB DCM III GCHOES

2. Outline. Treponema pallidum (syphilis) Haemophilus Ducreyi ( Chancroid ) Chlamydia trachomatis (LGV and genital discharge) Neisseria Gonorrhoea. Klebsiella granulomatosis ( Donovanosis ).

3. Syphilis/ Lues . T.Pallidum is a delicate spiral bacterium that measures 6-20micrometre in length and 0.1-0.18 in width. Because of this narrow width, it is not visible by normal light microscopy and must be visualized by darkfield microscopy or by silver stains( ie warthin starry or modified Steiners ). The organism reproduces by transverse fission . Epidemiology studies show that chances are 1/3 of one getting syphilis on having sexual intercourse with an infected person. It is believed that the treponemes cannot penetrate intact epidermis or mucosa and that most infections occur in microscopic and macroscopic breaks in the skin . Syphilis is most commonly acquired as a STD but may also be acquired congenitally ( transplacental ) or rarely by blood transfusion . The organism is very fragile and easily killed by heat, cold, drying , disinfectants. Since the organism is very fragile, the possibility that an infection could be acquired from a toilet seat is statistically very remote.

4. Primary syphilis. 3-4weeks after infection Primary ulcer: 3-15mm, hard and initially painless. Sometimes instead the syphilitis lesion maybe papular or crusted and mimic a balanitis . Enlarged regional lymphnodes Spontaneous healing of primary chanre in 6weeks.

5. Diagnosis of Primary syphilis Darkfield microscopy. Specimen: exudates/fluid from primary chancre, lymphnode aspirate.

6. Secondary syphilis 1.5-2months after initial infection Condylomata lata . Syphilitis roseola Mucus patches (asymptomatic erosive patches on the mucus membranes of oral cavity or genitals). Palmoplantar syphilid Constitutional symptoms (fever, malaise, headache) Lymphadenopathy Hepatospleenomegaly Diffuse moth eaten alopecia

7. Secondary syphilis.

8. Secondary syphilis..

9. Diagnosis of secondary syphilis… Serological tests: Helpful in secondary and probably tertiary stages Specific: TPHA Nonspecific: RPR, VDRL

10. Advantages of nonspecific tests . These tests are positive in some cases of primary syphilis and are almost always positive in secondary syphilis The titre of these non specific antibodies decreases with effective treatment. The tests is inexpensive and easy to perform. Therefore are used as a method of screening the population for infection. NOTE: Results of non specific tests usually became negative after treatment and should be used to determine the response to treatment.

11. Disadvantages of nonspecific tests . False positive reactions occur in infections such as Leprosy, Hepatitis B and Infectious mononucleosis and in various autoimmune diseases. False negative reaction; This is a result of prozone phenomenon. Early in primary syphilis Late in tertiary syphilis

12. Specific serological tests . This tests involve the use of treponemol antigens. It is more specific than those described above. This include:- Immunofluorescence (FTA-ABS) assay Hemagglutination (TPHA, MHA-TP,TP-PA) assay Treponemol Enzyme linked immunosorbent assay (ELISA) HOW IT WORKS??? T. pllidum reacts in immunofluorescence(FTA-ABS) or hemagglutination (TPHA, MHA-TP) assays with specific treponemal antibodies in the patient’s serum.

13. Specific tests: disadvantages . These tests remaining positive for life after effective treatment. Can not be used to determine the response to treatment or reinfection. They are more expensive and more difficult to perform. They are not used as screening procedures.

14. Late/ tertiary syphilis 4-40years after the infection. Cardiovascular and neurological symptoms predominate Gummas . Nodular lesions which cause the skin to break down and form punched out necrotic ulcers. (painless). Skeletal system: periostitis , osteitis and osteomyelitis Eye lesions: iritis , choreoretinitis and may result in visual impairment Cardiovascular: asymptomatic aortitis , which lead to dilatation of ascending aorta and eventually to calcification.

