L 95-96 Syphilis, Gonorrhea, Chlamydia MisSTDs Flashcards
What is the causative agent of Syphilis?
Treponema pallidum
It is a g(-) spirochete that has axial filaments which give it its spiral shape
Don’t live long outside body
What are the hosts of Syphilis and how is it spread?
Humans only hosts
Spread through sexual contact
Intact skin is resistant, needs an abrasion or mucous membrane to invade
Only takes 4-8 spirochetes to get infected
How many stages are possible with syphilis?
Primary, Seconday, Tertiary, Latent, Congenital
Describe the primary stage of syphilis
After 2-4 weeks of sexual contact PAINLESS chancres will appear on any surface that was involved in the contact–genital, lips, anal region, etc.
No systemic manifestations
Untreated cases will spontaneously resolve in most cases
Describe secondary syphilis
2-10 weeks after the primary chancre heals
Sprichetemia is present along with other systemic manifestations–fever, sore throat, headache, LAD, rash, arthralgias, anorexia
Maculopapular rash can appear anywhere on the body, but especially on the palms and soles–rash is very contagious
Ocular manifestations are possible
Condylomas on the genitals
Describe Tertiary Syphilis
Shows up years later
Gummas: granulomatous lesions on the skin and anywhere in the body including bone
Tabes: degenerative atrophy of CNS
Treponemas are rare in tertiary lesions
Describe congenital Syphilis
Syphilis can cross the placenta and infect the fetus
Classic SSx are: hutchinson’s teeth, interstitial keratitis, 8th CN deafness, saddle nose deformity
Syphilis diagnostic tests
Dark Field Microscopy: visualize motile spirochetes
Blood Tests: VDRL and RPR used for screening and look for flocculation
Fluorescent antibody test: tagged antibodies light up when bound to target
Syphilis treatment
Penicillin G or Ceftriaxone (latter only requires one dose)
For penicillin allergy use: Doxycycline, Azithromycin
Causative agent of gonorrhea and its characteristics
Neisseria gonorrhoeae
G(-) diplococci, has LOS, no capsule, non-motile, may possess pili which are necessary for cell attachment and infection
Facultative intracellular, grows on chocolate agar
What are the similarities and differences between Neisseria gonorrhoeae and meningitides?
Both are g(-) diplococci
meningitides has a capsule and gonorrhoeae does not
Patient presents with a mucopurulent discharge from the urethra. What is the DDx?
Gonorrhea
Chlamydia
Trichomonas vaginalis
Patient is known to have decreased levels of complement and they develop a mucopurulent discharge from the urethra, bacteremia, and pustules on the hands and feet. What is the likely diagnosis?
Disseminated gonorrhea
Opsonization by complement and antibodies is important in the destruction of gonorrhea. Decreased levels of C5-9 are associated with disseminated gonorrhea.
Gonorrhea likes to live inside monocytes after being phagocytosed. How do they survive the lysosome and subsist in the cell?
They produce catalase which converts H2O2 into water and oxygen. This allows it to resist oxidative damage and death.
How does gonorrhea present in males and females?
Mucopurulent discharge in both sexes
Men can progress to epididymitis and become sterile
Women can progress to any form of PID
The bacteria can infect the eyes of adults from self-inoculation
Neonates can be infected by their mothers in the eyes and go blind without treatment
What is the greatest risk factor for gonorrhea?
Sexual promiscuity
A male presents with penile discharge and the following is visualized under microscope. How would you treat this disease?
There are g(-) diplococci inside a PMN. This is a sign of gonorrhea.
This is treated with Ceftriaxone
Why might a gram stain work for diagnosing gonorrhea in men but not women?
Gram staining in women is less diagnostic because they have a large number of g(-) bacteria that are part of their normal vaginal flora
What virulence factor helps Neisseria gonorrhea attach to cells?
Pili
Which of the bacterial STD’s discussed is g(-), spherical, has LPS, no peptidoglycan, obligate intracellular, has serotypes D-K?
This describes Chlamydia trachomatis
Explain the life cycle of chlamydia
Elementary body: hardy infective form
Reticulate body: fragile intracellular form
Intracellular inclusions: vacuole w/ elementary bodies
The elementary body will penetrate cells by phagocytosis. Inside vacuoles, reticulate bodies produce new elementary bodies that are released and spread.
What types of chlamydia cause NGU (non-gonococcal urethritis)?
Strains D-K
How will chlamydia present?
Clinically it resembles GC and has a mucopurulent discharge.
It is the most common cause of epididymitis in men and PID in women.
Alos causes inclusion conjunctivitis in neonates
Treatment for chlamydia
Doxycycline
Azithromycin
