Microbio: STIs Flashcards
What type of bacteria is chlamydia trachomatis?
obligate intracellular Gram –ve pathogen.
Cannot be cultured on agar
What are the symptoms of chalmydia trachomatis?
Asymptomatic (80% females, 50% males)
M: urethral discharge, dysuria
F: vaginal discharge, abnormal bleeding, abdo pain (-> PID)
How can chlamydia be classified?
Serovars A, B, C: trachoma (Eye infection)
Serovars D-K (MAIN): genital chlamydia, ophthalmia neonatorum (sticky eye in neonates)
Serovars L1, L2, L3: lympho-granuloma venereum (LGV) - tropical
How is chlamydia diagnosed?
Genital swab (F) / urine sample (M) –> NAAT (nucleic acid amplication tests)
This is done as it cant culture on agar
Mx of chlamydia?
Azithromycin 1g stat - increasing resistence
or
Doxycycline 100mg 7d
What are the complications of chlamydia infection?
PID -> infertility, ectopic pregnancy, chronic pelvic pain
Epididymitis
Reiter’s syndrome - reactive arthritis
Adult conjunctivitis, ophthalmia neonatorum
What type of bacteria is neisseria gonorrhoeae?
Obligate intracellular Gram –ve diplococcus
What are the main symptoms of gonorrhoea?
M: urethral discharge (MAIN - copious amounts)
F: vaginal discharge, abnormal bleeding, pain
How is gonorrhoea diagnosed?
Swabs / urine sample -> culture / NAAT (preferred)
How is gonorrhoea treated?
Ceftriaxone 250mg IM STAT
What organism causes syphilis infection? what type of organism is this?
Treponema pallidum which is a gram -ve spirochaete
What are the different types of syphillis infection?
Primary Syphilis
Secondary Syphilis
Latent Syphilis
Tertiary Syphilis
What are the features of second syphilis?
Primary goes systemic -> Bacteraemia after 1-6 months -> fever, lymphadenopathy
Rash on palms and soles (MAIN)
Condyloma acuminate (genital warts)
What are the features of latent syphilis?
Asymptomatic
What are the features of tertiary syphilis?
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
What is argyll-robertson pupil?
Argyll-Robertson pupil = accommodates but does not react
This is seen as a feature of tertiary syphilis (neurosyphilis)
What is Tabes dorsalis?
Tabes dorsalis = weakness, sensory ataxia, numbness
This is seen as a feature of tertiary syphilis (neurosyphilis)
How is syphilis diagnosed?
IF PRIMARY LEISONS PRESENT:
Dark-ground microscopy from primary lesions -> visualise Treponemes
IF AFTER PRIMARY:
Antibody tests: (need to do both)
-
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)
Why in patient presenting after primary leisons have disappeared do you need to do both antibody tests for syphilis?
Non-treponemal tests = detect ab against non-specific antigens however false positives are common
Treponemal tests = more specifc (only issue is can be positive for years after, even w treatment)
What is the mx of syphilis?
IM benzathine penicillin STAT
A 22yo female attends GUM clinic and is diagnosed with chlamydia. Which treatment is most appropriate?
a) Azithromycin 100mg BD 7d
b) Azithromycin 1g STAT
c) Doxycycline 100mg OD 3d
d) Doxycycline 1g STAT
e) Co-amoxiclav 625mg TDS 7d
b) Azithromycin 1g STAT
A man presents to GUM clinic with fever, widespread lymphadenopathy and a rash on his palms and soles. You suspect syphilis. Which clinical stage of syphilis does he have?
a) Primary syphilis
b) Secondary syphilis
c) Tertiary syphilis
d) Latent syphilis
e) Gummatous syphilis
b) Secondary syphilis
