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Review from last lecture

Review from last lecture. Skin Infections : Contrasting Staph aureus with Strep pyogenes Folliculitis, boils and carbuncles Rocky mountain spotted fever ( R. rickettsii ) Lyme disease ( B. burgdorferi ) Anthrax ( Bacillus anthracis ) Bacterial infections of Wounds: Tetanus ( C. tetani )

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Review from last lecture

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  1. Review from last lecture • Skin Infections: • Contrasting Staph aureus with Strep pyogenes • Folliculitis, boils and carbuncles • Rocky mountain spotted fever (R. rickettsii) • Lyme disease (B. burgdorferi) • Anthrax (Bacillus anthracis) • Bacterial infections of Wounds: • Tetanus (C. tetani) • Gangrene (C. perfringens) • Burn infections (P. auerginosa) • Actinomycosis (A. israelii)

  2. Sexually-transmitted Diseases Denise Kirschner,PhD Dept of Micro/Immuno MICRO 532 Nov 29, 2001

  3. Outline • Epidemiological principles of STDs • UTI/Bladder infections • Infections of mucosal surfaces • Neisseria gonorrhea and Chlamydia trachomatis • Ulcerative Infections • Syphilis (T. pallidium) and Chancroid (H. ducreyi)

  4. General uro-genital tract information • More female infections that males • Urine is sterile • Above bladder entrance-sterile, below lots of IM: Lactobacillus, Staphylococcus, Cornybacterium, Haemophilus, Streptococcus, Bacteriodes • Urinary tract infections (UTI): • More than 100,000 bacteria/ml indicated • Bladder infection • Catherization is the major cause of infection (usually IM) • Intercourse (for women)

  5. Sexually-transmitted Diseases Mucosal infections Proliferative infections • papillomavirus • gonorrhea • chlamydia Systemic infections • HIV Ulcerative infections • hepatitis B • herpes simplex • syphilis • chancroid • LGV

  6. Epidemiologic Principles of STDs

  7. Occurrence of STDs in the U.S. Disease Incidence Prevalence -- Chlamydia 4,000,000 -- Gonorrhea 1,400,000 Papillomavirus 800,000 45,000,000 Herpes simplex 300,000 30,000,000 Syphilis (primary) 50,000 (all stages) 100,000 100,000 HIV 70,000 1,500,000 Chancroid ~4,000 ?

  8. Trends in common STDs 500 400 chlamydia gonorrhea syphilis 300 chancroid 200 60 40 100 20 0 1950 1960 1970 1980 1990 1995 1980 1990 1995 Year Note: 60% of all N. gonorrhea infection are ages 15-24

  9. Determinants of STD Morbidity • Rate of transmission • Sexual behavior (rate of new partner acquisition) • Duration of infectivity

  10. Factors That Affect the Transmission of STDs: • Age • Gender • Genetic susceptibility • Sexual practices • Contraceptive and "hygienic" practices • Circumcision

  11. Determinants of the Duration of Infectivity in STDs • Etiologic agent • tendency to asymptomatic carriage • antimicrobial resistance • Access and utilization of the health care system • Compliance with therapy • Contact tracing

  12. Theoretical Structure of an STD Core Group

  13. PPNG in Colorado Springs, Dec. 1989 - Dec. 1991 - not gang-related - gang-related C A S E S D J F M A M J J A S O N D J F M A M J J A S O N D

  14. PPNG Outbreak, Colorado Spgs., 1989-91 • 56 cases in a 2-year period • Traced to a network of 578 persons • 410 (218 males and 192 females) were affiliated with a street gang that moved to the area in May 1988. • Mean age: females (19.7 yrs); males (21.5 yrs) • Prominent behaviors among females: multiple partners, heavy crack use, drugs for sex

  15. CO-INFECTIONS

  16. Relevance of STD Co-infections • May identify a core group member • i.e., a "sentinel event" • STDs increase transmission of HIV • ulcerative and mucosal infections only • Effect of HIV on expression of STDs • accelerates HPV-associated tumors • facilitates spread of gonococcus • alters the natural course of syphilis • Presumptive therapy • 80-90% of college men with 1 STD have others (50% with Chlamydia)

