Microbiology of genital tract infections Flashcards
state the main group of normal vagina flora and what they produce?
-other organisms?
Lactobacillus, produce:
Lactic acid & hydrogen peroxide
these suppress growth of other bacteria
-Strep viridian’s
Group B beta haemolytic Strep
Candida Spp
what might normally be seen on a smear?
lactobacilli might be seen on epithelial cells
name the 3 non sexually transmitted genital tract infections
Candida infection
Bacterial vaginosis
Prostitis
candida infection
- predisposing factors? (4)
- indications for investigating candida?
- presentation?
- Dx?
- Treatment?
- appearance under microscope?
-recent antibiotic therapy
high oestrogen levels (preg) poorly controlled diabetes
immunocompromised patients
- ONLY if patient is SYMPTOMATIC
- intensely itchy white vaginal discharge
- Diagnosis is clinical, might take high vaginal swab for culture, likely C.albicans
-topical clotrimazole pessary/cream (available OTC)
Oral fluconazole
-see yeast with hyphae (budding)
Bacterial vaginosis
- causative organism?
- Predisposing factors?
- Symptoms?
- Dx?
- investigations?
- treatment?
- Gardnerella vaginalis/ Mobiluncus and other anaerobes
- dont really know :/ an increased Ph might mean an overgrowth of anaerobes
- thin, watery, fishy smelling vaginal discharge
- Clinical dx + raised vaginal Ph (Ph>4.5)
-high vaginal swab sent to laboratory and examined microscopically to look for the presence of CLUE CELLS, Hay-Ison scoring system estimates proportion of clue cells to to epithelial cells and lactobacilli
clue cells: stippled appearance full of gram neg anaerobes
-Metronidazole
give the 3 classifications of prostatitis
- Acute bacterial prostatitis
- chronic bacterial Prostatitis
- Chronic Prostatitis/Chronic Pelvic pain syndrome
Acute bacterial prostatitis
- presentation?
- cause?
- causative organisms?
- Dx?
- treatment?
- UTI symptoms + lower abdo/back/perineal/penile pain with tender prostate on examination
- rare complication of UTI in men
-same as UTI, e.coli & other coliforms, enterococcus
however check for STI if patient under 35
- Clinical dx + midstream urine sample for serology and cytology (chlamydia &gonorrhoea)
- ciprofloxacin for 28 days, trimethoprim if high C.diff risk
sexually transmitted genital tract infections (give organism and infection)
- bacterial? (3)
- viral? (3)
- Parasites? (3)
-chlamydia trachomatis
Neisseria gonorrhoeae
Treponema pallidum (syphilis)
-HPV (genital warts)
Herpes simplex (genital herpes)
Hepatitis & HIV
-Trichomonas vaginalis
Phthirus pubis (pubic lice or “crabs”)
Scabies
Chlamydia trachomatis
- sites of infection?
- type of organism?
- gram stain?
- serological groups? (3)
- treatment?
- urethra, rectum, throat, eyes, endocervix
- obligate intracellular bacteria with biphasic life cycle can’t reproduce outside host cell
- does NOT stain with gram stain as no peptidoglycan in the cell wall
- serovars A-C= trachoma (eye infection/NOT STI)
serovars D-K= genital infection
Serovars L1-L3= Lymphogranuloma venereum
-Azithromycin (1g oral) if uncomplicated
Lymphogranuloma venereum (LGV)
- presentation?
- treatment?
- complications?
-can mimic IBS in those who have contracted it via receptive anal intercourse
inflammation of the rectum gives constant feeling of fullness and PR bleeding, histologically the same as IBD
- doxycycline 100 mg twice-daily for 21 days
- fistulas etc.
describe the replication of chlamydia?
attachment and entry migration to the perinuclear area and EB (elementary body) > RB (reticulate body) transition
inclusion biogenesis and bacterial replication
RB > EB transition and cell lysis
Neisseria gonorrhoea
- site of infection?
- gram stain?
- type of organism?
- presentation?
-urethra, rectum, throat, eyes, endocervix
-gram neg diplococcus
looks like 2 kidney beans facing each other, often appears intracellularly on a gram film as easily easily phagocytosed
- fastidious organism, does not survive well outside the body
- Purulent discharge, i.e dripping tap with pus pouring from e.g. urethra
Diagnosis of chlamydia & gonorrhoea
- name test used
- how are the samples for this test obtained?
-combined nucleic acid amplification tests (NAATs) or polymerase chain reaction (PCR) these test for both organisms in 1 and are highly sensitive and specific
-male: first pass urine sample
female: HVS/vulvo vaginal swab (VVS)/endocervical swab
HVS & VVS can be self taken by the patient or by clinician
+ rectal and throat swabs
eye swabs
tests for N.gonorrhoeae only?
Microscopy of urethral or endocervical swabs
culture on selective agar plates (selective agar suppresses growth of normal flora)
Not done on high vaginal swabs
done to check sensitivities in the SRH clinic
swabs from GP usually come back neg as organism would die in transit
PCR/NAATs
advantages (4) & disadvantages (2) ?
-how long will it take till you can do a test of cure?
adv
much less invasive specimens required esp if patient is asymptomatic (urine in men and VVS in women)
more sensitive than culture
will be + even if organisms have died in transit
test takes hours, not days
Disadv
cannot test antibiotic sensitivities without culture
will detect dead organisms
-have to wait 5 weeks
