4.2: Microbiology of UTI Flashcards

1
Q

True or False:

Urine in the kidneys, ureter and bladder is usually sterile?

Lower urethra is also sterile?

A

TRUE: Urine in the kidneys, ureter and bladder is usually sterile

FALSE: Bacteria colonise the lower urethra

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2
Q

Describe the colonisation of the lower urethra?

A

Colonised by normal bowel flora

Eg: Coliforms and Enterococci

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3
Q

Define a UTI?

A

The presence of micro-organisms in the urinary tract that are causing clinical infection

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4
Q

Describe a lower UTI?

Describe an upper UTI?

A

LOWER UTI = Infection confined to the bladder (Eg: Cystitis)

Upper UTI = Infection involving the ureters and also kidneys (Eg: Pyleonephritis)

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5
Q

Describe a complicated UTI?

A

This is a UTI complicated by something else, EG:

  • systemic sepsis,
  • urinary structure abnormality
  • stones
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6
Q

Describe bacteriuria?

Describe the clinical significance of this?

A

Presence of bacteria in the urine

Doesn’t always mean infection, especially in elderly with catheters

Can have chronic bacteriuria - DOESN’T NEED ANTIBIOTICS AS THEY HAVE NO SYMPTOMS

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7
Q

What is cystitis?

What causes it?

A

Inflammation of the bladder

Can be caused by infections BUT there are other causes

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8
Q

Are UTIs common or rare?

Who are they seen in? (Name 3 groups)

A

Very common

  1. More common in women due to shorter urethra
  2. Those with catheters
  3. Patients with abnormalities of the urinary tract
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9
Q

True or False:

Women often get UTIs during pregnancy?

A

True

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10
Q

Describe the two routes of UTI infection?

Which is the commonest?

A

Ascending infection* MOST COMMON

(Bacteria from bowel, enters urethra, enters bladder, enters ureter, enters kidneys)

Infection from blood

(Bacteriaemia causes bacteria in blood, infection enters kidney, multiple small abscesses, bacteria in urine)

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11
Q

Describe the causative organisms of UTI?

Describe their gram film appearance?

A

Coliforms (Eg: E.coli, Klebsiella, Enterobacter, Proteus)

Found in the bowel

GRAM NEGATIVE BACILLI

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12
Q

Most common causative organism for UTI?

A

E.Coli

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13
Q

Describe proteus UTI?

A

Associated with renal stone formation

Causes particularly smelly urine

Produces urease which breaks down urea to ammonia - increases pH and increases stones

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14
Q

What are the two types of Enterococci UTI?

How sensitive are they to treatment?

A

Enterococcus Faecalis (Sensitive to antibiotics)

Enterococcus Faecalum (Harder to treat)

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15
Q

Describe Staph UTI?

A

Staphylococcus Saphrohyticus

Causes UTI in young women of child bearing age

Staph aureus can also cause UTI but less common

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16
Q

Give the full name of the Pseudomonas that causes UTI

What kind of organism is this?

When is this seen?

Treatment?

A

Pseudomonas Aeruginosa

Gram negative bacilli but not a coliform

Very common in catheters/instrumentation

Hard to treat

Only treatment is Ciprofloxacin

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17
Q

Ciprofloxacin has a negative side effect - what is this?

What UTI organism can only be treated by Ciprofloxacin?

A

Causes c.diff

Pseudomonas Aeruginosa

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18
Q

Symptoms and signs of UTI?

A

Dysuria

Frequency

Nocturia

Haematuria

Fever*

Loin Pain*

Rigors*

*suggests upper UTI*

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19
Q

Describe how to collect a good urine specimen?

A

First pass urine is normally contaminated

Collect MID STREAM

(First part into toilet, middle part into bowl, last part past into toilet)

20
Q

What should you do once you’ve collected a urine sample?

A

Transport promptly to lap

Boric Acid container lasts for up to 24 hours (RED TOP)

Sterile universal container must reach lab within 2 hours (WHITE TOP)

21
Q

Describe what you may see on Dipstick that would suggest UTI?

A
  • Leukocytes
  • Nitrites
  • Protein
  • Blood
22
Q

Describe clean catch urine sample?

Describe bag urine sample?

Describe suprapubic aspiration?

A

Nurse tries to catch mid stream - elderly and children

Bag urine used in babies as you don’t know when they’re going to go - often contaminated

Often done in babies and young children - less chance of contamination than bag urine

23
Q

Describe how the labratory can diagnose UTI?

A

Microscopy (Only in selected urgent cases)

Culture - Done in all cases (Looks for significant Bacteriuria as all urine contains bacteria)

24
Q

Describe significant bacteriuria?

A

>105/ml

Usually one type of colony only

25
Q

Describe Kass’s Criteria?

A

>105 organisms = Probable UTI

104 = UNSURE

<103 = Probably not significant

This applies to women of child bearing age

26
Q

True or false?

