SEXUALLY TRANSMITTED DISEASES (STDs)

1. SEXUALLY TRANSMITTED DISEASES (STDs) Dr. Sudheer Kher Prof & Head Dept of Microbiology, Gulf Medical College, Ajman, UAE.

2. Important Features • Transmitted by sexual intercourse. • Generally caused by very delicate organisms which do not survive in environment for a long time. • Direct contact between mucosal surfaces essential for transmission. • Generally produce genital lesions but may also cause severe systemic disease.

3. Changing incidence & pattern of STDs • High incidence in first world war. Cure was not available. • High incidence in second world war but cure was available. • High incidence in 1960-1985 due to emergence of drug resistance. • Pattern change from gonorrhea to syphilis to Chlamydia to HIV.

4. Sexually Transmitted Diseases

5. Sexually Transmitted Diseases

6. Sexually Transmitted Diseases

7. Sexually Transmitted Diseases * Not always sexually transmitted

8. Sexually Transmitted Diseases Not always sexually transmitted

9. Gonorrhea • Clin Features – • Purulent urethral or vaginal discharge of acute onset. • Dysuria & frequency in males • Asymptomatic in females • May involve rectum or oropharynx (usually asymptomatic) • Diagnosis – Specimens – Urethral, cervial, rectal, or throat smears & swabs. Plate directly or send to lab in transport medium (Amies’) Direct Gram Film –Typical intracellular GNC in males.

10. Gonorrhea • Isolation – • Culture – Gonococcal selective media (Thayer-Martin) • Observe – • Typical translucent colonies turning purple with oxidase reagent • Identify –Rapid carbohydrate utilization test for enzymes; Coagglutination with monoclonal antibody in a test kit • Rapid diagnostic techniques –Direct immunofluorescence, ELISA, DNA probe. • Antibiotic sensitivity testing –A must since resistance is increasing to many antibiotics particularly to Penicillin.

11. Chancroid (soft sore) • Common in developing countries, strong association with HIV infection. • Clinical features – Papule on genital area, erodes, forms painful, non-indurated ulcer with ragged edges & yellow exudate at the base. Associated often with painful enlargement of local lymph nodes. • Diagnosis – • Direct Gram film: Slender GNB arranged en masse giving appearance of ‘shoals of fish’. • Culture: 25% Rabbit blood agar. Selective media with growth factor X • Molecular: PCR, Highly sensitive

12. Non-specific urethritis or cervicitis • 50% due to Chlamydia & 50% due to Mycoplasma • Clin Features – • Males: Acute purulent urethral discharge with dysuria and urethral discomfort. Pus cells present in first 10-15 ml of voided urine. Complications: Epididymitis, prostatitis, proctotitis, Reiter’s syndrome (urethritis +arthritis +conjunctivitis). • Women: Mostly asymptomatic Complications: Pelvic Inflammatory Disease, Salpingitis, Infertility • Diagnosis –Smear & swabs examined for antigen by ELISA /Immunofluorescence / DNA probe or by PCR • Isolation rarely done. • Speciemens – urethral, cervical smears and swabs. Tiisue culture can be employed. Intracytoplasmic inclusions can be seen by Immunofluorescence.

13. Lymphogranuloma venereum • Endemic in Asia, Africa & South America. • Clin Features – Painless ulcer on the penis followed by painful enlargement of LN in groin. Suppuration follows leading to sinuses • Diagnosis – Serology by CFT or microimmunofluorescence

14. Trichomoniasis • Clin Features – Common disease of women. Frothy, offenesive greenish-yellow discharge • Diagnosis – Bedside examination of discharge showing motile parasite. • Culture may not be required in most.

15. Thrush (Candidiasis) • Clin Features – • White membranous patches with itching and irritation. Discharge could be white thick or thin watery • Diagnosis – Usually clinical • Swab can be taken. Gram stain shows Gram positive yeast cells with budding pseudohyphae. Culture – Sabaraud’s medium.

16. Syphilis • Clinical Features – • Primary stage • Secondary stage • Tertiary stage • Latent syphilis • Congenital • Latent • Early • Late

17. Syphilis • Diagnosis – • Direct Demonstration • DGI • Serology • Non-treponemal • VDRL • RPR • ART (automated reagin test) • Treponemal • TPHA • FTA – ABS • ELISA

18. Important principles in syphilis serology • Use either TPHA and VDRL combination, or ELISA for screening. • A different treponemal test from that used for sceening should be used to confirm a reactive result. • Other treponemal diseases such as yaws also give positive test in all serological tests for syphilis. • Always test a patient with positive syphilis test for HIV infection ( with consent ).

19. Bacterial vaginosis • Agents – Gardenerella vaginalis, Mycoplasma hominis, Bacteroides, various other anaerobes. • Features – • Thin watery discharge • Complications in pregnancy • Chorioamnionitis • Premature rupture of membranes • Preterm delivery

20. Bacterial vaginosis • Diagnosis – • Thin watery discharge • Vaginal fluid pH of ≥ 4.5 • Presence of fishy or amine odour intensified by addition of KOH – The amine or whiff test • Demonstration of “clue cells” ie demonstration of squamous epithelial cells with many Gram variable adherent bacilli in wet or stained films. Few polymorphs present.