3.7 Commensal Flora of the Genitals Flashcards
What key factors determine the composition of the commensal microflora?
Local defenses (innate ad acquired) Temperature pH Availability of oxygen sources of nutrients (host secretions, dead cells, metabolites produced by other members of commensal flora)
What are the local defences of the Genitals?
Cervical mucociliary escalator
Mucus (contains antimicrobial proteins, serves as source of microbial nutrients, protects cells from microbial adhesions, serves as a target for microbial adhesions)
What is the availability of oxygen in the genitals?
Microaerophilic (2% of typical air)
What factors affect the availability of air in female genitals?
Hormones, tampons, contraceptives
What are the energy and nutrient sources of the female genitals?
mucus, vaginal fluid, menstrual fluid, glycogen (only in reproductive years) and sexual fluids
Describe lactobacilli
Gram positive, non spore forming, non motile, obligate anaerobe, acidophilic, mesophilic
COMMENSAL
What is associated with decreased lactobacilli in the vagina?
vaginal candidiasis and bacterial vaginosis
What is the most common cause of vaginal candidiasis
Candida albicans (yeast)
What can be caused as a result of candida albicans?
vulvovaginitis/vagintis
what are the risk factors for candida vaginitis?
recent antibiotic therapy pregnancy hormone replacement (OCT,HRT) diabetes (more glucose) use of condoms frequent sexual activity
Symptoms and diagnosis for candida vaginitis
inflammation, burning, itching and cheesy discharge
treatment o candida vaginitis
change reversible factors, topical or oral antifungal agents
What factors can lead to bacterial vaginosis?
decrease/change in lactobacilli onset of menses use of vaginal medications use of spermicides increased number/frequency f of sexual partners/intercourse and oral sex
Symptoms and diagnosis of bacterial vaginosis
Excessive malodorous vaginal discharge (metabolic activities of anaeroves may be implicated in iritation)
Whiff test (fishy odour)
pH > 4.5
Loss of lactobacilli
increase in gram variable coccobacilli
clue cells - squamous cells coated with bacteria
treatment of bacterial vaginosis
Metronidazole
Clindamycin
How can foetal infections occur?
Haematogenous dissemination
direct infection by endogenous or exogenous pathogens
Infection during delivery
What does group B strep cause in newborns? and which strep?
neonatal septicemia and meningitis
Strep. agalactiae
How does group B strep cause infection in babies?
Able to traverse the placental membranes and may lead to rupture/pre term birth and may access the foetal lungs though aspiration of infected amniotic fluid or neonatal lungs via aspiration of vaginal fluid during delivery
What is the commensal flora of the female genital tract?
Lactobacilli
