STIs Flashcards
General principles of STIs?
Human to human transmission most of the time
immunity is rare in STIs, reinfection is common and vaccine development has been difficult
co-infections e.g. chlamydia and gonorrhea are common
What is included in a standard STI screen?
NAAT swab for chlamydia and gonorrhoea
blood test for HIV and syphilis
Describe normal vaginal flora?
Lactobacillus species predominate and are protective e.g. L crispatus and L jensenii
acid pH is normal 4-4.5
other organisms that may be present include group B beta haemolytic strep (only important in pregnancy), candida (in small numbers), strep viridans group
Is candida infection classified as an STI?
no
Most candida infections are?
candida albicans
Candida is a type of?
fungal infection
Predisposing factors to candida infection?
recent antibiotic therapy, high oestrogen levels, poorly controlled diabetes, immunocompromised patients
Symptoms of candida infection?
main symptom= vulval itching
other symptoms include increased thick, white vaginal discharge, vulval burning, external dysuria and superficial dyspareunia
What may be seen on exam of someone with candida?
white, curly adherent plaques on the vaginal wall
Diagnosis of candida?
often clinical but can do high vaginal swab for culture
Describe treatment of candida?
treatment is with azoles, topical clotrimazole pessary or cream (available OTC) or oral fluconazole
note that non albicans candida are more likely to be azole resistant
note that topical treatments can interfere with latex in condoms or diaphragms so may need to use other form of contraception for small amount of time
Gonorrhoea is more common in __1___ vs chlamydia more common in ___2__
1) men
2) women
Describe the bacteria that causes gonorrhoea?
gram negative intracellular diplococcus which infects the urethra, endocervix, rectum and pharynx
Gonorrhoea is a ____ organism so doesn’t survive well when not in ideal growth conditions
fastidious
Coinfection with what two STIs is common?
chlamydia and gonorrhoea
Symptoms of gonorrhoea in men and women?
In women GC can cause increased vaginal discharge, dysuria, postcoital or intermenstrual bleeding and lower abdo pain
In men GC can cause anterior urethritis with mucopurulent or purulent urethral discharge and dysuria
Tests for gonorrhoea?
NAATs (nucleic acid amplification tests) are test of choice as has better sensitivity that culture however as GC antimicrobial resistance is high culture on selective media should be performed prior to any treatment being given
in men FVU or urethral swabs and in women VVS or endocervical
MSM may need pharyngeal or rectal
Incubation of gonorrhoea?
incubation of urethral infection in males is usually 2-5 days and in females 2-14 days
males are more likely to pass it on to a female than a female to a male
Treatment of gonorrhoea?
must refer to SRH to test for sensitivities as there are high rates of antibiotic resistance
first line is usually ceftriaxone and may give azithromycin on top of this but need to do selective culture due to high rates of resistance
What is the commonest bacterial STI in the UK?
chlamydia
Where can chlamydia infect?
the urethra, the endocervix, the rectum, pharynx and conjunctiva
Describe asymptomatic individuals in chlamydia?
up to 80% women and 50% men with chlamydia may be asymptomatic
Incubation of chlamydia?
thought to be 7-21 days
Does gram staining work with chlamydia?
no as it doesn’t have a cell wall
Describe chlamydia serovars?
Serovars D-K cause genital infection, A-C eye infection and L1-L3 lymphogranuloma venereum
Symptoms of chlamydia in women and men?
In women usually infects the endocervix but can infect the urethra. Symptoms include increased vaginal discharge, dysuria, post coital or intermenstrual bleeding and lower abdo pain. Exam of cervix may reveal mucopurulent cervicitis or contact bleeding
in men it can cause urethritis with milky discharge and dysuria
Complication of chlamydia? Who does it particularly affect?
HLA B27 individuals
reiters syndrome or reactive arthritis
Tests for chlamydia?
NAATs
get sample in men FVU or urethral swabs and women VVS or endocervical swabs