Microbiology

Question 1

What is a UTI?

Answer 1

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

Question 2

compare a lower and upper UTI?

Answer 2

lower: confined to bladder
upper: ureters +/- kidneys

Question 3

what is a complicated UTI?

Answer 3

UTI with systemic sepsis, stones or urinary structural abnormality

Question 4

what is bacteriuria?

Answer 4

presence of bacteria in the urine

Question 5

what is cystitis?

Answer 5

inflammation of the bladder

Question 6

compare the length of antibiotic courses in a complicated an uncomplicated UTI?

Answer 6

uncomplicated: short course
complicated: long course

Question 7

why can pregnancy increase risk of UTI?

Answer 7

pressure on bladder can cause incomplete emptying

stasis of urine can lead to infection

Question 8

what group of organisms are the most common causative organisms of UTI?

Answer 8

coliforms

Question 9

which organisms is the most common cause of a UTI?

Answer 9

E. coli

Question 10

which UTI causative organism is associated with formation of calculi?

Answer 10

proteus sp (a type of coliform)

Question 11

why does proteus UTI cause calculi formation?

Answer 11

proteus produces urease which breaks down urea to ammonium

this increased urinary pH leads to salt precipitation

Question 12

what type of patient does Staph saphrophycticus cause UTIs in?

Answer 12

women of child bearing age

Question 13

pseudomonas UTI is associated with what risk factor?

Answer 13

catheters and urinary tract instrumentation

Question 14

what is the only oral antibiotic which pseudomonas is sensitive to?

Answer 14

ciprofloxacin

Question 15

why should ciprofloxacin be avoided unless necessary?

Answer 15

C. dif risk

Question 16

what are the 3 main symptoms/signs of a lower UTI?

Answer 16

dysuria
frequency/nocturia
haematuria

Question 17

what 3 main symptoms/signs of a UTI suggest upper urinary tract involvement?

Answer 17

fever
loin pain
rigors

Question 18

what part of the stream do you want for a urine specimen?

Answer 18

mid-stream

Question 19

what kind of patients are ‘clean catch’ urine specimens obtained in?

Answer 19

children

elderly

Question 20

what kind of patients are bag urine specimens obtained in?

Answer 20

babies

Question 21

what kind of patients are suprapubic aspiration urine specimens obtained in?

Answer 21

babies

Question 22

compare red top and white top urine containers?

Answer 22

red top- boricon preservative container

white top- sterile universal container

Question 23

compare the time period for specimen reaching the lab in red and white top urine containers?

Answer 23

red- 24 hours

white- 2 hours

Question 24

what does boricon preservative do in a red top container?

Answer 24

prevents bacterial multiplication

Question 25

what 4 things on urine dipstick may be present in infection?

Answer 25

leukocytes nitries protein blood

Question 26

compare coliforms and entercoccus sp on the presence of nitrites on urine dipstick?

Answer 26

coliforms: present enterococcus: not present (only gram negs convert)

Question 27

what kind of bacterial are coliforms?

Answer 27

gram neg bacilli

Question 28

why might urine microscopy be done for a suspected UTI?

Answer 28

urgent cases

Question 29

what is Kass's criteria for UTI?

Answer 29

more than 10^5 organisms/ml- probable UTI 10^4 organisms- repeat specimen less than 10^3 organisms- not significant

Question 30

what type of patients does the Kass criteria for UTI apply to?

Answer 30

women of child bearing age

Question 31

what antibiotics are ESBL (extended spectrum beta-lactamase) organisms resistant to?

Answer 31

all cephalosporins | almost all penicillins

Question 32

what imported food stuff do you see ESBL (extended spectrum beta-lactamase) organisms in?

Answer 32

imported chicken

Question 33

what are carbapenamase-producing enterobacteriaceae? (CPE)

Answer 33

gram negative bacilli (coliforms) that are resistant to meropenem (ie resistant to all current antibiotics)

Question 34

what sub-continent are carbapenamase-producing enterobacteriaceae (CPE) associated with?

Answer 34

indian sub-continent

Question 35

in women, how long are antibiotic courses for an uncomplicated lower UTI?

Answer 35

3 days

Question 36

what are the 4 first line antibiotics for UTI?

Answer 36

amoxicillin (IV, PO) trimethoprim (PO) nitrofurantoin (PO) gentamicin (IV)

Question 37

why is amoxicillin not a goot choice for empirical treatment of a UTI?

Answer 37

50% of E.coli strains are resistant

Question 38

what is the action of trimethoprim?

Answer 38

inhibits bacterial folic acid synthesis

Question 39

what trimester must trimethoprim be avoided in and why?

Answer 39

first trimester, inhibits folic acid so can cause spina bifida

Question 40

what combination is co-trimoxazole?

Answer 40

trimethoprim and sulphamethoxazole

Question 41

what serious dermatological side effect can occur with co-trimoxazole?

Answer 41

Steven- Johnson's syndrome

Question 42

why can nitrofurantoin not be used in upper UTI?

Answer 42

because it only becomes activated in the urine

Question 43

why must gentamicin only be prescribed for 3 days?

Answer 43

because of toxicity to CN VIII (deafness and balance problems) and kidneys

Question 44

what is the empirical treatment for a female lower UTI?

Answer 44

trimethoprim or nitrofurantoin PO 3 days

Question 45

what is the empirical treatment for a uncatheterised male UTI?

Answer 45

trimethoprim or nitrofurantoin PO 7 days

Question 46

what is the empirical treatment of a complicated UTI or pyelonephritis within GP?

Answer 46

co-amoxiclav or co-trimoxazole PO 14 days

Question 47

what is the empirical treatment of a complicated UTI or pyelonephritis within hospitial?

Answer 47

amoxicillin AND gentamicin IV 3 days | then step down dguided by antibiotic sensitivities

Question 48

compare the treatment asymptomatic UTI (ie bacteraemia) in non-pregnancy and pregnant women?

Answer 48

non-pregnant: no treatment | pregnant: antibiotic treatment

Question 49

what is the empirical treatment for UTI/bacteraemia for a pregnant woman?

Answer 49

1/2 trimester: nitrofurantoin (7 days) 3 trimester: trimethoprim (7 days) all trimesters cefalexin (7 days)

Question 50

why should pregnnat women with bacteriauria be treated with antibiotics even if asymptomatic?

Answer 50

may progress to pyelonephritis may lead to intra-uterine growth retardation may lead to premature labour