  17. Infections of mucosal surfaces

  18. + + Infections caused by gonococci and chlamydiae • urethritis • cervicitis • epididymitis • proctitis • pharyngitis • eye infection + >> >

  19. Epidemiologic characteristics of chlamydial and gonococcal infections GONOCOCCUS CHLAMYDIA PATIENT AGE SEXUAL HISTORY ASX INFECTION (male) ASX INFECTION (female) teenagers > young adults usually acquired from a recent contact ~ 5% of infected males ( higher in some areas) 50 - 80% of infected females teenagers > young adults may have been acquired in the remote past ~ 50% of infected sexual partners ~ 50% of infected sexual partners ASX=asymptomatic

  20. Microbiology of gonorrhea • Strict human pathogen • Gram-negative diplococcus • Adherent- pilus (antigenic variation) • IgA protease (cleaves IgA) • Oxidase-positive • Fastidious growth • Modified Thayer-Martin media (VCN)

  21. Virulence determinants of Neisseria gonorrhoeae • pilus colonization factor--> antigenic variation • opa proteins-------------------> phase variation • lipooligosaccharide--------->antigenic variation • IgA1 protease • transferrin/lactoferrin binding proteins • intracellular environment?

  22. Treatment of gonococcal infections • PPNG • Tetracycline resistance • Quinolone resistance Single-dose treatment options for uncomplicated disease: • 1944 10^5 units of penicillin • 1970 10^7 units • Resistance (R plasmids) • PPNG strain

  23. Microbiology of Chlamydia trachomatis • Obligate intracellular bacteria • Not G+/G- (lacks part of LPS) • Complex, 2-stage life cycle • Elementary body (spore like) • Reticulated body (vegetative like) • Treatment: antibiotics: tetracyclines (not penicillin-why?)

  24. Chlamydial infections • urethritis (NGU) • epididymitis • proctitis • mucopurulent cervicitis • pelvic inflammatory disease • trachoma (serotypes A-C) • LGV (L1, L2, L3)

  25. 50-60% of women with infertility have serologic evidence of chlamydia or gonococcus, but no history of symptoms!

  26. Ulcerative infections

  27. Frequency of genital ulcer infections HSV>>syphilis>>chancroid

  28. Distinguishing features of genital ulcers • anatomical location • multiplicity • pain • induration

  29. Microbiology of syphilis • Treponema pallidum • spirochete -- labile spiral bacterium with axial filaments • man is the only recognized host • non-cultivable • Gram-negative like

  30. T. pallidum darkfield examination

  31. % reactive cases iary ge

  32. Manifestations of 1° Syphilis • Chancre (may be unnoticed) • painless, but tender • indurated • highly contagious • rapid dissemination • motility of the organism? • Congenital • MANIFESTATIONS OF SECONDARY SYPHILIS • Rash • Lesions • mucous patches • Fever

  33. Natural history of secondary syphilis spontaneous resolution 1/3 Secondary infection 1/3 infected without clinical disease 1/3 tertiary syphilis: Neurosyphilis DTH Organisms rare

  34. Syphilis- principles of treatment • T. pallidum is exquisitely sensitive to penicillin • Dosing and penicillin formulation used depends on the stage of the disease

  35. Microbiology of chancroid • Haemophilus ducreyi • Gram-negative coccobacilli • fastidious and labile • Diagnosis is usually clinical, by exclusion of other agents of genital ulcers

  36. Epidemiology and treatment of chancroid • CDC reported a 10-fold increase in incidence from 1978 - 1987 • 10% of patients are co-infected with either HSV or T. pallidum • Males >> females • Occurs in sustained, urban outbreaks • Associated with female commercial sex workers and “sex-for-drugs” trade • TREATMENT: sensitive to ceftriaxone or azithromycin in single dose

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