Microbiology GU Tract Flashcards
all of the organisms are passed human-human, except one which has the potential to be sourced from an object - which ones?
trichomonas vaginalis - eg towels
what 3 things influence the susceptibility to infection>
- Concentration and phenotype of organism in genital tract
- Susceptibility of the sexual partner
- Resistance of the host – acquired, hereditary or innate
co infections are common with STIs - which 2 organisms commonly co infect
chlamydia and gonorrhoea
what is the standard group of organsisms screened for at STI clinic
chlamydia, gonorrhoea, HIV, syphilis and hepatitis B and C
what is the predominate clonozing bacteria in the healthy vagina
Lactobacilllus
how does Lactobacillus exert its anti bacterial action in the vagina
glycogen secreted from the stratified squamous epithelium of the vagina is metabolized to produce lactic acid and hydrogen peroxide which help tp suppress bacterial growth
HO has anti microbial properties
outline the type of epithelium found in the uterus, cervix and vagina
does candida colonisation always cause symtpoms
no, 30% of females are colonised with no symptoms
what things can predispose to candida infection
- recent ABx therapy
- high oestrogen levels - pregnancy, contraceptives
- poorly controlled diabetes
- IC
how does thrush rpesent
very itchy white vaginal discharge
what is it called when candida infects the head of the penis
candida balanitis
which group of patients is candida balnitis typically seen in
diabetics, other immunosuppressed too
how is thrush diagnosed
the diagnosis is clinical
if you want to do a culture can take a high vaginal swab
which type of candida causes most cases of thrush
candida albicans
management of thrush
topical clotrimazole (pessary/cream) or oral fluconazole
management of thrush in pregnancy
topical clotrimazole, oral fluconzole CI as it is associated with congenital abnormalities
do cases of thrush need partner notification
NO
general advice for avoiding thrush
avoid tight clothing and soap etc
BV
replacement of the normal vaginal flora with lots of anaerobes, aprticularly Gardnelle vaginalis
is BV sexually transmitted?
no, but it is more common in the sexually active
how does BV present
a homogenous, creamy discharge that may contain bubbles, and has a strong odour (‘fishy’)
BV whiff test
10% potassium hydroxide + BV discharge = amine like fishy odour
= positive whiff test
what is seen on microscopy of BV
vaginal epithelial cells with coccobacili (anaerobes) stuck to them = clue cells
leucocytes (WBCs) are not normally seen on microscopy of BV, if they are what does this suggest
presence of intercurrnet infection
BV and pregnancy
it is assocated with premature births and adverse outcomes, routine screening not offered - no benefit shown
management of BV - drug and course length
metronidazole for 7 days
relapse rate of BV high?
30%
what is the most common STI in the UK
chlamydia
what abnormal features does the chlamydia bacteria have
- biphasic life cycle so only reproduces inside the host cell
- has no peptidoglycan in the cell wall so doesnt stain with Gram stain = PCR
outline what the 3 serological groupings of chlamydia are respondible for: A-C, D-K L1-L3
- A-C = trachoma eye infection
- D-K = genital infection
- L1-3 = lymphogranuloma verenum
what is lymphogranuloma vereneum
an infection of the lymphatic system that can manifest primarily as inflammation and ulcers in genitals
is it only really seen in MSM with prococolitis - rectal pain, discharge and bleeding
clinical features of chlamydia
asymptomatic in many
inflammation, discharge, pain, dysuria
management of chlamydia
doxycycline 100mg bd for 7 days
why have the recent guidelines changed from azithromycin to doxycycline for chlamydia
to reduce the risk of resistnace to treatment - rates were increasing
management of LV (chlamydia)
doxycycline for 3 weeks
what is the major complication of chlamydia
pelvic inflammatory disease
chalnydia and pregnancy
there are assoicated risks and risk of transmission to neonate, but screening is not routinely offered
warn women <25 that they are in the at risk age group and direct them towards screening
what presentation would make you suspected PID
lower pelvic pain, raised temperature and pulse, peritonism, cervical excitation and raised WCC
N Gonorrhoeae - gram stain, intra/extra cellular, type
gram negative intracellular diplococci - 2 kidneys beans facing each other
what is the significance of gonorrhoea being a fastidious organism
it doesnt survive long in less than ideal growth conditions - falesely negative samples
is Gonorrhoeae more commonly asymptomatic in men or women
up to 50% females are asymptomatic, <10% males
how do males tend to present with Gonorrhoeae
urethral discharge in 80%
how do females tend to present with Gonorrhoeae
vaginal discharge in 40%, up to 50% asymptomatic
how do rectal and pharyngeal infections with Gonorrhoeae present
mostly asymptomatic
what are the significant complications of Gonorrhoeae
PID
epididymitis
prostastitis etc
abscess
which STI is the most common cause of PID
chlamydia
what are the long term risks of PID
infertility - inflammation of tubes creates scar tissue tha blocks the fallopian tubes
what is a major complication of PID in the liver
Fitz-Hugh-Curtis syndrome
liver capsule and diaphragm inflammation leads to the formation of adhesions
how does FHC present
with RUQ pain and pleuritic chest pain
note there may be no signs of PID
chlamydia and gonorrhoea frequently co-infect - they are tested for together
how long after infection can they be picked up on test
14 days
how do you test for chlamydia and gonorrhoea?
