Week 6- Urinary tract infections

Question 1

where do infections most commonly ascend from in UTIs

Answer 1

urethra

Question 2

what mechanisms are in place to avoid UTIs

Answer 2

• diluting and flushing action of urine
• valve between bladder and ureter prevents reflux
• extreme low pH, high osmolarity, IgA secretion, high urea concentration
• proteins that prevent attachment

Question 3

which proteins prevent attachement to avoid UTIs

Answer 3

• Tamm Horsfall protein (uromodulin) produced by kidney, coats epithelium binds E.coli
• GP51 protein secreted by bladder epithelial cells binds many bacteria preventing adhesion
• Manno-oligosaccharide in urine- binds E.coli

Question 4

what are risk factors of UTIs

Answer 4

• catheterisation -CAUTI
• obstruction
• vesicoureteric reflux
• pregnancy
• diabetes
• autonomic neuropathy leads to incomplete emptying of the bladder

Question 5

what obstructions can cause UTIs

Answer 5

enlarged prostate, urinary stones, congenital malformations

Question 6

what is Vesicoureteric reflux caused by

Answer 6

abnormal valve development

Question 7

how can pregnancy cause UTIs

Answer 7

impaired urine flow due to hormonal changes (may cause dilution of ureters) and pressure on the UT

Question 8

what are the community associated UTIs

Answer 8

• staphylococcus saprophytic- common in sexually active women
• ESBL- producing E.coli are seen in community patients who have had no contact with the health care system

Question 9

what is hospital associated UTI

Answer 9

pathogens are often resistant to antimicrobial

Question 10

what is Candida albicans

Answer 10

unicellular yeast which divides by budding

Question 11

what is Candida albicans commensal on

Answer 11

skin, GIT, female genitalia

Question 12

what is Candida albicans associated with

Answer 12

urinary catheters

Question 13

slide 10

Question 14

what is cystitis

Answer 14

inflammation of the bladder caused by E.coli. accounts for 95% of lower UTIs

Question 15

what are symptoms of cystitis

Answer 15

dysuria frequency, suprapubic pain (pain in the lower abdomen)

Question 16

what is acute pyelonephritis

Answer 16

infection of the kidney which is most commonly caused by E.coli

Question 17

what are symptoms of acute pyelonephritis

Answer 17

flank pain, fever, nausea, vomiting, rigors

Question 18

what is chronic pyelonephritis

Answer 18

chronic inflammation of the kidneys

Question 19

what is chronic pyelonephritis associated with

Answer 19

• obstruction of the urinary tract
• vesicoureteric reflux in children

Question 20

when is a short term Foley catheter used

Answer 20

during operations

Question 21

what is short term foley catheter made up from

Answer 21

latex

Question 22

when is a long term Foley catheter used

Answer 22

prostate problems, physical disability

Question 23

what is long term foley catheter made up from

Answer 23

silicone, PVC, teflon, silver coated

Question 24

what kind of pathogens can be sources from CAUTI

Answer 24

• endogenous (metal, rectal, or vaginal colonisation)
• exogenous: usually via contaminated hands or manipulation of the collecting system

Question 25

what are the leading pathogens of CAUTI

Answer 25

e.coli, pseudomonas, klebsiella, serratia, staphylococci, enterococci and candida

Question 26

how do biofilms form

Answer 26

bacterial growth on the surface, urinary proteins, urinary salts

Question 27

how are symptoms from CAUTI resolved

Answer 27

removal of catheter

Question 28

what is mid-stream urine (MSU)

Answer 28

accounts for majority of samples. first urine passed is discarded - contaminated with organism colonising the distal region of the urethra. Mid-stream urine collected in a sterile pot

Question 29

what is catheter stream urine (CSU)

Answer 29

samples taken through a port aseptically

Question 30

how are urine samples collected from very young children

Answer 30

• pad urine
• bag urine
• clean-catch urine
• suprapubic aspirate

Question 31

what is pad urine

Answer 31

absorbents pad placed in nappy and checked regularly

Question 32

what is bag urine

Answer 32

bag collects the sample

Question 33

what is clean-catch urine

Answer 33

sample caught into a sterile container (equivalent to MSU)

Question 34

what is suprapubic aspirate

Answer 34

a needle through the skin aspirates urone directly from the bladder (collected if alternatives have failed)

Question 35

why should samples be transported quickly at lower temperatures

Answer 35

to avoid false positive results

Question 36

what should be done if there are delays with transporting a sample

Answer 36

• Refrigerate at 4°C for max. of 24 h
• add boric acid to preserve
• use a dip-slide. commercially available agar coated slide dipped int freshly voided urine

Question 37

what information can help confirm an infection from a sample

Answer 37

• detection of a single bacterial pathogen associated with UTI-bacteriuria
• elevated number of white blood cells (WBC) in the sample- pyuria
• observation of fungi or parasites in the sample

Question 38

how is microscopy used in sample processing

Answer 38

slide 27

Question 39

what does direct microscopy show

Answer 39

• epithelial cells- indicates skin contamination
• bacterial cells, fungi and parasites- visible bacteria is not diagnostic; fungi or parasites is diagnostic
• casts- proteinaceous structures produced by the kidneys. may occur due to different pathologies