Microbiology

Question 1

What type of bacteria colonise the end of the urethra?

Answer 1

Coliforms and enterococci from the large bowel

Question 2

UTI definition?

• Lower
• Upper

Answer 2

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

• infection confined to the bladder (cystitis)
• infection involving the ureters +/- the kidneys (pyelonephritis)

Question 3

What is a complicated UTI?

Answer 3

UTI complicated by systemic sepsis or urinary structural abnormality or stones

Question 4

3 groups at increased risk of UTI

Answer 4

Women
Catheterised patients
Patients with abnormalities of the urinary tract

Question 5

Why are women more likely to get UTI? (3)

Answer 5

short wide urethra
proximity of urethra to anus
increased risk with sexual activity/pregnancy (urinary stasis)

Question 6

Name and plain the 2 routes of UTI infection

Answer 6

-Ascending
bacteria from bowel-perineal skin- lower urethra- bladder-ureters-kidneys

-From bloodstream
bactareamia/speticeamia-bacteria in blood-seeded into kidneys-multiple small abscesses- bacteria in urine

Question 7

Name the commonest casual organisms in UTI (4)

-gram stain?

Answer 7

coliforms :E.coli, Klebsiella, Enterobacter, Proteus

-Gram negative bacilli

Question 8

What is the proteus bacteria associated with?

• why?
• feature of urine?

Answer 8

• calculi
• produces urease, this breaks down urea to form ammonia which increases urinary Ph= precipitation of salts and calculi
• Foul smelling

Question 9

Name the other causal organisms in UTI (3)

2. age group and feature
3. gram stain, assoc, antibiotic

Answer 9

Enterococcus- enterococcus faecalis & Enterococcus faecium

Staphylococcus saphrophyticus
-coagulase negative, women of child bearing age

Pseudomonas aeruginosa
-Gram neg bacillus assoc with catheters and UT instrumentation
ciprofloxacin sensitive

Question 10

Symptoms lower UTI (3)

-Upper UTI (3)?

Answer 10

Dysuria
Frequency of urination/nocturia
Haematuria

-Fever
loin pain
rigors

Question 11

How to collect a urinary specimen?

• why?
• 4 other methods
• container used

Answer 11

Mid stream specimen of urine:
Wash perineum / urethral meatus with sterile saline (not antiseptic)
Give patient a sterile foil bowl
First urine passed into toilet
Next part collected in foil bowl
Last urine passed in toilet

-avoid contamination

-Clean catch
Bag urine (babies)
Catheter specimen
Suprapubic aspiration

-Boricon container (boric acid acts as preservative), red lid

Question 12

Dipstick findings that might indicate infection? (4)

Answer 12

Leukocyte esterase (WBC in urine)
Nitrites (indicate presence of bacteria reducing nitrates to nitrites)
Protein
Blood

Question 13

What is Kass’s Criteria used in?

-give the 3 criteria

Answer 13

Culture of urine
->10*5 organisms / ml
significant =probable UTI

Question 14

What is ESBL

• antibiotics it is resistant to?
• possible useful antibiotics? (6)

Answer 14

Extended spectrum beta lactamase

-All cephalosporins, most penicillins

-Nitrofurantoin (oral), pivmecillinam (oral), 
fosfomycin (oral), 
temocillin (IV), 
meropenem(IV), 
ertapenem (IV)

Question 15

What is CPE?

• gram stain?
• resistance?

Answer 15

Carbapenemase-producing enterobacteriaceae (CPE)

• Gram neg bacilli
• meropenem (last choice)

Question 16

Length of course in simple UTI in women?

Answer 16

3 days

Question 17

Empirical treatment in

• Female lower UTI
• uncatheterised male UTI
• Complicated UTI/pyelonphritis (GP)
• Complicated UTI/pyelonphritis (hospital)

Answer 17

• Trimethoprim or nitrofurantoin orally (3 days)
• Trimethoprim or nitrofurantoin orally (7 days)
• Co-amoxiclav or co-trimoxazole (14 days)
• Amoxicillin and gentamicin IV for 3 days (cotrimoxazole and gentamicin if penicillin allergy)

Question 18

Amoxicillin

• Advantages
• Organisms treated

Answer 18

-Can be given orally or IV
Safe, even in pregnancy
High conc achieved in urine
Very cost-effective

-Enterococcus faecalis