UTIs

Question 1

What percentage of kids have UTIs?

Answer 1

~5% of girls and 1% of boys have a UTI before 5 y.o.

Question 2

What are the stats for women and UTIs?

Answer 2

~50% of women report at least one UTI by 50 years

Sexually active women have one UTI every 2 years

Question 3

What is acute cystitis?

Answer 3

Inflammation of the urinary bladder

Question 4

What is Pyelonephritis?

Answer 4

Inflammation of the urinary bladder and kidneys

Question 5

What is sterile pyuria?

Answer 5

Pus in the urine with a negative culture

Question 6

What are the sterile areas of the urinary tract?

Answer 6

The kidneys, ureter and bladder

Question 7

Does the urethra have bacteria in it?

Answer 7

Yes - it has a microbiota

Question 8

What is the source of most UTIs?

Answer 8

The microbiota (E. Coli is predominant and it the predominant cause of UTI)

Question 9

What percentage of community acquired UTIs are caused by:
E. coli
Proteus species 
Staph. saprophyticus
Other

Answer 9

80
5
10
5

Question 10

What percentage of hospital acquired UTIs are caused by:
E. coli
Proteus species 
Staph. saprophyticus
Other

Answer 10

40
10
2
48

Question 11

What are the other bacteria which cause UTIs?

Answer 11

Other GNRs: Klebsiella, Enterobacter, Serratia, Pseudomonas.

G+ bacteria: Enterococcus, other Staphylococcus.

Question 12

With regard to CMV why is the urinary tract important?

Answer 12

The patient may have asymptomatic shedding (i.e. they may transmit the virus through urine)

Question 13

How do bacteria access the urinary tract?

Answer 13

Most infections are ascending (i.e. from commensals in the distal urethra)
They can make their way up into the bladder and then occasionally to the kidneys

Question 14

What bacteremias can cause UTIs?

Answer 14

Requires systemic infections
• Staph. aureus (renal abscess)
• Salmonella Typhi
• TB

Question 15

What type of epithelium is present in the urinary tract?

Answer 15

Transitional epithelium

Question 16

What is the benefit of having transitional epithelium in the urinary tract?

Answer 16

It resists bacterial colonisation

Question 17

Do bacteria grow in urine?

Answer 17

Many do not like this medium

Question 18

What are the elements of innate immunity of the UT?

Answer 18

Transitional epithelium
Many bacteria do not grow in urine
Constant flushing of urine and regular bladder emptying plays a key role in resistance to infection

Question 19

What are the effects of constant flushing of urine from the bladder?

Answer 19

Bacteria cannot reach sufficient numbers to activate virulence mechanisms.
Those who cannot empty their bladder completely are much more susceptible

Question 20

What are females more commonly affected by UTIs?

Answer 20

Shorter urethra

Infection comes from the perineum and female urethra essentially opens in the perineum

Sexual intercourse massages bacteria up the female urethra

Question 21

What may protect against UTIs in infant boys?

Answer 21

Circumcision

Question 22

What is thought about the colonisation of the distal urea with regard to UTIs?

Answer 22

Suggested that the higher the level of colonisation the more susceptible to infection

Question 23

What are some abnormal host factors which contribute to UTIs?

Answer 23

Incomplete bladder emptying

Catheterization

Question 24

What are some causes of incomplete bladder emptying?

Answer 24

Structural abnormality (congenital, tumour, pregnancy, stone, enlarged prostate). 
(May be first evidence in a child - always investigate boys girls are allowed a couple)

Functional abnormality (neurological conditions, vesico-ureteric reflux - urine pushed up the ureters)

Question 25

What allows bacteria to adhere to the bladder?

Answer 25

Type 1 pili (Almost all E. Coli can produce these) PAP pili - these allow for good adhesion to the transitional epithelium

Question 26

What the role of flagella in UTI causing bacteria?

Answer 26

It allows for motility - perhaps to reach the kidneys

Question 27

Bacteria which are more likely to produce UTIs do what with the epithelium?

Answer 27

Can invade transitional epithelium and form intracellular communities

Question 28

What is a biofilm?

Answer 28

A community of microbes within a matrix

Question 29

What are biofilms usually made out of?

Answer 29

Polysaccharides

Question 30

What are siderophores?

Answer 30

These are compounds with very high affinity for iron

Question 31

Which bacteria is noted for producing urease?

Answer 31

Proteus sp

Question 32

What does urease do?

Answer 32

It changes the pH of urine and promotes the formation of struvite stones

Question 33

Where are PAP effective?

Answer 33

In the kidneys

Question 34

Where are flagella effective?

Answer 34

In the ureter

Question 35

Where are type 1 pili effective?

Answer 35

In the bladder

Question 36

Are filaments produced by E.Coli a virulence factor?

