STIs Flashcards
Pregnancy treatment of C4
Amoxicillin, erithromycin, azithromycin
% of asymp CT
50% men and 70% women
What is CT bacteria
Obligate intracellular human parasite
Life cycle length of CT
48-72 hours
How does CT enter a cell
Endocytosis
CT life cycle
- Infectious elementary body attaches via endocytosis
- Differentiates into larger replicating bodies
- Inclusion membrane formed
- EBs form in inclusion membrane
- Cells lyase and release CT
Test of choice for CT
NAAT
What temp.for.NAAT storage
Room temp
CT NAAT turn around
2-3 days
Are NAATs approved for extra-genital sampling
No.
Does appear to work well for it however.
NAAT limitation
- DNA contamination
- Inhibition of assay
- Detection of non viable organism
Positive predictive value of CT Naat
> 95%
Where is new variant CT most common
Sweden
Most at risk group of LGV
MSM (and HIV)
CT TOC time?
5 weeks
(6 weeks if azithromycin)
Why must TV micro be done immediately
20% lose motility in 10 minutes
What TV test cannot be used for men
Direct antigen POC test
Most successful chance of TV culture
Direct innoculation to growth medium
Hallmark of trichomonads?
Characteristic tumbling motility
Best stain for TV?
Acridine orange
Sensitivity of wet microscopy for TV
45-60% in women
Lower in men
Highest sensitivity test for tv
NAAT (88-97%)
NAAT specifity for TV
98-99%
Male NAAT sensitivity TV
Urine 74%
Swab 95%
TV window period
10 days
Culture plate for thrush
Sabourauds medium
Direct microscopy signs of candida
Gram positive spores
Pseudohyphae
Steps to dry microcoscopy
- Fix with heat
- Stain with violet
- Aqueous iodine
- Decolourise with acetone
- Red counterstain
Sensitivity of thrush slide
Gram stain - 65%
Wet - 40-60%, specific
Accuracy of germ tube formation for candida albicans
> 95%
Rate of non-albicans in vvc cases
5-10%
Asymp Candida rates?
20% non pregnant
40% pregnant
Most common cause of recurrent thrush
Candida albicans
When is repeat testing for thrush indicated
After treatment of persistent non-albicans infection.
Cure is 2 neg cultures at least 7 days apart
How many of Amsels criteria to diagnose BV
3 of 4
Normal vaginal ph
4.5
Vaginal.ph in BV
Greater than 4.5
Factors that elevate vaginal PH
BV
TV
Sperm
Menses
What is used to perform.whiff test for BV
10% KOH
What is Zheil neelsen staining used for
TB and leprosy
What colour do gram stained bacteria go
Gram +ve purple
Gram -ve red/pink
What is the Ison-Hay grading for
Vaginal flora (grades 0-4)
Grade 3 is BV
What is Amsels criteria
- Thin homogeneous vaginal discharge
- Vaginal ph > 4.5
- Positive whiff test
- Clue cells on wet mount micro
Which HSV tends to affect only genitals
HSV 2
Recurrence of HSV 1
20-50% year 1, rapid decline after
Recurrence of HSV 2
70-90% have >1 recurrence
Average recurrence 4 a year
Slow decline in recurring, usually 3-5 years
25% increase in recurrence after yr 4
Frequency of asymp viral shedding in HSV 1
Infrequent
Frequency of asymp viral shedding in HSV 2
Frequent
Incubation period of herpes
2-14 days
Does HSV increase your risk of HIV infection
HSV 2 can increase infection and transmission
Is visible ulceration common in HSV proctitis
No
(HSV swab should always be done in MSM with proctitis)
Diagnostic gold standard for type specific HSV antibody
Western blot
What do HIV tests look for?
HIV antibodies and HIV antigens (p24 etc)
WP for 4th gen HIV serological test
18-45 days
Does someone who has had HIV seroconversion have to test +be for HIV
No, may test negative if seroconverts before 45 day window period
Does someone who has had HIV seroconversion have to test +ve for HIV
No, may test negative if seroconverts before 45 day window period
Window period of HIV POCT
90 days
Can you give a HIV positive result from one positive test
No, must be at least 2 positive results
Male to female GC transmission rate
50-90%
Female to male GC transmission rate
20% (60-80% after 4 exposures)
GC incubation in men
3-5 days