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Flashcards in Microbiology Deck (50):
1

What is a UTI?

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

2

compare a lower and upper UTI?

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

3

what is a complicated UTI?

UTI with systemic sepsis, stones or urinary structural abnormality

4

what is bacteriuria?

presence of bacteria in the urine

5

what is cystitis?

inflammation of the bladder

6

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

uncomplicated: short course
complicated: long course

7

why can pregnancy increase risk of UTI?

pressure on bladder can cause incomplete emptying
stasis of urine can lead to infection

8

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

coliforms

9

which organisms is the most common cause of a UTI?

E. coli

10

which UTI causative organism is associated with formation of calculi?

proteus sp (a type of coliform)

11

why does proteus UTI cause calculi formation?

proteus produces urease which breaks down urea to ammonium
this increased urinary pH leads to salt precipitation

12

what type of patient does Staph saphrophycticus cause UTIs in?

women of child bearing age

13

pseudomonas UTI is associated with what risk factor?

catheters and urinary tract instrumentation

14

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

ciprofloxacin

15

why should ciprofloxacin be avoided unless necessary?

C. dif risk

16

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

dysuria
frequency/nocturia
haematuria

17

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

fever
loin pain
rigors

18

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

mid-stream

19

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

children
elderly

20

what kind of patients are bag urine specimens obtained in?

babies

21

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

babies

22

compare red top and white top urine containers?

red top- boricon preservative container
white top- sterile universal container

23

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

red- 24 hours
white- 2 hours

24

what does boricon preservative do in a red top container?

prevents bacterial multiplication

25

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

leukocytes
nitries
protein
blood

26

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

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

27

what kind of bacterial are coliforms?

gram neg bacilli

28

why might urine microscopy be done for a suspected UTI?

urgent cases

29

what is Kass's criteria for UTI?

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

30

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

women of child bearing age

31

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

all cephalosporins
almost all penicillins

32

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

imported chicken

33

what are carbapenamase-producing enterobacteriaceae? (CPE)

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

34

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

indian sub-continent

35

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

3 days

36

what are the 4 first line antibiotics for UTI?

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

37

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

50% of E.coli strains are resistant

38

what is the action of trimethoprim?

inhibits bacterial folic acid synthesis

39

what trimester must trimethoprim be avoided in and why?

first trimester, inhibits folic acid so can cause spina bifida

40

what combination is co-trimoxazole?

trimethoprim and sulphamethoxazole

41

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

Steven- Johnson's syndrome

42

why can nitrofurantoin not be used in upper UTI?

because it only becomes activated in the urine

43

why must gentamicin only be prescribed for 3 days?

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

44

what is the empirical treatment for a female lower UTI?

trimethoprim or nitrofurantoin PO 3 days

45

what is the empirical treatment for a uncatheterised male UTI?

trimethoprim or nitrofurantoin PO 7 days

46

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

co-amoxiclav or co-trimoxazole PO 14 days

47

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

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

48

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

non-pregnant: no treatment
pregnant: antibiotic treatment

49

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

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

all trimesters cefalexin (7 days)

50

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

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