genitourinary tract

Question 1

What are some facts about UTIs?

Answer 1

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

Question 2

What are some definitions?

Answer 2

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)

Question 3

What are host factors that contribute to UTIs?

Answer 3

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

Question 4

What are pathogenic factors contributing to UTIs?

Answer 4

Adhesion to uroepithelium (eg P. fimbriae)

Capsules avoid detection

Toxins (hemolysins) affecting kidneys

Urease changes pH- may lead to kidney stones

Question 5

What is the diagnosis of UTIs?

Answer 5

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

Question 6

What is the culprit of UTIs?

Answer 6

E. coli- gram -ve rod 80%
P. mirabilis- gram -ve pleomorphic rod- swarming motility
S. saprophyticus- gram +ve coccus

Question 7

What media is used to diagnose?

Answer 7

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

Question 8

What do the organisms look like on a CLED plate?

Answer 8

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

Question 9

What are UPEC E.coli?

Answer 9

Gram-be motile bacillus
Have 1000 extra genes than enteric strains
Have potent adhesions to attach to epithelium (pili)

Question 10

What are the different types of pili?

Answer 10

Type I pili
-bind to mannose receptors
-on glycoproteins in uroepithelium

P-fimbriae
-bind to globobiose
-linked ceramics host lipids

Question 11

What does a urinary dipstick check?

Answer 11

Positive for nitrates and others if Proteus/E.coli
Misleading if negative

Question 12

What is P.mirabilis?

Answer 12

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

Question 13

What is S.saprophyticus?

Answer 13

Gram +ve cocci
Coagulase -ve
Clumps together (looks like cluster of grapes)
Haemagglutinin key to attachment to cells
Novobiocin resistant
Common in young women

Question 14

How do we treat UTIs?

Answer 14

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

Question 15

What organisms are culprit with catheterisation?

Answer 15

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

Question 16

What are the ESKAPE pathogens?

Answer 16

V problematic due to resistance

Enterococcus faecium
Staphylococcus aureus
Klebsiella pneumoniae
Actinobacter baumannii
Pseudomonas aeruginosa
Enterobacter species

Question 17

How do we treat hospital UTIs?

Answer 17

IV antibiotics- nitrofurantoin, cefalexin
Immediate removal and changing of catheter

Question 18

What is the most common STI?

Answer 18

Chlamydia
More in women than men
First line- azithromycin

Question 19

What are the main culprits in STIs?

Answer 19

Neisseria gonorrhoeae (gram -ve)- gonorrhoea
Chlamydia trachomatis- chlamydia
Treponema pallidum (spirochete)- syphilis
HIV
Genital herpes
Hep B

Question 20

What is N.gonorrhoeae?

Answer 20

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

Question 21

What is the pathogenesis of N.gonorrhoeae?

Answer 21

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

Question 22

How do you diagnose and treat gonorrhoea?

Answer 22

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

Question 23

What is syphilis?

Answer 23

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

Question 24

What is the diagnosis and treatment for syphilis?

Answer 24

Immunofluorescence- Treponema direct antigen test
Unculturable
Need long acting course as slow growing- sensitive to penicillin

Question 25

What is the pathogenesis of syphilis?

Answer 25

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

Question 26

What is chlamydia?

Answer 26

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

Question 27

What are the serotypes of chlamydia?

Answer 27

A-C- trachoma (3rd world)

D-K- urethritis, cervicitis, procitis, conjunctivitis, pelvic inflam disease

L1-3- LGV severe venereal disease (tropical)

Question 28

How does chlamydia affect you?

Answer 28

Men- acute epididymitis, prostatitis, male infertility, proctitis, arthritis

Women- mucopurulent cervicitis, urethral infection, pelvic inflam disease, chronic pelvic pain, ectopic pregnancy, infertility

Conjunctivitis

Question 29

What is the diagnosis and treatment for chlamydia?

Answer 29

1. Culture in cells
2. Direct immunofluorescence and ELISA
3. PCR tests

Tx= Azithromycin and doxycycline