6: Microbiology of genital tract infections Flashcards
Gonorrhoea produces a ___ discharge.
Chlamydia produces a ___ discharge.
gonorrhoea - purulent
chlamydia - watery
The normal vaginal pH is (acidic / basic).
acidic
Which commensal bacteria is most commonly found in the vagina?
Lactobacillus
Apart from Lactobacillus, what other organisms are found naturally found in the vagina?
Group B Strep
Candida
Strep viridans
Which fungal infection commonly affects the female genital tract?
Candida albicans
Non-albicans Candida infections are more common in ____ patients.
immunosuppressed
Poorly controlled ___ is a risk factor for Candida infection.
diabetes
What is the presentation of Candida infection?
White vaginal discharge
Itch
How is candida infection investigated?
Vaginal swab for culture
Which antifungal is used for Candida infection?
Clotrimazole
What causes bacterial vaginosis?
?Lack of balance
What is the presentation of bacterial vaginosis?
Intensely smelly, frothy vaginal discharge
In bacterial vaginalis, the normal vaginal bacteria are replaced with which bacteria?
Gardnerella vaginalis
and anaerobes
What happens to the vaginal pH in bacterial vaginosis?
Becomes alkaline
i.e the pH increases
Bacterial vaginosis is an imbalance of bacteria, not an infection.
Why is it treated regardless?
Risk of genital tract infection
Which antibiotic, effective against anaerobes, is effective for treating bacterial vaginosis?
Metronidazole
STIs tend to ___.
co-exist
so you test for all of them
What is the most common STI in the UK?
Chlamydia trachomatis
Chlamydia trachomatis can be split into subtypes depending on its ___.
serology
what it produces
How does Chlamydia appear on a Gram stain?
Doesn’t stain
Which serovars of chlamydia trachomatis cause genital tract infections?
D-K
The guidance for antibiotic treatment of chlamydia trachomatis has just changed.
What is the empirical treatment?
Doxycycline 100mg BD for 7 days
Before it became doxycycline 100mg, what was the antibiotic treatment for chlamydia?
Azithromycin 1g
What are the investigations for genital chlamydia and gonorrhoea in
a) males
b) females?
a) First pass urine sample
b) Vulvo-vaginal swab
What other investigations, apart from genital ones, exist for chlamydia and gonorrhoea?
Rectal swab
Throat swab
Eye swab
What is the appearance of gonorrhoea on a Gram stain?
Gram -ve intracellular diplococcus
What does neisseria gonorrhoeae look like on microscopy?
Gram negative diplococcus
“Two kidney beans facing one another”
What type of media is used to culture neisseria gonorrhoeae?
Selective media
kills competitors
The samples obtained from first pass urine samples or vulvovaginal swabs are sent for which type of testing?
Nucleic acid amplification tests (NAATs)
More sensitive for diagnosing chlamydia/gonorrhoea than culture
Which antibiotic is given for gonorrhoea infection?
Ceftriaxone
Neisseria gonorrhoea has recently become ___ in some places.
untreatable
resistant to all antibiotics
Treated gonorrhoea infection is subjected to a ___ ___ ___ before discharging the patient.
test of cure
What is lymphogranuloma venerum?
What is the causal organism?
Infection of the lymph nodes, usually presenting as prostatitis in MSM
Chlamydia trachomatis (serovars L1 - L3)
How is bacterial prostatitis treated empirically?
Ciprofloxacin
One month course
Which antibiotic is used to treat acute bacterial prostatitis?
Ciprofloxacin
Which organism causes syphilis?
Treponema pallidum
What is the appearance of Treponema pallidum on microscopy?
Spirochaete
Does Treponema pallidum appear on Gram film?
No
How is Treponema pallidum detected?
PCR
Can treponema pallidum be grown in culture?
No
PCR
What is the primary lesion of syphilis called?
Chancre
What does a chancre look like?
Ulcer
Are chancres painful?
Painless
What is the baseline blood test for suspected syphilis?
Syphilis IgM & IgG test
What antibiotic is used to treat syphilis?
Injectable, long-acting penicillin
i.e benzylpenicillin
Which virus can cause genital infection?
Herpes simplex 1 & 2
What structures does HSV infiltrate?
Nerves
What is the investigation for genital herpes?
Genital swab > PCR
What is the treatment for genital herpes?
Aciclovir
Analgesia
Trichomonas vaginalis is a protozoan parasite which causes vaginal discharge and irritation.
How is it investigated and managed?
Ix: High vaginal swab for MICROSCOPY
Rx: ORAL METRONIDAZOLE
What is the treatment for genital lice?
Malathion lotion
