Microbiology Flashcards
What is bacterial vaginosis?
altered vaginal flora - pH becomes alkaline
Why does the vaginal pH change in bacterial vaginosis?
normal vaginal flora (lactobacillus - produces lactic acid) replaced with Gardnerella vaginalis and other anaerobic bacteria
How does bacterial vaginosis present?
fishy discharge
What can bacteria vaginosis increase the risk of?
preterm labour
intra amniotic infection in preg
susceptibility to HIV
2nd trimester miscarriage
How is bacterial vaginosis diagnosed?
mixed with 10% potassium hydroxide on a slide - whiff of ammonia
wet mount microscopy - clue cells (epithelial cells coated with coccobacilli)
What is the treatment of bacterial vaginosis?
metronidazole 7 days
What causes thrush?
candida albicans
What are risk factors for developing thrush?
pregnancy
diabetes
immunodeficiency
antibiotics
How does thrush present?
red, fissured, sore vulva and vaina
cottage cheese discharge
itch
How is thrush diagnosed?
clinical diagnosis
HVS, microscopy and culture
How is thrush treated?
topical - clotrimazole
oral - fluconazole
What is the most common bacterial STI in the UK?
chlamydia
what causes chlamydia?
Chlamydia trachomatis
Where does chlamydia infect?
urethra rectum throat eyes endocervix
Why does chlamydia stain with gram?
no peptidoglycan in cell wall
What are the 3 serological groupings of chlamydia?
A-C: trachoma (eye) - not an STI
D-K: genital infections
L1-L3: lymphogranuloma venereum (rectal pain, discharge, bleeding, MSM)
What is the presentation of chlamydia in females?
usually asymptomatic
mucopurulent cervicitis
lower abdo pain
postcoital/intermenstrual bleeding, dyspareunia
What is the presentation of chlamydia in males?
asymptomatic dysuria urethritis proctitis (LGV) urethral discharge
What are the complication of chlamydia infection?
reactive arthritis PID tubal damage chronic pelvic pain transmission to neonate - pneumonia, conjunctivitis Fitz-Hugh-Curtis syndrome
How is chlamydia diagnosed?
males: first void urine sample (add rectal swab if receptive anal sex)
females: HVS
for NAATs/ PCR
What is the treatment of chlamydia?
aczithromycin - 1g oral dose (uncomplicated)
What causes gonorrhoea?
Neisseria gonorrhoea
gram negative diplococcus
Where can gonorrhoea infect?
urethra rectum eyes throat endocervix
How does gonorrhoea present?
males: urethral discharge, dysuria, ?asymptomatic, rectal and pharyngeal symptoms
females: asymptomatic, dysuria, pelvic pain, altered vaginal discharge
How is gonorrhoea diagnosed?
same as chlamydia
men: first void urine sample + rectal swab/pharyngeal swab
women: HVS
NAAT/PCR
How is gonorrhoea treated?
IM ceftriaxone
oral azithromycin
What organism causes syphilis?
Treponema pallidum
spirochaete
Does Treponema pallidum stain with gram?
no
What is the primary stage of syphilis?
chancre (painless ulcer, heals without treatment)
What is the secondary stage of syphilis?
flu like symptoms
generalised rash
snail track mouth ulcers
What is the latent stage of syphilis?
early latent stage: no symptoms
late latent stage: near and cardiac complications
What is the treatment of syphilis?
penicillin benzathine
How is syphilis diagnosed?
PCR and serological tests
dark ground microscopy
What is trochomonas vaginalis?
single celled protozoal parasite
sexually transmitted
How does trichomonas vaginalis present?
thin, bubbly, fish smelling discharge
How is trichomonas vaginalis diagnosed?
HVS for microscopy
How is trichomonas vaginalis treated?
oral metronidazole
How are pubic lice treated?
malathion lotion
What type of herpes simplex is sexually transmitted?
type 2 (type 1 - coldsores)
How does herpes simplex present?
very painful blisters
dysuria
discharge
How is HSV diagnosed?
swab of deroofed blister for PCR
How is HSV treated?
analgesia acyclovir (shortens symptoms and infectivity)
What are the high risk HPVs?
16 and 18 (CIN)