Microbiology of GU Tract Flashcards
What are bacterial causes of STI’s?
- Treponema pallidum (syphilis)
- Neisseria gonorrhoea (gonorrhoea)
- Chlamydia trachomatis (chlamydia)
What are viral causes of STI’s?
- Human papilloma virus (genital warts)
- Herpes simplex virus (genital herpes)
- HIV & hepatitis
What parasites cause STI’s?
- Trichomonas vaginalis
- pthirus pubis (pubic lice/”crabs”)
- scabies
What are common non sexually transmitted genital infection?
- candidiasis (vaginal thrush)
- bacterial vaginosis
- prostatitis
What are the normal vaginal flora?
- lactobacillus species: gram + rods (predominate in healthy vagina)
- streptococcus viridans
- group b haemolytic streptococcus
- candida species (small amount)-only problematic if symptomatic
What do lactobacillus produce?
-lactic acid & hydrogen peroxide (suppresses growth of microorganism)
What is candida infection?
- non STI
- responsive to treatment
- most caused by candida albicans
What are the predisposing factors for candida infection?
- recent antibiotic therapy
- immunosuppression
- poorly controlled DM
- high oestrogen levels (pregnancy, certain contraceptives)
What is the presentation for candida infection?
-intensely itchy white vaginal discharge
How is candida diagnosed?
- clinical diagnosis
- culture (high vaginal swab)
What is the management for candida infection?
-150mg fluconazole
avoid oral treatment in pregnancy, breastfeeding
What are the topical treatments available for candida? (suitable for pregnancy)
- clotrimazole (pessary)-500mg
- clotrimazole (vaginal cream)-5g
Which parts of the body can be infected by chlamydia trachomatis?
- urethra
- eyes
- throat
- endocervix
- *same as gonorrhoea
What are the characteristics of chlamydia trachomatis
- obligate intracellular organism
- biphasic life cycle
- does not reproduce outside of host cell
- does not stain with gram stain
Which serological group is responsible for genital infection?
serovars D-K (most common)
What is the treatment for chlamydia?
doxycycline 100mg bd for 7 days
What is the organism responsible for gonorrhoea what are their characteristics?
Neisseria gonorrhoeae
- Gram negative diplococci (two kidney beans facing each other)
- easily phagocytosed by polymorphs (so appear intracellularly)
- cannot survive in less than ideal conditions (outside the body)
What symptom is typical of gonorrhoea
purulent discharge
What is the treatment for gonorrhoea
- IM ceftriaxone alone
- Test of cure is recommended
How are chlamydia and gonorrhoea diagnosed?
- combined nucleic acid amplification test (NAATs)/ polymerase chain reaction test (PCR)
- tests for both organism in 1 test
- highly sensitive and specific
What other tests can be done for diagnosis for gonorrhea?
- culture (for antibiotic sensitivity)
- microscopy
What samples are taken?
- first pass urine (male)
- high vaginal swab/vulvovaginal swab (self taken)
- endocervical swab (by clinician)
- rectal & throat swabs
- eye swabs (babies and adults)
What are the advantages of NAATs/PCR?
- less invasive specimen required (urine and VVS)
- more sensitive than culture
- will be positive even if organims die during transit
- test takes hours instead of days
What are the disadvantages of NAATs/PCR?
- cannot test antibiotic sensitivity (unlike culture)
- will detect dead organism so 5 weeks required to perform test of cure