Answer 36

Yes - some evidence

Question 37

How is UTI diagnosed?

Answer 37

* History and physical examination * Imaging * Collect appropriate samples * Interpret lab report

Question 38

What comes up in the history of someone with a UTI?

Answer 38

Pain Frequency Urgency (it is hard to distinguish between upper and lower UTI - fever is an indication)

Question 39

When is a person with a UTI imaged?

Answer 39

Usually only done in people who we do not expect to get a UTI

Question 40

What samples are collected to test for UTIs?

Answer 40

Urine in most cases | Blood - if pyelonephritisis suspected

Question 41

What is the most common urine sample?

Answer 41

A midstream urine sample (only collect middle bit of urine, not end or start)

Question 42

What are some other types of urine samples?

Answer 42

* Catheter/nephrostomy sample * Bag sample (in babies - not very helpful) * Suprapubic aspirate (paediatrics - needle directly into bladder)

Question 43

Where is urine for analysis collected from the catheter?

Answer 43

From the catheter itself

Question 44

What examinations are done of urine samples?

Answer 44

* Microscopy * Count * Quantitative culture for bacteria * Susceptibility testing

Question 45

What are the pathologists looking for in microscopy?

Answer 45

``` WBC, RBC, epithelial cells, casts, crystals, microorganisms incl. parasitic forms ```

Question 46

What parasite infects the bladder?

Answer 46

Flatworm - fluke

Question 47

What is the level of WBC in the urine for it to be considered an infection?

Answer 47

>10^5/ml | Could also be due to stones or tumours or other inflammatory processes

Question 48

What is the normal squamous epithelial presence in a urine sample?

Answer 48

0 - any present = not well collected sample

Question 49

What is one colony forming unit?

Answer 49

One bacterium before culturing

Question 50

What is the infectious level of colony forming unit/ml?

Answer 50

>10^5 CFU/ml is strongly suggestive of infection (especially if only one species isolated)

Question 51

What is the CFU threshold for urine taken from the catheter?

Answer 51

>10^2 CFU/ml

Question 52

What is the CFU threshold for urine taken via suprapubic aspirate?

Answer 52

0 - should be sterile

Question 53

How quickly should urine samples be transported to the lab?

Answer 53

Less than 1 hour | Or can be kept at less than 4 degrees for a period of up to 18 hours

Question 54

What is sterile pyuria?

Answer 54

No growth with WBC consistently >10^5/ml

Question 55

What are the causes of sterile pyuria?

Answer 55

* non-infectious conditions * partial treatment * difficult to grow bacteria, e.g., TB

Question 56

What is a treatment for uncomplicated cystitis?

Answer 56

Alkalanise urine (check pH first)

Question 57

Why is alkalanising the urine helpful?

Answer 57

It may stop burning | The burning on micturition is due to the acid which the bacteria are producing

Question 58

Why does the pH need to be checked before the alkalanising the urine?

Answer 58

Proteus species produces ammonia during its growth and thus the urine will already be alakaline. Making it more so may precipitate the formation of struvite stones

Question 59

What is the recomended treatment for uncomplicated cystitis?

Answer 59

Trimethoprim OR cephalexin OR co-amoxyclav OR nitrofurantoin

Question 60

How long is the recommended treatment dosage for uncomplicated cystitis?

Answer 60

5 days [women & children] or 7 days [men]

Question 61

If a child less then 2 y.o. has a UTI what needs to happen?

Answer 61

Need to check for UT abnormality | A girl may allow one but a boy = none

Question 62

What drugs are used to treat pyelonephritis?

Answer 62

co-amoxyclav OR cephalexin OR trimethoprim

Question 63

How long do we treat for in Pyelonephritis?

Answer 63

10-14 days

Question 64

How is sepsis treated?

Answer 64

If severe sepsis, use ampi/amoxycillin + gentamicin

Question 65

When is asymptomatic bacteriuria treated?

Answer 65

In pregnancy (it is associated with prem delivery and other obstetrics complications)

Question 66

What is used to treat women with asymptomatic bacteriuria in pregnancy?

Answer 66

cephalexin OR co-amoxyclav OR other

Question 67

What is considered to be a recurrent UTI in women?

Answer 67

>2 UTIs in 6 months | most are reinfections i.e. not relapse

Question 68

What causes recurrent UTIs?

Answer 68

Genetic predisposition | Behaviour: intercourse, spermicide, incontinence, etc

Question 69

How can reccurent UTIs be managed?

Answer 69

``` Change behaviour; ↑ fluid intake; postcoital voiding Antimicrobial prophylaxis (different regimes)/early intervention ```

Question 70

What is the normal level of WBC in the urine?

Question 71

What is the normal level of RBC in the urine?

Question 72

What is the normal colony forming unit/ml?