genitourinary tract Flashcards
What are some facts about UTIs?
30% women have recurrent
One of the most common bacterial infections
Main defence- drink lots and pee
Usually from external site up the UT continuum
Can involve kidneys
Catheterisation common route of infection
Urethra closer to anus for women
What are some definitions?
Urethritis- urethra inflam
Cystitis- bladder inflam
Dysuria- painful pee
Pyuria- pee w pus (cloudy often)
Pyelonephritis- kidney infection- fever and back pain
Haematuria- bloody pee (pink)
What are host factors that contribute to UTIs?
Any blockages (stones etc)- empty bladder poorly- reflux of liquid and bacterial growth
Prostate enlargement/pregnancy/tumour- polyuria
Neurologic problems/drug side effects- emptying bladder problems
Short urethra
Catheterisation
What are pathogenic factors contributing to UTIs?
Adhesion to uroepithelium (eg P. fimbriae)
Capsules avoid detection
Toxins (hemolysins) affecting kidneys
Urease changes pH- may lead to kidney stones
What is the diagnosis of UTIs?
Sample midstream urine
Cloudy/clear/pink
Culture on agar
If >500 colonies- infection
Traces of protein, leukocytes >10/ml
Raised nitrates (bacterial metabolism)
Dipstick tests
Pure/mixed growth- normally pure
Gram stain under microscope
What is the culprit of UTIs?
E. coli- gram -ve rod 80%
P. mirabilis- gram -ve pleomorphic rod- swarming motility
S. saprophyticus- gram +ve coccus
What media is used to diagnose?
CLED media
- contains lactose and lacks electrolytes to repress swarming
- CLED Andrade indicator stains E. coli pink
Then-
MacConkey agar if E.coli suspected- pink colonies
What do the organisms look like on a CLED plate?
E.coli
- large opaque yellow colonies
P.mirabilis
- translucent blue colonies
S.aureus/saprophyticus
- pale yellow colonies
Coagulase test
-S.aureus is positive
-all other Staphylococci are negative
What are UPEC E.coli?
Gram-be motile bacillus
Have 1000 extra genes than enteric strains
Have potent adhesions to attach to epithelium (pili)
What are the different types of pili?
Type I pili
-bind to mannose receptors
-on glycoproteins in uroepithelium
P-fimbriae
-bind to globobiose
-linked ceramics host lipids
What does a urinary dipstick check?
Positive for nitrates and others if Proteus/E.coli
Misleading if negative
What is P.mirabilis?
Proteus (sea god shape shifter)
More common in older pts
Swarmer- at regular intervals
Goes from small rod to large rod w many flagella
Contains urease- urea into ammonia and CO2- raises pH of urine, precipitates minerals to form stones
IgA protease- reduces flushing
Many pili adhesins
What is S.saprophyticus?
Gram +ve cocci
Coagulase -ve
Clumps together (looks like cluster of grapes)
Haemagglutinin key to attachment to cells
Novobiocin resistant
Common in young women
How do we treat UTIs?
If not pregnant- drink lots of water and come back if worse
If fever of pain in kidney area- antibiotics (always in men/pregnant
3 days women
7 days men
First line- Nitrofurantoin
Resistance growing issue esp. E.coli
What organisms are culprit with catheterisation?
E.coli 40%
Other gram -ves 25% eg. Klebsiella, Enterococcus, Pseudomonas spp.
Other gram +ves 16% eg. S.aureus/epidermidis
Usually skin commensals
Problematic as v antibiotic resistant
What are the ESKAPE pathogens?
V problematic due to resistance
Enterococcus faecium
Staphylococcus aureus
Klebsiella pneumoniae
Actinobacter baumannii
Pseudomonas aeruginosa
Enterobacter species
How do we treat hospital UTIs?
IV antibiotics- nitrofurantoin, cefalexin
Immediate removal and changing of catheter
What is the most common STI?
Chlamydia
More in women than men
First line- azithromycin
What are the main culprits in STIs?
Neisseria gonorrhoeae (gram -ve)- gonorrhoea
Chlamydia trachomatis- chlamydia
Treponema pallidum (spirochete)- syphilis
HIV
Genital herpes
Hep B
What is N.gonorrhoeae?
Gram -ve diplococcus
Fully virulent
Asymptomatic carrier state- mainly female
Acute urethritis
Ascend to Fallopian tubes- acute salpingitis, pelvic inflam disease, sterility
Men symptoms- reddening of tip and pus discharge, dysuria
Women symptoms- 50% discharge, dysuria
Can lead to infant blindness
Oral gonorrhoea- v rare, oral sex
Coinfection of HIV and G risk 5x likely
What is the pathogenesis of N.gonorrhoeae?
Bundle forming surface pili and opa proteins (attachment)
LPS- host mimicry
-antigenic variation aids pathogenicity and hinder vaccine development
Por proteins- aids cell invasion
IgA protease- aids survival
If in bloodstream- fever, arthritis, endocarditis
How do you diagnose and treat gonorrhoea?
Urethral swab
-transport medium used
-subculture on chocolate agar
-glucose +ve
-oxidase test +ve
Contact tracing and then antibiotic prophylaxis for them
First line- ceftriaxone and azithromycin
What is syphilis?
More in men than women
Treponema pallidum, spirochete- slow growing
Sexual contact via skin abrasions
Vertical transmission (cross placental)
Initial incubation period (2-10 weeks)
PRIMARY lesion- CHANCRE- painless ulcer- resolves spontaneously
SECONDARY- after 6-8 weeks, flu like symptoms, rash
LATENT- 3-30 yrs, no symptoms
TERTIARY- neurosyphilis (CNS), cardiovascular (aortic lesions, HF), skin and bone deformity
What is the diagnosis and treatment for syphilis?
Immunofluorescence- Treponema direct antigen test
Unculturable
Need long acting course as slow growing- sensitive to penicillin
What is the pathogenesis of syphilis?
1. Multiplication of treponema at site of infection, host response
2. Proliferation of treponema at regional lymph nodes
3. Lesion in lymph nodes, liver, joints, muscle, skin, mucous membranes
4. Treponema dormant in liver/spleen
5. Reawakening and multiplication
6. Further dissemination, invasion, host response
7. Gummas in skin, bone, testes
What is chlamydia?
Chlamydia trachomatis- v small, obligate intracellular parasite, avoids immune, specialised life cycle
Asymptomatic in females
50% symptomatic in males
Reinfection common
Incubation 7-14 days
Direct damage to cells and immunopatholgy causing fibrosis and scarring
Conjunctivitis- common co-occurrence
What are the serotypes of chlamydia?
A-C- trachoma (3rd world)
D-K- urethritis, cervicitis, procitis, conjunctivitis, pelvic inflam disease
L1-3- LGV severe venereal disease (tropical)
How does chlamydia affect you?
Men- acute epididymitis, prostatitis, male infertility, proctitis, arthritis
Women- mucopurulent cervicitis, urethral infection, pelvic inflam disease, chronic pelvic pain, ectopic pregnancy, infertility
Conjunctivitis
What is the diagnosis and treatment for chlamydia?
1. Culture in cells
2. Direct immunofluorescence and ELISA
3. PCR tests
Tx= Azithromycin and doxycycline