  • A geniune UTI in a non-catherizated patient is normally a single organism?
  • A mixed growth (2 or more organisms) over 105 is probably significant?
A

TRUE: A geniune UTI is a non-catetherization patient is usually a single organism

FALSE: A mixed growth of 2 or more organism over 10^5 is probably NOT significant

27
Q

Treatment for ESBL bacteria?

Where does this organism come from?

A

This is resistant to most antibiotics and penicillins and gentamicin and ciprofloxacin

Nitrofurantoin may be helpful

Comes from imported chickens

28
Q

Describe CPE bacteria?

Treatment?

Where is this seen?

A

Gram negative bacteria that are resistant to the majority of antibiotics

Resistant to MEROPENEM (this is usually the last line antibiotic)

Seen in Indian Sub Continent (New Delhi) and now affects hospitals in london and manchester

29
Q

How long should the course of antibiotics be for an uncomplicated UTI in women?

A

3 day course usually adequate

30
Q

Name some 1st line antibiotic treatments?

A

Amoxicillin

Trimethoprim

Nitofurantoin

Genatmicin

31
Q

Name some 2nd line antibiotics?

A

Ciprofloxacin

Co-Amoxiclav

Cefalexin

Temocillin

32
Q

Describe Amoxicillin in UTI:

How is it given?

Pregnancy?

Cost?

Organisms treated?

Empirical Use?

A

Very good antibiotic

Given IV and Oral

Safe in Pregnancy

Cheap

Enterococcus Faecilis

Not used empirically due to resistant E.coli

33
Q

Describe Trimethoprim in UTI?

How is it given?

Pregnancy?

Cost?

Range of Organisms treated?

Risk?

A

Given alone or in combination

Used as empirical treatment

Avoided in the first trimester of pregnancy

Cheap

  • Most coliforms
  • Staph aureus including MRSA
  • Not pseudomonas

RIKS OF STEPHEN JOHNSTON SYNDROME

34
Q

Describe Nitrofurantoin in UTI?

When used?

When is it activated?

Cost?

Pregnancy?

Organisms?

A

Used in lower uncomplicated UTI

Only activated in urine

Cheap

Avoided in late pregnancy and breastfeeding

Organisms:

Most coliforms

Staph aureus and MRSA

Not pseudomonas

35
Q

Describe Gentamicin in UTI:

  • When used?
  • Pregnancy?
  • Organisms?
  • Where is it very effective?
  • How long should it be prescribed for?
A

Used in hospital for UTI

AVOID IN PREGNANCY

Most organisms: Coliforms, Staph aureus and MRSA, Pseudomonas,

Very effective in gram negative sepsis (coliforms)

DON’T USE FOR MORE THAN 3 DAYS

36
Q

Describe Cefalexin use in UTI?

Pregnancy?

Cost?

Describe why you’d use this?

Range of organisms?

A

Safe in pregnancy

Broad spectrum so only used if Amoxicllin and Trimethoprim resistant

Most coliforms, Staph Aureus,

37
Q

Describe co-amoxiclav in UTI?

Side effects?

Cost?

Pregnancy?

A

C. diff infection

Cheap

Safe in pregnancy

38
Q

Describe Ciprofloxacin in UTI

  • Side effects?
  • Pregnancy?
  • Organisms?
A

C. diff is side effect

Generally safe but not used in young children or pregnant women

Pseudomonas, Almost all coliforms, enterococci

39
Q

What is the only oral pseudomonas-treating antibiotic?

A

Ciprofloxacin

40
Q

Describe female lower UTI empirical treatment?

A

Trimethroprim or nitrofuratoin for 3 days

41
Q

Describe uncatherised male UTI treatment?

A

Trimethroprim or Nitrofurantoin for 7 days

42
Q

Describe treatment of complicated UTI or Pyleonpehritis (Community)?

In hospital?

A

Co-Amoxiclav or Co-trimoxazole for 14 days

Amoxicillin + Gentamicin for 3 days

If penicillin allergic - Co-trimoxazole + Gentamicin

43
Q

Describe treatment of asymptomatic bacteriuria?

If the patient was pregnant?

A

Doesn’t need treatment

Antibiotics to prevent pyleonephritis and complications

44
Q

Describe abacterial cystitis?

Causes?

Treatment?

A

Patient has UTI symptoms and pus cells in urine but no significant growth of bacteria

Causes:

  1. Early stage of UTI
  2. Urethral trauma (Honeymoon Cystitis)
  3. May be due to STI

Alkalising urine may help

45
Q

Describe treatment of an asymptomatic catherized patient with significant bacteriuria?

Symptomatic?

A

Asymptomatic = No treatment

Symptomatic = Antibiotics

46
Q

What antibiotics should be used to treat UTIs in pregnancy?

A

First and second trimester: Nitrofuratonin

Third trimester: Trimethoprim

(KGB)