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Genital Tract Infections

Genital Tract Infections. MLAB 2434 – Microbiology Keri Brophy-Martinez. Definitions. STI = Sexually Transmitted Infection STD = Sexually Transmitted Disease VD = Venereal Disease After Venus, goddess of love. Modes of Transmission. Intimate person-person sexual contact

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Genital Tract Infections

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  1. Genital Tract Infections MLAB 2434 – Microbiology Keri Brophy-Martinez

  2. Definitions • STI = Sexually Transmitted Infection • STD = Sexually Transmitted Disease • VD = Venereal Disease • After Venus, goddess of love

  3. Modes of Transmission • Intimate person-person sexual contact • Vaginal intercourse • Oral sex • Anal sex • Mother to child • Pregnancy • Childbirth • Blood products/ tissue transplant

  4. Sexually Transmitted Infections • Genital Chlamydiosis • Chlamydia trachomatis • Obligate intracellular bacterium • Most common bacterial STD • Symptoms • Male: urethritis, discharge • Female: Usually asymptomatic; can progress to PID

  5. Chlamydia trachomatis • Lab Diagnosis • Not culturable • Identified by nucleic acid probes

  6. Sexually Transmitted Infections • Neisseria gonorrhoeae • Infects columnar epithelial cells of the GU tract • Incubation period 2-7 days • Can spread in blood, producing rash on extremities and arthritis in joints

  7. Neisseria gonorrhoeae • Symptoms • Male: urethral inflammation with dysuria, pyuria, urethral discharge • Female: asymptomatic; can lead to PID • Treatment • Cephalosporin antibiotic class • Cefixime or ceftriaxone with doxycycline

  8. Neisseria gonorrhoeae • Laboratory Diagnosis • Typical GN dc, kidney- bean shape • Gram stain significant in males, not in females( due to other GN normal flora) • Identify via CTA sugars or other rapid kits • Market using DNA probes instead of culture

  9. Sexually Transmitted Infections (cont’d) • Ulcerative STI’s • Syphilis – Treponema pallidum • Incubation period of 1-90 days • Chancre development at site of inoculation, full-body rash, potential to affect the CNS • Can not be cultured; DFA or serology testing (RPR) used

  10. Sexually Transmitted Infections (cont’d) • Chancroid – Haemophilus ducreyi • Seen in underdeveloped countries • Incubation period 4-7 days after exposure • Erythematous papule develops into a pustule which ruptures to form an ulcer. Ulcer usually found on external genitalia • Lab diagnosis • Direct smear (school of fish) and culture of ulcer • Oxidase positive; catalase negative

  11. Sexually Transmitted Infections (cont’d) • Genital Herpes- Herpes Simplex Virus • HSV-1: fever blisters/ cold sores • HSV-2: genital herpes • Virus is shed in the absence of symptoms • Transmitted by sexual contact with secretions from infected sites • Incubation period 1-26 days after exposure • Lab diagnosis • Viral isolation-cheap • Molecular testing- improved sensitivity & TAT

  12. Sexually Transmitted Infections (cont’d) • Bacterial vaginitis • Signs • Discharge • Vaginal itching • Odor • STD’s • Bacterial vaginosis • Trichomoniasis

  13. Bacterial vaginosis • Loss of normal vaginal flora • Mobiluncus, Mycoplasma hominis, and Gardnerella vaginalis take over • pH increases causing a fish-like odor • Bedside diagnosis • pH- greater than 4.5 • Whiff test-addition of KOH, smell for a fishy odor

  14. Bacterial Vaginosis • Lab diagnosis • Wet Prep • Clue cells: exfoliated vaginal epithelial cells covered with GVR and curved GNR’s • Lack of PMN’s • Presence of odor, pH >4.5 • Culture • No growth on BAP • V agar: shows as beta hemolytic colonies • Catalase/Oxidase negative

  15. Trichomonas vaginalis • Flagellated, urogential parasite • Symptoms • Itching • Burning • Yellow-green frothy discharge • Foul-smelling odor • Lab Diagnosis • Wet Prep • Observance of moving parasites in vaginal discharge

  16. Human Papilloma Virus (HPV) • Common STD in individuals under 24 • Skin- skin transmission • Asymptomatic • Self-limiting • Associated with genital warts and cervical cell dysplasias and cancers

  17. Human Immunodeficiency Virus (HIV) • Systemic illness • Transmission via sexual contact, exposure to blood or body fluids • Virus attacks the CD4 helper T-cells • Increased potential for opportunistic pathogens • Symptoms include: • fever, malaise, lymphadenopathy, skin rash • Lab Diagnosis • HIV-1 antibody test- screen • Western blot/immunofluorescence- confirmatory

  18. Genital Bacterial Cultures: Specimen Collection, Transport and Handling • Specimen types • Urethral discharge • Cervical/ vaginal • Throat • Anus • Specimen collection, transport and handling • Cotton, rayon or dacron swabs • Isolation of gonococci • Place in modified Stuart’s or Amie’s (with charcoal) • prevents drying • Culture within 6 hours of collection • Viral culture • Place swab in viral transport media.

  19. Genital Cultures • Direct Examination • Gram stain • Performed on male urethral discharge • Examine for bacteria (intra & extra-cellular), PMN’s and other cells • Wet mount • Performed on vaginal discharge • Examine for clue cells, yeast, Trichomonas vaginalis • Examine for PMN’s

  20. Genital Bacterial Cultures:Culture Set-Up • Examples of media to inoculate • BAP • MAC • Chocolate • CNA • V- agar • Thayer-martin, Modified Thayer-Martin, GC-Lect • Lim broth • Incubate media • Temperature: 35OC • Atmosphere: CO2 • Time: 18-24 hours

  21. Genital Bacterial Cultures:Culture Interpretation • Quantitate and identify all potential pathogens • Preliminary report sent out at 24 hours • Hold all plates 72 hours

  22. Genital Tract: Pathogens • Neisseriagonorrhoeae • Hemophilusducreyi • Gardnerellavaginalis • Trichomonasvaginalis • Beta-hemolytic Streptococci Groups A and B • Listeriaspecies • Staphylococcus aureus • In predominant numbers • Candida/yeast species • In predominant numbers • Gram negative rods • Accompanied by an absence of normal flora

  23. Genital Tract:Normal Flora • Lactobacillus sp. • Coagulase negative Staphylococcus species • Diptheroids • Anaerobic cocci and gram negative rods • Enterococcus species

  24. References • Hook, E. W. (2012, July). A new look at genital herpes: the critical role of the laboratory in diagnosis and management. Medical Laboratory Observer, 44(7), 8-12. • http://www.atsu.edu/faculty/chamberlain/golden2000/case5.htm • http://tiny.cc/kcpyhw • Kiser, K. M., Payne, W. C., & Taff, T. A. (2011). Clinical Laboratory Microbiology: A Practical Approach . Upper Saddle River, NJ: Pearson Education. • Mahon, C. R., Lehman, D. C., & Manuselis, G. (2011). Textbook of Diagnostic Microbiology (4th ed.). Maryland Heights, MO: Saunders.

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