NAAT or PCR - combined in 1 test
why do you not use a culture for chlamydia and gonorrhoea?
chlamydia cannot be grown on normal culture
can do culture for gonorrhoea, see later
what samples are taken for chlamydia and gonorrhoea test for - males, females, rectal, throat and eye
males - first pass urine
females HVS/VVS taken by patient
rectal, throat or eye swabs
rectal adn throat gonorrhoeae is asymtpomatic - when would you take swabs for testing
if indicated in MSM
when would you use an endocervical swab for chlamydia and gonorrhoea
the clinician may do one if they were already performing eg a speculum examination
what 2 other tests can be done for gonorrhoea
microscopy and culture
what swabs can be used for culture of gonorrhoea
all but VVS/HVS - need endocervical
name one advantage and disadvantage of culture>NAATs for gonorrhoea diagnsois
- check for ABx sensitivites - this is useful as gonorrhoea has cases of resistance
- much more invasive - important if patient is asymptomatic
name 2 benefits of NAATS
- increased sensitivity
- much less invasive, can test VVS and male first pass urine sample
what is the main disadvantage of NAATs
- it detects the dead genetic material of chlamydia so you have to wait around 5 weeks to test for eradication of infection
- also deskilling and more expensive
is NAAT sensitive
it is slightly more sensitive than cultures
however, there is the possibility of a false-positive result
management of gonorrhoea, and problems with treatment
IM ceftriaxone - have to have in hospital
a test of cure must be done as there are lots of concerns around resistnace - super gonorrhoeae
how does prostatitis present
urinary symptoms and lower abdominal/back pain, tender prostaste on examination
what sample si taken for prostatitis
MSSU - not first pass
management of prostatitis
ciprofloxacin for 28 days, trimethoprime if there is a high risk of C diff
outline the 4 stages of syphilis
- painless ulcer = chancre, at inoculation site
- red hands and feet, mouth ulcers, flu like symptoms. at this stage there are lots of bacteria in the blood
latent stage
late stage - CV and neurological symotoms often years later
what are the ulcers like that are seen in the mouth with 2y syphilis
snail track
what test can be done to demonstrate the TP organism i syphillis
swab lesions etc and do PCR
what is the purpose of specific adn non specific tests for syphilis
the specific ones confirm the diagnosis, but stay as Ab levels decrease v slowly, they often remain postive for life
the non specific ones are used to tell how active the disease is and monitor treatment response
what are the 2 specific tests for syphilis
TPPA and TPHA
(TPHA is not actually specific??)
what test is used as a screening test, and why cant TPPA + TPHA be used
combined IgG and IgM ELISA
they cant be used because Ab take around 6 weeks to form
what are VDRL and RPR actuallly markers of
tissue inflammation
management of syphilis
IM penicillin, long acting
the injection is often painful, what pain relief can be given
lidocaine
what types of HSV most commonly cause mouth and genital symptoms
1 - mouth 2 - genital
how does the HSV virus behave in the body
initially, it replicates inside the epi/dermis. it then enters the nerve endings of the sensory nerves and can become latent and remain here for ever
periodically reactivates during times of stress/IC
the first clinical manifestations may actually be years after infection
how does genital herpes present
painful blistering and ulceration of the external genitalia
testing for genital herpes
unroof the vesicles and take a swab - PCR
management of genital herpes
oral acyclovir 400mg TDS
what ointment can be used for pain relief in genital herpes
topical lidocaine 5%
does treatment eradicate herpes?
i dont think so, it can fail in the IC population
think it just puts virus to rest
is a pregnant mother with genital herpes likely to pass it on to her baby?
unlikely (<1%)
there is the highestrisk of transmision if the mother acuiqred the infection late in pregnancy
what do genital warts look like and are they painful
tend not to be
cauliflower
management of genital warts
- some clear spontaenously, some with Tx and some persist (those with IC, diabetes etc)
- topical salicylic acid or podophyllum can be used
- cryotherapy and liquid nitrogen therapy - to freeze off wart
- imiquimod can be used (immune modifier)
can you get vaccinations against genital herpes?
there are 2 types of vaccine but these protect against cerivcal cancer (types 16 and 18)??
given to girls aged 11-13 and available to MSM <45 years old
how can trichomonas vaginalis be spread
human to human, but also from objects eg towels
what type of organism is trichomonas vaginalis
a parasite - protozoal
how does trichomonas vaginalis present
frothy, green/yellow discharge and musty smell
post coital bleeding
management of trichomonas vaginalis
metronidazole
what is seen on examination with trichomonas vaginalis infection
strawberry cervix - lots of small haemorrhagic areas
