1017 - Commensal Flora of the Female Genital Tract

Question 1

What factors influence the composition of the commensal flora in the female genital tract?

Answer 1

Local defences - cervical mucociliary escalator, mucus itself
Temperature
pH
Availability or lack of oxygen
Sources of energy and nutrients - e.g. secretions, dead cells, flora metabolites
Other (protective) flora - e.g. lactobacilli

Question 2

What are the main sources of energy and nutrients in the female genital tract?

Answer 2

Mucus - mucins, proteins, organic and inorganic compounds
Vaginal fluid - proteins, AAs, carbs, lipids, inorganic ions
Menstrual fluid - various nutrients including iron
Glycogen (in reproductive years) - very important
Sexual fluids

Question 3

What are the main commensal flora of the female genital tract?

Answer 3

Lactobacillus spp. (50-90% - important and beneficial)
Strep spp.
G. Vaginalis
Yeasts (candida)
Other obligate anaerobes

Question 4

Outline the key attributes of lactobacilli

Answer 4

Gram Positive
Non-spore forming, non-motile
Anaerobic - obligate anaerobe to aerotolerant
Aciduric/acidophilic (pH3-7)
Mesophilic (15-45 degrees)

Question 5

Name two diseases associated with decreased vaginal lactobacilli

Answer 5

Vaginal Candidiasis

Bacterial vaginosis

Question 6

Discuss the risk factors, clinical features, diagnosis and treatment of Bacterial vaginosis

Answer 6

RF - Anythign that allows Gram-variable anaerobes (G. Vaginalis) to overgrow - Decreased lactobacillus, onset of menses, vaginal medications, spermicides, increased sexual activity (NOT an STI)
Clinical Features - Excessive malodorous vaginal discharge due to metabolism of anaerobes (-osis, not -itis)
Diagnosis - Swab, ‘whiff test’. Microscopy shows loss of lactobacilli, increase in gram-variable coccobacilli, and clue cells - squamous cells coated in bacteria.
Treatment - Antibiotics - Metronidazole or Clindamycin

Question 7

Discuss the risk factors, clinical features, diagnosis and treatment of Candidiasis

Answer 7

RF - Recent antibiotic therapy, pregnancy, hormones (OCP/HRT), Diabetes, condoms, frequent sexual activity.
Features - Inflammation, burning, itching, and cheesy discharge
Diagnosis - Can be symptoms and/or microscopy and culture
Treatment - Change reversible factors, and topical or oral antifungals

Question 8

Describe the relationship between vaginal Group B Streptococcus carriage and neonatal infection

Answer 8

GBS is part of commensal flora for 20-30% of women. 50-70% of neonates born to GBS-women will be infected, and it is the leading cause of neonatal septicaemia and meningitis. Can be spread via placenta, aspiration into lungs, and can traverse neonatal respiratory epithelium (bacteraemia) and blood-brain barrier (meningitis)