Microbiology

Question 1

What is a lower UTI?

Answer 1

infection confined to the bladder

Question 2

What is an upper UTI?

Answer 2

infection involving the ureters and kidney - pylonephritis

Question 3

Which parts of the urinary tract are normally sterile?

Answer 3

bladder, ureters and kidneys

Question 4

Which parts of the urinary tract are not normally sterile?

Answer 4

urethra - colonised by coliforms and enterococci due to proximity to the large bowel

Question 5

What is a complicated UTI?

Answer 5

UTI complicated by systemic symptoms or abnormal structure

Question 6

What is bacteriuria?

Answer 6

bacteria is present in the urine but does not always indicate infection e.g. catheter or elderly patient

Question 7

What are the risk factors for UTIs?

Answer 7

female>male due to shorter, wider urethra, close to anus
increased risk with sexual activity or pregnancy
catheterised patients
structural abnormalities

Question 8

What are the two routes of infection for UTI?

Answer 8

Ascending

Bloodstream

Question 9

Describe ascending UTIs?

Answer 9

most common
bladder -> ureter -> kidney
often E.coli as they have fimbrae that can climb up the ureters
bacteria from bowel

Question 10

Describe bloodstream UTIs?

Answer 10

less common
often septicaemia or bacteriaemia
multiple small abcesses seeded into the kidneys

Question 11

What are the investigations done for a UTI?

Answer 11

specimen to lab for:
dipstick - nitrites and leucocytes
culture
microscopy - not routine

Question 12

What must the urine specimen be transferred in?

Answer 12

must be sent in either a boricon container - contains boric acid which stops the bacteria from multiplying for around 24hours
OR
in a sterile universal container - must reach the lab within 2 hours

Question 13

What type of urine sample is needed?

Answer 13

mid stream sample - urine passed from the urethra will initially get contaminated with bacteria from the peritoneum or lower urethra

Question 14

What is the presentation of a UTI (mainly lower)?

Answer 14

dysuria - pain passing urine
frequency of urination
change in nocturne
haematuria

Question 15

What are the signs of an upper UTI?

Answer 15

loin pain
fevers
rigors

Question 16

What are the main pathogens that cause UTIs?

Answer 16

E.coli 
Proteus
Kleibsella
Enterbacter
Serratia
Citrobacter
Maganella
Providericia

Question 17

What is the gram stain and classification of pathogens that cause UTIs?

Answer 17

gram negative coliforms

Question 18

What is the one organism that is not a coliform that can cause a UTI?

Answer 18

psuedomonas - it is a gram negative bacillus

Question 19

How does a UTI caused by proteus present?

Answer 19

STAG HORN CALCULI
produces urase which breaks down urea to form ammonia which increases urinary pH and precipitation of salts
foul smelling, burnt chocolate

Question 20

What is the only oral antibiotic that treats pseudomonas?

Answer 20

ciprofloxacin

Question 21

What gram positive organisms can cause UTIs?

Answer 21

enterococcus faecalis and fasecium - most commonly aquired in hospital not in normal healthy people
staph saphrophyticus - coagulase negative staph, usually affects women of child bearing age
stay aureus - in bacteraemia

Question 22

What is the diagnostic criteria for UTIs?

Answer 22

Kass Criteria
>10^5 organisms/ml = significant/probable UTI
10^4 organisms/ml = repeat - may be contaminated may be infection
<10^3 organisms/ml = not significant

Question 23

What is a genuine UTI normally due to?

Answer 23

just one organism - if more than 2 its probably not significant

Question 24

What is the action of ciprofloxacin?

Answer 24

inhibits bacterial DNA gyrase - not used in pregnant women or young children

Question 25

What is antibacterial cystitis/urethral syndrome?

Answer 25

patient has symptoms of UTI, there are pus cells present in the urine but no bacterial growth on culture may be due to urethral trauma, urethritis caused by STI, or just early phase of UTI

Question 26

What is honeymoon cystitis?

Answer 26

urethral trauma due to sexual activity - presents with same symptoms as a UTI

Question 27

What can help honeymoon and antibacterial cystitis and urethral syndrome?

Answer 27

alkalising the urine

Question 28

What is asymptomatic bacteriuria?

Answer 28

bacteriuria >10^5 but the patient is asymptomatic so is detected incidentally - no treatment is needed

Question 29

When is treatment needed for asymptomatic bacteriuria?

Answer 29

in prengancy

Question 30

When are pregnant women screened for aysymptomatic bacteriuria?

Answer 30

1st antenatal unit appointment

Question 31

What are the risks of not treating asymptomatic bacteriuria in pregnant women?

Answer 31

can progress to pylonephritis | and cause intra uterine growth retardation or premature labour

Question 32

When shoud catheratised patients be given antibiotics for bacteriuria?

Answer 32

IF THEY HAVE SYMPTOMS

Question 33

What is the treatment of a complicated UTI/pylonephritis/urosepsis in hospital?

Answer 33

amoxicillin and gentamicin IV - 3 days step down: co trimoxazole PO cotrimoxazole if pen allergic

Question 34

What is the treatment of a complicated UTI/pylonephritis/urosepsis in primary care?

Answer 34

coamoxiclav PO - 14 days | cotrimoxazole if pen allergic

Question 35

What is the treatment of a female lower UTI?

Answer 35

Nitrofuratoin or Trimethoprim PO - 3 days

Question 36

What is the treatment of a male lower UTI?

Answer 36

Nitrofuratoin or Trimethoprim PO - 7 days

Question 37

What are the characteristics of gentamicin?

Answer 37

``` IV only avoid in pregnancy narrow therapeutic index gram -ve cover only to be given for 3 days ```

Question 38

What are the characteristics of Trimethoprim?

Answer 38

NOT FOR 1ST TRIMESTER inhibits folic acid synthesis (part of cotrimoxazole) oral

Question 39

What are the characteristics of Nitrofurantoin?

Answer 39

``` NOT FOR 2ND OR 3RD TRIMESTER - can cause neonatal haemolysis AVOID IN BREAST FEEDING AND CHILDREN < 3 oral only used in lower, uncomplicated UTIs doesnt treat proteus or pseudomonas ```

Question 40

What are the characteristics of co-amoxiclav?

Answer 40

combo of amoxicillin and clauvulanic acid (beta lactamase inhibitor)

Question 41

What are the characteristics of Pivmecillinam?

Answer 41

oral treats lower, uncomplicated UTIs has activtiy against ESBLs NOT FOR PREGNANCY

Question 42

What are the characteristics of Temocillin?

Answer 42

IV has activity against ESBLs useful for complicated UTIs/urosepsis - patients whose renal function is too poor for gentamicin

Question 43

What are the characteristics of Cefalexin?

Answer 43

oral only used when amoxicillin and trimethoprim are resistnat 1st generation cephalosporin

Question 44

Name some antibiotics that might treat ESBLs?

Answer 44

``` nitrofurantoin pivmecillinam fosfomycin temocillin meropenem entrapenem ```

Question 45

What are carbapenem producing enterobactams?

Answer 45

gram -ve coliform/bacilli that are resistant to meropenem - resistance is plasma mediated

Question 46

How is ESBLs resistnace carried?

Answer 46

on a plasmid