15. Neurosyphilis Asymptomatic neurosyphilis : describes positive CSF serology without signs Meningovascular syphilis : causes subacute meningitis with cranial nerve palsies and papilloedema . A gumma as a localized expanding mass can cause epilepsy, raised intracranial pressure and focal signs eg hemiparesis

16. Neurosyphilis cont … Tabes Dorsalis : syndrome due to demyelination in the dorsal roots. Patients have; lightening pains in the legs, ataxia, neuropathic ( charcot joints), ptosis, optic atrophy, Argyl-robertson pupils General Paresis of the insane : there is madness n weakness, dementia, progressive cognitive decline, brisk reflexes, extensor plantars . Death occurs in 3 years of onset

17. Congenital syphilis Early congenital syphilis develops before age of two years. Typically child is underweight pale and shrunken Other features: Bullous lesions on palms and soles; with paronychia; snuffles- mucus patches producing a purulent or hemorrhagic discharge; maculopapular or pustular lesions, condylomata lata , infantile alopecia. Osteochondritis of the long bones may cause ‘ syphilitis pseudoparalysis ’ or later osteoperiostitis of the proximal phalanges may lead to syphilitis dactylitis

18. Prevention of congenital syphilis Treating primary and secondary syphilis and active case detection through contact tracing Follow up and treatment of VDRL positive blood donors Apart from the routine antenatal RPR screening women, high-risk women should be rescreened in the third trimester of pregnancy thus preventing reinfection in the later part of pregnancy

19. Chancroid Haemophilus ducreyi IP: 4-10 days A papule or pustule occurs, rapidly breaks down into multiple, large, soft and purulent ulcers. Men: coronal sulcus or penile shaft Women: labia Enlarged inguinal lymphnodes -Buboes

20. Chancroid lab diagnosis. Specimen: lymphnode aspirate, or discharge from chancre Procedure: Gram stain Results: chained tiny gram negative rods

21. Chancroid treatment. Ulcerated lesions should be kept clean. Fluctuant lymphnodes should be aspirated Ciprofloxacin 500mg bid for 3days or Azithromycin Ig stat. Then 500mg/d for 6days or Erythromycin 500mg qid for 14days

22. Urethral discharge.. Gonococcal … Non- gonococcal : Chlamydia trachomatis

23. CHLAMYDIA TRACHOMATIS. Causes non gonococcal urethritis. L1, L2, L3 serovariants cause lymphogranuoma venereum … Inguinal Buboes. Chlamydia are obligate intracellular bacteriae Cell wall similar to those of gram negative bacteria but lack muramic acid Can be grown in cell cultures treated with cycloheximide which inhibit host cell but not chlamydial protein synthesis

24. Laboratory diagnosis: chlamydia Specimen: Exudates Test : Giemsa stain Findings: Blue mauve stained mass consisting of closely packed reticulate bodies or less dense mass consisting of mauver -red staining elementary particles will be seen. Other tests: chlamydial antigens can also be detected by ELISA in exudates or urine. Chlamydia NAAT (nucleic acid amplification testing). Use first catch urine.

25. GONORHOEA Gonorrhoea is caused by infection with Neisseria gonorrhoeae . These organisms infect columnar epithelium in the lower Genital tract Rectum. Pharynx. Eyes. NOTE The incubation period in men with gonnococal urethritis is 2 – 10 days

26. Characteristics of Neisseria gonorrhoea . In Gram stain: they are Gram negative intracellular diplococci that resemble paired kidney beans. They contain endotoxin in their outer membrane. The growth is inhibited by toxic trace metals and fatty acids found in certain culture media, eg blood agar plates. They grow in chocolate agar containing blood heated to 80 degree Celsius, which inactivates the inhibitors. They are Oxidase –positive . They cause disease only in human.

27. Laboratory diagnosis. Laboratory diagnosis depends on: Gram stain Culture Serological test Specimens from mucosal sites:- Urethral discharge Vaginal/cervical discharge HVS Note:- For male: patient should not urinate for 2hours before the specimen is collected.

28. Culture: Medium used: Thayer-Martin medium (chocolate agar containing antibiotics , vancomycin , colistin , trimethroprin and nystatin ) INTERPRETATION Colony appearance :- They are tiny greyish colonies. Biochemical test:- They are oxidase + ve

29. Donovanosis Klebsiella granulomatis . IP; 3-6weeks. Initial lesion is a small, non painful papule, that breaks down to form large, raised beefy red ulcers that become painful when secondarily infected. Not accompanied by lymphadenopathy.

30. Donovanosis Diagnosis. Giemsa stain Treatment. Doxycycline 100mg bd for 14-21days or Azithromycin 1g day one, then 500mg/d for 14-21 days or Erythromycin 500mg x4/d for 21days