Microbio - STIs Flashcards
What pathogen causes Chlamydia?
Chlamydia trachomatis
What type of pathogen is Chlamydia?
obligate intracellular Gram –ve pathogen
(cannot be cultured on agar)
Chlamydia presentation
Asymptomatic (80%F, 50%M)
F: vaginal discharge, abnormal bleeding, abdo pain (-> PID)
M: urethral discharge, dysuria
What is chlamydia serotypes A, B, C?
Trachoma - infx of eyes -> can cause blindness
What is chlamydia serotypes D-K?
genital chlamydia, ophthalmia neonatorum
What is chlamydia serotypes L1, L2, L3?
lympho-granuloma venereum (LGV) -> lymphatic infx –> +++lymphadenopathy
*Chlamydia investigations
Genital swabs / urine sample –> NAAT (nucleic acid amplification tests)
As can’t culture on Agar
Chlamydia treatment
1) Doxycycline
2) Azithromycin (if preg)
Complications of chlamydia
- !PID -> infertility, ectopic pregnancy, chronic pelvic pain
- Epididymitis
- Reactive arthritis
- Adult conjunctivitis, ophthalmia neonatorum
*What pathogen causes Gonorrhoea?
Neisseria gonorrhoeae
(obligate intracellular Gram –ve diplococcus)
Gonorrhoea presentation
F: many asymptomatic / vaginal discharge, abnormal bleeding, pain
M: urethral discharge (copious)
Gonorrhoea investigations
swabs / urine sample -> culture / NAAT
Gonorrhoea treatment
IM ceftriaxone
or PO Cefixime + azithromycin
*What pathogen causes Syphilis?
Treponema pallidum
(obligate Gram –ve spirochaete - spiral shape)
Types of Syphilis (4)
- Primary
- Secondary
- Latent
- Tertiary
*Primary syphilis presentation
Painless solitary (indurated) genital ulcer (chancre) May persist 4-6wks
*Secondary syphilis presentation
Bacteraemia after 1-6 months-> fever, lymphadenopathy
Rash on palms and soles
Condyloma acuminate (genital warts)
Snail track ulcers
Latent syphilis presentation
Asymptomatic
Tertiary syphilis presentation
2-30yrs later -> 3 different syndromes:
- Gummatous: skin/bone/mucosal granulomas
- Cardiovascular: mimics any cardiac disease; aortic root dilatation
- Neurosyphilis: dementia, tabes dorsalis, Argyll-Robertson pupil (accomodates but doesn’t react to light)
Syphilis investigations
- Dark-ground microscopy from primary lesions -> visualise Treponemes
- Antibody tests (use both)
1. Non-Treponemal tests:
Detect antibodies against non-specific antigens
e.g. VDRL test, RPR test
False positives are common (need to confirm with treponemal test)
Titre falls in response to treatment -> can be used to monitor response
-
Treponemal tests:
Detect antibodies against specific antigens from T. pallidum
e.g. EIA, FTA, TPHA, TP-PA
More specific than non-treponemal
Remains positive for years (even after treatment)
Syphilis management
IM benzathine penicillin STAT
*What is genital warts cuased by?
HPV
*What can be found on wet slide microscopy?
- Candida
- BV
- Trichomoniasis
*Trichomonas mx
Metronidazole
Trichomonas findings
- pH>4.5
- Strawberry cervix
- Flagellated protozoa
PID Mx
Doxy + ceftriaxone + metronidazole
*HSV Ix
NAAT
*BV Mx
Metronidazole
*Ix for invasive candida albicans
Beta-D-Glucan